This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 2 years ago.
i'm getting java.lang.NullPointerException. And i don't know how to solve it. looking for some help here
What i'v tried:
to look here java.lang.RuntimeException: Unable to start activity ComponentInfo But, it didn't help me
to clean and Rebuild project.
to Invalidate Cache and Restart in Android studio
and i'v discovered some problems in LayoutInflater.java
It cant resolve some imports"
sorry cant import images yet this is and image of errors in LayoutInflater.java
My XML file activity_main.XML:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:weightSum="100">
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="50"
android:orientation="vertical">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:layout_marginBottom="16dp"
android:gravity="center"
android:text="Team A" />
<TextView
android:id="#+id/team_a_score"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:layout_marginBottom="24dp"
android:gravity="center"
android:textSize="50sp"
android:text="0" />
<Button
android:id="#+id/three_points_button_a"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp"
android:layout_marginLeft="24dp"
android:layout_marginRight="24dp"
android:onClick="plusThreePointsA"
android:text="+3 Points" />
<Button
android:id="#+id/two_points_button_a"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp"
android:layout_marginLeft="24dp"
android:layout_marginRight="24dp"
android:onClick="plusTwoPointsA"
android:text="+2 Points" />
<Button
android:id="#+id/free_throw_button_a"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp"
android:layout_marginLeft="24dp"
android:layout_marginRight="24dp"
android:onClick="plusOnePointA"
android:text="Free Throw" />
</LinearLayout>
<view
android:layout_width="1dp"
android:layout_height="match_parent"
android:background="#android:color/darker_gray"
/>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="50"
android:orientation="vertical">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:layout_marginBottom="16dp"
android:gravity="center"
android:text="Team B" />
<TextView
android:id="#+id/team_b_score"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:layout_marginBottom="24dp"
android:gravity="center"
android:textSize="50sp"
android:text="0" />
<Button
android:id="#+id/three_points_button_b"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp"
android:layout_marginLeft="24dp"
android:layout_marginRight="24dp"
android:onClick="plusThreePointsB"
android:text="+3 Points" />
<Button
android:id="#+id/two_points_button_b"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp"
android:layout_marginLeft="24dp"
android:layout_marginRight="24dp"
android:onClick="plusTwoPointsB"
android:text="+2 Points" />
<Button
android:id="#+id/free_throw_button_b"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp"
android:layout_marginLeft="24dp"
android:layout_marginRight="24dp"
android:onClick="plusOnePointB"
android:text="Free Throw" />
</LinearLayout>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="bottom|center"
android:orientation="vertical">
<Button
android:id="#+id/reset_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_margin="24dp"
android:onClick="reset"
android:text="Reset" />
</LinearLayout>
</LinearLayout>
My MainActivity.java
package com.example.problems;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
public class MainActivity extends AppCompatActivity {
int scoreA = 0;
int scoreB = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void plusThreePointsA(View view){
scoreA = scoreA+3;
displayScoreA(scoreA);
}
public void plusTwoPointsA(View view){
scoreA = scoreA+2;
displayScoreA(scoreA);
}
public void plusOnePointA(View view){
scoreA = scoreA+1;
displayScoreA(scoreA);
}
public void plusThreePointsB(View view){
scoreB = scoreB+3;
displayScoreB(scoreB);
}
public void plusTwoPointsB(View view){
scoreB = scoreB+2;
displayScoreB(scoreB);
}
public void plusOnePointB(View view){
scoreB = scoreB+1;
displayScoreB(scoreB);
}
public void displayScoreA (int score){
TextView viewScore = findViewById(R.id.team_a_score);
viewScore.setText(String.valueOf(score));
}
public void displayScoreB (int score){
TextView viewScore = findViewById(R.id.team_b_score);
viewScore.setText(String.valueOf(score));
}
public void reset (View view){
scoreA = 0;
scoreB = 0;
displayScoreA(scoreA);
displayScoreB(scoreB);
}
}
Error that i get
--------- beginning of crash
05-11 08:14:25.720 4084-4084/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.problems, PID: 4084
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.problems/com.example.problems.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:715)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:806)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:809)
at android.view.LayoutInflater.inflate(LayoutInflater.java:504)
at android.view.LayoutInflater.inflate(LayoutInflater.java:414)
at android.view.LayoutInflater.inflate(LayoutInflater.java:365)
at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:555)
at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:161)
at com.example.problems.MainActivity.onCreate(MainActivity.java:17)
at android.app.Activity.performCreate(Activity.java:5933)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
05-11 08:19:26.000 4084-4084/com.example.problems I/Process: Sending signal. PID: 4084 SIG: 9
Use :
<View android:layout_width="1dp" android:layout_height="match_parent" android:background="#android:color/darker_gray" />
instead of :
<view
android:layout_width="1dp"
android:layout_height="match_parent"
android:background="#android:color/darker_gray"
/>
Related
This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 3 years ago.
I'm creating an app for a sensor and when I start it the app crashes.
I tried the app on 2 different phones and 2 emulators but crashes un every device.
Here is the MainActivity.java file:::
package com.example.ir_sensor;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
openMenu = findViewById(R.id.Open_menu);
closeMenu = findViewById(R.id.Close_menu);
}
View openMenu = findViewById(R.id.Open_menu);
View closeMenu = findViewById(R.id.Close_menu);
public void menu() {
if (openMenu.getVisibility() == View.VISIBLE) {
closeMenu.setVisibility(View.GONE);
} else if (closeMenu.getVisibility() == View.GONE){
openMenu.setVisibility(View.VISIBLE);
}
}
}
Here is the activity_main.xml file:::
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<ImageView
android:id="#+id/LOGO"
android:layout_width="0dp"
android:layout_height="248dp"
android:layout_marginStart="8dp"
android:layout_marginTop="52dp"
android:layout_marginEnd="8dp"
android:layout_weight="1"
android:contentDescription="#string/logo"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#drawable/logo_int_lukka" />
<ImageView
android:id="#+id/Close_menu"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="49dp"
android:visibility="gone"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/LOGO"
app:srcCompat="#drawable/ic_menu_less" />
<ImageView
android:id="#+id/Open_menu"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="49dp"
android:contentDescription="#string/openmenu"
android:visibility="visible"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/LOGO"
app:srcCompat="#android:drawable/ic_menu_more" />
<LinearLayout
android:id="#+id/menuLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="48dp"
android:layout_marginTop="380dp"
android:baselineAligned="false"
android:orientation="horizontal"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="horizontal">
<ImageView
android:id="#+id/houseMenu"
android:layout_width="4dp"
android:layout_height="70dp"
android:layout_weight="1"
android:contentDescription="#string/housemenu"
app:srcCompat="#drawable/house_menu" />
<FrameLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="2">
</FrameLayout>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1"
android:orientation="horizontal">
<ImageView
android:id="#+id/IR_LED"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_weight="1"
android:contentDescription="#string/ir_led"
app:srcCompat="#drawable/ir_led" />
<FrameLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="2">
</FrameLayout>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="horizontal">
<ImageView
android:id="#+id/alarmSign"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_weight="1"
android:contentDescription="#string/alarmsign"
app:srcCompat="#drawable/on_off__alert" />
<FrameLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="2">
</FrameLayout>
</LinearLayout>
</LinearLayout>
<androidx.constraintlayout.widget.Guideline
android:id="#+id/gridline380FromTop"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="380dp"
android:orientation="horizontal"
app:layout_constraintGuide_begin="380dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<androidx.constraintlayout.widget.Guideline
android:id="#+id/gridline48FromLeft"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="48dp"
android:orientation="vertical"
app:layout_constraintGuide_begin="48dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
This is the Logcat:::
2019-08-12 17:14:39.966 9648-9648/com.example.ir_sensor E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.ir_sensor, PID: 9648
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.ir_sensor/com.example.ir_sensor.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.Window$Callback android.view.Window.getCallback()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3194)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7356)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.Window$Callback android.view.Window.getCallback()' on a null object reference
at androidx.appcompat.app.AppCompatDelegateImpl.(AppCompatDelegateImpl.java:249)
at androidx.appcompat.app.AppCompatDelegate.create(AppCompatDelegate.java:182)
at androidx.appcompat.app.AppCompatActivity.getDelegate(AppCompatActivity.java:520)
at androidx.appcompat.app.AppCompatActivity.findViewById(AppCompatActivity.java:191)
at com.example.ir_sensor.MainActivity.(MainActivity.java:18)
at java.lang.Class.newInstance(Native Method)
at android.app.AppComponentFactory.instantiateActivity(AppComponentFactory.java:95)
at androidx.core.app.CoreComponentFactory.instantiateActivity(CoreComponentFactory.java:43)
at android.app.Instrumentation.newActivity(Instrumentation.java:1243)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3182)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7356)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
What can I do?
The error is that you are defining the openMenu and closeMenu variables, outside the onCreate() method. The thing is however that before onCreate you haven't defined your view, so getting the view by id before the view has been defined results in a NullPointerException (the program can't find the variable you were asking for and crashes). So do this:
package com.example.ir_sensor;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
openMenu = findViewById(R.id.Open_menu);
closeMenu = findViewById(R.id.Close_menu);
}
View openMenu;
View closeMenu;
public void menu() {
if (openMenu.getVisibility() == View.VISIBLE) {
closeMenu.setVisibility(View.GONE);
} else if (closeMenu.getVisibility() == View.GONE){
openMenu.setVisibility(View.VISIBLE);
}
}
}
I am relatively new to coding but have some experience in Java and Android. I have a really basic problem that I have done over and over again but for some reason, this occurrence doesn't work!
I have an edittext field which is populated by the user. When an enter button is pressed the app then takes this and saves it as a String. The String is then used to populate the TextView with the user input.
I have created the findviewbyids, I have set the String to equal the edittext input and then set the text in the text view to be the String as per the code below. I have checked previous apps I have made and this has always worked before...
package com.example.android.golfhandicap;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
EditText playerName;
TextView playerOneName;
String name;
int handicap;
EditText playerHandicap;
TextView playerOneHcp;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.front_page);
}
//set view by IDs
public void views() {
playerName = findViewById(R.id.inputPlayerName);
playerOneName = findViewById(R.id.playerOneName);
playerHandicap = findViewById(R.id.inputPlayerHcp);
playerOneHcp = findViewById(R.id.playerOneHcp);
}
/**
* Add the codes for the button to navigate around the app
*/
public void enterScore1(View view) {
setContentView(R.layout.front_page);
}
public void addPlayer(View view) {
setContentView(R.layout.new_player);
}
public void addScore(View view) {
setContentView(R.layout.input_page);
}
public void enterPlayer(View view) {
views();
name = playerName.getText().toString();
//handicap = Integer.parseInt(playerHandicap.getText().toString());
playerOneName.setText(name);
//playerOneHcp.setText(handicap);
Toast.makeText(this, "player name is " + name + " and handicap is
" + handicap , Toast.LENGTH_SHORT).show();
setContentView(R.layout.front_page);
}
}
The XML for the page with the text view I want to display the String in:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:visibility="visible"
tools:context=".MainActivity">
<TextView
android:id="#+id/appName2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="8dp"
android:text="Golf handicap"
android:textAlignment="center"
android:textColor="#color/colorPrimaryDark"
android:textSize="24sp"
android:textStyle="bold"
android:visibility="visible"
android:editable="false"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/playerOneName"
android:layout_width="136dp"
android:layout_height="30dp"
android:layout_marginStart="8dp"
android:editable="false"
android:layout_marginTop="32dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/appName2" />
<TextView
android:id="#+id/playerOneName2"
android:editable="false"
android:layout_width="136dp"
android:layout_height="30dp"
android:layout_marginStart="8dp"
android:layout_marginTop="24dp"
android:visibility="invisible"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/playerOneName3" />
<TextView
android:id="#+id/playerOneName3"
android:editable="false"
android:layout_width="136dp"
android:layout_height="30dp"
android:layout_marginStart="8dp"
android:layout_marginTop="24dp"
android:visibility="invisible"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/playerOneName" />
<Button
android:id="#+id/addScore"
android:layout_width="200dp"
android:layout_height="40dp"
android:layout_marginBottom="16dp"
android:background="#android:color/holo_green_light"
android:onClick="addScore"
android:text="Add new score"
android:visibility="visible"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="#+id/addPlayer" />
<Button
android:id="#+id/addPlayer"
android:layout_width="200dp"
android:layout_height="40dp"
android:layout_marginBottom="16dp"
android:background="#android:color/holo_green_light"
android:onClick="addPlayer"
android:text="Add new player"
android:visibility="visible"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toStartOf="#+id/addScore"
app:layout_constraintStart_toStartOf="parent" />
<TextView
android:id="#+id/playerOneHcp"
android:layout_width="43dp"
android:layout_height="30dp"
android:layout_marginStart="31dp"
android:layout_marginTop="32dp"
android:editable="false"
android:ems="10"
android:inputType="number"
android:textAlignment="center"
android:visibility="visible"
app:layout_constraintStart_toEndOf="#+id/playerOneName"
app:layout_constraintTop_toBottomOf="#+id/appName2" />
<TextView
android:id="#+id/editText2"
android:editable="false"
android:layout_width="43dp"
android:layout_height="30dp"
android:layout_marginStart="31dp"
android:layout_marginTop="24dp"
android:ems="10"
android:inputType="number"
android:textAlignment="center"
android:visibility="invisible"
app:layout_constraintStart_toEndOf="#+id/playerOneName2"
app:layout_constraintTop_toBottomOf="#+id/editText3" />
<TextView
android:id="#+id/editText3"
android:editable="false"
android:layout_width="43dp"
android:layout_height="30dp"
android:layout_marginStart="31dp"
android:layout_marginTop="24dp"
android:ems="10"
android:inputType="number"
android:textAlignment="center"
android:visibility="invisible"
app:layout_constraintStart_toEndOf="#+id/playerOneName3"
app:layout_constraintTop_toBottomOf="#+id/playerOneHcp" />
</android.support.constraint.ConstraintLayout>
The XML for the layout with the edittext which I get the user input from:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/enterHcpText"
android:layout_width="136dp"
android:layout_height="50dp"
android:layout_marginStart="8dp"
android:layout_marginTop="24dp"
android:editable="false"
android:text="Current handicap :"
android:textAlignment="center"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/enterAgeText" />
<TextView
android:id="#+id/enterAgeText"
android:layout_width="136dp"
android:layout_height="50dp"
android:layout_marginStart="8dp"
android:layout_marginTop="24dp"
android:editable="false"
android:text="Player age :"
android:textAlignment="center"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/enterNameText" />
<TextView
android:id="#+id/enterNameText"
android:layout_width="136dp"
android:layout_height="50dp"
android:layout_marginStart="8dp"
android:layout_marginTop="32dp"
android:editable="false"
android:text="Player name :"
android:textAlignment="center"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/appName3" />
<TextView
android:id="#+id/appName3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="8dp"
android:editable="false"
android:text="Golf handicap"
android:textAlignment="center"
android:textColor="#color/colorPrimaryDark"
android:textSize="24sp"
android:textStyle="bold"
android:visibility="visible"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<EditText
android:id="#+id/inputPlayerName"
android:layout_width="130dp"
android:layout_height="50dp"
android:layout_marginTop="32dp"
android:layout_marginEnd="33dp"
android:maxLength="25"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#+id/appName3" />
<EditText
android:id="#+id/inputPlayerAge"
android:layout_width="130dp"
android:layout_height="50dp"
android:layout_marginTop="24dp"
android:layout_marginEnd="33dp"
android:inputType="number"
android:maxLength="2"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#+id/inputPlayerName" />
<EditText
android:id="#+id/inputPlayerHcp"
android:layout_width="130dp"
android:layout_height="50dp"
android:layout_marginTop="24dp"
android:layout_marginEnd="33dp"
android:inputType="number"
android:maxLength="2"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#+id/inputPlayerAge" />
<Button
android:id="#+id/enterPlayer"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="148dp"
android:layout_marginTop="96dp"
android:layout_marginEnd="148dp"
android:onClick="enterPlayer"
android:text="Enter"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/inputPlayerHcp" />
</android.support.constraint.ConstraintLayout>
If I comment out the line p1Name.setText(name); then it works fine, I have a toast to check the name is taken and name is set as the input. So there seems to be something wrong with the p1Name. I have checked and triple checked all the IDs are correct.
I have spent over an hour now trying to figure it out and can't see what I am doing wrong!
This is the lines I get on logcat (These are all the lines shown in red)
2019-01-24 23:29:39.376 9545-9545/com.example.android.golfhandicap E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.android.golfhandicap, PID: 9545
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:390)
at android.view.View.performClick(View.java:6294)
at android.view.View$PerformClick.run(View.java:24770)
at android.os.Handler.handleCallback(Handler.java:790)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:385)
at android.view.View.performClick(View.java:6294)
at android.view.View$PerformClick.run(View.java:24770)
at android.os.Handler.handleCallback(Handler.java:790)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
at com.example.android.golfhandicap.MainActivity.enterPlayer(MainActivity.java:65)
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:385)
at android.view.View.performClick(View.java:6294)
at android.view.View$PerformClick.run(View.java:24770)
at android.os.Handler.handleCallback(Handler.java:790)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
Any help would be gratefully received.
The problem is simply because of the following:
you haven't bind the view with the findViewById. This is because of the following code:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.front_page);
// Here you haven't bind the view.
}
you should directly bind the view with your views() method. So, change the code to this:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.front_page);
// bind the view.
views();
}
You're changing the layout view each time a button is clicked with this method:
public void addScore(View view) {
setContentView(R.layout.input_page);
}
which is become one of the source for your problem. First, it's not recommended because you're redrawing entire layout when calling setContentView. Second, you need to make sure all the layout onClick is implemented in your code.
Last but not the least, you better using setOnClickListener in code instead onClick attribute in layout. It is because you should separate between logic and UI.
This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 5 years ago.
There is the eror message on the monitor:
07-20 17:00:05.234 17194-17194/com.example.champion.courtcounter E/AndroidRuntime: FATAL EXCEPTION: main java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.champion.courtcounter/com.example.champion.courtcounter.MainActivity}: android.view.InflateException: Binary XML file line #69: Error inflating class null
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2129)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2154)
at android.app.ActivityThread.access$700(ActivityThread.java:146)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1260)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4949)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1043)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:810)
at dalvik.system.NativeStart.main(Native Method)
Caused by: android.view.InflateException: Binary XML file line #69: Error inflating class null
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:710)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:752)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:760)
at android.view.LayoutInflater.inflate(LayoutInflater.java:495)
at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
at android.view.LayoutInflater.inflate(LayoutInflater.java:353)
at android.support.v7.app.AppCompatDelegateImplV9.setContentView(AppCompatDelegateImplV9.java:292)
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:140)
at com.example.champion.courtcounter.MainActivity.onCreate(MainActivity.java:16)
at android.app.Activity.performCreate(Activity.java:5185)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2093)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2154)
at android.app.ActivityThread.access$700(ActivityThread.java:146)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1260)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4949)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1043)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:810)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at android.support.v7.app.AppCompatViewInflater.createView(AppCompatViewInflater.java:101)
at android.support.v7.app.AppCompatDelegateImplV9.createView(AppCompatDelegateImplV9.java:1029)
at android.support.v7.app.AppCompatDelegateImplV9.onCreateView(AppCompatDelegateImplV9.java:1087)
at android.support.v4.view.LayoutInflaterCompatHC$FactoryWrapperHC.onCreateView(LayoutInflaterCompatHC.java:47)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:681)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:752)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:760)
at android.view.LayoutInflater.inflate(LayoutInflater.java:495)
at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
at android.view.LayoutInflater.inflate(LayoutInflater.java:353)
at android.support.v7.app.AppCompatDelegateImplV9.setContentView(AppCompatDelegateImplV9.java:292)
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:140)
at com.example.champion.courtcounter.MainActivity.onCreate(MainActivity.java:16)
at android.app.Activity.performCreate(Activity.java:5185)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2093)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2154)
at android.app.ActivityThread.access$700(ActivityThread.java:146)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1260)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4949)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1043)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:810)
at dalvik.system.NativeStart.main(Native Method)
There is my xml code:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<LinearLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="vertical"
tools:context=".MainActivity">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fontFamily="sans-serif-medium"
android:gravity="center_horizontal"
android:padding="16dp"
android:text="Team A"
android:textColor="#616161"
android:textSize="14sp" />
<TextView
android:id="#+id/team_a_score"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fontFamily="sans-serif-light"
android:gravity="center_horizontal"
android:paddingBottom="24dp"
android:text="0"
android:textColor="#000000"
android:textSize="56sp" />
<Button
android:layout_width="match_parent"
android:layout_height="48dp"
android:layout_marginLeft="24dp"
android:layout_marginRight="24dp"
android:onClick="points3"
android:text="+3 points" />
<Button
android:layout_width="match_parent"
android:layout_height="48dp"
android:layout_marginBottom="8dp"
android:layout_marginLeft="24dp"
android:layout_marginRight="24dp"
android:layout_marginTop="8dp"
android:onClick="points2"
android:text="+2 points" />
<Button
android:layout_width="match_parent"
android:layout_height="48dp"
android:layout_marginLeft="24dp"
android:layout_marginRight="24dp"
android:onClick="point"
android:text="free throw" />
</LinearLayout>
<view
android:layout_width="1dp"
android:layout_height="match_parent"
android:layout_marginTop="16dp"
android:background="#android:color/darker_gray" />
<LinearLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="vertical"
tools:context=".MainActivity">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fontFamily="sans-serif-medium"
android:gravity="center_horizontal"
android:padding="16dp"
android:text="Team B"
android:textColor="#616161"
android:textSize="14sp" />
<TextView
android:id="#+id/team_b_score"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fontFamily="sans-serif-light"
android:gravity="center_horizontal"
android:paddingBottom="24dp"
android:text="0"
android:textColor="#000000"
android:textSize="56sp" />
<Button
android:layout_width="match_parent"
android:layout_height="48dp"
android:layout_marginLeft="24dp"
android:layout_marginRight="24dp"
android:onClick="points3B"
android:text="+3 points" />
<Button
android:layout_width="match_parent"
android:layout_height="48dp"
android:layout_marginBottom="8dp"
android:layout_marginLeft="24dp"
android:layout_marginRight="24dp"
android:layout_marginTop="8dp"
android:onClick="points2B"
android:text="+2 points" />
<Button
android:layout_width="match_parent"
android:layout_height="48dp"
android:layout_marginLeft="24dp"
android:layout_marginRight="24dp"
android:onClick="pointB"
android:text="free throw" />
</LinearLayout>
</LinearLayout>
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="32dp"
android:onClick="reset"
android:text="reset" />
</RelativeLayout>
There is my java code:
package com.example.champion.courtcounter;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.TextView;
import com.example.champion.courtcounter.R;
public class MainActivity extends AppCompatActivity {
int numA=0;
int numB=0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void displayForTeamA(int score) {
TextView scoreView = (TextView) findViewById(R.id.team_a_score);
scoreView.setText(String.valueOf(score));
}
public void points3(View view) {
numA = numA + 3;
displayForTeamA(numA);
}
public void points2(View view) {
numA = numA + 2;
displayForTeamA(numA);
}
public void point(View view) {
numA = numA + 1;
displayForTeamA(numA);
}
public void displayForTeamB(int score) {
TextView scoreView = (TextView) findViewById(R.id.team_b_score);
scoreView.setText(String.valueOf(score));
}
public void points3B(View view) {
numB = numB + 3;
displayForTeamB(numB);
}
public void points2B(View view) {
numB = numB + 2;
displayForTeamB(numB);
}
public void pointB(View view) {
numB = numB + 1;
displayForTeamB(numB);
}
public void reset(View view) {
numB = 0;
displayForTeamB(numB);
numA = 0;
displayForTeamA(numA);
}
}
I can't even open it. When I try to open it's says:"Unfortunately, Court Counter(the name of my app) has stopped.
Thank for help.
<view
android:layout_width="1dp"
android:layout_height="match_parent"
android:layout_marginTop="16dp"
android:background="#android:color/darker_gray" />
Change view with View
I am getting the following error when I go from my Main Activity page to my New Activity page. The New Activity page crashes unless it has <10 images or so, which is pathetic (the app runs fine emulated on my computer, however):
06-22 16:53:04.841 15058-15058/? D/AndroidRuntime: Shutting down VM
06-22 16:53:04.841 15058-15058/? W/dalvikvm: threadid=1: thread exiting with uncaught exception (group=0x41e35c08)
06-22 16:53:04.851 15058-15058/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.matthewscompany.matthew.test1, PID: 15058
java.lang.OutOfMemoryError
at android.graphics.BitmapFactory.nativeDecodeAsset(Native Method)
at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:683)
at android.graphics.BitmapFactory.decodeResourceStream(BitmapFactory.java:513)
at android.graphics.drawable.Drawable.createFromResourceStream(Drawable.java:889)
at android.content.res.Resources.loadDrawable(Resources.java:3436)
at android.content.res.TypedArray.getDrawable(TypedArray.java:602)
at android.widget.ImageView.<init>(ImageView.java:133)
at android.support.v7.widget.AppCompatImageView.<init>(AppCompatImageView.java:57)
at android.support.v7.widget.AppCompatImageView.<init>(AppCompatImageView.java:53)
at android.support.v7.app.AppCompatViewInflater.createView(AppCompatViewInflater.java:102)
at android.support.v7.app.AppCompatDelegateImplV7.createView(AppCompatDelegateImplV7.java:972)
at android.support.v7.app.AppCompatDelegateImplV7.onCreateView(AppCompatDelegateImplV7.java:1030)
at android.support.v4.view.LayoutInflaterCompatHC$FactoryWrapperHC.onCreateView(LayoutInflaterCompatHC.java:44)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:690)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:761)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:769)
at android.view.LayoutInflater.inflate(LayoutInflater.java:498)
at android.view.LayoutInflater.inflate(LayoutInflater.java:398)
at android.view.LayoutInflater.inflate(LayoutInflater.java:354)
at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:276)
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:136)
at com.example.matthew.test1.NewActivity.onCreate(NewActivity.java:23)
at android.app.Activity.performCreate(Activity.java:5451)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1093)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2377)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2471)
at android.app.ActivityThread.access$900(ActivityThread.java:175)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1308)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5602)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
at dalvik.system.NativeStart.main(Native Method)
06-22 16:53:04.861 2430-2769/? W/ActivityManager: Force finishing activity com.matthewscompany.matthew.test1/com.example.matthew.test1.NewActivity
06-22 16:53:04.866 2430-2769/? W/ActivityManager: Force finishing activity com.matthewscompany.matthew.test1/com.example.matthew.test1.MainActivity
I understand that the out of memory error occurs when the ram for a phone runs out when processing too many bitmaps.
Yes, I have read the Android Developer webpages on tips for processing bitmaps. However, I still don't understand which groups of code from their guides I'm supposed to insert, and where I'm supposed to insert it. I've tried inserting some of their stuff into my .java files but I just end up getting errors. I owe this to me being a beginner at Java and not understanding how to apply the example codes.
Again, I am a beginner to Java and Android Studio so please go easy on me and explain things as simply as you can, if possible.
Here's my code:
MainActivity.java:
package com.example.matthew.test1;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.ImageButton;
public class MainActivity extends AppCompatActivity {
//Main Menu
//Main Activity Mario Icon:
ImageButton Mario;
ImageButton Luigi;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Mario= (ImageButton) findViewById(R.id.Mario);
Mario.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intentLoadNewActivity = new Intent(MainActivity.this, NewActivity.class);
startActivity(intentLoadNewActivity);
}
});
Luigi= (ImageButton) findViewById(R.id.Luigi);
Luigi.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intentLoadNewActivity = new Intent(MainActivity.this, Main2Activity.class);
startActivity(intentLoadNewActivity);
}
});
}
}
NewActivity.java:
public class NewActivity extends AppCompatActivity implements View.OnClickListener {
ViewFlipper viewFlipper;
Button next;
Button previous;
TextView pageCounter;
int count = 1;
private static final int TOTAL_IMG_COUNT = 23;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_new);
viewFlipper = (ViewFlipper)findViewById(R.id.viewFlipper);
next = (Button) findViewById(R.id.next);
previous = (Button) findViewById(R.id.previous);
pageCounter = (TextView)findViewById(R.id.textView2);
pageCounter.setText(String.valueOf(count));
next.setOnClickListener(this);
previous.setOnClickListener(this);
}
#Override
public void onClick(View v) {
if (v == next) {
viewFlipper.showNext();
if (next.getId() == (R.id.ImageView23)) {
count = 1;
} else {
count++;
}
pageCounter.setText(String.valueOf(count) + "/" + TOTAL_IMG_COUNT);
}
else if (v == previous) {
viewFlipper.showPrevious();
if(previous.getId() == (R.id.ImageView1)) {
count = TOTAL_IMG_COUNT;
} else {
count--;
}
pageCounter.setText(String.valueOf(count) + "/" + TOTAL_IMG_COUNT);
}
}
}
content_main.xml:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context="com.example.matthew.test1.MainActivity"
tools:showIn="#layout/activity_main">
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/Mario"
android:src="#drawable/mario_select"
android:layout_above="#+id/samus_select"
android:layout_alignLeft="#+id/samus_select"
android:layout_alignStart="#+id/samus_select" />
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/Luigi"
android:src="#drawable/luigi_select"
android:layout_above="#+id/samus_select"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/dk_select"
android:src="#drawable/dk_select"
android:layout_above="#+id/falcon_select"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true" />
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/link_select"
android:src="#drawable/link_select"
android:layout_below="#+id/fox_select"
android:layout_alignParentLeft="true" />
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/samus_select"
android:src="#drawable/samus_select"
android:layout_above="#+id/kirby_select"
android:layout_centerHorizontal="true" />
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/falcon_select"
android:src="#drawable/falcon_select"
android:layout_alignTop="#+id/samus_select"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true" />
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/ness_select"
android:src="#drawable/ness_select"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/yoshi_select"
android:src="#drawable/yoshi_select"
android:layout_below="#+id/falcon_select"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true" />
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/kirby_select"
android:src="#drawable/kirby_select"
android:layout_above="#+id/pika_select"
android:layout_alignLeft="#+id/samus_select"
android:layout_alignStart="#+id/samus_select" />
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/fox_select"
android:src="#drawable/fox_select"
android:layout_alignParentStart="true"
android:layout_below="#+id/Luigi"
android:layout_alignParentLeft="true" />
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/pika_select"
android:src="#drawable/pika_select"
android:layout_alignParentBottom="true"
android:layout_alignLeft="#+id/kirby_select"
android:layout_alignStart="#+id/kirby_select" />
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/jiggly_select"
android:src="#drawable/jiggly_select"
android:layout_below="#+id/yoshi_select"
android:layout_alignLeft="#+id/yoshi_select"
android:layout_alignStart="#+id/yoshi_select" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Hitbox64"
android:id="#+id/textView"
android:textSize="48dp"
android:layout_above="#+id/Mario"
android:layout_centerHorizontal="true" />
</RelativeLayout>
activity_new.xml:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.matthew.test1.NewActivity">
<ViewFlipper
android:layout_width="480dp"
android:layout_height="480dp"
android:id="#+id/viewFlipper">
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView1"
android:scaleType="centerCrop"
android:src="#drawable/b1"/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView2"
android:scaleType="centerCrop"
android:src="#drawable/b2"/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView3"
android:scaleType="centerCrop"
android:src="#drawable/b3"/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView4"
android:scaleType="centerCrop"
android:src="#drawable/b4"/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView5"
android:scaleType="centerCrop"
android:src="#drawable/b5"/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView6"
android:scaleType="centerCrop"
android:src="#drawable/b6"/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView7"
android:scaleType="centerCrop"
android:src="#drawable/b7"/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView8"
android:scaleType="centerCrop"
android:src="#drawable/b8"/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView9"
android:scaleType="centerCrop"
android:src="#drawable/b9"/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView10"
android:scaleType="centerCrop"
android:src="#drawable/b10"/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView11"
android:scaleType="centerCrop"
android:src="#drawable/b11"/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView12"
android:scaleType="centerCrop"
android:src="#drawable/b12"/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView13"
android:scaleType="centerCrop"
android:src="#drawable/b13"/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView14"
android:scaleType="centerCrop"
android:src="#drawable/b14"/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView16"
android:scaleType="centerCrop"
android:src="#drawable/b17"/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView18"
android:scaleType="centerCrop"
android:src="#drawable/b18"/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView19"
android:scaleType="centerCrop"
android:src="#drawable/b19"/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView20"
android:scaleType="centerCrop"
android:src="#drawable/b20"/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView21"
android:scaleType="centerCrop"
android:src="#drawable/b21"/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView22"
android:scaleType="centerCrop"
android:src="#drawable/b22"/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/ImageView23"
android:scaleType="centerCrop"
android:src="#drawable/b23"/>
</ViewFlipper>
<Button
android:id="#+id/next"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Next"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"/>
<Button
android:id="#+id/previous"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Prev"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentBottom="true"
android:layout_alignTop="#+id/next"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Frame Counter"
android:id="#+id/textView2"
android:layout_below="#+id/textView3"
android:layout_centerHorizontal="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Bair"
android:id="#+id/textView3"
android:layout_alignTop="#+id/previous"
android:layout_centerHorizontal="true" />
</RelativeLayout>
If your images are too high-resolution, they can eat up a LOT of memory, especially if you have 20 of them as you say. Consider using Picasso or some other library to load your images.
I have a NullpointerException but i can't figure out why! please your help as i'm struggling with it :
Here's my XML resource :
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#FFFFFF" >
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_margin="20dp"
android:orientation="horizontal" >
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="3dp"
android:gravity="right"
android:orientation="vertical" >
<TextView
android:id="#+id/txt_speciality_type"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Name: " />
<TextView
android:id="#+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="add:" />
<TextView
android:id="#+id/textView5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="phone :" />
</LinearLayout>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="3dp"
android:orientation="vertical" >
<TextView
android:id="#+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="abc abc abc" />
<TextView
android:id="#+id/textView44"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="abc" />
<TextView
android:id="#+id/textView55"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="230020202" />
</LinearLayout>
</LinearLayout>
<ImageView
android:id="#+id/imageViewClose"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:src="#drawable/close_selector" />
</RelativeLayout>
Below my Java instructions :
The setContentView is before the use of the actual TextView
final Dialog dialog = new Dialog(searchActivity.this);
dialog.setContentView(R.layout.custom_dialog);``
ImageView closeBtn =(ImageView)findViewById(R.id.imageViewClose);
closeBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View arg0) {
finish();
}
});
Logcat errros :
java.lang.NullPointerException
at com.itraan.Test.searchActivity$2.onItemClick(searchActivity.java:902)
at android.widget.AdapterView.performItemClick(AdapterView.java:308)
at android.widget.AbsListView.performItemClick(AbsListView.java:1483)
at android.widget.AbsListView$PerformClick.run(AbsListView.java:3485)
at android.widget.AbsListView$3.run(AbsListView.java:4843)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:157)
at android.app.ActivityThread.main(ActivityThread.java:5356)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
at dalvik.system.NativeStart.main(Native Method)
Thank you in advance.