I'm new to android.
I tried to create a simple toggle button and catch it's state change. But it crashes when I run it on my device.
Here is the MainActivity.java code:
package com.example.addimagebutton;
import android.os.Bundle;
import android.app.Activity;
import android.widget.CompoundButton;
import android.widget.CompoundButton.OnCheckedChangeListener;
import android.widget.Toast;
import android.widget.ToggleButton;
public class MainActivity extends Activity {
private ToggleButton tbSwitch;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tbSwitch = (ToggleButton) findViewById(R.id.swButton);
tbSwitch.setOnCheckedChangeListener(toggleListener);
}
OnCheckedChangeListener toggleListener = new OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton buttonView,
boolean isChecked) {
// TODO Auto-generated method stub
if (isChecked) {
Toast.makeText(getApplicationContext(), "On",
Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(getApplicationContext(), "Off",
Toast.LENGTH_SHORT).show();
}
}
};
}
Here is activity_main.xml code:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<Switch
android:id="#+id/swButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Switch"
android:textOff="Off"
android:textOn="On" />
</LinearLayout>
I tried to run this code without the listener objects.(commenting those) But it gave me the same result.
You are casting a switch to Toggle Button so it gives you ClassCastException..
Change this
<Switch
android:id="#+id/swButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Switch"
android:textOff="Off"
android:textOn="On" />
into
<ToggleButton
android:id="#+id/swButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Switch"
android:textOff="Off"
android:textOn="On" />
Used ToggleButton instead of Switch like
<ToggleButton
android:id="#+id/swButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Switch"
android:textOff="Off"
android:textOn="On"" />
Becoz your layout contains Switch and you cast it with ToggleButton. That's wrong
Change switch to ToggleButton
<ToggleButton
android:id="#+id/swButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Switch"
android:textOff="Off"
android:textOn="On" />
in your xml you should use ToggleButton instead of Switch - it should look like this:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<ToogleButton
android:id="#+id/swButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Switch"
android:textOff="Off"
android:textOn="On" />
Related
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
android:orientation="vertical">
<TextView
android:id="#+id/away"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="100dp"
android:text="#string/away"
android:gravity="center"
android:textSize="20sp"/>
<TextView
android:id="#+id/score"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="50dp"
android:layout_marginTop="50dp"
android:gravity="center"
android:text="#string/_0"
android:textSize="20sp" />
<Button
android:id="#+id/one"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginBottom="50dp"
android:onClick="score1"
android:text="#string/score" />
<TextView
android:id="#+id/home"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="50dp"
android:layout_marginTop="50dp"
android:text="#string/home"
android:textSize="20sp"
android:gravity="center"/>
<TextView
android:id="#+id/score2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:layout_marginBottom="50dp"
android:text="#string/_0"
android:textSize="20sp" />
<Button
android:id="#+id/two"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:onClick="score2"
android:text="#string/score" />
<Button
android:id="#+id/reset"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/reset"
android:layout_gravity="center"
android:layout_marginTop="50dp"
android:textColor="#ff1100"/>
</LinearLayout>
I searched it on multiple websites but I still can't the answer. I also tried using the__setText("")it
didn't work as well as the the if() method. I have also tried the intent method also doesn't seem to
work, and many other codes , please help me because I am stuck at this bit , I know that it is simple but
I just can't find it. Thank you
The following codes will set the TextView score to blank when Button one is clicked
First approach
To use the android:onClick="score1" in your XML
Add this to your activity
TextView mTvScore1 = (TextView) findViewById(R.id.score)
public void score1(View v) {
mTvScore1.setText("");
}
Second approach
Button mBtn = (Button) findViewById(R.id.one)
TextView mTvScore1 = (TextView) findViewById(R.id.score)
mBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
mTvScore1.setText("");
}
});
Activity code
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView mTvScore1 = (TextView) findViewById(R.id.score);
Button mBtn = (Button) findViewById(R.id.one);
mBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
score1(v);
}
});
}
public void score1(View v) {
mTvScore1.setText("");
}
}
I have image-buttons in one of the fragments of an activity and want to open corresponding fragments containing webViews on button clicks in another activity.
I am a beginner so please do give appropriate codes for this.
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<ScrollView
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/activity_main"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
tools:context="com.example.administrator.hiha.MainActivity"
>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<include
android:id="#+id/toolbar"
layout="#layout/tool_bar">
</include>
<fragment
android:id="#+id/upperFragment"
android:layout_width="match_parent"
android:layout_height="200dp"
android:name="com.example.administrator.hiha.Upper_main_Fragment"
android:layout_below="#id/toolbar"
>
</fragment>
<fragment
android:layout_below="#id/upperFragment"
android:id="#+id/lowerFragment"
android:layout_width="match_parent"
android:layout_height="140dp"
android:name="com.example.administrator.hiha.Lower_main_Fragment"
>
</fragment>
<fragment
android:layout_below="#id/lowerFragment"
android:id="#+id/Bottom_Most_Fragment"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:name="com.example.administrator.hiha.BottomMostFragment"
tools:layout="#layout/fragment_bottom_most">
</fragment>
<View
android:id="#+id/hLastRow"
android:layout_centerHorizontal="true"
android:layout_below="#id/Bottom_Most_Fragment"
android:layout_width="300dp"
android:layout_height="2dp"
android:background="#EEEEEE"
/>
<TextView
android:layout_alignParentBottom="true"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#id/hLastRow"
android:layout_centerHorizontal="true"
android:text="Designed \u0026 Developed by me © 2016."/>
</RelativeLayout>
</ScrollView>
MainActivity.java
package com.example.administrator.hiha;
import android.support.v4.app.FragmentActivity;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.Toast;
public class MainActivity extends FragmentActivity {
//Toolbar toolbar;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//toolbar=(Toolbar)findViewById(R.id.toolbar);
}
}
fragment_lower_main.xml
<FrameLayout 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.administrator.hiha.Lower_main_Fragment">
<HorizontalScrollView
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
>
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<ImageButton
android:layout_width="100dp"
android:layout_height="80dp"
android:src="#drawable/about_board"
android:id="#+id/about_img_btn"
android:onClick="onAboutBoardClick"
/>
<TextView
android:id="#+id/text_about_img_btn"
android:text="About Board"
android:layout_below="#id/about_img_btn"
android:layout_width="100dp"
android:layout_height="wrap_content"
android:gravity="center"
/>
<ImageButton
android:layout_width="100dp"
android:layout_height="80dp"
android:src="#drawable/sarasvati"
android:id="#+id/sarasvati_img_btn"
android:layout_toRightOf="#id/about_img_btn"
android:onClick="onSarasvatiClick"
/>
<TextView
android:layout_toRightOf="#id/text_about_img_btn"
android:id="#+id/text_sarasvati_img_btn"
android:text="Sarasvati"
android:layout_below="#id/sarasvati_img_btn"
android:layout_width="100dp"
android:layout_height="wrap_content"
android:gravity="center"
/>
<ImageButton
android:layout_toRightOf="#id/sarasvati_img_btn"
android:layout_width="100dp"
android:layout_height="80dp"
android:src="#drawable/scientific_evidences"
android:id="#+id/scientific_evidences_img_btn"
android:onClick="onScientificEvidencesClick"
/>
<TextView
android:layout_toRightOf="#id/text_sarasvati_img_btn"
android:id="#+id/text_scientific_evidences_img_btn"
android:text="Scientific EVidences"
android:layout_below="#id/scientific_evidences_img_btn"
android:layout_width="100dp"
android:layout_height="wrap_content"
android:gravity="center"
/>
<ImageButton
android:layout_toRightOf="#id/digital_library_img_btn"
android:layout_width="100dp"
android:layout_height="80dp"
android:src="#drawable/affltd_organization"
android:id="#+id/affltd_oragnization_img_btn"
android:onClick="onAffltdOrganizationClick"
/>
<TextView
android:layout_toRightOf="#id/text_digital_library_img_btn"
android:id="#+id/text_affltd_oragnization_img_btn"
android:text="Affiliated Organizations"
android:layout_below="#id/affltd_oragnization_img_btn"
android:layout_width="100dp"
android:layout_height="wrap_content"
android:gravity="center"
/>
<ImageButton
android:layout_toRightOf="#id/affltd_oragnization_img_btn"
android:layout_width="100dp"
android:layout_height="80dp"
android:src="#drawable/tender"
android:id="#+id/tender_img_btn"
android:onClick="onTenderClick"
/>
<TextView
android:layout_toRightOf="#id/text_affltd_oragnization_img_btn"
android:id="#+id/text_tender_img_btn"
android:text="Tenders"
android:layout_below="#id/tender_img_btn"
android:layout_width="100dp"
android:layout_height="wrap_content"
android:gravity="center"
/>
</RelativeLayout>
</LinearLayout>
</HorizontalScrollView>
</FrameLayout>
Lower_Main_Fragment.java
package com.example.administrator.hiha;
import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageButton;
public class Lower_main_Fragment extends Fragment {
ImageButton about_img_btn;
ImageButton sarasvati_img_btn;
ImageButton scientific_evidences_img_btn;
ImageButton digital_library_img_btn;
ImageButton affltd_oragnization_img_btn;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View rootView=inflater.inflate(R.layout.fragment_lower_main_,container,false);
//cast image buttons
about_img_btn=(ImageButton)getView().findViewById(R.id.about_img_btn);
sarasvati_img_btn=(ImageButton)getView().findViewById(R.id.sarasvati_img_btn);
scientific_evidences_img_btn=(ImageButton)getView().findViewById(R.id.scientific_evidences_img_btn);
digital_library_img_btn=(ImageButton)getView().findViewById(R.id.digital_library_img_btn);
affltd_oragnization_img_btn=(ImageButton)getView().findViewById(R.id.affltd_oragnization_img_btn);
return rootView;
}
//onclick methods of image buttons
public void onAboutBoardClick(View view){
}
}
These are the files in which i want that if i click on about_img_btn then it should open a fragment containing a webView in another activity. The same should be repeated for all the buttons.
Please define the further code that i have to use and mention the files where i have to use it. Thanks!
try this:
in your fragment_lower_main xml:
Give an id to the Framelayout:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.administrator.hiha.Lower_main_Fragment">
<FrameLayout
android:id="+#id/fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent">
<--Rest of the code -->
/>
</LinearLayout>
Now in code open new Fragment during button click using:
about_img_btn=(ImageButton)rootView.findViewById(R.id.about_img_btn);
about_img_btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
AboutUS fragment = new AboutUS();
Replace_fragment(fragment); //pass the fragment u want to replace
}
});
public void ReplaceFragment(Fragment r_fragment) {
FragmentManager fragmentManager = getActivity.getSupportFragmentManager();
fragmentManager.beginTransaction().replace(R.id.fragment_container, r_fragment).commit();
}
I'm creating a simple quiz according to this tutorial, but the app crashes with the button "Next answer" which is related to a checked radio button.
Main code:
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;
public class Display extends Activity {
TextView tv;
Button btnNext;
RadioGroup rg;
RadioButton rb1, rb2,rb3;
String questions[]={"Capital of Portugal?", "Capital of Spain?", "Capital of France?"};
String answers[]={"Lisbn","Madrid","Paris"};
String options[]={"Zuriq", "London","Lisbon","Manchester","Buenos Aires","Madrid", "NY", "Paris","Moscow"};
int flag=0;
public static int marks,correct,wrong;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.dispaly);
tv=(TextView) findViewById(R.id.tvque);
btnNext=(Button) findViewById(R.id.btnNext);
rb1= (RadioButton) findViewById(R.id.radioButton);
rb2= (RadioButton) findViewById(R.id.radioButton2);
rb3= (RadioButton) findViewById(R.id.radioButton3);
tv.setText(questions[flag]);
rb1.setText(options[flag*3]);
rb2.setText(options[(flag*3)+1]);
rb3.setText(options[(flag*3)+2]);
Toast.makeText(this, "Negative Marks: " + MainActivity.tbflag, 1000).show();
btnNext.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
//The error comes from the line bellow, i believe:
RadioButton user_answer= (RadioButton)findViewById(rg.getCheckedRadioButtonId());
String answerText=user_answer.getText().toString();
if(answerText.equalsIgnoreCase(answers[flag])){
correct++;
}else{
wrong++;
flag++;
if(flag<questions.length){
tv.setText(questions[flag]);
rb1.setText(options[flag*3]);
rb2.setText(options[(flag*3)+1]);
rb3.setText(options[(flag*3)+2]);
}
else
{
if(MainActivity.tbflag)
{
marks=correct-wrong;
}
else
{
marks=correct;
}
Intent in =new Intent(getApplicationContext(), ResultActivity.class);
startActivity(in);
}
}
}
});
}
}
Log message:
java.lang.NullPointerException: Attempt to invoke virtual method 'int android.widget.RadioGroup.getCheckedRadioButtonId()' on a null object reference
I don't understand this error, why isn't the method being called? Can someone help?
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:id="#+id/activity_main"
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"
tools:context="com.example.vtorferreira.anew.MainActivity">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/tvque"
tools:text="Questions" />
<RadioGroup xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:id="#+id/group">
<RadioButton
android:text="RadioButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/textView"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginTop="32dp"
android:id="#+id/radioButton" />
<RadioButton
android:text="RadioButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/radioButton"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:id="#+id/radioButton2" />
<RadioButton
android:text="RadioButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/radioButton3"
android:layout_below="#+id/radioButton2"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
</RadioGroup>
<Button
android:text="Next Question"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginLeft="60dp"
android:layout_marginStart="60dp"
android:layout_marginBottom="125dp"
android:id="#+id/btnNext" />
</RelativeLayout>
The reason you are getting the first NullPointerException is because you must inflate rg before it is used.
The second NullPointerException is possibly due to the fact that you are pressing the "Next" button with no radio button selected. To prevent this, you can add a null check inside the OnClickListener or select one of the radio buttons by default. To select a radio button by default, add the following to your XML:
<RadioGroup
...
android:checkedButton="#+id/some-radio-button-id">
...
</RadioGroup>
Alternatively, you can set the default checked RadioButton in your Activity:
rg.check(R.id.radioButton)
I honestly do not know what is wrong with my code. I have searched for answers here and have done everything and i simply cannot tell what is wrong, Please help?
This is my MainActivity.java,
package com.example.myname.easternmusic;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import java.util.Timer;
import java.util.TimerTask;
public class MainActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.splash);
TimerTask task=new TimerTask() {
#Override
public void run() {
finish();
startActivity(new Intent(MainActivity.this, Main.class));
}
};
Timer opening=new Timer();
opening.schedule(task,5000);
}
}
My splash.xml which is the layout for the MainActivity.java
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Sounds of the East"
android:id="#+id/textView"
android:layout_alignParentTop="true"
android:textSize="20dp"
android:textColor="#000000"
android:textStyle="bold"
android:gravity="center_horizontal"
android:background="#drawable/bell"
android:layout_alignParentBottom="true"
android:layout_alignParentStart="true"
android:layout_alignParentEnd="true" />
My Main.java which is the extra class I created for the main_activity.xml file
package com.example.myname.easternmusic;
import android.app.Activity;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
public class Main extends Activity {
Button btBamboo, btPalace;
MediaPlayer mpBamboo, mpPalace;
int playing;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ImageView imageView=(ImageView)findViewById(R.id.imageView);
ImageView imageView1=(ImageView)findViewById(R.id.imageView2);
btBamboo=(Button)findViewById(R.id.button1);
btPalace=(Button)findViewById(R.id.button2);
btBamboo.setOnClickListener(bBamboo);
btPalace.setOnClickListener(bPalace);
mpBamboo=new MediaPlayer();
mpBamboo=MediaPlayer.create(this,R.raw.bamboo);
mpPalace=new MediaPlayer();
mpPalace=MediaPlayer.create(this,R.raw.palace);
playing=0;
}
Button.OnClickListener bBamboo=new Button.OnClickListener(){
#Override
public void onClick(View v) {
switch (playing){
case 0:
mpBamboo.start();
playing=1;
btBamboo.setText("Pause Bamboo Song");
btPalace.setVisibility(View.INVISIBLE);
break;
case 1:
mpBamboo.pause();
playing=0;
btBamboo.setText("Play Bamboo Song");
btPalace.setVisibility(View.VISIBLE);
break;
}
}
};
Button.OnClickListener bPalace=new Button.OnClickListener(){
#Override
public void onClick(View v) {
switch (playing){
case 0:
mpPalace.start();
playing=1;
btPalace.setText("Pause Palace Song");
btBamboo.setVisibility(View.INVISIBLE);
break;
case 1:
mpPalace.pause();
playing=0;
btPalace.setText("Play Palace Song");
btBamboo.setVisibility(View.VISIBLE);
break;
}
}
};
}
and finally, the activity_main.xml file
<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" android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin" tools:context=".Splash">
<ImageView
android:layout_width="320dp"
android:layout_height="150dp"
android:id="#+id/imageView"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="20dp"
android:src="#drawable/band" />
<Button
android:layout_width="320dp"
android:layout_height="wrap_content"
android:text="Play Bamboo Song"
android:id="#+id/button1"
android:layout_below="#+id/imageView"
android:layout_centerHorizontal="true"
android:textSize="22dp"
android:layout_marginBottom="10dp" />
<ImageView
android:layout_width="320dp"
android:layout_height="150dp"
android:id="#+id/imageView2"
android:layout_below="#+id/button1"
android:layout_centerHorizontal="true"
android:layout_marginTop="20dp"
android:src="#drawable/drums" />
<Button
android:layout_width="320dp"
android:layout_height="wrap_content"
android:text="Play Palace Song"
android:id="#+id/button2"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:textSize="22dp"
android:layout_marginBottom="10dp"
android:layout_alignParentStart="false" />
When the app is run, it should pull up a splash screen with the splash layout for five seconds, and then display the activity_main layout, but it stops right after it switches screens. Please help.
write
startActivity(new Intent(MainActivity.this, Main.class));
then write
finish();
here You first finish your activity and after that you are try to call that activity. That is not possible.
I am realitavely new to Java coding and am trying to use a button press (in an Android App) to update a text view. The code I am currently using is causing my app to crash whenever I try to press the button.
Here is my XML
<LinearLayout>
<TextView
android:id="#+id/myTextView_text_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="0" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="calculateNewNumber"
android:text="Calculate New Number" />
</LinearLayout>
And Here is my Java
package com.example.android.myapp;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
int startNumber = 0;
public void calculateNewNumber(View view) {
startNumber = startNumber + 1;
display(startNumber);
}
private void display(int number) {
TextView myTextView = (TextView) findViewById(
R.id.myTextView_text_view);
myTextView.setText("" + number);
}
}
Thanks for any help you can give.
The code itself works fine so the problem must be with your XML, assuming you have provided it in full here.
Using this XML, your MainActivity code works fine for me.
<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" android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin" tools:context=".MainActivity">
<LinearLayout
android:layout_height="wrap_content"
android:layout_width="fill_parent">
<TextView
android:id="#+id/myTextView_text_view"
android:layout_width="60dp"
android:layout_height="wrap_content"
android:text="0" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="calculateNewNumber"
android:text="Calculate New Number" />
</LinearLayout>
</RelativeLayout>