I am doing a Android app where I want to show the list of travels contact numbers in a separate screen when clicked on "Travels and Holidays" button. Here is the code:
AppActivity.java
package com.example.android;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class App2Activity extends Activity {
String number=getIntent().getStringExtra("no");
String name=getIntent().getStringExtra("no");
Button button;
Context context = this;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main2);
button = (Button) findViewById(R.id.button1);
button.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Intent i=new Intent(context,AppActivity.class);
i.putExtra("no","yourno");
i.putExtra("name","yourname");
startActivity(i);
}
});
return;
}
}
App2Activity.java
package com.example.android;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class App2Activity extends Activity {
String number=getIntent().getStringExtra("784568435,438756435,435784365");
String name=getIntent().getStringExtra("Travels1,Travels2,Travels3");
Button button;
Context context = this;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main2);
button = (Button) findViewById(R.id.button1);
button.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Intent i=new Intent(context,AppActivity.class);
i.putExtra("number","784568435,438756435,435784365");
i.putExtra("name","Travels1,Travels2,Travels3");
startActivity(i);
}
});
return;
}
}
main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/linearLayout1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge" />
<Button
android:id="#+id/button1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Travels and Holidays" />
</LinearLayout>
strings.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="app_name">Travels and Holidays Details</string>
</resources>
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.mkyong.android"
android:versionCode="1"
android:versionName="1.0" >
<uses-permission android:name="android.permission.CALL_PHONE" />
<application
android:icon="#drawable/ic_launcher"
android:label="#string/app_name" >
<activity
android:label="#string/app_name"
android:name=".AppActivity" >
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:label="#string/app_name"
android:name=".App2Activity" >
</activity>
</application>
</manifest>
What I want is: When I click on "Travels and Holidays" button in the first screen, I want the travels name and contact number to be shown on another screen. When clicked on any travels, it should redirect to the call option of that number.
Where am I going wrong? Please help. Thanks in advance
You need to get your intents inside the onCreate() method. Also, while getting the intent values, you're using the same key "no" both times. You're going to get the same value in both number and name. Do this instead
String number=getIntent().getStringExtra("no");
String name=getIntent().getStringExtra("yourname");
Your onCreate() method inside AppActivity should look like this
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main2);
button = (Button) findViewById(R.id.button1);
button.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Intent i=new Intent(context,AppActivity.class);
i.putExtra("number","784568435,438756435,435784365");
i.putExtra("name","Travels1,Travels2,Travels3");
startActivity(i);
}
});
return;
}
Then delete the getIntent() code, from above the onCreate() method.
You should only use getIntent() inside onCreate().
In your button listener you have to call the App2Activity, also note a typo in context,App2Activity.class
button = (Button) findViewById(R.id.button1);
button.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Intent i=new Intent(context,App2Activity.class);
// ↑: number 2 missing!!
// note you're harcoding the no and name variables!
i.putExtra("no","yourno");
i.putExtra("name","yourname");
startActivity(i);
}
});
After,
remove the similar code in App2Activity (is not necessary to show content)
make a layout with label or TextView to show the info
in oncreate of App2Activity get the extras
put in this label or textview the extras from the intent
To get extras:
String no = intent.getStringExtra("no");
String name = intent.getStringExtra("name");
You should getIntent() on the Activity's onCreate() method not when initializing the Activity. Because instance variables initialization is actually put in the constructor(s) by the compiler, I think the intent was not initialized in the Constructor.
public class App2Activity extends Activity {
String number;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main2);
number = getIntent().getStringExtra("no");
}
}
Related
I'm trying to store the users input from a text field in shared preferences and use that input in a webview link.
Here's what I have so far;
LoginActivity.java
package com.example.app;
import android.app.Activity;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.content.Intent;
public class LoginActivity extends Activity {
EditText subdomain;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
subdomain = (EditText) findViewById(R.id.subdomain);
Button btn=(Button)findViewById(R.id.sign_in_button);
btn.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
Intent myIntent = new Intent(LoginActivity.this,
MainActivity.class);
LoginActivity.this.startActivity(myIntent);
}
});
}
public void saveInfo (View view) {
SharedPreferences sharedPref = getSharedPreferences("spfile",
Activity.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPref.edit();
editor.putString("name", YourSchool.getText().toString());
editor.commit();
}
}
MainActivity.java
package com.example.app;
import android.app.Activity;
import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
public class MainActivity extends Activity {
private WebView mWebView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mWebView = (WebView) findViewById(R.id.activity_main_webview);
// Force links and redirects to open in the WebView instead of in a
browser
mWebView.setWebViewClient(new WebViewClient());
// Enable Javascript
WebSettings webSettings = mWebView.getSettings();
webSettings.setJavaScriptEnabled(true);
// Use remote resource
mWebView.loadUrl("https://"+client_subdomain+".domain.co.uk/texts");
// Stop local links and redirects from opening in browser instead
of WebView
mWebView.setWebViewClient(new MyAppWebViewClient());
}
public void displayData (View view) {
SharedPreferences sharedPref = getSharedPreferences("spfile",
Activity.MODE_PRIVATE);
String client_subdomain = sharedPref.getString("name", "");
}
// Prevent the back-button from closing the app
#Override
public void onBackPressed() {
if(mWebView.canGoBack()) {
mWebView.goBack();
} else {
super.onBackPressed();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is
present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
activity_login.xml
<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:gravity="center_horizontal"
android:orientation="vertical"
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.app.LoginActivity">
<LinearLayout
android:id="#+id/email_login_form"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<EditText
android:id="#+id/YourSchool"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Your school"
android:maxLines="1"
android:singleLine="true" />
<Button
android:id="#+id/sign_in_button"
style="?android:textAppearanceSmall"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:onClick="webView"
android:text="SIGN IN"
android:textStyle="bold" />
</LinearLayout>
</ScrollView>
</LinearLayout>
activity_main.xml
<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=".MainActivity">
<WebView
android:id="#+id/activity_main_webview"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</RelativeLayout>
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.app">
<uses-permission android:name="android.permission.INTERNET" />
<!-- To auto-complete the email text field in the login form with the
user's emails -->
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="android.permission.READ_PROFILE" />
<uses-permission android:name="android.permission.READ_CONTACTS" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#android:style/Theme.NoTitleBar.Fullscreen">
<activity
android:name=".MainActivity"
android:label="#string/app_name"></activity>
<activity
android:name=".LoginActivity"
android:label="#string/title_activity_login">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER"
/>
</intent-filter>
</activity>
</application>
</manifest>
My problem is that the client_subdomain is flagged as red in the MainActivity.java and when I try to build the project, I get the error: cannot find symbol variable client_subdomain
I think it's probably something small that I've missed out but any help would be greatly appreciated.
Many thanks,
Sam
Its because haven't declared "client_subdomain" as a variable within scope of onCreate
why don't you try changing displayData to
public String displayData () {
SharedPreferences sharedPref = getSharedPreferences("spfile",
Activity.MODE_PRIVATE);
return sharedPref.getString("name", "");
}
and in onCreate of the Main Activity
...
// Enable Javascript
WebSettings webSettings = mWebView.getSettings();
webSettings.setJavaScriptEnabled(true);
// Use remote resource
mWebView.loadUrl("https://"+displayData()+".domain.co.uk/texts");
...
Also, I don't see you ever calling "saveInfo" anywhere in your Login Activity. As well, you should probably change the function too. You aren't grabbing the text from the EditText correctly (whatever YourSchool) is
public void saveInfo() {
SharedPreferences sharedPref = getSharedPreferences("spfile", Activity.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPref.edit();
editor.putString("name", subdomain.getText().toString());
editor.commit();
}
And this will be what your onCreate should have,
protected void onCreate(Bundle savedInstanceState) {
...
btn.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
saveInfo();
Intent myIntent = new Intent(LoginActivity.this, MainActivity.class);
LoginActivity.this.startActivity(myIntent);
}
});
...
}
I'd seen this asked in many, many places and have tried to follow the instructions given to no avail. I dont know if the questions are old, i'm doing things incorrectly or if my android studio program isnt working. What i want to do is to only open a new activity when a button is clicked. I'm very new to developing android applications.
I've recently tried to follow the answer provided here: How do I get a button to open another activity in Android Studio?
OnClick on the button is called "goTutorials"
My original activity is called home (Not mainActivity)
The new one is called tutorials.
This is what i added from trying to follow the link above:
In home's java file:
btn = (Button)findViewById(R.id.open_activity_button);
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
startActivity(new Intent(home.this, tutorials.class));
}
});
In manifest file:
<activity
android:name="tutorials"
android:label="#string/app_name">
</activity>
Method 1
Use the onclick attribute in XML (so that whenever you click the button, defined method will trigger)
Step 1. - go to the XML where you button is(activity_home) & add
<Button
............
android:onClick="gotoTutorial"/>
Step 2. - then go to the home.Java & add following
public void gotoTutorial(View v){
Intent tutorialPage = new Intent (this, tutorials.class);
startActivity(tutorialPage);
}
Method 2
Use the setOnClickListener
Step 1. -
//create the link to the button in the interface
btn_tutorial = (Button)findViewById(R.id.tutorial_button);
btn_tutorial.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent tutorialPage = new Intent (this, tutorials.class);
startActivity(tutorialPage);
}
}
I have created a sample app please see the code below.
You need to specify information of all activities in Manifest file.
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.nextech.startnewactivity">
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity
android:name=".MainActivity"
android:label="#string/app_name"
android:theme="#style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".TutorialsActivity"
android:label="#string/title_activity_tutorials"
android:theme="#style/AppTheme.NoActionBar"></activity>
</application>
</manifest>
My Launcher activity is MainActivity.java
package com.nextech.startnewactivity;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button startTutorials = (Button)findViewById(R.id.startTutorials);
startTutorials.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent tutorialsActivityIntent = new Intent(MainActivity.this,TutorialsActivity.class);
MainActivity.this.startActivity(tutorialsActivityIntent);
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
activity_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.nextech.startnewactivity.MainActivity"
tools:showIn="#layout/activity_main">
<TextView android:id="#+id/welcomeText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="20dp"
android:layout_centerHorizontal="true"
android:text="Hello World! This is main activity!" />
<Button android:id="#+id/startTutorials"
android:layout_below="#+id/welcomeText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:text="Start Tutorials"/>
</RelativeLayout>
TutorialsActivity.java
package com.nextech.startnewactivity;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
public class TutorialsActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tutorials);
}
}
activity_tutorials.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.nextech.startnewactivity.TutorialsActivity"
tools:showIn="#layout/activity_tutorials">
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="This is tutorial activity"
android:layout_centerInParent="true"/>
</RelativeLayout>
I hope it helps.
Your manifest file is not displaying, but make sure you add the activity in your manifest AndroidManifest.xml in the application field. Here's an example from Google: Link
<application ... >
...
<activity
android:name="com.mycompany.myfirstapp.DisplayMessageActivity"
android:label="#string/title_activity_display_message"
android:parentActivityName="com.mycompany.myfirstapp.MyActivity" >
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="com.mycompany.myfirstapp.MyActivity" />
</activity>
Otherwise, the method you're using should be correct. You create an intent to the class of the Activity you want to start.
Intent intent = new Intent(this, tutorials.class);
startActivity(intent);
Make sure you have the necessary methods such as onCreate(Bundle savedInstance) Overrided.
Note that in the sample above android:name="" is your activity's full path name to the class (without .class/.java) and label is going to be the action toolbar string you'll see. In the <meta-data/> section you can alter the android:value="" to the starting activity's name so that will need to change based on what you call it.
Finally, make sure it has an XML view to go with it, as it gets inflated in the onCreate(Bundle savedInstance) call.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_layout_here);
}
inside your activity file write this
Button btn = (Button)findViewById(R.id.open_activity_button);
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
startActivity(new Intent(home.this, tutorials.class));
}
});
XML
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/button_send"
android:onClick="sendMessage" />
.Java class
/** Called when the user clicks the Send button */
public void sendMessage(View view) {
Intent intent = new Intent(this, YourActivityYouWantToOpen.class);
startActivity(intent);
}
I am currently trying to develop a simple feature for switching from one page to another but every time I launch the app it crashes.
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/linearLayout1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Screen One......"
android:textAppearance="?android:attr/textAppearanceLarge" />
<Button
android:id="#+id/scan"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Click me to another screen" />
</LinearLayout>
MainActivity.java
package com.example.mdpmk1;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.widget.Button;
import android.view.View;
import android.view.View.OnClickListener;
public class MainActivity extends Activity {
Button button;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addListenerOnButton();
}
public void addListenerOnButton() {
final Context context = this;
button = (Button) findViewById(R.id.scan);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
Intent intent = new Intent(context, ScanScreen.class);
startActivity(intent);
}
});
}
}
ScanScreen.java
package com.example.mdpmk1;
import android.app.Activity;
import android.os.Bundle;
import android.widget.Button;
public class ScanScreen extends Activity {
Button button;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.scan_screen);
}
}
scan_screen.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/linearLayout1"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="You have done it!!"
android:textAppearance="?android:attr/textAppearanceLarge" />
</LinearLayout>
Im quite new to this sort of stuff but i am doing an app for my major at school and would like to have it actually working. Any help would be lovely. Thanks
You forgot to write following statement in your MainActivity's onCreate() method,
setContentView(R.layout.activity_main);
Write here,
public class MainActivity extends Activity
{
Button button;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main); // You forgot this line
addListenerOnButton();
}
Also change following line of code,
public void onClick(View arg0)
{
Intent intent = new Intent( MainActivity.this, ScanScreen.class ); // Change here
startActivity(intent);
}
Try editing intent statement in class MainActivity to:
Intent intent = new Intent(MainActivity.this, ScanScreen.class);
startActivity(intent);
You must also add:
setContentView(R.layout.activity_main);
in your ActivityMain class onCreate function to set a view.
setContentView(R.your_layout) doesnt exists in your MainActivity's onCreate(). Try providing your activity a layout.
In your MainActivity onCreate you need to add
setContentView(R.layout.activity_main);
First of all, add SetContentView(R.layout.activity_main) in your MainActivity.OnCreate method befor call to addListenerOnButton.
then be sure that you add your activities entries in your manifest.xml and make MainActivity as your Main Application Activity, like below:
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
<activity android:name=".ScanScreen"/>
It doesnt have any errors ..when i run on my emulator it UNFORTUNATELY STOPS
i am trying to make my button when i click it takes me to the next page....kindly help!
Here is codes for MyActivity.java
package com.example.INIKO_EVENTS;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MyActivity extends Activity {
/**
* Called when the activity is first created.
*/
Button login;
Button sign_up;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
login=(Button)findViewById(R.id.Button15);
login.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent i = new Intent(MyActivity.this,HomeActivity.class);
MyActivity.this.
startActivity(i);
}
});
sign_up=(Button)findViewById(R.id.signUpButton);
sign_up.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent i = new Intent(MyActivity.this,SignUpActivity.class);
MyActivity.this.
startActivity(i);
}
});
}
}
and heres my HomeActivity.java - it has buttons linking to other pages
package com.example.INIKO_EVENTS;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class HomeActivity extends Activity {
/**
* Created by eddie kamau on 2/14/14.
*/
Button button2;
Button button3;
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.home);
button2 = (Button)findViewById(R.id.toEventButton);
button2.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View arg0) {
Intent i = new Intent(HomeActivity.this,EventActivity.class);
HomeActivity.this.
startActivity(i);
}
});
button3=(Button)findViewById(R.id.manage_your_guestButton2);
button3.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View arg0) {
Intent i = new Intent(HomeActivity.this,GuestActivity.class);
HomeActivity.this.
startActivity(i);
}
});
}
}
main.xml
<Button
android:layout_width="141dp"
android:layout_height="wrap_content"
android:text="#string/login"
android:layout_margin="10sp"
android:id="#+id/Button15"
android:layout_gravity="center_horizontal"
android:clickable="true"
android:onClick="onClick"/>
<Button
android:layout_width="121dp"
android:layout_height="wrap_content"
android:text="#string/sign_up"
android:id="#+id/signUpButton"
android:layout_gravity="center_horizontal"
android:maxWidth="600dp"
android:clickable="true"
android:onClick="onClick"/>
</LinearLayout>
home.xml
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="#string/create_your_event"
android:id="#+id/toEventButton"
android:layout_gravity="center_horizontal"
android:clickable="true"
android:onClick="onClick"/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="#string/manage_your_event"
android:id="#+id/manage_your_guestButton2"
android:layout_gravity="center_horizontal" android:clickable="true"/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="#string/your_events"
android:id="#+id/your_eventsButton3"
android:layout_gravity="center_horizontal" android:clickable="true"/>
</LinearLayout>
try this
mainactivity.java
public class MainActivity extends Activity {
Button login;
Button sign_up;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
login=(Button)findViewById(R.id.button1);
login.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent i = new Intent(MainActivity.this,HomeActivity.class);
startActivity(i);
}
});
sign_up=(Button)findViewById(R.id.button2);
sign_up.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent i = new Intent(MainActivity.this,HomeActivity.class);
startActivity(i);
}
});
}
}
homeactivity.java
public class HomeActivity extends Activity{
Button button2;
Button button3;
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.home);
button2 = (Button)findViewById(R.id.button2);
button2.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View arg0) {
Intent i = new Intent(HomeActivity.this,EventActivity.class);
HomeActivity.this.
startActivity(i);
}
});
button3=(Button)findViewById(R.id.button3);
button3.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View arg0) {
Intent i = new Intent(HomeActivity.this,GuestActivity.class);
HomeActivity.this.
startActivity(i);
}
});
}
}
manifest.xml
define all this class in mainfest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.target"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="18" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.target.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="com.example.target.EventActivity" >
</activity>
<activity android:name="com.example.target.GuestActivity" >
</activity>
<activity android:name="com.example.target.HomeActivity" >
</activity>
</application>
this is my codes LoginActivity.java file
package com.example.crims;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.View;
import android.widget.TextView;
public class LoginActivity extends Activity {
TextView screen;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
screen = (TextView) findViewById(R.id.link_to_register);
// Listening to register new account link
screen.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Switching to Register screen
Intent i = new Intent(getApplicationContext(), RegisterActivity.class);
startActivity(i);
}
});
}
}
this is my code for 'activity_login.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: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=".LoginActivity" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/hello_world" />
</RelativeLayout>`
And Finally this is my menifest file
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.crims"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="18" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.crims.LoginActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".RegisterActivity"
android:label="Register New Account">
</activity>
</application>
</manifest>
All of these files are here and i want to find my error as I m new to android app development...
You have NullPointerException(NPE) here:
10-01 21:02:07.580: E/AndroidRuntime(1299):
at com.example.crims.LoginActivity.onCreate(LoginActivity.java:17)
So, check line 17 of LoginActivity.java (you can just double click on this message in the logcat view and you will be navigated to this line).
It seems, line 17 is this:
registerScreen.setOnClickListener(new View.OnClickListener() {
As this is NPE, registerScreen is null. So, you should inspect why it is null. This is because Activity can't find it in line above and it returns null instead:
TextView registerScreen = (TextView) findViewById(R.id.link_to_register);
This can be one of two possibilities: either you do not have widget with id 'link_to_register' in activity_login.xml, or something other is wrong :)
Check this please and show your activity_login.xml file, please.
Listen brother take this code. Change it according to you.
public class MainActivity extends Activity {
TextView screen;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
screen = (TextView) findViewById(R.id.screen);
// Listening to register new account link
screen.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Switching to Register screen
Intent i = new Intent(getApplicationContext(), Register.class);
startActivity(i);
}
});
}
}
You need to register your activity in manifest.xml file too in case if you don't know about it.