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Unfortunately [yourapp], has stopped

I'm using intent method to make a simple app that takes you from main screen [with an enter button] to another screen which has three options. Code sourced online and seems to be error free, though my app crashes saying "Unfortunately [yourapp], has stopped" immediately after i press the button which is meant to take to the the other screen.
This is my first activity code:
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);
setContentView(R.layout.activity_main);
addListenerOnButton();
}
public void addListenerOnButton() {
final Context context = this;
button = (Button) findViewById(R.id.enterBtn);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
Intent intent = new Intent(context, HomeActivity.class);
startActivity(intent);
}
});
}
}`
And this is my landing screen's activity code:
import android.app.Activity;
import android.os.Bundle;
import android.widget.Button;
public class HomeActivity extends Activity {
Button button;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.home);
}
}
I'm really stuck with this issue and any help would be much appreciated. Many thanks in advance.

Every activity needs to be added in your manifest file under application tag. This seems to be the problem in your case.

Try to post you LogCat so that we might get some more information and if you have not yet added your Activity in the manifest, this is the way of adding it (Activities go under application tag)
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.southmp3"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="14"
android:targetSdkVersion="21" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".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=".HomeActivity"
android:label="#string/app_name" >
</activity>
</application>
all the Activities should be going under the application tag

I had forgotten to register my new activity on the androidmanifest.xml file. That's what sorted my app crash issue.

Cannot load new blank activity - android tutorial

I am a new android developer and encountered a problem while following the tutorial on Android's site - http://developer.android.com/training/basics/firstapp/starting-activity.html
My program loads on the emulator fine, but when you type something into the EditText and then hit the send button, a window pops up saying "App has stopped working". It seems as though my new activity isn't being created and I'm not sure as to why. I've scoured the web (and my code) to see if I could get a solution but did so to no avail. Any help would be appreciated.
The code for my first activity:
package com.example.appli;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
public class MainActivity extends Activity {
public final static String EXTRA_MESSAGE = "com.example.myapp.MESSAGE";
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.testlayout);
//////Button myButton = (Button) findViewById(R.id.my_button); //Told in tutorial to put this in onCreate
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
/** Called when the user selects the Send button */
public void sendMessage(View view) {
// Do something in response to button
Intent intent = new Intent(this, DisplayMessageActivity.class);
EditText editText = (EditText) findViewById(R.id.edit_message);
String message = editText.getText().toString();
intent.putExtra(EXTRA_MESSAGE, message);
startActivity(intent);
}
}
The code for my second activity (the one being called)
package com.example.appli;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;
public class DisplayMessageActivity extends Activity{
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//get message from intent
Intent intent = getIntent();
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
// Create the text view
TextView textView = new TextView(this);
textView.setTextSize(40);
textView.setText(message);
setContentView(textView);
}
}
The Manifest
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.appli"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="15" />
<application
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity android:name="com.example.myapp.DisplayMessageActivity" />
<activity
android:name=".MainActivity"
android:label="#string/title_activity_main" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>

In AndroidManifest File you have declared incorrect package
change
<activity android:name="com.example.myapp.DisplayMessageActivity" />
to
<activity android:name="com.example.appli.DisplayMessageActivity" />
or just
<activity android:name=".DisplayMessageActivity" />

you have declared only one Activity that's also wrong package name
already your manifest has the package name
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.appli"
so just declare like this
<activity android:name=".DisplayMessageActivity" />
and you need to add this in your manifest also
<activity android:name=".MainActivity />
remove the target SDK version that you mentioned
android:targetSdkVersion="15"

Try this
<activity android:name=".DisplayMessageActivity"/>
Instead of
<activity android:name="com.example.myapp.DisplayMessageActivity" />
in your Manifest.xml file.

You has defined the package package com.example.appli; in your activities.
Why have you defined you activity in manifest like <activity android:name="com.example.myapp.DisplayMessageActivity" />?
Replace this line with
<activity android:name=".DisplayMessageActivity" />.

New intent, how to link to my class?

I'm beginner in Android (and java), and I'm just playing around and want to create new View after clicking a button. Here is my code so far:
Main class
package myTests.homeSpace;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class TestsActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button button1 = (Button) findViewById(R.id.button1);
button1.setOnClickListener( new OnClickListener()
{
public void onClick(View v)
{
Intent myIntent = new Intent(TestsActivity.this, screen1.class);
startActivity(myIntent);
}
});
}
}
Class to run after clicking button
package myTests.homeSpace;
import android.app.Activity;
import android.os.Bundle;
public class screen1 extends Activity {
#Override
public void onCreate(Bundle SavedBundleInstance)
{
super.onCreate(SavedBundleInstance);
setContentView(R.layout.screen1);
}
}
The problem is, after hitting button I got "Unforunately, Tests has stopped" error. ("Tests" is application name). I know (or guess) the problem is in this line Intent myIntent = new Intent(TestsActivity.this, screen1.class);
I guess my reference to class screen1 is wrong somehow, but I have no idea why. There are no compilation errors nor warnings, layout .xmls shouldn't be wrong.
Could any of you please advice me any solution?
EDIT
MANIFEST
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="myTests.homeSpace"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="15" />
<application
android:icon="#drawable/ic_launcher"
android:label="#string/app_name" >
<activity
android:name=".TestsActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
CONSOLE OUTPUT
[2012-06-20 19:56:21 - ddms] null
java.lang.NullPointerException
at com.android.ddmlib.JdwpPacket.writeAndConsume(JdwpPacket.java:213)
at com.android.ddmlib.Client.sendAndConsume(Client.java:575)
at com.android.ddmlib.HandleHello.sendHELO(HandleHello.java:142)
at com.android.ddmlib.HandleHello.sendHelloCommands(HandleHello.java:65)
at com.android.ddmlib.Client.getJdwpPacket(Client.java:672)
at com.android.ddmlib.MonitorThread.processClientActivity(MonitorThread.java:317)
at com.android.ddmlib.MonitorThread.run(MonitorThread.java:263)

I bet if you read the crash log somewhere in there says did you forget to declare this activity in the Manifest?

I agree, not declaring the activity in your Manifest file (AndroidManifest.xml) is most likely your problem. See the android developer page on activities for more information. Here is the relevant description:
Declares an activity (an Activity subclass) that implements part of
the application's visual user interface. All activities must be
represented by elements in the manifest file. Any that are
not declared there will not be seen by the system and will never be
run.
I just posted this so you would have more space to research on your own.

Declare your second activity in the Manifest.xml as:
<activity
android:name=".screen1">
</activity>
Just below the declaration of your first activity.

Android. Broadcast Receiver

I have some trouble while try using broadcast receiver.
Target:
I have three app which will work next schema
1. First - is broadcast receiver app which will write some data to database when it will get a message.
2. Second - is app android which will send some intent with data which must be saved in database.
3. Third - is widget in home screen which will also send some intent with data which must be saved in database.
So, I make three app on eclipse.
1. BroadcastReceiverExample - broadcast receiver it has next files
package com.test.receive;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;
import android.widget.Toast;
public class SimpleReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
Toast.makeText(context, "service get started action", Toast.LENGTH_LONG).show();
Log.e("START","START");
}
}
and the manifest file source
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.test"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="7" />
<application android:icon="#drawable/icon" android:label="#string/app_name">
<receiver android:enabled="true" android:name=".receive.SimpleReceiver" android:exported="false">
<intent-filter android:priority="999">
<action android:name="com.test.SIMPLE_TEST_SERVICE"></action>
</intent-filter>
</receiver>
</application>
</manifest>
also I create App project (BroadcastSenderExample) in Eclipse
and it has file with next sender code
package com.test.sender;
import com.test.R;
import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class BroadcastSenderExample extends Activity {
public final static String ACTION="com.test.SIMPLE_TEST_SERVICE";
public final static String TYPE="type";
public final static int START=1;
public final static int STOP=0;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
btnStart=(Button)findViewById(R.id.btnStart);
btnStart.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
Intent bcIntent=new Intent(ACTION);
sendBroadcast(bcIntent);
}
});
btnEnd=(Button)findViewById(R.id.btnEnd);
btnEnd.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
Intent bcIntent=new Intent(ACTION);
sendBroadcast(bcIntent);
}
});
}
private Button btnStart=null;
private Button btnEnd=null;
}
Then I install first app on device (and emulator try too), and install second app.
And then second app run intent call nothing happen.
What am I doing wrong?
I make two projects with next code
Project one wBRReceiver
File WBRReceiver.java
package com.x.brreceiver;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;
import android.widget.Toast;
public class WBRReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context arg0, Intent arg1) {
Log.i("THIS IS A TEST RECEIVER","THIS IS A TEST RECEIVER");
Toast.makeText(arg0, "this is a test receiver", Toast.LENGTH_LONG).show();
}
}
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.x.brreceiver"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="8" />
<application android:icon="#drawable/icon" android:label="#string/app_name">
<receiver android:name="WBRReceiver">
<intent-filter>
<action android:name="com.x.START"></action>
</intent-filter>
</receiver>
</application>
</manifest>
And project two wBRSender
File WBRSenderActivity.java
package com.x.brsender;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
public class WBRSenderActivity extends Activity {
private String ACTION_NAME="com.x.START";
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Intent brr=new Intent(ACTION_NAME);
//I can't use this
//brr.setClass(this, WBRReceiver.class);
//Because i just don't have this class in this case
sendBroadcast(brr);
}
}
And manifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.x.brsender"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="8" />
<application android:icon="#drawable/icon" android:label="#string/app_name">
<activity android:name=".WBRSenderActivity"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
And then I install first app onto emulator, and then run second app. And it works.

Did you look at the logcat output? There's a very good chance it tells you exactly what's wrong.
Without staring at your code too much, it seems that your manifest is broken. In your receiver, you state the android:name is ".receive.SimpleReceiver"... this value (when starting with a .) is not simply "the part that follows the Android package name) -- though it works out that way most of the time. In your case, your Android package is "com.test" however the package containing your receiver is "com.test.receive.SimpleReceiver" and its Java package is "com.test.receive". Try changing your android:name to "com.test.receive.SimpleReceiver".

JAVA - Android error: The application has stopped unexpectedly please try again

I made an app which is just working fine. But when i click on "cancel" or "ok" button when i run the program, instead of linking me to result.java, the simulator give me "The application has stopped unexpectedly please try again" Here's the code
import android.app.Activity;
import android.content.ComponentName;
import android.content.Intent;
import android.database.CursorJoiner.Result;
import android.os.Bundle;
import android.view.View;
import android.widget.AutoCompleteTextView;
public class lib_main extends Activity {
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
public void onAddClick (View botton){
AutoCompleteTextView title = (AutoCompleteTextView)findViewById(R.id.Title);
AutoCompleteTextView author = (AutoCompleteTextView)findViewById(R.id.Author);
AutoCompleteTextView isbn = (AutoCompleteTextView)findViewById(R.id.ISBN);
Intent intent = new Intent();
intent.setClass(this,Result.class);
intent.putExtra("Title", title.getText().toString());
intent.putExtra("Author", author.getText().toString());
intent.putExtra("ISBN", isbn.getText().toString());
startActivity(intent);
}
public void onCancelClick(View botton){
Intent intent = new Intent();
intent.setComponent(new ComponentName(this,Result.class));
intent.putExtra("Cancel","Cancel");
startActivity(intent);
}
}
this is Result.java
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class Result extends Activity {
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.result);
TextView resultText=(TextView)findViewById(R.id.resultText);
Bundle bundle =getIntent().getExtras();
if(bundle.getString("Cancel")!= null)
{resultText.setText("operation cancel");}
else
{ String book =bundle.getString ("Title");
String title =bundle.getString ("Author");
String isbn =bundle.getString ("ISBN");
resultText.setText(
getString (R.string.resultOk)+""+book+""+ title+""+isbn);
}
}
}
the error log write "No command output when running:'am start-n com.Library.doc/com.Library.doc.lib_main-a android.intent.action.MAIN-c android.intent.category.LAUNCHER' in device emulator-5554"
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.Library.doc"
android:versionCode="1"
android:versionName="1.0">
<application android:icon="#drawable/icon" android:label="#string/app_name">
<activity android:name=".lib_main"
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=".Result"
android:label="#string/result">
</activity>
</application>
<uses-sdk android:minSdkVersion="8" />
Can anyone help me with this problem?

Quick question, have you registered both Activities? If you only provide for one in your manifest file you're going to get this error every time you attempt to do something involving the unregistered activity.