Question

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>

Answer 1

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"