Question

Hi Ive written a simple android application with two xml pages, one has an image button which ive rigged to open the second xml page when it is clicked. The code returns no errors and runs fine but when I click the button in the android emulator it crashes and asks me to force close. Here is the code I am working on:

First Activity:

package com.android.Train;

import com.android.TrainMenu.MenuActivity;

    import android.app.Activity;
    import android.content.Intent;
    import android.os.Bundle;
    import android.view.View;

    public class TrainActivity extends Activity 
    {
        /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }

    public void goMenu(View v)
    {
      Intent myIntent = new Intent(this, MenuActivity.class);
      startActivity(myIntent);
    }    
}

First XML File:

 <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <ImageButton
        android:id="@+id/enterButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/button_enter"
        android:clickable="true"
        android:onClick="goMenu" />

    </LinearLayout>

Second Activity:

package com.android.TrainMenu;

import android.app.Activity;
import android.os.Bundle;

import com.android.Train.R;

public class MenuActivity extends Activity 
{
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.menu);
    }
}

Second XML File:

 <?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" >

</RelativeLayout>

Any ideas on why this should crash?

Thanks in advance

I just ran it again, here is the logCat file

01-26 14:21:37.784: D/AndroidRuntime(287): Shutting down VM
01-26 14:21:37.784: W/dalvikvm(287): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
01-26 14:21:37.815: E/AndroidRuntime(287): FATAL EXCEPTION: main
01-26 14:21:37.815: E/AndroidRuntime(287): java.lang.IllegalStateException: Could not execute method of the activity
01-26 14:21:37.815: E/AndroidRuntime(287):  at android.view.View$1.onClick(View.java:2072)
01-26 14:21:37.815: E/AndroidRuntime(287):  at android.view.View.performClick(View.java:2408)
01-26 14:21:37.815: E/AndroidRuntime(287):  at android.view.View$PerformClick.run(View.java:8816)
01-26 14:21:37.815: E/AndroidRuntime(287):  at android.os.Handler.handleCallback(Handler.java:587)
01-26 14:21:37.815: E/AndroidRuntime(287):  at android.os.Handler.dispatchMessage(Handler.java:92)
01-26 14:21:37.815: E/AndroidRuntime(287):  at android.os.Looper.loop(Looper.java:123)
01-26 14:21:37.815: E/AndroidRuntime(287):  at android.app.ActivityThread.main(ActivityThread.java:4627)
01-26 14:21:37.815: E/AndroidRuntime(287):  at java.lang.reflect.Method.invokeNative(Native Method)
01-26 14:21:37.815: E/AndroidRuntime(287):  at java.lang.reflect.Method.invoke(Method.java:521)
01-26 14:21:37.815: E/AndroidRuntime(287):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
01-26 14:21:37.815: E/AndroidRuntime(287):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
01-26 14:21:37.815: E/AndroidRuntime(287):  at dalvik.system.NativeStart.main(Native Method)
01-26 14:21:37.815: E/AndroidRuntime(287): Caused by: java.lang.reflect.InvocationTargetException
01-26 14:21:37.815: E/AndroidRuntime(287):  at com.android.Train.TrainActivity.goMenu(TrainActivity.java:23)
01-26 14:21:37.815: E/AndroidRuntime(287):  at java.lang.reflect.Method.invokeNative(Native Method)
01-26 14:21:37.815: E/AndroidRuntime(287):  at java.lang.reflect.Method.invoke(Method.java:521)
01-26 14:21:37.815: E/AndroidRuntime(287):  at android.view.View$1.onClick(View.java:2067)
01-26 14:21:37.815: E/AndroidRuntime(287):  ... 11 more
01-26 14:21:37.815: E/AndroidRuntime(287): Caused by: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.android.Train/com.android.TrainMenu.MenuActivity}; have you declared this activity in your AndroidManifest.xml?
01-26 14:21:37.815: E/AndroidRuntime(287):  at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1404)
01-26 14:21:37.815: E/AndroidRuntime(287):  at android.app.Instrumentation.execStartActivity(Instrumentation.java:1378)
01-26 14:21:37.815: E/AndroidRuntime(287):  at android.app.Activity.startActivityForResult(Activity.java:2817)
01-26 14:21:37.815: E/AndroidRuntime(287):  at android.app.Activity.startActivity(Activity.java:2923)
01-26 14:21:37.815: E/AndroidRuntime(287):  ... 15 more

Android Manifest.XML

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.android.Train"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="7" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:label="@string/app_name"
            android:name=".TrainActivity" >
            <intent-filter >
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity
        android:name=".MenuActivity"
        android:label="@string/app_name" />

    </application>

</manifest>

Answer 1

I think its because your MenuActivity class is in a different package to your TrainActivity class. I’m not sure how to do it with the package layout you have, but if you had the following:

com.ardroid.train.TrainActivity
com.ardroid.train.menu.MenuActivity

Then your manifest entry would be:

<activity 
    android:name=".menu.MenuActivity "
    android:label="@string/app_name" />