开发应用程序每次都被强制关闭

Question

I am new to android programming and now I'm learning how to build an Android alarm clock application where it will display "rise and shine" after 20 seconds from whatever the time happened to be when the button was clicked. However, each time it would force close in both emulator and my phone. And the popped-out window keep displaying "The application alarmmanager2 (process com.example.alarmmanager2) has stopped unexpectedly. Pls try again."

And this is the source code: layout:

<?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"
android:layout_gravity="center"
android:gravity="center">
<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Alarm Example" />
<Button
    android:id="@+id/the_button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Set"/>

</LinearLayout>

src/java:

        package alarmmanager2;

    import com.example.alarmmanager2.*;
    import android.os.Bundle;
    import android.os.SystemClock;
    import android.app.Activity;
    import android.app.AlarmManager;
    import android.app.PendingIntent;
    import android.content.BroadcastReceiver;
    import android.content.Context;
    import android.content.Intent;
    import android.content.IntentFilter;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.Toast;
    public class Main extends Activity implements OnClickListener{
           final static private long ONE_SECOND = 1000;
           final static private long TWENTY_SECONDS = ONE_SECOND * 20;
           PendingIntent pi;
           BroadcastReceiver br;
           AlarmManager am;
           @Override
           protected void onCreate(Bundle savedInstanceState) {
                  super.onCreate(savedInstanceState);
                  setContentView(R.layout.main);
                  setup();
                  findViewById(R.id.the_button).setOnClickListener(this);
           }

           private void setup() {
                  br = new BroadcastReceiver() {
                         @Override
                         public void onReceive(Context c, Intent i) {
                                Toast.makeText(c, "Rise and Shine!", Toast.LENGTH_LONG).show();
                                }
                         };
                  registerReceiver(br, new IntentFilter("com.authorwjf.wakeywakey") );
                  pi = PendingIntent.getBroadcast( this, 0, new Intent("com.authorwjf.wakeywakey"),
            0 );
                  am = (AlarmManager)(this.getSystemService( Context.ALARM_SERVICE ));
            }

           @Override
           public void onClick(View v) {
                  am.set( AlarmManager.ELAPSED_REALTIME_WAKEUP, SystemClock.elapsedRealtime() + 
           TWENTY_SECONDS, pi );
           }
    }

manifest:

        <?xml version="1.0" encoding="utf-8"?>
    <manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="com.example.alarmmanager2"
        android:versionCode="1"
        android:versionName="1.0" >

        <uses-sdk
            android:minSdkVersion="8"
            android:targetSdkVersion="8" />

        <uses-permission android:name="android.permission.WAKE_LOCK"/>

        <application
            android:allowBackup="true"
            android:icon="@drawable/ic_launcher"
            android:label="@string/app_name"
            android:theme="@style/AppTheme" >

            <activity
                android:name=".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>

            <receiver android:name="alarmmanager.AlarmManagerBroadcastReceiver">
            </receiver>


        </application>

    </manifest>

EDIT : guys thank you for lending me your helping hand, after i change the class to com.example.alarmmanager2, but same problem still happening and the following is the log i copy from the logcat

05-20 07:18:55.302: D/AndroidRuntime(324): Shutting down VM
05-20 07:18:55.313: W/dalvikvm(324): threadid=1: thread exiting with uncaught exception    (group=0x4001d800)
05-20 07:18:55.422: E/AndroidRuntime(324): FATAL EXCEPTION: main
05-20 07:18:55.422: E/AndroidRuntime(324): java.lang.RuntimeException: Unable to instantiate activity  ComponentInfo{com.example.alarmmanager2/com.example.alarmmanager2.Main}: java.lang.ClassNotFoundException: com.example.alarmmanager2.Main in loader dalvik.system.PathClassLoader[/data/app/com.example.alarmmanager2-1.apk]
05-20 07:18:55.422: E/AndroidRuntime(324):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2585)
05-20 07:18:55.422: E/AndroidRuntime(324):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
05-20 07:18:55.422: E/AndroidRuntime(324):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
05-20 07:18:55.422: E/AndroidRuntime(324):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
05-20 07:18:55.422: E/AndroidRuntime(324):  at android.os.Handler.dispatchMessage(Handler.java:99)
05-20 07:18:55.422: E/AndroidRuntime(324):  at android.os.Looper.loop(Looper.java:123)
05-20 07:18:55.422: E/AndroidRuntime(324):  at android.app.ActivityThread.main(ActivityThread.java:4627)
05-20 07:18:55.422: E/AndroidRuntime(324):  at java.lang.reflect.Method.invokeNative(Native Method)
05-20 07:18:55.422: E/AndroidRuntime(324):  at java.lang.reflect.Method.invoke(Method.java:521)
05-20 07:18:55.422: E/AndroidRuntime(324):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
05-20 07:18:55.422: E/AndroidRuntime(324):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
05-20 07:18:55.422: E/AndroidRuntime(324):  at dalvik.system.NativeStart.main(Native Method)
05-20 07:18:55.422: E/AndroidRuntime(324): Caused by: java.lang.ClassNotFoundException: com.example.alarmmanager2.Main in loader dalvik.system.PathClassLoader[/data/app/com.example.alarmmanager2-1.apk]
05-20 07:18:55.422: E/AndroidRuntime(324):  at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:243)
05-20 07:18:55.422: E/AndroidRuntime(324):  at java.lang.ClassLoader.loadClass(ClassLoader.java:573)
05-20 07:18:55.422: E/AndroidRuntime(324):  at java.lang.ClassLoader.loadClass(ClassLoader.java:532)
05-20 07:18:55.422: E/AndroidRuntime(324):  at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
05-20 07:18:55.422: E/AndroidRuntime(324):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2577)
05-20 07:18:55.422: E/AndroidRuntime(324):  ... 11 more

Do not hesitate to correct my mistakes.

Answer 1

As per the comments above, I am going to assume (without being able to read your LogCat file) that your application is crashing because of this:

 registerReceiver(br, new IntentFilter("com.authorwjf.wakeywakey") );
                      pi = PendingIntent.getBroadcast( this, 0, new Intent("com.authorwjf.wakeywakey")

Your app is trying to find com.authorwjf.wakeywakey but because there isn't a class in your program called wakeywakey it won't work. Again it wouldn't work unless you called it com.example.wakeywakey as your program is called com.example.alarmmanager2

If you are using Eclipse, try and see at the bottom there is a tab call LogCat, this will tell you exactly where the issue is. If you can upload what the logcat says by editing your question

Answer 2

Your application package is com.example.alarmmanager2 , and in your manifest you have declared the launcher activity like this:

<activity
    android:name=".Main" ..>
    ....
</activity>

So the Android runtime will try to load the class com.example.alarmmanager2.Main when your application starts. But your Main class is in the package alarmmanager2 , so it fails to find the class com.example.alarmmanager2.Main .

So you have two options:

1. Move the Main class to package com.example.alarmmanager2
2. Precede your activity name with the package name in the manifest file: android:name="alarmmanager2.Main"