Android小部件是否需要啓動默認活動？

Question

我搜索了很多這個問題，並嘗試在互聯網上提到的一切，但仍然無法找到解決方案。我的小部件已安裝，但不會在點擊時更新。我還沒有爲它創建一個默認的活動。 我的問題是，我點擊按鈕的動作沒有改變。

這裏是我的代碼：// Android清單

<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
    package="com.example.android.pictureapp" 
    android:versionCode="1" 
    android:versionName="1.0" > 

    <uses-sdk 
     android:minSdkVersion="7" 
     android:targetSdkVersion="17" /> 

    <application 
     android:allowBackup="true" 
     android:icon="@drawable/ic_launcher" 
     android:label="@string/app_name" 
     android:theme="@style/AppTheme" > 
     <receiver android:name=".MyWidgetProvider" > 
      <intent-filter> 
       <action android:name="android.appwidget.action.APPWIDGET_UPDATE" /> 
      </intent-filter> 

      <meta-data 
       android:name="android.appwidget.provider" 
       android:resource="@xml/widget_info" /> 
     </receiver> 
     <receiver 
      android:name="MyWidgetIntentReceiver" 
      android:exported="false" > 
      <intent-filter> 
       <action android:name="com.example.android.intent.action.CHANGE_PICTURE" /> 
      </intent-filter> 

      <meta-data 
       android:name="android.appwidget.provider" 
       android:resource="@xml/widget_info" /> 
     </receiver> 
    </application> 

</manifest> 

//MyWidgetProvider.java-這個類包含的onUpdate方法，有聽衆。

package com.example.android.pictureapp; 

import android.app.PendingIntent; 
import android.appwidget.AppWidgetManager; 
import android.appwidget.AppWidgetProvider; 
import android.content.ComponentName; 
import android.content.Context; 
import android.content.Intent; 
import android.util.Log; 
import android.widget.RemoteViews; 

import com.example.android.pictureapp.R; 

public class MyWidgetProvider extends AppWidgetProvider { 


    @Override 
    public void onUpdate(Context context, AppWidgetManager appWidgetManager,int[] appWidgetIds){ 

     //Log.i("Tag","In onUpdate method"); 
     System.out.println("Tag In onUpdate method"); 
     RemoteViews views=new RemoteViews(context.getPackageName(),R.layout.widget_layout); 
     views.setOnClickPendingIntent(R.id.widget_button, buildButtonPendingIntent(context)); 
     Log.i("Tag","Context value after setOnClickPI before pushWIDGET:"+context); 

     pushWidgetUpdate(context,views); 
     Log.i("Tag","after pushwidget update:"+context); 
    } 

    public static PendingIntent buildButtonPendingIntent(Context context){ 

     Intent intent=new Intent(); 
     intent.setAction("com.example.android.intent.action.CHANGE_PICTURE"); 

     Log.i("Tag","intent's action:"+intent); 
     return PendingIntent.getBroadcast(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT); 
    } 

    public static void pushWidgetUpdate(Context context,RemoteViews views){ 

     System.out.println("Inside pushwidget"); 
     ComponentName myWidget=new ComponentName(context, MyWidgetProvider.class); 
     AppWidgetManager manager=AppWidgetManager.getInstance(context); 
     manager.updateAppWidget(myWidget, views); 
    } 
} 

//MywidgetIntentReceiver.java - 此類包含onReceive方法並執行單擊後執行的函數。

package com.example.android.pictureapp; 

import com.example.android.pictureapp.R; 

import android.content.BroadcastReceiver; 
import android.content.Context; 
import android.content.Intent; 
import android.util.Log; 
import android.widget.RemoteViews; 

public class MyWidgetIntentReceiver extends BroadcastReceiver { 

    private static int clickCount = 0; 

    @Override 
    public void onReceive(Context context, Intent intent) { 

     // Log.i("Tag1","In onReceive:"+intent); 
     System.out.println("In onReceive()"); 

     if (intent.getAction().equals(
       "com.example.android.intent.action.CHANGE_PICTURE")) { 
      updateWidgetPictureAndButtonListener(context); 
     } 
    } 

    private void updateWidgetPictureAndButtonListener(Context context) { 

     RemoteViews views = new RemoteViews(context.getPackageName(), 
       R.layout.widget_layout); 
     views.setImageViewResource(R.id.widget_image, getImageToSet()); 

     System.out.println("in updateWidgetPicture method"); 
     // Log.i("Tag","in updaeWIdgetPicture method"); 
     // remember to set ur button click listeners 
     views.setOnClickPendingIntent(R.id.widget_button, 
       MyWidgetProvider.buildButtonPendingIntent(context)); 

     MyWidgetProvider.pushWidgetUpdate(context.getApplicationContext(), 
       views); 
    } 

    private int getImageToSet() { 
     clickCount++; 
     Log.i("Tag", "in getImageToSet()" + clickCount); 

     return clickCount % 2 == 0 ? R.drawable.paypal_logo : R.drawable.paypaldonation; 
    } 
} 

//layout/widget_layout.xml

<?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="wrap_content" 
    android:orientation="vertical" 
    android:layout_margin="5sp" 
    > 

    <ImageView 
     android:id="@+id/widget_image" 
     android:layout_width="110dp" 
     android:layout_height="110dp" 
     android:layout_gravity="center" 
     android:src="@drawable/paypal_logo" 
     /> 

    <Button 
     android:id="@+id/widget_button" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_gravity="center" 
     android:text="Change it" 
     /> 

</LinearLayout> 

//xml/widget_info.xml

<?xml version="1.0" encoding="utf-8"?> 
<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android" 
    android:minWidth="146dp" 
    android:minHeight="146dp" 
    android:updatePeriodMillis="5000" 
    android:initialLayout="@layout/widget_layout" 
    > 


</appwidget-provider> 

// MainACtivity

package com.example.android.pictureapp; 

import com.example.android.pictureapp.R; 

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

public class MainActivity extends Activity { 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     //setContentView(R.layout.activity_main); 
    } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     //getMenuInflater().inflate(R.menu.main, menu); 
     return true; 
    } 

} 

而這些變化到清單：

<activity 
      android:name="com.example.android.pictureapp.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> 

Answer 1

開始的Android 3.1，你的應用程序必須有一個用戶可以在啓動之前，它將接收任何廣播等

既然你沒有一個活動，Widget的廣播可能ISN至少一個活動」 t因爲系統認爲你的應用程序處於停止狀態而收到。嘗試添加一個活動。