AppWidge的使用

AppWidget是在桌面上生成小图标的类

先来看看效果.（代码是在GitHub上下载下来的）
https://github.com/cstew/AppWidget.git

运行效果如下.

但是需要注意的是.要想显示AppWidget你得在桌面长按住。这样会弹出一个选项框.
选择Widget然后添加你的应用名.

1.首先你得要添加显示的ui.xml
 注意要添加的文件路径。看xml的话大概能的看得出来了.


2.要设置一个广播来通知显示.Intet-filter里是UPDATE那么更新的时候就会发送到该广播,


3.监听AppWidgetProvider

下面有一大堆代码.但这里用到的主要只是点是RemoteView与PendingIntent.
因为AppWidget跟应用的线程不一样.所以为了在其他线程里绘制UI所以需要使用到
RemoteView

public class AdvancedWidgetAppProvider extends AppWidgetProvider {

        

         private static final String SWITCH_ACTION_FAR = "com.bignerdranch.android.widgetapp.AdvancedWidgetAppProvider.switchActionFar";

         private static final String SWITCH_ACTION_CLOSE = "com.bignerdranch.android.widgetapp.AdvancedWidgetAppProvider.switchActionClose";

        

         @Override

         public void onReceive(Context context, Intent intent) {

                 

                  String action = intent.getAction();

                  if (SWITCH_ACTION_FAR.equals(action) || SWITCH_ACTION_CLOSE.equals(action)) {

                          

                           AppWidgetManager manager = AppWidgetManager.getInstance(context);

                           int appWidgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID);

                          

                           RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.widget_advanced_layout);

                          

                           boolean isFar = SWITCH_ACTION_FAR.equals(action);

                           views.setImageViewResource(R.id.widget_image, isFar? R.drawable.brian_the_human : R.drawable.brian_up_close);

                           manager.partiallyUpdateAppWidget(appWidgetId, views);

                  }

                 

                  super.onReceive(context, intent);

         }

        

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

        final int n = appWidgetIds.length;

        for (int i = 0; i < n; i++) {

            int appWidgetId = appWidgetIds[i];

            RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.widget_advanced_layout);

            views.setOnClickPendingIntent(R.id.widget_far_button, generatePendingIntent(context, SWITCH_ACTION_FAR, appWidgetId));

            views.setOnClickPendingIntent(R.id.widget_close_button, generatePendingIntent(context, SWITCH_ACTION_CLOSE, appWidgetId));

            appWidgetManager.updateAppWidget(appWidgetId, views);

        }

    }

        

         private PendingIntent generatePendingIntent(Context context, String action, int appWidgetId) {

                  Intent switchIntent = new Intent(context, AdvancedWidgetAppProvider.class);

        switchIntent.setAction(action);

        switchIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);

        return PendingIntent.getBroadcast(context, 0, switchIntent, PendingIntent.FLAG_UPDATE_CURRENT);

         }

}