带数据集的桌面控件

StackWidgetProvider.java

public class StackWidgetProvider extends AppWidgetProvider
{
    public static final String TOAST_ACTION
            = "org.crazyit.desktop.TOAST_ACTION";
    public static final String EXTRA_ITEM
            = "org.crazyit.desktop.EXTRA_ITEM";
    @Override
    public void onUpdate(Context context,
                         AppWidgetManager appWidgetManager, int[] appWidgetIds)
    {
        // 创建RemoteViews对象，加载/res/layout目录下的widget_layout.xml文件
        RemoteViews rv = new RemoteViews(context.getPackageName(),
                R.layout.widget_layout);
        Intent intent = new Intent(context, StackWidgetService.class);
        // 使用intent更新rv中的stack_view组件（StackView）
        rv.setRemoteAdapter(R.id.stack_view, intent);  // ①
        // 设置当StackWidgetService提供的列表项为空时，直接显示empty_view组件
        rv.setEmptyView(R.id.stack_view, R.id.empty_view);
        // 创建启动StackWidgetProvider组件（作为BroadcastReceiver）的Intent
        Intent toastIntent = new Intent(context,
                StackWidgetProvider.class);
        // 为该Intent设置Action属性
        toastIntent.setAction(StackWidgetProvider.TOAST_ACTION);
        // 将Intent包装成PendingIntent
        PendingIntent toastPendingIntent = PendingIntent
                .getBroadcast(context, 0, toastIntent,
                        PendingIntent.FLAG_UPDATE_CURRENT);
        // 将PendingIntent与stack_view进行关联
        rv.setPendingIntentTemplate(R.id.stack_view,
                toastPendingIntent);
        // 使用AppWidgetManager通过RemteViews更新AppWidgetProvider
        appWidgetManager.updateAppWidget(
                new ComponentName(context, StackWidgetProvider.class), rv); // ②
        super.onUpdate(context, appWidgetManager, appWidgetIds);
    }
    @Override
    public void onDeleted(Context context, int[] appWidgetIds)
    {
        super.onDeleted(context, appWidgetIds);
    }

    @Override
    public void onDisabled(Context context)
    {
        super.onDisabled(context);
    }
    @Override
    public void onEnabled(Context context)
    {
        super.onEnabled(context);
    }
    // 重写该方法，将该组件当成BroadcastReceiver使用
    @Override
    public void onReceive(Context context, Intent intent)
    {
        if (intent.getAction().equals(TOAST_ACTION))
        {
            // 获取Intent中的数据
            int viewIndex = intent.getIntExtra(EXTRA_ITEM, 0);
            // 显示Toast提示
            Toast.makeText(context, "点击第【" + viewIndex + "】个列表项",
                    Toast.LENGTH_SHORT).show();
        }
        super.onReceive(context, intent);
    }
}

widget_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_margin="8dp">
    <StackView
        android:id="@+id/stack_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:loopViews="true" />
    <TextView
        android:id="@+id/empty_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:background="#ff0f"
        android:textColor="#ffffff"
        android:textStyle="bold"
        android:text="@string/no_item"
        android:textSize="20sp" />
</FrameLayout>

widgrt_item.xml

<?xml version="1.0" encoding="utf-8"?>
<ImageView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/widget_item"
    android:layout_width="120dp"
    android:layout_height="120dp"
    android:gravity="center"/>

StackWidgetService.java

public class StackWidgetService extends RemoteViewsService
{
    // 重写该方法，该方法返回一个RemoteViewsFactory对象
    // RemoteViewsFactory对象的作用类似于Adapter
    // 它负责为RemoteView中的指定组件提供多个列表项
    @Override
    public RemoteViewsFactory onGetViewFactory(Intent intent)
    {
        return new StackRemoteViewsFactory(this.getApplicationContext(),
            intent);  // ①
    }
    class StackRemoteViewsFactory implements
            RemoteViewsService.RemoteViewsFactory
    {
        // 定义一个数组来保存该组件生成的多个列表项
        private int[] items = null;
        private Context mContext;
        public StackRemoteViewsFactory(Context context, Intent intent)
        {
            mContext = context;
        }
        @Override
        public void onCreate()
        {
            // 初始化items数组
            items = new int[] { R.drawable.bomb5, R.drawable.bomb6,
                    R.drawable.bomb7, R.drawable.bomb8, R.drawable.bomb9,
                    R.drawable.bomb10, R.drawable.bomb11, R.drawable.bomb12,
                    R.drawable.bomb13, R.drawable.bomb14, R.drawable.bomb15,
                    R.drawable.bomb16
            };
        }
        @Override
        public void onDestroy()
        {
            items = null;
        }
        // 该方法的返回值控制该对象包含多少个列表项
        @Override
        public int getCount()
        {
            return items.length;
        }
        // 该方法的返回值控制各位置所显示的RemoteViews
        @Override
        public RemoteViews getViewAt(int position)
        {
            // 创建RemoteViews对象，加载/res/layout目录下的widget_item.xml文件
            RemoteViews rv = new RemoteViews(mContext.getPackageName(),
                    R.layout.widget_item);
            // 更新widget_item.xml布局文件中的widget_item组件
            rv.setImageViewResource(R.id.widget_item,
                    items[position]);
            // 创建Intent、用于传递数据
            Intent fillInIntent = new Intent();
            fillInIntent.putExtra(StackWidgetProvider.EXTRA_ITEM, position);
            // 设置当单击该RemoteViews时传递fillInIntent包含的数据
            rv.setOnClickFillInIntent(R.id.widget_item, fillInIntent);
            // 此处让线程暂停0.5秒来模拟加载该组件
            try
            {
                System.out.println("加载【" + position + "】位置的组件");
                Thread.sleep(500);
            }
            catch (InterruptedException e)
            {
                e.printStackTrace();
            }
            return rv;
        }
        @Override
        public RemoteViews getLoadingView()
        {
            return null;
        }
        @Override
        public int getViewTypeCount()
        {
            return 1;
        }
        @Override
        public long getItemId(int position)
        {
            return position;
        }
        @Override
        public boolean hasStableIds()
        {
            return true;
        }
        @Override
        public void onDataSetChanged()
        {
        }
    }
}

Manifest.xml

       <!-- 配置AppWidgetProvider，即配置桌面控件 -->
        <receiver android:name=".StackWidgetProvider">

            <!-- 通过该intent-filter指定该Receiver作为桌面控件 -->
            <intent-filter>
                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
            </intent-filter>
            <!-- 为桌面控件指定meta-data -->
            <meta-data
                android:name="android.appwidget.provider"
                android:resource="@xml/stackwidgetinfo" />
        </receiver>
        <!--
        配置RemoteViewsService
        必须指定权限为android.permission.BIND_REMOTEVIEWS
        -->
        <service
            android:name=".StackWidgetService"
            android:exported="false"
            android:permission="android.permission.BIND_REMOTEVIEWS" />

stackwidgetinfo.xml

<?xml version="1.0" encoding="utf-8"?>
<appwidget-provider
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:minWidth="110dp"
    android:minHeight="110dp"
    android:updatePeriodMillis="3600000"
    android:previewImage="@drawable/ic_launcher"
    android:initialLayout="@layout/widget_layout"
    android:resizeMode="horizontal|vertical"
    android:autoAdvanceViewId="@id/stack_view">
</appwidget-provider>