android appwidget笔记

一：实现一个Activity配置widget

（1）：在widget配置文件中加入如下代码：

<span style="white-space:pre"><appwidget-provider
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:minWidth="250dp"
  android:minHeight="180dp"
  android:updatePeriodMillis="0"
  android:initialLayout="@layout/widget_layout"
  android:resizeMode="vertical"
  android:configure="xx.widgets.ExampleAppWidgetConfigure"
  android:previewImage="@drawable/ic_launcher">
</appwidget-provider></span>

（2）：在Activity中加入如下代码：

Intent launchIntent = getIntent();
Bundle extras = launchIntent.getExtras();
if (extras != null) {

    appWidgetId = extras.getInt(AppWidgetManager.EXTRA_APPWIDGET_ID,AppWidgetManager.INVALID_APPWIDGET_ID);
    Intent cancelResultValue = new Intent();
    cancelResultValue.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID,appWidgetId);
    //未配置完成返回结果
    setResult(RESULT_CANCELED, cancelResultValue);
} else {
    // only launch if it's for configuration
    // Note: when you launch for debugging, this does prevent this
    // activity from running. We could also turn off the intent
    // filtering for main activity.
    // But, to debug this activity, we can also just comment the
    // following line out.
    finish();
}

if (appWidgetId != AppWidgetManager.INVALID_APPWIDGET_ID)
{

    Intent resultValue = new Intent();
    resultValue.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID,appWidgetId);
    //配置完成返回结果
    setResult(RESULT_OK, resultValue);

}

二：如何在RemoteViews中使用ListView

（1）：通过RemoteViewsService 渲染器实现

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import android.annotation.SuppressLint;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.IBinder;
import android.os.Looper;
import android.widget.RemoteViews;
import android.widget.RemoteViewsService;
public class UpdateService extends RemoteViewsService {

    @Override
    public void onStart(Intent intent, int startId) {

        super.onCreate();
    }

    @Override
    public IBinder onBind(Intent intent) {
        return super.onBind(intent);
    }

    @Override
    public RemoteViewsFactory onGetViewFactory(Intent intent) {
        return new ListRemoteViewsFactory(this.getApplicationContext(), intent);
    }


    class ListRemoteViewsFactory implements
            RemoteViewsService.RemoteViewsFactory {

        private final Context mContext;
        private final List<String> mList;

        public ListRemoteViewsFactory(Context context, Intent intent) {
            mContext = context;
            mList = getDataSources();//获取数据源
            if (Looper.myLooper() == null) {
                Looper.prepare();
            }
        }

        @Override
        public void onCreate() {

        }


        @Override
        public void onDataSetChanged() {

        }

        @Override
        public void onDestroy() {

            mList.clear();
        }

        @Override
        public int getCount() {

            return mList.size();
        }

        @Override
        public RemoteViews getViewAt(int position) {
            if (position < 0 || position >= mList.size())
                return null;
            String content = mList.get(position);
            final RemoteViews rv = new RemoteViews(mContext.getPackageName(),
                    R.layout.row);
            Intent intent = new Intent();
            // TODO
            // intent.setComponent(new ComponentName("包名", "类名"));
            // 与CustomWidget中remoteViews.setPendingIntentTemplate配对使用实现ListView中的Item的点击事件
            rv.setOnClickFillInIntent(R.id.widget_list_item_layout, intent);
            rv.setTextViewText(android.R.id.text1, content);

            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;
        }
    }

    public List<String>getDataSources() {
        List<String> list = new ArrayList<String>();
        ......
        return list;
    }
}

（2）：在widget的onUpdate中添加代码：

for (int i = 0; i < appWidgetIds.length; i++) {//如果使用循环，当调试重新运行程序或者重启机器时widget点击事情会失灵
        Intent intent = new Intent(ctxt, WidgetService.class);
        RemoteViews widget = new RemoteViews(ctxt.getPackageName(),
                R.layout.widget);
        widget.setRemoteAdapter(appWidgetIds[i], R.id.words, intent);

        Intent clickIntent = new Intent(ctxt, LoremActivity.class);
        PendingIntent clickPI = PendingIntent.getActivity(ctxt, 0,
                clickIntent, PendingIntent.FLAG_UPDATE_CURRENT);
        widget.setPendingIntentTemplate(R.id.words, clickPI);//配合getViewAt方法中的setOnClickFillInIntent实现listView中Item的点击事件

        appWidgetManager.updateAppWidget(appWidgetIds[i], widget);
    }

（3）：widget.xml

<?xml version="1.0" encoding="utf-8"?>
<ListView xmlns:android="http://schemas.android.com/apk/res/android"
  android:id="@+id/words"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:layout_marginTop="3dp"
  android:layout_marginLeft="3dp"
  android:background="@drawable/widget_frame"
/>

（4）：row.xml

<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@android:id/text1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:gravity="center_vertical"
    android:paddingLeft="6dip"
    android:minHeight="?android:attr/listPreferredItemHeight"
/>

三：如何更新widget

（1）：定时更新

在widget配置文件中有这句 android:updatePeriodMillis="0"，这种更新方式已经不能使用了，一般定时更新使用AlarmManager，如下代码

private void setAlarm(Context context, int appWidgetId, int updateRateSeconds) {
      Intent widgetUpdate = new Intent();
      widgetUpdate.setAction(AppWidgetManager.ACTION_APPWIDGET_UPDATE);
      widgetUpdate.putExtra(AppWidgetManager.EXTRA_APPWIDGET_IDS, new int[] { appWidgetId });

      // make this pending intent unique by adding a scheme to it
      widgetUpdate.setData(Uri.withAppendedPath(Uri.parse(ImagesWidgetProvider.URI_SCHEME + "://widget/id/"), String.valueOf(appWidgetId)));
      PendingIntent newPending = PendingIntent.getBroadcast(context, 0, widgetUpdate, PendingIntent.FLAG_UPDATE_CURRENT);

      // schedule the updating
      AlarmManager alarms = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
      if (updateRateSeconds >= 0) {
          alarms.setRepeating(AlarmManager.ELAPSED_REALTIME, SystemClock.elapsedRealtime(), updateRateSeconds * 1000, newPending);
      } else {
          alarms.cancel(newPending);
      }
  }

（2）：事件更新，不通过时间更新widget一般使用广播来更新

public void onReceive(Context context, Intent intent) {
        // TODO Auto-generated method stub
        if (intent.getAction().equals(
                "com.example.widgettestone.WIDGET_CONTROL")) {
            AppWidgetManager manager = AppWidgetManager.getInstance(context);
            ComponentName thisWidget = new ComponentName(context, TaskPad.class);
            int[] appWidgetIds = manager.getAppWidgetIds(thisWidget);
            manager.notifyAppWidgetViewDataChanged(appWidgetIds,R.id.widget_list);//通知RemoteViews刷新数据，在渲染器中重写onDataSetChanged方法重写获取数据源
        } else {
            super.onReceive(context, intent);
        }

    }

AndroidManifest.xml中widget的配置中添加：

<action android:name="com.example.widgettestone.WIDGET_CONTROL" />

当需要更新的时候发出该广播即可更新：

Intent intentUpdate = new Intent("com.example.widgettestone.WIDGET_CONTROL");
pan style="white-space:pre">        </span>context.sendBroadcast(intentUpdate);

四：小问题：

（1）：ListView的getview()中重复调用（position重复调用）问题：

网友提供的解决方法：

重写的listview adapter中，在getView()方法中，打印语句时，相同的position打印了多次，修改方法：
将布局文件中ListView的高度改为“fill_parent”
 <ListView
   android:id="@+id/dynamic_list"
   android:layout_height="fill_parent"
   android:layout_width="fill_parent"
   android:scrollbars="vertical"
   android:layout_weight="1"
   android:drawSelectorOnTop="false"
   android:fadingEdgeLength="0dip"
   android:divider="@null"
   android:dividerHeight="0dip"
   android:cacheColorHint="#00000000"
   android:background="@color/listview_bg_color" />

原文：http://blog.csdn.net/limitemp/article/details/9101763