Android小部件Widget开发过程中的坑和问题小结

概述

官方参考

Build an App Widget

效果图

放张效果图，这是我玩的桌面 app 文件夹

AndroidManifest.xml

Receiver

切记里面的字母不要弄错，最好复制粘贴再修改相对应自定义的地方就好，一个字母的错误搞了我一天，吐血

<receiver android:name=".desktop.DesktopWidget">
  <meta-data
    android:name="android.appwidget.provider"
    android:resource="@xml/widget_desktop_options" />
  <intent-filter>
    <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
  </intent-filter>
</receiver>

Service

如果小部件中使用到了列表项如 ListView，GridView 等，在绑定数据时需要使用 RemoteViewsService 并提供一个 RemoteViewsFactory 实例来填充数据 而非 Adapter
再提，这里面一定不能敲错字母，特别是那个 permission 也一定要有，不然无法绑定数据

<service
  android:name=".desktop.DesktopViewsService"
  android:permission="android.permission.BIND_REMOTEVIEWS" />

Options

res/xml/

widget_desktop_options.xml

<?xml version="1.0" encoding="utf-8"?>
<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
  android:minWidth="40dp"
  android:minHeight="40dp"
  android:initialLayout="@layout/widget_desktop"
  android:resizeMode="horizontal|vertical"
  android:widgetCategory="home_screen">
</appwidget-provider>

常用参数

Size

• 尺寸大小最终以单元格数据来显示，但定义时为 dp
• 单元格数转换基本工式 size = 70 x cells - 30
• 如：1格 = 70 x 1 - 30 = 40dp
• 最小尺寸定义时最好不要超过 4 个单元格就是 250dp

updatePeriodMillis

更新时间毫秒数，即间隔多少时间呼叫一次 onUpdate() 方法

initialLayout

加载布局文件

Using App Widgets with Collections

小部件中使用列表项

官方参考

Google Develper

AppWidgetProvider

public class DesktopWidget extends AppWidgetProvider {

  public String ACTION_START_ACTIVITY = "STARTACTIVITYACTION";

  public DesktopWidget() {
    super();
  }

  //当接收到广播的时候会被调用
  //onUpdate, onEnabled等时都会发送广播
  @Override
  public void onReceive(Context context, Intent intent) {
    super.onReceive(context, intent);
    pub.log("onReceive:" + intent.getAction());
    if (intent.getAction().equals(ACTION_START_ACTIVITY)) {
      String strPackage = intent.getStringExtra("app_package");
      Intent appIntent = context.getPackageManager().getLaunchIntentForPackage(strPackage);
      pub.log(appIntent.getPackage());
      if (appIntent != null) {
        appIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        pub.log("start activity");
        context.startActivity(appIntent);
        pub.log("finish");
      }
    }
  }

  //被添加或者被更新时调用
  @Override
  public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
    super.onUpdate(context, appWidgetManager, appWidgetIds);

    // There may be multiple widgets active, so update all of them
    for (int appWidgetId : appWidgetIds) {
      updateAppWidget(context, appWidgetManager, appWidgetId);
    }
  }
  private void updateAppWidget(Context context, AppWidgetManager appWidgetManager, int appWidgetId) {
    pub.log("onUpdate:" + appWidgetId);
    // Construct the RemoteViews object
    RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.widget_desktop);
    //设定小部件上 TextView 值
    //views.setTextViewText(R.id.tv_widget_desktop_title, "ZGTools");
    //setRemoteAdapter设定Listivew,Gridview等复杂布局的adapter
    //第一个参数为要绑定的widget的Gridview的id，第二个参数为RemoteViewsService的intent
    Intent intent = new Intent(context, DesktopViewsService.class);
    intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
    intent.setData(Uri.parse(intent.toUri(Intent.URI_INTENT_SCHEME)));
    views.setRemoteAdapter(R.id.gv_app_group, intent);

    //绑定 item 的定点事件
    //Activity方式测试不成功，改用广播的方式进行发送并执行事件
    //此处不能是空的Intent 否则广播无法发送
    //定义Intent事件模板，相当于公用设定，再在fillIntent里面设定具体的 extra 值
    Intent templateIntent = new Intent(context, DesktopWidget.class);
    templateIntent.setAction(ACTION_START_ACTIVITY);
    templateIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
    templateIntent.setData(Uri.parse(intent.toUri(Intent.URI_INTENT_SCHEME)));
    PendingIntent pendingIntent = PendingIntent.getBroadcast(context, appWidgetId, templateIntent, PendingIntent.FLAG_UPDATE_CURRENT);
    views.setPendingIntentTemplate(R.id.gv_app_group, pendingIntent);

    // Instruct the widget manager to update the widget
    appWidgetManager.updateAppWidget(appWidgetId, views);
  }

  //被添加或者更改大小时调用，在这个方法中可以选择性的根据界面大小显示或隐藏某些控件
  @Override
  public void onAppWidgetOptionsChanged(Context context, AppWidgetManager appWidgetManager, int appWidgetId, Bundle newOptions) {
    super.onAppWidgetOptionsChanged(context, appWidgetManager, appWidgetId, newOptions);
    updateAppWidget(context, appWidgetManager, appWidgetId);
  }
  @Override
  public void onEnabled(Context context) {
    super.onEnabled(context);
    // Enter relevant functionality for when the first widget is created
  }
  @Override
  public void onDisabled(Context context) {
    super.onDisabled(context);
    // Enter relevant functionality for when the last widget is disabled
  }
}

RemoteViewsService

public class DesktopViewsService extends RemoteViewsService {
  @Override
  public RemoteViewsFactory onGetViewFactory(Intent intent) {
    return new DesktopViewsFactory(this, intent);
  }
}

RemoteViewsFactory

类型于 BaseAdapter，重点是 onCreate() 加载数据， getViewAt() 方法返回布局绑定数据

public class DesktopViewsFactory implements RemoteViewsService.RemoteViewsFactory {
  private Context mContext;
  private int mAppWidgetId;
  private List<AppPackage> lstApps = new ArrayList<AppPackage>();

  public DesktopViewsFactory(Context context, Intent intent){
    this.mContext = context;
    this.mAppWidgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID);
  }

  @Override
  public void onCreate() {
    DesktopDbHelper dbHelper = new DesktopDbHelper(mContext);
    SQLiteDatabase db = dbHelper.getReadableDatabase();
    String strSql = "Select * from tb_app";
    try {
      Cursor cursor = db.rawQuery(strSql, null);
      if (cursor != null && cursor.getCount() > 0) {
      	lstApps.clear();
        while (cursor.moveToNext()) {
          byte[] blob = cursor.getBlob(cursor.getColumnIndex("app_icon"));
          Bitmap bmpIcon = BitmapFactory.decodeByteArray(blob, 0, blob.length);
          String strLabel = cursor.getString(cursor.getColumnIndex("app_label"));
          String strPackage = cursor.getString(cursor.getColumnIndex("app_package"));
          lstApps.add(new AppPackage(strLabel, strPackage, bmpIcon));
        }
      }
      if (cursor != null) {
        cursor.close();
      }
    } catch (Exception e) {
      db.close();
      e.printStackTrace();
    }
    db.close();
  }

  @Override
  public void onDataSetChanged() {
  	//这里我加了重新加载数据的调用，用于更新小部件的列表内容
		onCreate();
	}
  @Override
  public void onDestroy() {}
  @Override
  public int getCount() {return 0;}

  @Override
  public RemoteViews getViewAt(int i) {
    if (i < 0 || i >= lstApps.size()) return null;
    //Construct a remote views item based on the app widget item XML file
    RemoteViews views = new RemoteViews(mContext.getPackageName(), R.layout.widget_desktop_item);
    views.setTextViewText(R.id.tv_widget_desktop_label, lstApps.get(i).getAppLabel());
    views.setImageViewBitmap(R.id.iv_widget_desktop_icon, lstApps.get(i).getAppIcon());

    Intent intent = new Intent();
    Bundle bundle = new Bundle();
    bundle.putString("app_package", lstApps.get(i).getAppPackage());
    intent.putExtras(bundle);
    views.setOnClickFillInIntent(R.id.iv_widget_desktop_icon, intent);
    views.setOnClickFillInIntent(R.id.tv_widget_desktop_label, intent);

    return views;
  }

  @Override
  public RemoteViews getLoadingView() { return null;}
  @Override
  public int getViewTypeCount() {return 0;}
  @Override
  public long getItemId(int i) { return 0;}
  @Override
  public boolean hasStableIds() { return false; }
}

DesktopActivity

 //更新widget布局
  private void updateWidget(){
    AppWidgetManager widgetManager = AppWidgetManager.getInstance(this);
    ComponentName componentName = new ComponentName(this, DesktopWidget.class);
    int[] ids = widgetManager.getAppWidgetIds(componentName);
    widgetManager.notifyAppWidgetViewDataChanged(ids, R.id.gv_app_group);
  }

总结

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