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

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

Options

res/xml/

widget_desktop_options.xml

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 lstApps = new ArrayList();

 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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