Android小部件Widget开发过程中的坑和总结

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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);
    }