用户第一次拖动widget到桌面上，不用授权提示，直接安装

做sp31项目时测试这边提出一个要求，

手机添加小部件时弹出对话框"是否允许launcher3创建小部件并查看其数据"，建议去除该对话框

看了两天代码，结果只要加一行代码就能解决问题了。解决方法如下： 在Launcher.java里 函数

   void addAppWidgetFromDrop(PendingAddWidgetInfo info, long container, long screenId,
            int[] cell, int[] span, int[] loc) {
        if (LauncherLog.DEBUG) {
            LauncherLog.d(TAG, "addAppWidgetFromDrop: info = " + info + ", container = " + container + ", screenId = "
                    + screenId);
        }


        resetAddInfo();
        mPendingAddInfo.container = info.container = container;
        mPendingAddInfo.screenId = info.screenId = screenId;
        mPendingAddInfo.dropPos = loc;
        mPendingAddInfo.minSpanX = info.minSpanX;
        mPendingAddInfo.minSpanY = info.minSpanY;


        if (cell != null) {
            mPendingAddInfo.cellX = cell[0];
            mPendingAddInfo.cellY = cell[1];
        }
        if (span != null) {
            mPendingAddInfo.spanX = span[0];
            mPendingAddInfo.spanY = span[1];
        }


        AppWidgetHostView hostView = info.boundWidget;
        int appWidgetId;
        if (hostView != null) {
            appWidgetId = hostView.getAppWidgetId();
            addAppWidgetImpl(appWidgetId, info, hostView, info.info);
        } else {
            // In this case, we either need to start an activity to get permission to bind
            // the widget, or we need to start an activity to configure the widget, or both.
            appWidgetId = getAppWidgetHost().allocateAppWidgetId();
            Bundle options = info.bindOptions;


            boolean success = false;
            mAppWidgetManager.setBindAppWidgetPermission(this.getPackageName(), true);   //txk add 


            if (options != null) {
                success = mAppWidgetManager.bindAppWidgetIdIfAllowed(appWidgetId,
                        info.componentName, options);
            } else {
                success = mAppWidgetManager.bindAppWidgetIdIfAllowed(appWidgetId,
                        info.componentName);
            }
           
            if (success) {
                addAppWidgetImpl(appWidgetId, info, null, info.info);
            } else {


                /* 当用户第一次添加widget的时候会走到这里，弹出一个提示框让用户授权。为了不让代码走到这里，只要在
                 * mAppWidgetManager.bindAppWidgetIdIfAllowed(……)之前提前授权就好了。添加一行授权代码
                 * 
                 * mAppWidgetManager.setBindAppWidgetPermission(this.getPackageName(), true);    
                 *
                 * 但是需要在Launcher3的AndroidManifest.xml里添加相应权限
                 * <uses-permission android:name="android.permission.MODIFY_APPWIDGET_BIND_PERMISSIONS"/>
                 * 而这个权限是系统级权限，所以还需要把Launcher3改为系统级应用，在AndroidManifest.xml添加
                 *  android:sharedUserId="android.uid.system" 这个标签
                 *  还需要在Android.mk里 把LOCAL_CERTIFICATE := shared 改为LOCAL_CERTIFICATE := platform
                 */
                
                mPendingAddWidgetInfo = info.info;
                Intent intent = new Intent(AppWidgetManager.ACTION_APPWIDGET_BIND);
                intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
                intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_PROVIDER, info.componentName);
                // TODO: we need to make sure that this accounts for the options bundle.
                // intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_OPTIONS, options);
                startActivityForResult(intent, REQUEST_BIND_APPWIDGET);

            }




        }
    }

AndroidManifest.xml

<manifest
    xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.android.launcher3"
    android:sharedUserId="android.uid.system" >
    <uses-sdk android:targetSdkVersion="21" android:minSdkVersion="16"/>
     ………………
    <!-- xuankai.tang add 2015.5.20 start--> 
    <uses-permission android:name="android.permission.MODIFY_APPWIDGET_BIND_PERMISSIONS"/>
    <!-- xuankai.tang add 2015.5.20 end -->
    ………………
</manifest>