启动APK的默认Activity

 public static void startApkActivity(final Context ctx, String packageName) {        PackageManager pm = ctx.getPackageManager();        PackageInfo pi;        try {            pi = pm.getPackageInfo(packageName, 0);            Intent intent = new Intent(Intent.ACTION_MAIN, null);            intent.addCategory(Intent.CATEGORY_LAUNCHER);            intent.setPackage(pi.packageName);            List<ResolveInfo> apps = pm.queryIntentActivities(intent, 0);            ResolveInfo ri = apps.iterator().next();            if (ri != null) {                String className = ri.activityInfo.name;                intent.setComponent(new ComponentName(packageName, className));                ctx.startActivity(intent);            }        } catch (NameNotFoundException e) {            Log.e("startActivity", e);        }    }