如何判断应用已经安装，如何判断Service，BroastCastReceiver，ContentProvider是否存在

//判断BroadCastReceiver是否存在
PackageManager manager =  getPackageManager();
//要查找的BroadCastReceiver
Intent intent = new Intent("com.xiaoqiu.Action.XXXXX");

List<ResolveInfo> resolveInfos = manager.queryBroadcastReceivers(intent,
PackageManager.GET_INTENT_FILTERS);

if (resolveInfos.size() == 0) {
Log.d("debug", "该BroadCast不存在");
}

//判断包含某个Action的Activity的应用已经安装
Intent i = new Intent("com.xiaoqiu.phone.action.WAKAKA");
List<ResolveInfo> resolveInfos1 = manager.queryIntentActivities(intent,
PackageManager.GET_INTENT_FILTERS);
if (resolveInfos.size() == 0) {
Log.d("debug", "该应用没有安装");
}

//判断AIDL Service是否存在
if (!bindService(new Intent("com.xiaoqiu.service"), serviceConnection, Context.BIND_AUTO_CREATE))
{
Log.d("debug", "不存在");
}

//判断指定的ContentProvider是否存在
Uri uri = Uri.parse("content://mobile.android.regincontentprovider/cities");
Cursor cursor = getContentResolver().query(uri, new String[]{"city_code as _id", "city_name"},
null, null, null);
if (cursor == null) {
Log.d("debug", "不存在");
}