在9.0上使用ContentObserver报错，Failed to find provider aaa for user 0; expected to find a valid ContentProvider for this authority
代码：

 //注册ContentObserver
 private void registerResolver(){
        ContentResolver resolver = MainActivity.this.getContentResolver();
        resolver.registerContentObserver(Uri.parse("Content://com.qrscan.test"),true,myContentObserver);
 }

 // 数据变化通知
 public void dataChange(){
       MainActivity.this.getContentResolver().notifyChange(Uri.parse("Content://com.qrscan.test"),null);
 }

//数据变化处理
 private ContentObserver myContentObserver = new ContentObserver(new Handler()) {
        @Override
        public void onChange(boolean selfChange) {
            super.onChange(selfChange);
            Message message = Message.obtain();
            message.what = SCANDATA_CALLBACK;
            message.obj = "数据有变化";
            mHandler.sendMessage(message);
        } 
 };

 private Handler mHandler = new Handler(new Handler.Callback() {
        @Override
        public boolean handleMessage(Message msg) {
            if (msg.what == SCANDATA_CALLBACK){
                Toast.makeText(MainActivity.this," "+msg.obj.toString(),Toast.LENGTH_SHORT).show();
            }
            return true;
        }
});

上面代码直接报错，需要添加如下代码

1.添加一个类继承ContentProvider
2.在AndroidManifest.xml中添加

 <provider
       android:authorities="com.qrscan.test"
       android:name=".MyProvider"
       android:enabled="true"
       android:exported="true"/>

authorities 这个可以值随便，但是为了区分还是用包名，使用的Uri也必须是和这个authorities值一致