Why does the same code display different results on different versions of Android phones?

Question

I wrote an AccessibilityService service to control WeChat. But in the subsequent process, I encountered the following situation: some codes ran differently on an Android 4.4 machine (phone A, Huawei Honor 6, Android 4.4) and on an Android 7.0 machine (phone B, Huawei P9). Same, so 2 problems arise.

1. Run the AccessibilityService code on the mobile phone, which has the following two lines:

Log.d(TAG, "获取事件-->Log.d" + event);
Log.w(TAG, "获取事件-->Log.w" + event);

On mobile phone A, LogCat can display two Logs, but on mobile phone B, it can only display one Log.

2. When obtaining the window node:

 AccessibilityNodeInfo nodeInfo = getRootInActiveWindow();
        if(nodeInfo == null) {
            Log.w(TAG, "rootWindow为空");
            return ;
        }

On mobile phone A (Huawei Honor 6, Android 4.4), the node information of WeChat (com.tencent.mm) can be obtained, but on mobile phone B (Huawei P9, Android 7.0), the system interface (ui. laucher) node information. Very confused.

---

All codes are as follows:

public class AcceServ  extends AccessibilityService {

    private String TAG = getClass().getSimpleName();
    private  boolean  isFinish = false;
    private int index = 1;

    protected void onServiceConnected()
    {

        super.onServiceConnected();
        Log.d(TAG, "onServiceConnected！" );
        Log.w(TAG, "onServiceConnected！" );
        Toast.makeText(AcceServ.this,"连接服务成功。请开启AcceServ", Toast.LENGTH_LONG).show();}
    
    @Override
    public void onAccessibilityEvent(AccessibilityEvent event) {
        final int eventType = event.getEventType();
        Log.d(TAG, "获取事件-->" + event);
        Log.w(TAG, "获取事件-->" + event);

        AccessibilityNodeInfo nodeInfo = getRootInActiveWindow();
        if(nodeInfo == null) {
            Log.w(TAG, "rootWindow为空");
            return ;}
                do_some_thing();}

    @Override
    public void onInterrupt() {}
  
}

Answer 1

It shouldn’t be a problem with your code. Many things have been changed in each company’s UI System, so it’s impossible to know the real situation.

Answer 2

Thanks for the invitation.
I have never played with the AccessibilityService service. I want to say:
1. Do I need to enable permissions? First go to the permission management to see if the permissions are enabled.
2. Same as above, it may be a ROM problem.