【Android】setText调用导致的悬浮窗抖动问题

在Android13中，有这么一个bug，写一个可以拖到的悬浮窗，这个悬浮窗里有TextView，在拖到某个位置后，再调用TextView的setText方法，会发现出现了一个窗口动画，悬浮窗跳到了起始位置，从开始的位置又滑动到当前位置，看起来就是出现了一个跳动。

试验例子

package com.example.testfloatview;import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.graphics.PixelFormat;
import android.os.Build;
import android.os.Handler;
import android.os.IBinder;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowManager;
import android.widget.TextView;public class FloatWindowService extends Service {private WindowManager windowManager;private View floatView;private TextView textView;// 记录手指按下时的初始位置private int initialX, initialY;// 记录悬浮窗的初始位置private int initialWindowX, initialWindowY;@Overridepublic IBinder onBind(Intent intent) {return null;}@Overridepublic void onCreate() {super.onCreate();// 初始化 WindowManagerwindowManager = (WindowManager) getSystemService(Context.WINDOW_SERVICE);// 加载布局文件LayoutInflater inflater = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);floatView = inflater.inflate(R.layout.float_window_layout, null);// 获取TextView控件textView = floatView.findViewById(R.id.text_view);// 设置初始文本textView.setText("hello, this is a test");// 创建 WindowManager.LayoutParamsWindowManager.LayoutParams params = new WindowManager.LayoutParams(WindowManager.LayoutParams.WRAP_CONTENT,WindowManager.LayoutParams.WRAP_CONTENT,Build.VERSION.SDK_INT >= Build.VERSION_CODES.O ?WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY :WindowManager.LayoutParams.TYPE_PHONE,WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,PixelFormat.TRANSLUCENT);// 设置悬浮窗位置params.gravity = Gravity.TOP | Gravity.START;params.x = 0;params.y = 100;params.windowAnimations = 0;// 添加悬浮窗到窗口管理器windowManager.addView(floatView, params);// 设置触摸事件监听器floatView.setOnTouchListener(new View.OnTouchListener() {private int initialTouchX, initialTouchY;@Overridepublic boolean onTouch(View v, MotionEvent event) {switch (event.getAction()) {case MotionEvent.ACTION_DOWN:// 记录初始位置initialX = params.x;initialY = params.y;initialTouchX = (int) event.getRawX();initialTouchY = (int) event.getRawY();break;case MotionEvent.ACTION_MOVE:// 计算新的位置params.x = initialX + (int) (event.getRawX() - initialTouchX);params.y = initialY + (int) (event.getRawY() - initialTouchY);// 更新悬浮窗位置windowManager.updateViewLayout(floatView, params);break;case MotionEvent.ACTION_UP:floatView.invalidate();textView.setText("hello");//       textView.setText("hello, this is a test");break;default:break;}return true; // 消费触摸事件}});// 使用Handler延迟5秒后更新文本new Handler().postDelayed(() -> {//     textView.setText("hello world");//     textView.setText("hello, this is a tttt");textView.setText("hello");}, 5000);}@Overridepublic void onDestroy() {super.onDestroy();// 移除悬浮窗if (floatView != null && windowManager != null) {windowManager.removeView(floatView);}}
}

package com.example.testfloatview;import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.provider.Settings;
import android.view.View;
import android.widget.Toast;public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View view) {// 检查是否已经有悬浮窗权限if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {if (!Settings.canDrawOverlays(MainActivity.this)) {// 如果没有权限，跳转到系统设置页面申请权限Toast.makeText(MainActivity.this, "需要悬浮窗权限！", Toast.LENGTH_SHORT).show();Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION,Uri.parse("package:" + getPackageName()));startActivityForResult(intent, 1);} else {// 已经有权限，启动悬浮窗服务startService(new Intent(MainActivity.this, FloatWindowService.class));finish(); // 关闭主Activity}} else {// 启动悬浮窗服务（低版本设备不需要权限）startService(new Intent(MainActivity.this, FloatWindowService.class));finish(); // 关闭主Activity}}});}@Overrideprotected void onActivityResult(int requestCode, int resultCode, Intent data) {super.onActivityResult(requestCode, resultCode, data);if (requestCode == 1) {if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {if (Settings.canDrawOverlays(this)) {// 用户授予了权限，启动悬浮窗服务startService(new Intent(this, FloatWindowService.class));finish(); // 关闭主Activity} else {Toast.makeText(this, "未获得悬浮窗权限！", Toast.LENGTH_SHORT).show();}}}}
}

在开发者选项里，关闭掉 窗口动画缩放，就没有这个跳动问题了，所以这应该是窗口动画的bug，在调用setText的过程中，view的测量，布局中触发了窗口动画，并且使用了最初的坐标，大致是这样的思路。