Android实现触摸移动的悬浮窗口功能

<--! 说明一下，第一个权限是8.0之后悬浮窗窗口类型设置需要，第二个权限假如不加的话，我oppo手机跳转悬浮窗设置时，找不到这个app -->

package com.zh.pullrefresh;
 
import android.content.Context;
import android.graphics.PixelFormat;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.FrameLayout;
import android.widget.ImageView;
 
import androidx.annotation.NonNull;
 
public class SmallWindowsView extends FrameLayout {
 
  private int mSlop;//触发移动事件的最小距离
  private float downX;//手指放下去的x坐标
  private float downY;//手指放下去的Y坐标
  /**
   * 下面四个数据都为像素
   */
  private int screenWidth;//屏幕宽度
  private int screenHeight;//屏幕高度
  private int viewWidth;//小窗的宽度
  private int viewHeight;//小窗的高度
 
  private WindowManager wm;//窗口管理器，用来把view添加进窗口层
  private WindowManager.LayoutParams wmParams;
 
  public SmallWindowsView(@NonNull Context context) {
    super(context);
    init();
  }
 
  private void init() {
    ViewConfiguration vc = ViewConfiguration.get(getContext());
    mSlop = vc.getScaledTouchSlop();
    screenWidth = getContext().getResources().getDisplayMetrics().widthPixels;
    screenHeight = getContext().getResources().getDisplayMetrics().heightPixels;
    viewWidth = dp2px(getContext(), 130);
    viewHeight = dp2px(getContext(), 130);
 
    //可以根据你的实际情况在这个FrameLayout里添加界面控件之类的，
    // 我之前是用的实时音视频，把相关业务代码去掉了，直接放一个图标
    // 实际上就是拿到一个View从WindowManager给addView进去
    ImageView imageView = new ImageView(getContext());
    imageView.setImageResource(R.mipmap.ic_launcher);
    LayoutParams params = new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
        ViewGroup.LayoutParams.MATCH_PARENT);
    addView(imageView, params);
  }
 
  //dp转px
  public int dp2px(Context context, int dp) {
    return (int) (getDensity(context) * dp + 0.5);
  }
  public float getDensity(Context context) {
    return context.getResources().getDisplayMetrics().density;
  }
 
  public void show() {
    wm = (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE);
    wmParams = new WindowManager.LayoutParams(
        viewWidth, viewHeight,
        WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY,//8.0以上需要用这个权限
        WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
            | WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL,
        PixelFormat.TRANSLUCENT);
    wmParams.gravity = Gravity.NO_GRAVITY;
    wmParams.x = screenWidth/2 - viewWidth/2;
    wmParams.y = screenHeight/2 - viewHeight/2;
    wm.addView(this, wmParams);
  }
 
  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    //本来想在这边直接设置宽高，但是有问题
//    setMeasuredDimension(QMUIDisplayHelper.dp2px(getContext(), 130), QMUIDisplayHelper.dp2px(getContext(), 130));
  }
  //拦截触摸事件自己消费
  @Override
  public boolean onInterceptTouchEvent(MotionEvent ev) {
    return true;
  }
  private long downTime;
  private float lastMoveX;
  private float lastMoveY;
  //消费触摸事件
  @Override
  public boolean onTouchEvent(MotionEvent event) {
    switch (event.getAction()) {
      case MotionEvent.ACTION_DOWN:
        downX = event.getRawX();
        downY = event.getRawY();
        lastMoveX = downX;
        lastMoveY = downY;
        downTime = System.currentTimeMillis();
        break;
      case MotionEvent.ACTION_MOVE:
        float moveX = event.getRawX();
        float moveY = event.getRawY();
        //就两个坐标算他们距离要大于触发移动事件的最小距离
        //这里也可以减去lastMoveX lastMoveY 但是移动会有卡顿感 因此这里使用的还是downX downY
        if (Math.pow(Math.abs(moveX - downX), 2) + Math.pow(Math.abs(moveY - downY), 2) > Math.pow(mSlop, 2)) {
          updateViewPosition(moveX - lastMoveX, moveY - lastMoveY);
          lastMoveX = moveX;
          lastMoveY = moveY;
        }
 
        break;
      case MotionEvent.ACTION_UP:
        float upX = event.getRawX();
        float upY = event.getRawY();
        long upTime = System.currentTimeMillis();
        long time = upTime - downTime;
        //点击事件实现 点击小窗口消失
        //这里加了时间判断，是因为假如移动到原来的地方，也会触发成点击事件
        if (Math.pow(Math.abs(upX - downX), 2) + Math.pow(Math.abs(upY - downY), 2) 

@Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
 
    final SmallWindowsView smallWindowsView = new SmallWindowsView(getApplicationContext());
 
    Button btShowWindow = findViewById(R.id.bt_show_window);
    btShowWindow.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
        if (Build.VERSION.SDK_INT >= 23) {
          if (!(Settings.canDrawOverlays(MainActivity.this))) {
            Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION);
            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            startActivity(intent);
            return;
          }
        } else {
          if (!EasyPermissions.hasPermissions(MainActivity.this, Manifest.permission.SYSTEM_ALERT_WINDOW)) {
            EasyPermissions.requestPermissions(MainActivity.this, "需要权限用以展示悬浮窗",
                2048, Manifest.permission.SYSTEM_ALERT_WINDOW);
            return;
          }
        }
        smallWindowsView.show();
      }
    });
  }