Android实现带磁性的悬浮窗体效果

package com.manymore13.flowwindowdemo;
import android.content.Context;
import android.graphics.PixelFormat;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.WindowManager;
import android.view.WindowManager.LayoutParams;
import android.widget.ImageView;
/**
 * @author manymore13
 * @version 1.0
 */
public class FloatView extends ImageView{
  private float mTouchX;
  private float mTouchY;
  private float x;
  private float y;
  private int startX;
  private int startY;
  private Context c;
  private int imgId = R.drawable.ic_launcher;
  private int controlledSpace = 20;
  private int screenWidth;
  boolean isShow = false;
  private OnClickListener mClickListener;
  private WindowManager windowManager ;
  private WindowManager.LayoutParams windowManagerParams = new WindowManager.LayoutParams();
  public FloatView(Context context, AttributeSet attrs) {
    super(context, attrs);
  }
  public FloatView(Context c)
  {
    super(c);
    initView(c);
  }
  // 初始化窗体
  public void initView(Context c)
  {
    windowManager = (WindowManager) c.getApplicationContext().getSystemService(Context.WINDOW_SERVICE);
    screenWidth = windowManager.getDefaultDisplay().getWidth();
    this.setImageResource(imgId);
    windowManagerParams.type = LayoutParams.TYPE_PHONE;
    windowManagerParams.format = PixelFormat.RGBA_8888; // 背景透明
    windowManagerParams.flags = LayoutParams.FLAG_NOT_TOUCH_MODAL
        | LayoutParams.FLAG_NOT_FOCUSABLE;
    // 调整悬浮窗口至左上角，便于调整坐标
    windowManagerParams.gravity = Gravity.LEFT | Gravity.TOP;
    // 以屏幕左上角为原点，设置x、y初始值
    windowManagerParams.x = 0;
    windowManagerParams.y = 200;
    // 设置悬浮窗口长宽数据
    windowManagerParams.width = LayoutParams.WRAP_CONTENT;
    windowManagerParams.height = LayoutParams.WRAP_CONTENT;
  }
  public void setImgResource(int id)
  {
    imgId = id;
  }
  @Override
  public boolean onTouchEvent(MotionEvent event) {
    x = event.getRawX();
    y = event.getRawY();
    switch(event.getAction())
    {
      case MotionEvent.ACTION_DOWN:
      {
        mTouchX = event.getX();
        mTouchY = event.getY();
        startX = (int) event.getRawX();
        startY = (int) event.getRawY();
        break;
      }
      case MotionEvent.ACTION_MOVE:
      {
        updateViewPosition();
        break;
      }
      case MotionEvent.ACTION_UP:
      {
        if(Math.abs(x - startX) < controlledSpace && Math.abs(y - startY) < controlledSpace)
        {
          if(mClickListener != null)
          {
            mClickListener.onClick(this);
          }
        }
        Log.i("tag", "x="+x+" startX+"+startX+" y="+y+" startY="+startY);
        if(x <= screenWidth/2)
        {
          x = 0;
        }else{
          x = screenWidth;
        }
        updateViewPosition();
        break;
      }
    }
    return super.onTouchEvent(event);
  }
  // 隐藏该窗体
  public void hide()
  {
    if(isShow)
    {
      windowManager.removeView(this);
      isShow = false;
    }
  }
  // 显示该窗体
  public void show()
  {
    if(isShow == false)
    {
      windowManager.addView(this, windowManagerParams);
      isShow = true;
    }
  }
  @Override
  public void setOnClickListener(OnClickListener l) {
     this.mClickListener = l;
  }
  private void updateViewPosition() {
     // 更新浮动窗口位置参数
     windowManagerParams.x = (int) (x - mTouchX);
     windowManagerParams.y = (int) (y - mTouchY);
     windowManager.updateViewLayout(this, windowManagerParams); // 刷新显示
  }
}

public int getStatusBarHeight() {
    int titleBarHeight = 0;
    Rect frame = new Rect();
    mAct.getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);
    titleBarHeight = frame.top;
    if (titleBarHeight == 0) {
      int resourceId = getResources().getIdentifier("status_bar_height", "dimen", "android");
      if (resourceId > 0) {
        titleBarHeight = getResources().getDimensionPixelSize(resourceId);
      }
    }
    return titleBarHeight;
}