Android实现悬浮图片

@SuppressLint("AppCompatCustomView")
public class MoveImageView extends ImageView {

 //按下那一刻的坐标和 控件上下左右距离
 private float lastX;
 private float lastY;
 private int left;
 private int top;
 private int right;
 private int bottom;


 //如果是拖动事件就不用响应点击事件
 boolean isMove = false;
 boolean isAnimatoring = false;

 //屏幕宽高
 private int screenWidthPx;
 private int screenHeightPx;


 public MoveImageView(Context context) {
  this(context, null);
 }

 public MoveImageView(Context context, @Nullable AttributeSet attrs) {
  this(context, attrs, 0);
 }

 public MoveImageView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
  screenWidthPx = getScreenWidthPx(getContext());
  screenHeightPx = getScreenHeightPx(getContext());
 }

 @Override
 public boolean onTouchEvent(MotionEvent event) {
  switch (event.getAction()) {
   case MotionEvent.ACTION_DOWN:
    //动画执行过程中，不响应一切操作，
    // 这里相当于不让其走后面的MotionEvent.ACTION_MOVE:与MotionEvent.ACTION_UP:
    if (isAnimatoring) {
     return false;
    }
    lastX = event.getRawX();
    lastY = event.getRawY();
    left = getLeft();
    top = getTop();
    right = getRight();
    bottom = getBottom();
    break;
   case MotionEvent.ACTION_MOVE:
    isMove = true;
    float x = event.getRawX();
    float y = event.getRawY();


    int l = (int) (left + (x - lastX));
    int t = (int) (top + (y - lastY));
    int r = (int) (right + (x - lastX));
    int b = (int) (bottom + (y - lastY));
    layout(l, t, r, b);
    break;
   case MotionEvent.ACTION_UP:
    if (isMove) {
     //如果顶部拖出屏幕外面，回正
     if (getTop() < 0) {
      layout(getLeft(), 0, getRight(), getHeight());
     }

     //getBottom() 获取到的是 控件底部到父容器顶部的距离，所以需要减去状态栏的高度
     int bottomHeight = screenHeightPx - getStatusBarHeight(getContext());
     //如果底部拖出屏幕外面，回正
     if (getBottom() > bottomHeight) {
      layout(getLeft(), bottomHeight-getHeight(), getRight(), bottomHeight);
     }
     isMove = false;
     startAnimation();
     return true;
    }
    return super.onTouchEvent(event);
  }
  return super.onTouchEvent(event);
 }

 private void startAnimation() {

  isAnimatoring = true;

  //右边距
  int marinRight = DisplayUtils.dpToPx(20);
  int endValue = screenWidthPx - marinRight;
  ValueAnimator animator = ValueAnimator.ofInt(getRight(), endValue);

  animator.setDuration(Math.abs(endValue - getRight()) > 1000 ? 1000 : Math.abs(endValue - getRight()));

  animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
   @Override
   public void onAnimationUpdate(ValueAnimator animation) {
    int curValue = (int) animation.getAnimatedValue();
    layout(curValue - getWidth(), getTop(), curValue, getHeight() + getTop());
   }
  });
  animator.addListener(new AnimatorListenerAdapter() {
   @Override
   public void onAnimationStart(Animator animation) {

   }

   @Override
   public void onAnimationEnd(Animator animation) {
    isAnimatoring = false;
    animator.removeAllUpdateListeners();
    animator.removeAllListeners();
   }
  });
  animator.start();
 }

 /**
  * 获取状态栏高度
  */
 public static int getStatusBarHeight(Context context) {
  int result = 24;
  int resId = context.getResources().getIdentifier("status_bar_height", "dimen", "android");
  if (resId > 0) {
   result = context.getResources().getDimensionPixelSize(resId);
  } else {
   result = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,
     result, Resources.getSystem().getDisplayMetrics());
  }
  return result;
 }

 public static int getScreenWidthPx(Context context) {
  WindowManager windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
  DisplayMetrics dm = new DisplayMetrics();
  if (windowManager != null) {
//   windowManager.getDefaultDisplay().getMetrics(dm);
   windowManager.getDefaultDisplay().getRealMetrics(dm);
   return dm.widthPixels;
  }
  return 0;

 }

 public static int getScreenHeightPx(Context context) {
  WindowManager windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
  DisplayMetrics dm = new DisplayMetrics();
  if (windowManager != null) {
//   windowManager.getDefaultDisplay().getMetrics(dm);
   windowManager.getDefaultDisplay().getRealMetrics(dm);
   return dm.heightPixels;
  }
  return 0;

 }

}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 tools:context=".TestActivity">


 <com.lingtao.ltvideo.widgets.MoveImageView
  android:layout_width="50dp"
  android:id="@+id/MoveImageView"
  android:layout_height="50dp"
  android:layout_alignParentRight="true"
  android:layout_alignParentBottom="true"
  android:layout_marginBottom="100dp"
  android:layout_marginRight="20dp"
  android:src="#ff0000" />


</RelativeLayout>

public class TestActivity extends AppCompatActivity {

 private MoveImageView moveImageView;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_test2);
  moveImageView = ((MoveImageView) findViewById(R.id.MoveImageView));
  moveImageView.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View v) {
    Toast.makeText(TestActivity.this, "点击事件", Toast.LENGTH_SHORT).show();
   }
  });
 }
}