Android自定义View实现自动吸附功能

本文实例为大家分享了Android实现自动吸附功能的具体代码，供大家参考，具体内容如下

1.简述

最近开发app过程中要实现拖动view后要可以自动吸附功能，所以需要自定义view来在onTouchEvent中来利用动画来实现此功能

2.功能代码部分

import android.content.Context;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.animation.DecelerateInterpolator;
import android.widget.ImageView;

public class AdsorbentViews extends ImageView {
 
 private int maxWidth;
  private int maxHeight;
  private int viewWidth;
  private int viewHeight;
  private float downx;
  private float downy;
  private Context mContext;
  public CustomViews(Context context) {
    this(context, null);
  }
 
  public CustomViews(Context context, AttributeSet attrs) {
    this(context, attrs, 0);
  }
 
  public CustomViews(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    mContext = context;
  }
  @Override
  protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    DisplayMetrics outMetrics = new DisplayMetrics();
    WindowManager windowManager = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);
    windowManager.getDefaultDisplay().getRealMetrics(outMetrics);
    //屏幕的宽度
    maxWidth = outMetrics.widthPixels;
    //屏幕的高度
    maxHeight = outMetrics.heightPixels;
    
    viewWidth = canvas.getWidth();
    viewHeight = canvas.getHeight();
  }
  @Override
  public boolean onTouchEvent(MotionEvent event) {
    switch (event.getAction()) {
      case MotionEvent.ACTION_DOWN:
 clearAnimation();
 downx = event.getX();
 downy = event.getY();
 return true;
      case MotionEvent.ACTION_MOVE:
 float moveX = event.getRawX() - downx;
 float moveY = event.getRawY() - downy;
 moveX = moveX < 0 ? 0 : (moveX + viewWidth > maxWidth) ? (maxWidth - viewWidth) : moveX;
 moveY = moveY < 0 ? 0 : (moveY + viewHeight) > maxHeight ? (maxHeight - viewHeight) : moveY;
 this.setY(moveY);
 this.setX(moveX);
 return true;
      case MotionEvent.ACTION_UP:
 //做吸附效果
 float centerX = getX() + viewWidth / 2;
 if (centerX > maxWidth/2){
   //靠右吸附
   animate().setInterpolator(new DecelerateInterpolator())
.setDuration(500)
.x(maxWidth-viewWidth)
.y(maxHeight-viewHeight)
.start();
 }else {
   animate().setInterpolator(new DecelerateInterpolator())
.setDuration(500)
.x(0)
.y(maxHeight-viewHeight)
.start();
 }
 return true;
      default:
 return super.onTouchEvent(event);
    }
  }
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持考高分网。