本文例項為大家分享了Android實現自動吸附功能的具體程式碼，供大家參考，具體內容如下

1.簡述

最近開發app過程中要實現拖動view後要可以自動吸附功能，所以需要自定義view來在onTouchEvent中來利用動畫來實現此功能

2.功能程式碼部分

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,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);
    //螢幕的寬度
    maxWidth = outMetrics.widthPixels;
    //螢幕的高度
    maxHeight = outMetrics.heightPixels;
    /**
     * 控制元件的寬高
     */
    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內容，希望對大家的學習有所幫助，也希望大家多多支援我們。