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;
    /**
     * 控件的宽高
     */
    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内容，希望对大家的学习有所帮助，也希望大家多多支持。