var startPoint
Page({
  data: {
    //按钮位置参数
    buttonTop: 0,
    buttonLeft: 0,
    windowHeight: '',
    windowWidth: '',
    //角标显示数字
    corner_data:0,
  },
  onLoad:function(){
    //定义角标数字
    this.setData({
      corner_data:3
    })
    
    var that =this;
    wx.getSystemInfo({
      success: function (res) {
        console.log(res);
        // 屏幕宽度、高度
        console.log('height=' + res.windowHeight);
        console.log('width=' + res.windowWidth);
        // 高度,宽度 单位为px
        that.setData({
          windowHeight:  res.windowHeight,
          windowWidth:  res.windowWidth,
          buttonTop:res.windowHeight*0.70,//这里定义按钮的初始位置
          buttonLeft:res.windowWidth*0.70,//这里定义按钮的初始位置
        })
      }
    })
  },
 
  //以下是按钮拖动事件
  buttonStart: function (e) {
    startPoint = e.touches[0]//获取拖动开始点
  },
  buttonMove: function (e) {
    var endPoint = e.touches[e.touches.length - 1]//获取拖动结束点
    //计算在X轴上拖动的距离和在Y轴上拖动的距离
    var translateX = endPoint.clientX - startPoint.clientX
    var translateY = endPoint.clientY - startPoint.clientY
    startPoint = endPoint//重置开始位置
    var buttonTop = this.data.buttonTop + translateY
    var buttonLeft = this.data.buttonLeft + translateX
    //判断是移动否超出屏幕
    if (buttonLeft+50 >= this.data.windowWidth){
      buttonLeft = this.data.windowWidth-50;
    }
    if (buttonLeft<=0){
      buttonLeft=0;
    }
    if (buttonTop<=0){
      buttonTop=0
    }
    if (buttonTop + 50 >= this.data.windowHeight){
      buttonTop = this.data.windowHeight-50;
    }
    this.setData({
      buttonTop: buttonTop,
      buttonLeft: buttonLeft
    })
  },
  buttonEnd: function (e) {
  }
})

<view class="btn_Suspension" bindtap="btn_Suspension_click" catchtouchmove="buttonMove" bindtouchstart="buttonStart" bindtouchend="buttonEnd" style="top:{{buttonTop}}px;left:{{buttonLeft}}px;">
    <image class="Suspension_logo" src="XXXXXXX.png"></image>
    
    </view>
  </view>