Android 实现滑动的几种方法（二）LayoutParams

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通过改变layoutParams 来改变一个View的位置时，通常改变的是这个View的Margin属性

package com.example.administrator.myapplication;import android.content.Context;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;import android.view.ViewGroup;/** * Created by Administrator on 2015/11/22 0022. */public class MyView extends View {    int lastX ;    int lastY ;    public MyView(Context context) {        super(context);    }    public MyView(Context context, AttributeSet attrs) {        super(context, attrs);    }    @Override    public boolean onTouchEvent(MotionEvent event) {        int x = (int) event.getX();        int y = (int) event.getY();        switch (event.getAction()) {            case MotionEvent.ACTION_DOWN:                lastX = x;                lastY = y;                break;            case MotionEvent.ACTION_MOVE:                int offx = x - lastX;                int offy = y - lastY;        /*        *   通过改变layoutParams 来改变一个View的位置时，通常改变的是这个View的Margin属性        *        */                ViewGroup.MarginLayoutParams params = (ViewGroup.MarginLayoutParams) getLayoutParams();                params.leftMargin = getLeft()+offx;                params.topMargin = getTop()+offy;                setLayoutParams(params);                lastX = x;                lastY = y;                break;        }        return true;    }}

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