（转）qq5.0侧滑效果

package com.imooc.slidingmenu.view;

import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.Log;
import android.util.TypedValue;
import android.view.MotionEvent;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.HorizontalScrollView;
import android.widget.LinearLayout;

import com.imooc.slidingmenu.R;
import com.nineoldandroids.view.ViewHelper;

public class SlidingMenu extends HorizontalScrollView
{
private LinearLayout mWapper;
private ViewGroup mMenu;
private ViewGroup mContent;
private int mScreenWidth;
private int mMenuWidth;
// dp
private int mMenuRightPadding = 50;

private boolean once;

private boolean isOpen;

/**
* 未使用自定义属性时，调用
*
* @param context
* @param attrs
*/
public SlidingMenu(Context context, AttributeSet attrs)
{
this(context, attrs, 0);
}

/**
* 当使用了自定义属性时，会调用此构造方法
*
* @param context
* @param attrs
* @param defStyle
*/
public SlidingMenu(Context context, AttributeSet attrs, int defStyle)
{
super(context, attrs, defStyle);

// 获取我们定义的属性
TypedArray a = context.getTheme().obtainStyledAttributes(attrs,
R.styleable.SlidingMenu, defStyle, 0);

int n = a.getIndexCount();
for (int i = 0; i < n; i++)
{
int attr = a.getIndex(i);
switch (attr)
{
case R.styleable.SlidingMenu_rightPadding:
mMenuRightPadding = a.getDimensionPixelSize(attr,
(int) TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_DIP, 50, context
.getResources().getDisplayMetrics()));
break;
}
}
a.recycle();

WindowManager wm = (WindowManager) context
.getSystemService(Context.WINDOW_SERVICE);
DisplayMetrics outMetrics = new DisplayMetrics();
wm.getDefaultDisplay().getMetrics(outMetrics);
mScreenWidth = outMetrics.widthPixels;

}

public SlidingMenu(Context context)
{
this(context, null);
}

/**
* 设置子View的宽和高 设置自己的宽和高
*/
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
if (!once)
{
mWapper = (LinearLayout) getChildAt(0);
mMenu = (ViewGroup) mWapper.getChildAt(0);
mContent = (ViewGroup) mWapper.getChildAt(1);
mMenuWidth = mMenu.getLayoutParams().width = mScreenWidth
- mMenuRightPadding;
mContent.getLayoutParams().width = mScreenWidth;
once = true;
}
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}

/**
* 通过设置偏移量，将menu隐藏
*/
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b)
{
super.onLayout(changed, l, t, r, b);
if (changed)
{
this.scrollTo(mMenuWidth, 0);
}
}

@Override
public boolean onTouchEvent(MotionEvent ev)
{
int action = ev.getAction();
switch (action)
{
case MotionEvent.ACTION_UP:
// 隐藏在左边的宽度
int scrollX = getScrollX();

if (scrollX >= mMenuWidth / 2)
{
this.smoothScrollTo(mMenuWidth, 0);
isOpen = false;
} else
{
this.smoothScrollTo(0, 0);
isOpen = true;
}
return true;
}
return super.onTouchEvent(ev);
}

/**
* 打开菜单
*/
public void openMenu()
{
if (isOpen)
return;
this.smoothScrollTo(0, 0);
isOpen = true;
}

public void closeMenu()
{
if (!isOpen)
return;
this.smoothScrollTo(mMenuWidth, 0);
isOpen = false;
}

/**
* 切换菜单
*/
public void toggle()
{
if (isOpen)
{
closeMenu();
} else
{
openMenu();
}
}

/**
* 滚动发生时
*/
@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt)
{
super.onScrollChanged(l, t, oldl, oldt);
float scale = l * 1.0f / mMenuWidth; // 1 ~ 0

/**
* 区别1：内容区域1.0~0.7 缩放的效果 scale : 1.0~0.0 0.7 + 0.3 * scale
*
* 区别2：菜单的偏移量需要修改
*
* 区别3：菜单的显示时有缩放以及透明度变化 缩放：0.7 ~1.0 1.0 - scale * 0.3 透明度 0.6 ~ 1.0
* 0.6+ 0.4 * (1- scale) ;
*
*/
float rightScale = 0.7f + 0.3f * scale;
float leftScale = 1.0f - scale * 0.3f;
float leftAlpha = 0.6f + 0.4f * (1 - scale);

// 调用属性动画，设置TranslationX
ViewHelper.setTranslationX(mMenu, mMenuWidth * scale * 0.8f);

ViewHelper.setScaleX(mMenu, leftScale);
ViewHelper.setScaleY(mMenu, leftScale);
ViewHelper.setAlpha(mMenu, leftAlpha);
// 设置content的缩放的中心点
ViewHelper.setPivotX(mContent, 0);
ViewHelper.setPivotY(mContent, mContent.getHeight() / 2);
ViewHelper.setScaleX(mContent, rightScale);
ViewHelper.setScaleY(mContent, rightScale);

}

}