4.9学习内容view保存状态,ios屏幕亮度调整

http://blog.csdn.net/mennoa/article/details/44956341

SavedState

方法属于view

类概述

BaseSavedState 
Base class for derived classes that want to save and restore their own state in onSaveInstanceState().

直接子类

TextView.SavedState 
ViewPager.SavedState

    @Override    public void onRestoreInstanceState(Parcelable state) {        SavedState savedState = (SavedState)state;        super.onRestoreInstanceState(savedState.getSuperState());        mCurrentPage = savedState.currentPage;        mSnapPage = savedState.currentPage;        requestLayout();    }    /**     * 保存状态     * */    @Override    public Parcelable onSaveInstanceState() {        Parcelable superState = super.onSaveInstanceState();        SavedState savedState = new SavedState(superState);        savedState.currentPage = mCurrentPage;        return savedState;    }

ios调整屏幕亮度:

在iOS5.0以下，在程序中是不能直接设置系统屏幕亮度的，到了ios5.0以后将这个api开放给了开发者，这样我们就可以非常方更的更改系统屏幕的亮度，  
  
使用方法也很简单 ，如下：  
获取系统屏幕当前的亮度值  
float value = [UIScreen mainScreen].brightness;  
设置系统屏幕的亮度值  
[[UIScreen mainScreen] setBrightness:value];