ios-Frame和bounds的区别

NSLog(@"%@",NSStringFromCGRect([UIScreen mainScreen].bounds));//拿到当前设备的尺寸，为了防止硬编码呗
[UIApplication sharedApplication].keyWindow;//拿到当前应用的window，照理说一个应用是只有一个window的

   /**
     UIKIT_EXTERN const UIWindowLevel UIWindowLevelNormal;
     UIKIT_EXTERN const UIWindowLevel UIWindowLevelAlert;
     UIKIT_EXTERN const UIWindowLevel UIWindowLevelStatusBar;
     **/
    [UIApplication sharedApplication].keyWindow.windowLevel=UIWindowLevelNormal;

 //理解：状态栏是盖在了window上面，占用的告诉为20，ios7的那个状态栏是透明的，ios6的状态栏有个黑色的背景就这样，UIWindow也是一个特殊的视图

 NSLog(@"%@",NSStringFromCGRect([UIScreen mainScreen].bounds));
    //{{0, 0}, {320, 480}}
    NSLog(@"%@",NSStringFromCGRect([[UIScreen mainScreen] applicationFrame]));
    //{{0, 20}, {320, 460}}这个结果再ios6和ios7都一样