phonegap3+，ios7+ 状态栏问题的解决

使用phonegap混合开发时，在ios7+的设备中会出现系统状态栏和header重合的问题，加入代码使得状态栏和我们的应用分离：

MainViewController.m

- (void)viewWillAppear:(BOOL)animated{    // View defaults to full size.  If you want to customize the view's size, or its subviews (e.g. webView),    // you can do so here.    if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 7) {        CGRect viewBounds = [self.webView bounds];        viewBounds.origin.y = 20;        viewBounds.size.height = viewBounds.size.height - 20;        self.webView.frame = viewBounds;    }    [super viewWillAppear:animated];}