今天帮同事看bug，看到他用[[UIApplication sharedApplication].windows lastobject]来获取最上层window，添加view后，不显示。
demo地址：https://github.com/xuaimian/TopLevelWindow
所以整理了下面的方法：
方法一：
-(UIWindow *)topLevelWindowGet
{
UIWindow *topView = [UIApplication sharedApplication].keyWindow;
for (UIWindow *win in [[UIApplication sharedApplication].windows reverseObjectEnumerator]) {
if ([win isEqual: topView]) {
continue;
}
if (win.windowLevel > topView.windowLevel && win.hidden != YES ) {
topView =win;
}
}
return topView;
}
方法二：
UIWindow *topView = [UIApplication sharedApplication].keyWindow;
[topView endEditing:Yes];
return topView;
