devedbox
第一次进入ViewController 加载的是 HTML或者Data，叉叉的显示会不正确
Demo，TabbarViewController2，换成下面这个。
- (void)viewDidLoad {
[super viewDidLoad];
// [self loadURL:[NSURL URLWithString:@"https://www.baidu.com"]];
NSString *str = @"<p><a href=\"https://www.baidu.com\" target=\"_self\" title=\"https://www.baidu.com\">https://www.baidu.com</a><br/></p>";
[self loadHTMLString:str baseURL:[NSURL URLWithString:@"https://www.baidu.com"]];
}
webview会显示一个百度的链接，点击这个链接，会加载百度，这时左上角应该有关闭按钮，然而却没有显示。
运行出来后每次第一次加载这个控制器都非常慢。而且会报警告 objc[3809]: Class PLBuildVersion is implemented in both /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk/System/Library/PrivateFrameworks/AssetsLibraryServices.framework/AssetsLibraryServices (0x122646910) and /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk/System/Library/PrivateFrameworks/PhotoLibraryServices.framework/PhotoLibraryServices (0x122470210). One of the two will be used. Which one is undefined. 2017-02-16 11:18:52.732 xiaojiujinfu[3809:511272] unexpected nil window in __dispatchPreprocessedEventFromEventQueue, _windowServerHitTestWindow: (null) 2017-02-16 11:18:52.733 xiaojiujinfu[3809:511272] unexpected nil window in __dispatchPreprocessedEventFromEventQueue, _windowServerHitTestWindow: (null)
