问题一：
（“MBProgressHUD needs to be accessed on the main thread.”）
我用webView加载H5页面，并在webViewDelegate方法中使用MBProgressHUD控件，如下：
-(void)webViewDidStartLoad:(UIWebView *)webView
[self showLoadHUDMsg:@"正在加载..."];
}
-(void)webViewDidFinishLoad:(UIWebView *)webView{
[self hideLoadHUD];
}
但是，当我在webView中使用js交互push到下一个页面后，出现下列报错：（present到下一个页面却不会出现报错）
*** Terminating app due to uncaught exception ‘NSInternalInconsistencyException‘, reason: ‘MBProgressHUD needs to be accessed on the main thread.‘
‘MBProgressHUD needs to be accessed on the main thread.‘这个错误主要翻译成，MBProgressHUD必须在主线程上运行。
解决办法：
//充值缴费
-(void)recharge{
// present却不会出现问题
// JXSRechargeVC *rechangeVC = [JXSRechargeVC new];
// UINavigationController *nvi = [[UINavigationController alloc]initWithRootViewController:rechangeVC];
// [self presentViewController:nvi animated:YES completion:nil];
NSLog(@"线程1--->%d",[NSThread isMainThread]);
dispatch_async(dispatch_get_global_queue( DISPATCH_QUEUE_PRIORITY_LOW, 0), ^{
NSLog(@"线程2--->%d",[NSThread isMainThread]);
dispatch_async(dispatch_get_main_queue(), ^{
NSLog(@"线程3--->%d",[NSThread isMainThread]);
JXSRechargeVC *rechangeVC = [JXSRechargeVC new];
[self.navigationController pushViewController:rechangeVC animated:YES];
});
});
}
线程的打印结果如下：
0DCC7C1F-B5A0-44D8-AAD0-E07EC70BBDA6.png
问题二：
显示NSAssert(view, @"View must not be nil.")错误提示
我添加MBProgressHUD是使用的分类，将HUD显示在window上面，关键代码如下：
//隐藏加载提示
- (void)hideLoadHUD{
[MBProgressHUD hideAllHUDsForView:[self window] animated:YES];
}
//正在加载提示
- (void)showLoadHUDMsg:(NSString *)msg{
MBProgressHUD *progressHUD = [MBProgressHUD showHUDAddedTo:[self window] animated:YES];
progressHUD.labelText = msg;
//progressHUD.mode = MBProgressHUDModeText;
//progressHUD.dimBackground = YES;
}
-(UIWindow *)window{
return [UIApplication sharedApplication].keyWindow;
}
但是使用过程中会出现NSAssert(view, @"View must not be nil.")的错误提示，解决方法如下：([UIApplication sharedApplication].keyWindow替换[self window])
//隐藏加载提示
- (void)hideLoadHUD{
[MBProgressHUD hideAllHUDsForView:[UIApplication sharedApplication].keyWindow animated:YES];
}
//正在加载提示
- (void)showLoadHUDMsg:(NSString *)msg{
MBProgressHUD *progressHUD = [MBProgressHUD showHUDAddedTo:[UIApplication sharedApplication].keyWindow animated:YES];
progressHUD.labelText = msg;
//progressHUD.mode = MBProgressHUDModeText;
//progressHUD.dimBackground = YES;
}