我有以下代码:
@property (weak, nonatomic) IBOutlet UIView *loadingView;
-(void) hideLoadingScreen{
self.loadingViewRect = self.loadingView.frame;
[self.loadingView setHidden:YES];
[self.loadingView setFrame:CGRectMake(0,0,0,0)];
}
- (void)viewDidAppear:(BOOL)animated{
[self.apiClient checkLoggedInWithCallback:^(int status){
if(status == ONLINE_LOGGED_IN){
[self.dbAPI isPullSynchronized:^(BOOL isPullSynced){
if(isPullSynced){
self.data = [self.dbAPI getTodayVisits];
[[self tableView] reloadData];
[self hideLoadingScreen];
} else {
[self.apiClient getTodayVisits:^(NSArray* visits){
[self.dbAPI insertTodayVisits:visits withCallback:^(int status){
self.data = [self.dbAPI getTodayVisits];
[[self tableView] reloadData];
}];
}];
}
}];
} else if(status == ONLINE_NOT_LOGGED_IN || status == ONLINE_INVALID_TOKEN || status == OFFLINE_NOT_LOGGED_IN) {
//Redirect to login
} else {
//Get from Local DB
self.data = [self.dbAPI getTodayVisits];
[[self tableView] reloadData];
}
}];
}
hideLoadingScreen方法不会执行(我的意思是它会被执行,但UI不会更新)。
我尝试了所有的东西使其工作(包括通过GCD将[self hideLoadingScreen]调度到主线程并执行SelectorOnMainThread /使__block BOOL变量isLoading并在主线程上休眠直到该变量被更改等)。我还在viewDidAppear方法上调用了hideLoadingView方法并且它可以工作,但我希望它在执行回调时隐藏。不幸的是,我无法通过搜索stackoverflow找到解决方案,也没有在谷歌上找到(我必须说我尝试了所有解决方案)。
L.E。我记录了Rob Napier建议的self.loadingView
新代码:
-(void) hideLoadingScreen{
self.loadingViewRect = self.loadingView.frame;
NSLog(@"hideLoadingScreen before: %@",self.loadingView);
[self.loadingView setHidden:YES];
[self.loadingView setFrame:CGRectMake(0,0,0,0)];
NSLog(@"hideLoadingScreen after: %@",self.loadingView);
}
- (void)viewDidAppear:(BOOL)animated{
NSLog(@"%@",self.loadingView);
[self.apiClient checkLoggedInWithCallback:^(int status){
if(status == ONLINE_LOGGED_IN){
[self.dbAPI isPullSynchronized:^(BOOL isPullSynced){
if(isPullSynced){
dispatch_async(dispatch_get_main_queue(), ^{
self.data = [self.dbAPI getTodayVisits];
[[self tableView] reloadData];
NSLog(@"async before: %@",self.loadingView);
[self hideLoadingScreen];
NSLog(@"async after: %@",self.loadingView);
});
} else {
[self.apiClient getTodayVisits:^(NSArray* visits){
[self.dbAPI insertTodayVisits:visits withCallback:^(int status){
self.data = [self.dbAPI getTodayVisits];
[[self tableView] reloadData];
}];
}];
}
}];
} else if(status == ONLINE_NOT_LOGGED_IN || status == ONLINE_INVALID_TOKEN || status == OFFLINE_NOT_LOGGED_IN) {
//Redirect to login
} else {
//Get from Local DB
self.data = [self.dbAPI getTodayVisits];
[[self tableView] reloadData];
}
}];
}
日志:
2016-01-08 16:22:25.973 sunwaves.reporting[4566:282042] async before: <UIView: 0x7fa681e745d0; frame = (0 0; 1024 650); autoresize = RM+H+BM; layer = <CALayer: 0x7fa681e291c0>>
2016-01-08 16:22:25.973 sunwaves.reporting[4566:282042] hideLoadingScreen before: <UIView: 0x7fa681e745d0; frame = (0 0; 1024 650); autoresize = RM+H+BM; layer = <CALayer: 0x7fa681e291c0>>
2016-01-08 16:22:25.974 sunwaves.reporting[4566:282042] hideLoadingScreen after: <UIView: 0x7fa681e745d0; frame = (0 0; 0 0); hidden = YES; autoresize = RM+H+BM; layer = <CALayer: 0x7fa681e291c0>>
2016-01-08 16:22:25.974 sunwaves.reporting[4566:282042] async after: <UIView: 0x7fa681e745d0; frame = (0 0; 0 0); hidden = YES; autoresize = RM+H+BM; layer = <CALayer: 0x7fa681e291c0>>
答案 0 :(得分:2)
大多数UIKit调用必须在主队列上进行。您应该使用dispatch_async(dispatch_get_main_queue(),...
来执行此操作。
这包括您至少拨打reloadData
的电话。
您对self.data
的分配也可能不是线程安全的(除非您在setter中做了一些特殊的事情)。所以那些需要在主队列上。
当然,您拨打hideLoadingScreen
。
我假设大多数这些块都在主队列中执行,因此这意味着在几个地方放入dispatch_async
。
- (void)viewDidAppear:(BOOL)animated{
[self.apiClient checkLoggedInWithCallback:^(int status){
if(status == ONLINE_LOGGED_IN){
[self.dbAPI isPullSynchronized:^(BOOL isPullSynced){
if(isPullSynced){
dispatch_async(dispatch_get_main_queue(), ^{
self.data = [self.dbAPI getTodayVisits];
[[self tableView] reloadData];
[self hideLoadingScreen];
});
} else {
[self.apiClient getTodayVisits:^(NSArray* visits){
[self.dbAPI insertTodayVisits:visits withCallback:^(int status){
dispatch_async(dispatch_get_main_queue(), ^{
self.data = [self.dbAPI getTodayVisits];
[[self tableView] reloadData];
});
}];
}];
}
}];
} else if(status == ONLINE_NOT_LOGGED_IN || status == ONLINE_INVALID_TOKEN || status == OFFLINE_NOT_LOGGED_IN) {
//Redirect to login
} else {
//Get from Local DB
dispatch_async(dispatch_get_main_queue(), ^{
self.data = [self.dbAPI getTodayVisits];
[[self tableView] reloadData];
});
}
}];
}