I have method which makes UI changes in some cases.
For example:
-(void) myMethod {
if(someExpressionIsTrue) {
// make some UI changes
// ...
// show actionSheet for example
}
}
Sometimes myMethod
is called from the mainThread
sometimes from some other thread
.
Thats is why I want these UI changes to be performed surely in the mainThread
.
I changed needed part of myMethod
this way:
if(someExpressionIsTrue) {
dispatch_async(dispatch_get_main_queue(), ^{
// make some UI changes
// ...
// show actionSheet for example
});
}
So the questions:
dispatch_async(dispatch_get_main_queue()
in main thread? Does it influence on performance?[NSThread isMainThread]
method and call dispatch_async
only in case of other thread, but it will make me create one more method or block with these UI updates.There isn't a problem with adding an asynchronous block on the main queue from within the main queue, all it does is run the method later on in the run loop.
What you definitely don't want to do is to call dispatch_sync
adding a block to the main queue from within the main queue as you'll end up locking yourself.