objective-c - 从在后台线程上执行的其他方法内部在主线程上执行方法？

Question

这就是我的代码现在的样子，我想以串行方式调用这些方法:

-(void) methodOnBackThread // this method will run on a background thread
{
    [runner runThisMethod]; // and this will run on the same background thread as well

    [runner runThisOtherMethod]; // and so will this one

    // but I want this one to run on the main thread :       
    [runner runThisMethodOnTheMainThreadUsing:thisParameter using:thisOtherParamater andUsing:thisOtherOneAsWell]; 

    [runner runThisOtherMethod]; // this one will run on the background thread as well


     // but I want this one to run on the main thread :       
    [runner runThisMethodOnTheMainThreadUsing:thisParameter using:thisOtherParamater andUsing:thisOtherOneAsWell]; 

    [runner runThisOtherMethod]; // this one will run on the background thread as well

    // etc..

}

我相信我必须使用 dispatch_get_main_queue 但我不知道如何在上述情况下实现它。

如何将[runner runThisMethodOnTheMainThreadUsing:thisParameter using:thisOtherParamater andUsing:thisOtherOneAsWell];提交到主线程，然后返回执行我其余的后台方法，然后获取主线程下一个方法是否需要它？

Answer 1

如果您的目标是 iOS 4 及更高版本，请使用 grand central dispatch。你可以这样做:

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    //do some stuff here in the background
    dispatch_async(dispatch_get_main_queue(), ^{
        //do some stuff here in the main thread
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
           //do some stuff here in the background after finishing calling a method on the main thread
    });
    });
});