在后台和主线程ios中执行

Question

我有一个函数foo（），它在后台线程foo() {上调用一个函数栏

  [self performSelectorInBackground:@selector(bar:) withObject:nil]; }  bar() { //some initialsations //calling another function bar1();//also in background //after bar1() returns //marking following statement with * [self performSelectorOnMainThread:@selector(stopActivityIndicator:)withObject:nil wailUntilDone:YES]; } 

[self performSelectorInBackground:@selector(bar:) withObject:nil]; } bar() { //some initialsations //calling another function bar1();//also in background //after bar1() returns //marking following statement with * [self performSelectorOnMainThread:@selector(stopActivityIndicator:)withObject:nil wailUntilDone:YES]; }

  [self performSelectorInBackground:@selector(bar:) withObject:nil]; }  bar() { //some initialsations //calling another function bar1();//also in background //after bar1() returns //marking following statement with * [self performSelectorOnMainThread:@selector(stopActivityIndicator:)withObject:nil wailUntilDone:YES]; } 

bar（）在调用另一个函数之前做了一些事情。 bar（）所做的就是在后台。 同时，我正在展示ActivityIndi​​cator。 一旦我的函数在bar（）中返回，我正在调用一个函数，它将在MainThread上运行stopActivityIndi​​cator。

现在，我想在调用stopActivityIndi​​cator（）之前调用MainThread中的另一个函数我该怎么办？ 我可以把另一个[self performSelectorOnMainThread:@selector(functionIWantToCall:)withObject:nil wailUntilDone:YES]; 之前*？

Answer 1

您可以调度一个块以在主线程上运行，并将您需要的任何代码放入该块中：

[[NSOperationQueue mainQueue] addOperationWithBlock:^ {

   // Code here
   NSLog(@"This is the main thread");

}];

使用您的代码，这将成为：

bar()
{
    bar1();

    [[NSOperationQueue mainQueue] addOperationWithBlock:^ {
        [stopActivityIndidator];
        [functionIWant];
    }];
}