AlertView点击确定后再执行后面的代码

 1 - (BOOL)beforeBackButtonClickEvent {
 2     UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"提示" message:@"舍弃流程？" delegate:self cancelButtonTitle:@"否" otherButtonTitles:@"是", nil];
 3     [alert show];
 4     CFRunLoopRun();
 5     
 6     return back;
 7 }
 8 
 9 - (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
10     //否
11     if (buttonIndex == 0) {
12         back = NO;
13     }
14     //是
15     else {
16         back = YES;
17     }
18     CFRunLoopStop(CFRunLoopGetMain());
19 }