iphone - 使用 Time Profiler 分析的审查方法

Question

我已经使用 Time Profiler Instrument 来识别我的应用程序中的显着滞后。现在我知道问题出在哪里，但我不知道该怎么办。我正在使用 ARC 并且有一个调用方法“Go”的 viewController，如下所示。我也包含了 Time Profiler 结果的快照。有谁知道我该如何解决这个问题？谢谢!

这是该方法的代码:

- (void)go {

CGFloat width = self.imageViewA.bounds.size.width;

[UIView animateWithDuration:18.0 delay:0.0 options:UIViewAnimationOptionCurveLinear 
animations:^ {
    self.imageViewA.frame = CGRectOffset(self.imageViewA.frame, -width, 0);
    self.imageViewB.frame = CGRectOffset(self.imageViewB.frame, -width, 0);
    } 
completion:^(BOOL finished) {
    if (self.keepGoing) {
        // now B is where A began, so swap them and reposition B
        UIImageView *temp = self.imageViewA;
        self.imageViewA  = self.imageViewB;
        self.imageViewB = temp;
        self.imageViewB.frame = CGRectOffset(self.view.bounds, 
        self.view.bounds.size.width, 0.0);
        // recursive call, but we don't want to wind up the stack
        [self performSelector:@selector(go) withObject:nil afterDelay:0.0];
        }
    }];
}

这是我的时间文件的结果:

作为引用，我还包含了我的 .h 文件。

@interface ViewController : GAITrackedViewController

@property (weak, nonatomic) IBOutlet UIBarButtonItem *lButton;
@property (weak, nonatomic) IBOutlet UIBarButtonItem *rButton;

@property (nonatomic, assign) BOOL keepGoing;
@property (nonatomic, strong) UIImageView *imageViewA;
@property (nonatomic, strong) UIImageView *imageViewB;

- (IBAction)handleLPressed:(id)sender;
- (IBAction)handleRPressed:(id)sender;
@end

Answer 1

也许这可行:

- (void)go {

CGFloat width = self.imageViewA.bounds.size.width;

__weak typeof(self) self_ = self;

[UIView animateWithDuration:18.0 delay:0.0 options:UIViewAnimationOptionCurveLinear 
animations:^ {
    __strong typeof(self) self = self_;
    self.imageViewA.frame = CGRectOffset(self.imageViewA.frame, -width, 0);
    self.imageViewB.frame = CGRectOffset(self.imageViewB.frame, -width, 0);
    } 
completion:^(BOOL finished) {
    __strong typeof(self) self = self_;
    if (self.keepGoing) {
        // now B is where A began, so swap them and reposition B
        UIImageView *temp = self.imageViewA;
        self.imageViewA  = self.imageViewB;
        self.imageViewB = temp;
        self.imageViewB.frame = CGRectOffset(self.view.bounds, 
        self.view.bounds.size.width, 0.0);
        // recursive call, but we don't want to wind up the stack
        [self performSelector:@selector(go) withObject:nil afterDelay:0.0];
        }
    }];
}

这样做是保持对 self 的弱引用，而不是将其复制到堆栈中的 block 中。我不确定，但也许这可行。