移动UIButton

Question

我曾尝试在菜单中上下移动UIButton。我在以下解决方案中遇到的问题是计时器不准确。按钮有时会向上移动122px，有时仅会向上移动120px。我该怎么解决这个问题呢？

    -(IBAction)marketTabClicked:(id)sender {

    if (marketTabExtended) {
        NSLog(@"marketTabExtended = YES");
        return;
    }
    else {
        if (iPhoneAppsExtended) {
            timer = [NSTimer scheduledTimerWithTimeInterval:0.005 target: self selector: @selector(animateItemApps) userInfo: nil repeats: YES];
        }
        else {
            if (homepageExtended) {
                timer = [NSTimer scheduledTimerWithTimeInterval:0.005 target: self selector: @selector(animateItemHomepage) userInfo: nil repeats: YES];
            }
            else {
                timer = [NSTimer scheduledTimerWithTimeInterval:0.005 target: self selector: @selector(animateItemMarketing) userInfo: nil repeats: YES];
            }

        }

    }

    [self performSelector:@selector(stopTimer) withObject:self afterDelay:0.605];
    iPhoneAppsExtended = NO;
    homepageExtended = NO;
    marketTabExtended = NO;
    marketTabExtended = YES;

}



-(void)animateItemApps {
    CGPoint movement;
    movement = CGPointMake(0, -1);
    homepage.center = CGPointMake(homepage.center.x, homepage.center.y + movement.y);
}

-(void)animateItemHomepage {
    CGPoint movement;
    movement = CGPointMake(0, 1);
    homepage.center = CGPointMake(homepage.center.x, homepage.center.y + movement.y);
    //marketTab.center = CGPointMake(marketTab.center.x, marketTab.center.y + movement.y);
}

-(void)animateItemMarketing {
    CGPoint movement;
    movement = CGPointMake(0, -1);
    //marketTab.center = CGPointMake(marketTab.center.x, marketTab.center.y + movement.y);
    homepage.center = CGPointMake(homepage.center.x, homepage.center.y + movement.y);
}

-(void)stopTimer {
    [timer invalidate];
}

Answer 1

为什么不使用UIView动画块？

[UIView beginAnimations:nil context:nil];
//Change UIButton frame here
[UIView commitAnimations];

在动画块(注释所在的位置)中所做的更改将在commitAnimations之后生成动画。

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