iPhone使用进度条达到计时器流畅的动画效果 [英] iPhone achieve smooth animation using progress bar timer
问题描述
我想实现在学习的精神iphone的一个简单的测验应用程序，这个应用程序的一部分，是一个计时器。
I am trying to implement a simple quiz app on the iphone in the spirit of learning, part of this app is a timer.
我想我的定时器倒计时从10到0。我有一个简单的NSTimer的重复和调用方法每一秒，在这种方法我更新它显示剩余时间的标签，这很好地工作。
I want my timer to count down from 10 to 0. I had a simple NSTimer that repeats and calls a method every second and in this method I update a label which displays the remaining time, which works nicely.
现在，而不是使用一个标签，我想用一个图形化的进度条显示计时器，所以我创建了十张图片，一个完整长度（重presenting 10），尺寸的下一个9/10等对了，在我重复定时器的方法，而不是更新的标签我更新相应的图像一个UIImage等过段时间进度条变得越来越小。
Now instead of displaying the timer using a label I wanted to use a graphical progress bar, so I created ten images, one full in length (representing 10), the next 9/10 of the size and so on, and in my repeating timer method instead of updating a label I update a UIImage with the appropriate image so over time the progress bar gets smaller and smaller.
我的问题是，由于我的方式已经实现了进度条，它看起来并不很流畅时，它更新每一秒。有另一种方法我应该接近开发这种功能？我听说，你可以使用可伸缩的图像获得平滑的效果，但我不能看到任何很好的例子。
My problem is that due to the way I have implemented the progress bar, it doesn't look very smooth when it updates every second. Is there another way I should approach developing this kind of functionality? I have heard that you could use a stretchable image to get a smoother effect but I couldn't see any good examples of that.
任何意见和code样品的欢迎，只是想在这里学习。
Any advice and code samples welcome, just trying to learn here.
推荐答案
调查我决定用一个UIProgressView几个选项后（在评论须藤建议），再加上的NSTimer其更新进度十次十第二秒，我用这个解决方案，因为：
After investigating a few options I have decided to use a UIProgressView (suggested by sudo in comments) coupled with a NSTimer which updates the progress ten times a second for ten seconds, I used this solution because:
- 它是由苹果公司提供的标准元素。
- 此选项没有创建和加载100张图像（如氪在评论建议）的开销。
- 将在我的NSTimer可以添加一个检查功能updateProgressBar一些反馈添加到用户当定时器达到低，E.E.振动的最后3秒等（使用动画，我不认为我会这样的选择）。
使用code以下假设我有一个名为progressView，一个名为的NSTimer定时器一个UIProgressView变量并命名为时间一个浮点变量，那么：
Using the code below assume I have a UIProgressView variable named 'progressView', an NSTimer named 'timer' and a floating point variable named 'time', then:
-(void)updateProgressBar
{
if(time <= 0.0f)
{
//Invalidate timer when time reaches 0
[timer invalidate];
}
else
{
time -= 0.01;
progressView.progress = time;
}
}
-(void)animateProgressView2
{
progressView.progress = 1;
time = 1;
timer = [NSTimer scheduledTimerWithTimeInterval: 0.1f
target: self
selector: @selector(updateProgressBar)
userInfo: nil
repeats: YES];
}
我调查（看到迪斯科的评论之后），但决定对另一种方法是使用动画。在这种情况下我创建了两个png图片，名为redbar.png'和'greenbar.png'，这个想法让他们将被放置在彼此（绿色条是在顶部/在前台），超过期限动画绿坝缩小，揭示在背景中的红色吧。
Another way I investigated (after seeing Disco's comments) but decided against was to use animation. In this instance I created two png images, named 'redbar.png' and 'greenbar.png', the idea bring they would be placed over each other (the green bar being on top/in the foreground), and over the duration of the animation the green bar shrinks, revealing the red bar in the background.
UIImage *green= [UIImage imageNamed:@"greenbar.png"];
UIImage *red= [UIImage imageNamed:@"redbar.png"];
redBar.image = red; // allocate the red image to the UIImageView
redBar.frame = CGRectMake(20,250,220,30);// set the size of the red image
greenBar.image = green; // allocate the green image to the UIImageView
greenBar.frame = CGRectMake(20,250,220,30);//set the size of the green image
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDelegate:self];
[UIView setAnimationDuration:10]; //the time you want the animation to last for
[UIView setAnimationDidStopSelector:@selector(animationFinished)];//the method to be called once the animation is finished
//at the end of the animation we want the greenBar frame to disappear
greenBar.frame = CGRectMake(20,250,0,30);
[UIView commitAnimations];
这是理想的解决方案是将UIProgressView和UIAnimation块结合起来，但是这目前还不是一个选项（参见这个问题的动画一个UIProgressView的变化）。
An ideal solution would be to combine the UIProgressView and the UIAnimation block, but this is not currently an option (see this question animate a UIProgressView's change).
希望这可以帮助别人的未来。
Hope this helps someone in the future.
编辑：
它出现的理想的解决方案，我上面提到的是现已在iOS5中，从苹果网站引用次数：
It appears the ideal solution I mention above is now available in iOS5, taken from the apple reference site:
setProgress：动画：
调节接收机显示，可选动画改变目前的进展。
setProgress:animated: Adjusts the current progress shown by the receiver, optionally animating the change.
- （无效）setProgress：（浮点）进度动画：（BOOL）动画
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