IOS之活动指示器ActivityIndicatorView和进度条ProgressView

        指示器ActivityIndicatorView，俗称小菊花。进度条ProgressView不言而喻，就是显示进度的加载条。现在我们来模拟下载的过程。点击下面的Download按钮，使指示器ActivityIndicatorView动起来，并且使进度条ProgressView的进度每隔0.1s使进度加上1%，当进度达到100%时，停止指示器ActivityIndicatorView和进度条ProgressView。

 

//单击按钮触发的事件
- (IBAction)startProgress:(UIButton *)sender {
    //isDownloading初始状态为NO
    if(isDownloading==NO){
        self.progressView.progress = 0;
        timer = [NSTimer scheduledTimerWithTimeInterval:0.1
                                                 target:self
                                               selector:@selector(startDownload)
                                               userInfo:nil
                                                repeats:YES];
        NSLog(@"initialize timer finish");
        isDownloading=YES;
        [self.indicator startAnimating];
    }
}
//自定义模拟下载的事件，对应NSTimer绑定的事件
-(void)startDownload{
    self.progressView.progress = self.progressView.progress + 0.01;
    NSLog(@"progress = %f",self.progressView.progress);
    if(self.progressView.progress==1){
        [timer invalidate];
        NSLog(@"download finish");
        [self.indicator stopAnimating];
        isDownloading=NO;
    }
}