转自http://www.cnblogs.com/aipingguodeli/archive/2012/04/27/2473422.html
#import "ActivityViewController.h"
@interface ActivityViewController : UIViewController
{
UIProgressView *proView;
double proValue;
NSTimer *timer;
}
@property(nonatomic, retain) UIProgressView *proView;
-(IBAction)btnStartClick;
#import "ActivityViewController.m"
@implementation ActivityViewController
@synthesize proView;
#pragma mark - View lifecycle
-(IBAction)btnStartClick
{
proValue=0;
timer = [NSTimerscheduledTimerWithTimeInterval:1target:selfselector:@selector(changeProgress)userInfo:nilrepeats:YES]; //利用计时器，每隔1秒调用一次（changeProgress）
}
-(void)changeProgress
{
proValue += 1.0; ／／改变proValue的值
if(proValue > 5)
{
//停用计时器
[timer invalidate];
}
else
{
[proViewsetProgress:(proValue / 5)];//重置进度条
}
}
- (void)viewDidLoad
{
[super viewDidLoad];
proView = [[UIProgressViewalloc] initWithFrame:CGRectMake(100, 100, 150, 20)];
[proViewsetProgressViewStyle:UIProgressViewStyleDefault]; //设置进度条类型
[self.view addSubview:proView];
}