////  HMProgressView.h//  进度条////  Created by YaguangZhu on 15/9/9.//  Copyright (c) 2015年 YaguangZhu. All rights reserved.//#import 
     
      @interface HMProgressView : UIView@property(nonatomic,assign)CGFloat progress;@end////  HMProgressView.m//  进度条////  Created by YaguangZhu on 15/9/9.//  Copyright (c) 2015年 YaguangZhu. All rights reserved.//#import "HMProgressView.h"@interface HMProgressView()@property(nonatomic,weak)UILabel *label;@end@implementation HMProgressView- (UILabel *)label{    if (_label == nil) {        UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 100, 100)];        label.textAlignment = NSTextAlignmentCenter;        [self addSubview:label];        _label = label;    }    return _label;}- (void)setProgress:(CGFloat)progress{    _progress = progress;    self.label.text = [NSString stringWithFormat:@"%.2f%%",progress*100];    [self setNeedsDisplay];}// Only override drawRect: if you perform custom drawing.// An empty implementation adversely affects performance during animation.- (void)drawRect:(CGRect)rect {    // Drawing code    CGContextRef ctx = UIGraphicsGetCurrentContext();        CGPoint center = CGPointMake(50, 50);    CGFloat startA = -M_PI_2;    CGFloat radius = 50-2;    CGFloat endA = -M_PI_2 +_progress * M_PI *2;    UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:center radius:radius startAngle:startA endAngle:endA clockwise:YES];         CGContextAddPath(ctx, path.CGPath);        CGContextStrokePath(ctx);       }@end
     

////  ViewController.h//  进度条////  Created by YaguangZhu on 15/9/9.//  Copyright (c) 2015年 YaguangZhu. All rights reserved.//#import 
     
      @interface ViewController : UIViewController@end////  ViewController.m//  进度条////  Created by YaguangZhu on 15/9/9.//  Copyright (c) 2015年 YaguangZhu. All rights reserved.//#import "ViewController.h"#import "HMProgressView.h"@interface ViewController ()@property (weak, nonatomic) IBOutlet HMProgressView *progressView;@end@implementation ViewController- (IBAction)valueChange:(UISlider *)sender {    _progressView.progress = sender.value;}- (void)viewDidLoad {    [super viewDidLoad];    // Do any additional setup after loading the view, typically from a nib.}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}@end