iOS 实现进度条（progress）

#import <UIKit/UIKit.h>

@interface ZSDProgressView : UIView
{
    UIView *progressView;//进度view
}
//进度值
@property(nonatomic,assign)float progress;
@end
#define UIColorFromRGB(rgbValue) [UIColor \
colorWithRed:((float)((rgbValue & 0xFF0000) >> 16))/255.0 green:((float)((rgbValue & 0xFF00) >> 8))/255.0 blue:((float)(rgbValue & 0xFF))/255.0 alpha:1.0]
#import "ZSDProgressView.h"
@implementation ZSDProgressView

-(id)initWithFrame:(CGRect)frame
{
    if (self=[super initWithFrame:frame])
    {
        self.backgroundColor=UIColorFromRGB(0xDADADA);
    }

    return self;
}
-(void)awakeFromNib
{

    self.backgroundColor=UIColorFromRGB(0xDADADA);
    progressView=[[UIView alloc]init];
    progressView.translatesAutoresizingMaskIntoConstraints=NO;
    [self addSubview:progressView];

}
-(void)setProgress:(float)progress
{
    _progress=progress;

    /**
     *  activePartView添加约束
     */

    //左边约束
    [self addConstraint:[NSLayoutConstraint constraintWithItem:progressView attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeLeft multiplier:1 constant:0]];

     //上边约束
    [self addConstraint:[NSLayoutConstraint constraintWithItem:progressView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeTop multiplier:1 constant:0]];

    //高度约束
    [self addConstraint:[NSLayoutConstraint constraintWithItem:progressView attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeHeight multiplier:1 constant:self.frame.size.height]];

    //宽度约束
    NSLayoutConstraint *widthCon = [NSLayoutConstraint constraintWithItem:progressView
                                                                attribute:NSLayoutAttributeWidth
                                                                relatedBy:NSLayoutRelationEqual
                                                                   toItem:self
                                                                attribute:NSLayoutAttributeWidth
                                                               multiplier:_progress
                                                                 constant:0];
    [self addConstraint:widthCon];

    //用背景图来填充背景颜色
    UIImage *bgImage=[UIImage imageNamed:@"invest_jindu"];
    UIColor *bgColor=[UIColor colorWithPatternImage:bgImage];
    [progressView setBackgroundColor:bgColor];
    //更新约束
    [progressView needsUpdateConstraints];

}

@end

#import "ViewController.h"
#import "ZSDProgressView.h"
@interface ViewController ()
@property (weak, nonatomic) IBOutlet ZSDProgressView *progressView;

@end

@implementation ViewController

- (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.
}
- (IBAction)setBtnClick:(UIButton *)sender
{

    _progressView.progress=0.6;

}

@end