UIKit 框架之UIProgressView

//
//  ViewController.m
//  UIProgressView
//
//  Created by City--Online on 15/5/18.
//  Copyright (c) 2015年 XQB. All rights reserved.
//
 
#import "ViewController.h"
 
@interface ViewController ()
@property(nonatomic,strong) UIProgressView *progress;
@property(nonatomic,strong) NSTimer *timer;
@end
 
@implementation ViewController
 
- (void)viewDidLoad {
    [super viewDidLoad];
    //设置的高度对进度条的高度没影响，整个高度=进度条的高度，进度条也是个圆角矩形
    //但slider滑动控件：设置的高度对slider也没影响，但整个高度=设置的高度，可以设置背景来检验
     _progress=[[UIProgressView alloc]initWithFrame:CGRectMake(20, 200, 300, 10)];
//    typedef NS_ENUM(NSInteger, UIProgressViewStyle) {
//        UIProgressViewStyleDefault,     // normal progress bar
//        UIProgressViewStyleBar,         // for use in a toolbar
//    };
    //两种几乎无区别
    _progress.progressViewStyle=UIProgressViewStyleDefault;
    //进度颜色
//    _progress.progressTintColor=[UIColor redColor];
//    //背景色
//    _progress.backgroundColor=[UIColor blueColor];
//    //进度条颜色
//    _progress.trackTintColor=[UIColor yellowColor];
    //进度的背景图片
    _progress.progressImage=[UIImage imageNamed:@"2.jpg"];
    //进度条的背景图片
    _progress.trackImage=[UIImage imageNamed:@"1.jpg"];
    [self.view addSubview:_progress];
    _timer=[NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(btnClick:) userInfo:nil repeats:YES];
    [_timer fire];
}
-(void)btnClick:(UIButton *)sender
{
    if (_progress.progress<0.95) {
        _progress.progress+=0.05;
 
    }
    else
    {
        [_timer invalidate];
    }
     
}
 
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
 
@end

 设置的progressImage、trackImage属性不起作用,网上搜了好多，说是IOS7之后没有效果