新建一个single view 工程：

关闭ARC , 在.xib视图文件上拖放一个UIImageView  两个UIButton ，一个UISlider ，布局如图。

并为他们连线，

UIImageView 和 UISlider 分别定义插座变量，两个 UIButton 分别 连接两个Action next和previous ，在为 UISlider 连接一个Action  事件。

再在.h 文件中声明两个实例变量。   NSInteger index ; NSMutableArray* arrayPic ; 一个用来记录当前图片的index，一个用来做图片的容器，

用UISlider 来控制图片的透明度 （alpha 属性）。在slider 的界面构建起动作中添加代码，让图片的透明度等于 slider的value。

- (IBAction)sliderChangeValued:(id)sender {            self.imageView.alpha = slider.value;  }

- (IBAction)next:(id)sender {      if(index == [arrayPic count]){          index = 0;      }      self.imageView.image = [UIImage imageWithContentsOfFile:[arrayPic objectAtIndex:index]];      index++;  }- (IBAction)previous:(id)sender {      if(index == -1){          index = ([arrayPic count] -1);      }     self.imageView.image = [UIImage imageWithContentsOfFile:[arrayPic objectAtIndex:index]];      index--;  }

至此：简单的图片查看器已经完成，

整个控制器类中的代码：

// //  wsqViewController.h//  picLook// //  Created by administrator on 13-9-5.//  Copyright (c) 2013年 __MyCompanyName__. All rights reserved.// #import <UIKit/UIKit.h>@interface wsqViewController : UIViewController {      UIImageView *imageView;      UISlider *slider;      NSInteger index ;      NSMutableArray* arrayPic ;             }    @property (retain, nonatomic) IBOutlet UIImageView *imageView;  @property (retain, nonatomic) IBOutlet UISlider *slider;- (IBAction)sliderChangeValued:(id)sender;- (IBAction)next:(id)sender;- (IBAction)previous:(id)sender;@end

 //  //  wsqViewController.m  //  picLook  //  //  Created by administrator on 13-9-5.  //  Copyright (c) 2013年 __MyCompanyName__. All rights reserved.  //    #import "wsqViewController.h"    @implementation wsqViewController  @synthesize imageView;  @synthesize slider;    - (void)didReceiveMemoryWarning  {      [super didReceiveMemoryWarning];      // Release any cached data, images, etc that aren't in use.  }    #pragma mark - View lifecycle    - (void)viewDidLoad  {      [super viewDidLoad];      //获取mainbudle下所有 jpg格式的图片，        arrayPic = [[NSMutableArray alloc ] initWithArray: [[NSBundle mainBundle] pathsForResourcesOfType:@"jpg" inDirectory:nil]];      index = 0;      NSLog(@"%@",arrayPic);        }    - (void)viewDidUnload  {      [self setImageView:nil];      [self setSlider:nil];      [super viewDidUnload];      // Release any retained subviews of the main view.      // e.g. self.myOutlet = nil;  }    - (void)viewWillAppear:(BOOL)animated  {      [super viewWillAppear:animated];  }    - (void)viewDidAppear:(BOOL)animated  {      [super viewDidAppear:animated];  }    - (void)viewWillDisappear:(BOOL)animated  {      [super viewWillDisappear:animated];  }    - (void)viewDidDisappear:(BOOL)animated  {      [super viewDidDisappear:animated];  }    - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation  {      // Return YES for supported orientations      return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);  }    - (void)dealloc {      [arrayPic release];      [imageView release];      [slider release];      [super dealloc];  }  - (IBAction)sliderChangeValued:(id)sender {            self.imageView.alpha = slider.value;  }    - (IBAction)next:(id)sender {      if(index == [arrayPic count]){          index = 0;      }      self.imageView.image = [UIImage imageWithContentsOfFile:[arrayPic objectAtIndex:index]];      index++;  }    - (IBAction)previous:(id)sender {      if(index == -1){          index = ([arrayPic count] -1);      }     self.imageView.image = [UIImage imageWithContentsOfFile:[arrayPic objectAtIndex:index]];      index--;  }  @end