Objective-C ,ios,iphone开发基础:快速实现一个简单的图片查看器

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。

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