如何在按钮操作上显示图像

Posted 2023-03-16

【中文标题】如何在按钮操作上显示图像

【英文标题】：How to display images on button action

【发布时间】：2014-03-06 08:30:36

【问题描述】：

我有 10 个UIImages。当我单击UIButton 它显示在UIScrollView. But I need to implement theUIButtonlike **Next**, ifUIButtonis clicked first time, it displays the firstUIImage` 下，然后单击它会显示下一个图像。如果我点击后退按钮，应该会显示上一张图片。

int   currentIndex = 0;
int MAX_COUNT;

NSMutableArray *imageName = [[NSMutableArray alloc] initWithObjects:
                                @"spices.jpg",
                                @"spice_powder.jpg", 
                                @"turmeric.jpg",
                                @"whynani_img3.jpg",
                                @"spice_blends.jpg",
                                @"products1.png", nil];

currentIndex = currentIndex + 1;
if(currentIndex > MAX_COUNT) 
   currentIndex = MAX_COUNT;
        

for (int i = 0; i<[imageName count]; i++ ) 

   UIImageView  *mmageView = 
     [[UIImageView alloc] initWithFrame:CGRectMake(200,200,350,350)];
   [mmageView setImage:[UIImage imageNamed:[imageName objectAtIndex:i]]];            
   [self.view addSubview:mmageView];           

【问题讨论】：

只需根据其索引制作图像数组并点击显示即可。

@HimanshuJoshi：你能帮我编辑一下代码吗？

【参考方案1】：

在接口文件中声明一个全局imageView和一个int

UIImageView *imgView;
int index;

在viewDidLoad:

index = 0;

imgView = [[UIImageView alloc] initWithFrame:CGRectMake(200,200,350,350)];
[imgView setImage:[UIImage imageNamed:[imageName objectAtIndex:index]]];
[self.view addSubView:imgView]; 

在Next Button Action

-(void)nextButtonAction

  ++index;

  [previousBtn setEnabled:YES]; 

  if (index > [imageName count])
  
    index = [imageName count] - 1;
    [nextBtn setEnabled:NO];
  

  [imgView setImage:[UIImage imageNamed:[imageName objectAtIndex:index]]];

在Previous Button Action

-(void)previousButtonAction

  --index;

  [nextBtn setEnabled:YES]; 

  if (index < 0)
  
    index = 0;
    [previousBtn setEnabled:NO];
  

  [imgView setImage:[UIImage imageNamed:[imageName objectAtIndex:index]]];

【参考方案2】：

您可以使用具有 2 个 UIButtons 的 UIViewController 来执行相同的操作，其中自定义图像与 UIImageView 一起描绘前进和后退。在选择下一个/后退按钮时加载适当的图像。图像名称必须存储在 NSArray 中。

希望这会有所帮助。

编辑：示例代码如下，

在.h文件中

@property(nonatomic, weak) UIImageView *imageView;
@property(nonatomic, weak) UIButton *nextButton;
@property(nonatomic, weak) UIButton *backButton;

(IBAction)btnNextBtn:(id)sender;
(IBAction)btnBackBtn:(id)sender;

在 .m 文件中

(void)viewDidLoad 
    currentIndex = 0;
    NSMutableArray *imageName = [[NSMutableArray alloc] initWithObjects:@"Myprofile.png", 
                                 @"great_ideas_wordle2.png", @"Review.png", 
                                 @"collaborate.png", nil];

   imageView = [[UIImageView alloc] initWithFrame:CGRectMake(200,200,350,350)];
   [imageView setImage:[UIImage imageNamed:[imageName objectAtIndex:currentIndex]]];
   [self.view addSubView:imageView];


(IBAction)btnNextBtn:(id)sender 
     currentIndex = currentIndex + 1;
     if(currentIndex > MAX_COUNT) 
         currentIndex = MAX_COUNT;
     
     // load the image view with the currentIndex from the array.
     [imageView setImage:[UIImage imageNamed:[imageName objectAtIndex:currentIndex]]];


(IBAction)btnBackBtn:(id)sender 
     currentIndex = currentIndex - 1;
     if (currentIndex < 0) 
         currentIndex = 0;
     
     // load the image view with the currentIndex from the array.
     [imageView setImage:[UIImage imageNamed:[imageName objectAtIndex:currentIndex]]];

【讨论】：

在您的 for 循环中，您正在创建新的图像视图并将其添加到 UIView 中，这是不正确的。您使用情节提要创建 UIImageView 和 UIButton。应该使用相同的 UIImageView 来显示图像。

我不明白你的逻辑。我正在创建 UIImageView 和按钮。我没有使用故事板。不将 UIImageView 添加到 UIView 那么它将如何显示？

不正确。如果您使用的是 XIB，则添加这些 UIComponents 并将您的组件链接到其各自的变量名称。

这里我的代码有什么错误。我能做些什么。再次告诉我没有使用故事板。我应该怎么称呼 herr // 使用数组中的 currentIndex 加载图像视图。

您是在使用 XIB 还是以编程方式创建 UIControls？请找到我编辑的答案。

【参考方案3】：

将其写入 .h 文件

@property (nonatomic,retain)IBOutlet UIImageView *imageview1;

@property (nonatomic,retain)IBOutlet UIButton *pre,*next;

@property (nonatomic,retain) NSArray *images;

@property (nonatomic) int currentindex;

-(IBAction)prebtn:(id)sender;

-(IBAction)nextbtn:(id)sender;

将此代码写入 .m 文件

@implementation ViewController

@synthesize images;
@synthesize currentindex;
@synthesize pre,next;
@synthesize imageview1;

- (void)viewDidLoad

 [super viewDidLoad];
 // Do any additional setup after loading the view, typically from a nib.

  self.currentindex = 0;

  self.images = [[NSArray alloc] initWithObjects:@"images-2.jpeg",@"images-    3.jpeg",@"images.jpeg", nil];
 imageview1.image = [UIImage imageNamed:@"images-2.jpeg"];
 [pre setEnabled:NO];
   

- (void)didReceiveMemoryWarning
  
 [super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.


-(IBAction)nextbtn:(id)sender
currentindex = currentindex + 1;
[pre setEnabled:YES];
if (currentindex >= [images count])

currentindex = currentindex - 1;
[next setEnabled:NO];

imageview1.image = [UIImage imageNamed:[images objectAtIndex:currentindex]];    


-(IBAction)prebtn:(id)sender

currentindex = currentindex - 1;
[next setEnabled:YES];
if(currentindex < 0)

currentindex = 0;
[pre setEnabled:NO];

imageview1.image = [UIImage imageNamed:[images objectAtIndex:currentindex]];


@end

【参考方案4】：

试试这个代码

.h 文件

@property(nonatomic, strong) UIImageView *imageView;
@property(nonatomic, strong) UIButton *nextButton;
@property(nonatomic, strong) UIButton *previousButton;
@property(nonatomic, strong) NSMutableArray *imagesArrayName;
@property(nonatomic) int   currentIndex;

-(IBAction)btnNextImage:(id)sender;
-(IBAction)btnPreviousImage:(id)sender;

.m 文件

- (void)viewDidLoad 
    [super viewDidLoad];

    self.currentIndex = 0;

    NSMutableArray *imagesArrayName = [[NSMutableArray alloc] initWithObjects:
                                      @"spices.jpg",
                                      @"spice_powder.jpg", 
                                      @"turmeric.jpg",
                                      @"whynani_img3.jpg",
                                      @"spice_blends.jpg",
                                      @"products1.png", nil];

    [self.nextButton addTarget:self action:@selector(btnNextImage:) forControlEvents:UIControlEventTouchUpInside];
    [self.previousButton addTarget:self action:@selector(btnPreviousImage:) forControlEvents:UIControlEventTouchUpInside];

    [self.imageView setImage[UIImage imageNamed:(NSString*)[imagesArrayName objectAtIndex:currenIndex]]];

    [self.previousButton setEnabled:FALSE];



-(IBAction)btnNextImage:(id)sender 

    self.currentIndex = self.currentIndex + 1;

    [self.imageView setImage[UIImage imageNamed:(NSString*)[imagesArrayName objectAtIndex:currenIndex]]];

    if (self.currentIndex == [self.imagesArrayName count] - 1) 

        [self.nextButton setEnabled:FALSE];
    
    [self.previousButton setEnabled:TRUE];


-(IBAction)btnPreviousImage:(id)sender

    self.currentIndex = self.currentIndex - 1;

    [self.imageView setImage[UIImage imageNamed:(NSString*)[imagesArrayName objectAtIndex:currenIndex]]];

    if (self.currentIndex == 0) 

        [self.previousButton setEnabled:FALSE];
    
    [self.nextButton setEnabled:TRUE];