iOS教學 » iOS - Scroll View(捲動檢視)

iOS - Scroll View(捲動檢視)

使用Scroll View

捲動檢視用於顯示內容超過螢幕大小。它可以包含所有其他使用者介面元素，如影象檢視，標籤，文字檢視，甚至是另一個捲動檢視本身。

 

重要的屬性

  • contentSize

  • contentInset

  • contentOffset

  • delegate

 

重要的方法

- (void)scrollRectToVisible:(CGRect)rect animated:(BOOL)animated
- (void)setContentOffset:(CGYiibai)contentOffset animated:(BOOL)animated

 

重要的委託方法

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView
   willDecelerate:(BOOL)decelerate
- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView

 

更新ViewController.h 如下：

讓類符合捲動檢視委託協定通過新增<UIScrollViewDelegate>宣告捲動檢視範例如下圖所示，在ViewController.h
#import <UIKit/UIKit.h>

@interface ViewController : UIViewController<UIScrollViewDelegate>
{
    UIScrollView *myScrollView;
}	

@end

 

新增一個自定義的方法addScrollView

-(void)addScrollView{
    myScrollView = [[UIScrollView alloc]initWithFrame:
    CGRectMake(20, 20, 280, 420)];
    myScrollView.accessibilityActivationYiibai = CGYiibaiMake(100, 100);
    imgView = [[UIImageView alloc]initWithImage:
    [UIImage imageNamed:@"AppleUSA.jpg"]];
    [myScrollView addSubview:imgView];
    myScrollView.minimumZoomScale = 0.5;
    myScrollView.maximumZoomScale = 3;
    myScrollView.contentSize = CGSizeMake(imgView.frame.size.width,
    imgView.frame.size.height);
    myScrollView.delegate = self;
    [self.view addSubview:myScrollView];
}

注意事項：

我們必須命名為 “AppleUSA1.jpg”，我們可以通過拖動影象到我們的導航區域，專案檔案列出的專案中新增影象。影象的解析度高於裝置看到的影象的捲動。

實現捲動檢視在 ViewController.m 委託

-(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{
    return imgView;
}
-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
    NSLog(@"Did end decelerating");
}	
-(void)scrollViewDidScroll:(UIScrollView *)scrollView{
//    NSLog(@"Did scroll");
}
-(void)scrollViewDidEndDragging:(UIScrollView *)scrollView 
  willDecelerate:(BOOL)decelerate{
    NSLog(@"Did end dragging");
}
-(void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView{
    NSLog(@"Did begin decelerating");
}
-(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{
    NSLog(@"Did begin dragging");
}

 

更新 ViewController.m 中的 viewDidLoad 方法如下

(void)viewDidLoad
{
   [super viewDidLoad];
   [self addScrollView];
   //Do any additional setup after loading the view, typically from a nib
}

輸出

現在，當我們執行程式時，我們會得到下面的輸出。一旦捲動捲動檢視，將能夠看到影象的其餘部分。

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