停止網頁瀏覽反彈顯示錯誤

Question

嘗試阻止網頁瀏覽反彈，當用戶拖動應用程序/屏幕時，頂部會出現一個空白區域。這是不正常的代碼：

#import "Webview.h" 

@interface Webview() 

@end 

@implementation Webview 
@synthesize webView; 
- (void)viewDidLoad { 
    [super viewDidLoad]; 
    // Do any additional setup after loading the view. 
    NSString *urlAddress= [[NSBundle mainBundle] pathForResource:@"demos/index" ofType:@"html"]; 
    NSURL *url = [NSURL fileURLWithPath: urlAddress]; 
    NSURLRequest *requestObj = [NSURLRequest requestWithURL:url]; 

    [webView loadRequest:requestObj]; 

    webView.scrollView.delegate = self; 

    webView.scrollView.bounces = NO; 
    } 




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


- (void)scrollViewDidScroll:(UIScrollView *)scrollView{ 
    //The webview is is scrolling 
    int yPosition = [[webView stringByEvaluatingJavaScriptFromString: @"scrollY"] intValue]; 

    if([[webView stringByEvaluatingJavaScriptFromString: @"document.body.offsetHeight"] intValue] - yPosition == webView.frame.size.height) 
    { 
     //The user scrolled to the bottom of the webview 
     webView.scrollView.bounces = YES; 
    }else if([[webView stringByEvaluatingJavaScriptFromString: @"document.body.offsetHeight"] intValue] - yPosition > webView.frame.size.height + 100){ 
     webView.scrollView.bounces = NO; 
    } 

} 

- (void)scrollViewDidScrollToTop:(UIScrollView *)scrollView{ 
    NSLog(@"Finish"); 
} 



/* 
#pragma mark - Navigation 

// In a storyboard-based application, you will often want to do a little preparation before navigation 
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender { 
    // Get the new view controller using [segue destinationViewController]. 
    // Pass the selected object to the new view controller. 
} 
*/ 

@end 

有消息：分配到「身份證_Nullable」從omcompatible型「web視圖* const的__strong」

Answer 1

如果錯誤就行了：

_webView.scrollView.delegate = self; 

...然後錯誤是你的webView實例不是正確的類型。

1. 檢查您的webView實例是否爲UIWebView的子類。
2. 你應該採用UIScrollViewDelegate協議，通過包括用於所述接口的協議聲明：@interface ViewController : UIViewController <UIScrollViewDelegate>