iOS Coding项目片段记录（二）

1.加快CocoaPod 安装

$ pod install --no-repo-update 

2.判断字符串是否为null  nul nil等情况

- (NSString *)checkStringIsNullString:(NSString *)str  {
    
    if ([[NSString stringWithFormat:@"%@",str] isEqualToString:@""]|| ([NSString stringWithFormat:@"%@",str] == nil) ||[[NSString stringWithFormat:@"%@",str]isEqualToString:@"(null)"] ||[[NSString stringWithFormat:@"%@",str] isEqualToString:@"null"]||[[NSString stringWithFormat:@"%@",str] isEqualToString:@"nul"])
    {
        str = @"0";
        return str;
    }
    return str;
    
}

3.判断一张view 是否被加载过用 nil == view.superview

if (nil == view.superview) {     //判断一个view 是否被加载过    如果被加载过，它的superview就不会是nil
            CGRect frame = scrollView0.frame;
            frame.origin.x = frame.size.width * page;
            frame.origin.y = 0;
            view.frame = frame;
            [scrollView0 addSubview:view];
        }

 4.WebView图片自适应模式

- (void)webViewDidFinishLoad:(UIWebView *)webView {
  NSString *js = @"function imgAutoFit() { \
     var imgs = document.getElementsByTagName('img'); \
     for (var i = 0; i < imgs.length; ++i) {\
        var img = imgs[i];   \
        img.style.maxWidth = %f;   \
     } \
  }";
  js = [NSString stringWithFormat:js, [UIScreen mainScreen].bounds.size.width - 20];
 
  [webView stringByEvaluatingJavaScriptFromString:js];
  [webView stringByEvaluatingJavaScriptFromString:@"imgAutoFit()"];
}

5.强制APP退出

- (void)exitApplication {
    AppDelegate *app = [UIApplication sharedApplication].delegate;
    UIWindow *window = app.window;
    [UIView animateWithDuration:1.0f animations:^{
        window.alpha = 0;
    } completion:^(BOOL finished) {
        exit(0);
    }];
}