ios开发基础知识（ios基础知识点）

话不多说，直接进主题

一、防止UIButton，cell等重复点击

主要是快速点击button或者cell，所对应的action或者逻辑会走多次，例如：点击button或者cell调用拨打电话的方法，会弹出拨打电话框好多次；这个对用户不太友好；问了下哥们儿，他给了个宏，目前算是解决这个问题；代码如下：

1 2 3 4 5 6 7 8 // 防止多次调用 #define kPreventRepeatClickTime(_seconds_) \ static BOOL shouldPrevent; \ if (shouldPrevent) return; \ shouldPrevent = YES; \ dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)((_seconds_) * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{ \ shouldPrevent = NO; \ }); \

总的思路是设置一个bool变量，记录一下，延时更改下变量的值；使用：在所需要的button或者cell的action前调用即可：

1	`kPreventRepeatClickTime(0.5);`

二、获取当前视图最顶层的ViewController

获取当前视图最顶层的ViewController

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 + (UIViewController *)currentViewController { UIWindow * window = [[UIApplication sharedApplication] keyWindow]; if (window.windowLevel != UIWindowLevelNormal){ NSArray *windows = [[UIApplication sharedApplication] windows]; for(UIWindow * tmpWin in windows){ if (tmpWin.windowLevel == UIWindowLevelNormal){ window = tmpWin; break; } } } UIViewController *currentVC = window.rootViewController; while (currentVC.presentedViewController) { currentVC = currentVC.presentedViewController; } if ([currentVC isKindOfClass:[UITabBarController class]]) { currentVC = [(UITabBarController *)currentVC selectedViewController]; } if ([currentVC isKindOfClass:[UINavigationController class]]) { currentVC = [(UINavigationController *)currentVC topViewController]; } return currentVC; }

三、代码截图相关

截取指定的View：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 /// 截屏 - (void)actionForScreenShotWith:(UIView *)aimView savePhoto:(BOOL)savePhoto { if (!aimView) return; UIGraphicsBeginImageContextWithOptions(aimView.bounds.size, NO, 0.0f); [aimView.layer renderInContext: UIGraphicsGetCurrentContext()]; UIImage* viewImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); if (savePhoto) { /// 保存到本地相册 UIImageWriteToSavedPhotosAlbum(viewImage, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL); } }

保存图片的回调处理

1 2 3 4 5 6 7 - (void)image:(UIImage*)image didFinishSavingWithError:(NSError*)error contextInfo:(void*)contextInfo{ if (error) { NSLog(@"保存失败，请重试"); } else { NSLog(@"保存成功"); } }