iPhone - 如何处理多个 UIImagePickerControllerDelegate？

Question

我正在开发一个简单的应用程序扫描二维码。为了扫描 QR 码，我使用一种委托(delegate)方法，如下所示。

- (void) imagePickerController: (UIImagePickerController*) reader didFinishPickingMediaWithInfo: (NSDictionary*) info

我还有另一种委托(delegate)方法，用于源类型相机拍照。

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)img editingInfo:(NSDictionary *)editInfo 

我有 2 个按钮用于扫描 QR 和拍照。但问题是，当我拍摄新照片时，

- (void) imagePickerController: (UIImagePickerController*) reader didFinishPickingMediaWithInfo: (NSDictionary*) info

方法被调用。怎么解决这个问题。当我选择照片按钮时，我需要调用特定的委托(delegate)方法，当我调用选择 QR 按钮时，我需要调用其他委托(delegate)方法。

Answer 1

首先 - 值得一提的是这个方法:

- (void)imagePickerController:(UIImagePickerController *)picker 
        didFinishPickingImage:(UIImage *)img 
                  editingInfo:(NSDictionary *)editInfo 

自 iOS 3.0 起已弃用。现在唯一可以使用的方法是

- (void)imagePickerController:(UIImagePickerController *)picker  
didFinishPickingMediaWithInfo:(NSDictionary *)info

(您从字典中获取图像引用)

要回答这个问题:您需要一种方法来识别委托(delegate)回调中的每个选择器。做到这一点的一种方法是创建几个属性，每个选择器一个，并在调用选择器时设置该属性...

@property (nonatomic, weak) UIImagePickerController* QRpicker;
@property (nonatomic, weak) UIImagePickerController* cameraPicker;

正在创建您的 QRPicker...

 UIImagePickerController* QRpicker = [[UIImagePickerController alloc] init];
         //configure QRPicker
 [self presentViewController:QRpicker];
 self.QRpicker = QRpicker;

对cameraPicker执行相同的操作

然后你只需要检查哪种类型的选择器调用了委托(delegate)方法

- (void)imagePickerController:(UIImagePickerController *)picker  
didFinishPickingMediaWithInfo:(NSDictionary *)info
{
  if ([picker isEqual:self.QRPicker])
      //code for QRPicker delegate
  else 
      //code for cameraPicker delegate