Objective c 从内部块调用块

在Objective-c中，我们声明了一个作为web请求回调的完成块

如果请求失败，那么我希望能够从完成块中再次调用该函数。当我这样做时，由于未完全定义块，我获得了EXC_BAD_访问权限

这很烦人，因为在Java中，我可以通过侦听器来实现这一点

是否可以从内部调用完成块

谢谢

下面的代码抛出了错误，请问我如何修复它

CustomErrorBlock errorBlock = ^(NSError *error) {

    _processing = NO;
    loadingView.hidden = YES;

    self.infoText.hidden = NO;
    self.infoText.text = @"A network connection error has occurred.";
};


CustomCompletionBlock completionBlock = ^(NSData *data){

    if(![self processGetTransactions:data withDict:updateDict]) {

        [webClient getTransactions:updateDict WithCompletionBlock:completionBlock andErrorBlock:errorBlock];
    }
};
[webClient getTransactions:updateDict WithCompletionBlock:completionBlock andErrorBlock:errorBlock];

---

应该能够通过使用_块停止EXC_BAD_访问崩溃，该块告诉编译器必须以特殊的方式处理它，还可以使用_弱小，使对象无法保持强

__block CustomErrorBlock errorBlock = ^(NSError *error) {

    _processing = NO;
    loadingView.hidden = YES;

    self.infoText.hidden = NO;
    self.infoText.text = @"A network connection error has occurred.";
};


__block CustomCompletionBlock completionBlock = ^(NSData *data) {

    if(![self processGetTransactions:data withDict:updateDict]) {
        __weak CustomCompletionBlock weakCompletionBlock = completionBlock; // Note seems to always have retain cycle

        [webClient getTransactions:updateDict WithCompletionBlock:weakCompletionBlock andErrorBlock:errorBlock];
    }
};

    [webClient getTransactions:updateDict WithCompletionBlock:completionBlock andErrorBlock:errorBlock];

---

注意：由于某些原因，弱对象仍然显示一条关于对象变强的消息，但它可以正常工作

你能发布所有函数吗？你复制completionBlock吗？复制是什么意思？