UINavigationControllerDelegate的方法是不够的

Question

UINavigationControllerDelegate只能使用2种委派方法：

• navigationController:willShowViewController:
• navigationController:didShowViewController:

但是当我使用手势以交互方式弹出viewController时我想要被调用怎么办？类似的东西：

• navigationController:willStartDragging:
• navigationController:isDraggingWithPercentage:

协议中没有这样的委托方法。我怎样才能获得这些方法？

Answer 1

您可以将目标/操作添加到导航控制器的interactivePopGestureRecognizer，如下所示：

[navigationController.interactivePopGestureRecognizer addTarget:self action:@selector(handleInteractivePop:)];

然后跟踪手势的状态

- (void)handleInteractivePop:(UIScreenEdgePanGestureRecognizer *)recognizer {
    switch (recognizer.state) {
        case UIGestureRecognizerStateBegan:
            // Started Dragging
            break;

        case UIGestureRecognizerStateChanged:
            CGFloat percentComplete = [recognizer locationInView:yourView].x / yourView.frame.size.width;
            // Do something
            break;

        case UIGestureRecognizerStateEnded:
            // Released
            break;

        default:
            break;
    }
}