在iOS8委托方法中的零对象 - 自定义键盘

问题描述

我正在构建一个自定义键盘
，我正在我的 InputViewController 中实现以下委托方法。

但我总是获取 _textInput = nil _

I'm building a custom keyboardand I'm implementing the following delegate methods in my InputViewController.
But I always get _textInput = nil_

- (void)textWillChange:(id<UITextInput>)textInput
- (void)textDidChange:(id<UITextInput>)textInput
- (void) selectionWillChange:(id<UITextInput>)textInput
- (void) selectionDidChange:(id<UITextInput>)textInput

有人知道如何解决它吗？

是 nil 为什么？

我需要自己实现吗？

Does anybody know how to fix it?
Is it nil for a reason?
Do I need to implement something by myself?

推荐答案

好问题。但是似乎 UITextInputDelegate 不是您实现的协议。

Good question. But it seems that UITextInputDelegate is not a protocol that you implement.

从苹果标题为：

从：

And from the docs on UITextInputDelegate:

上面的含义是我们不实现这些委托方法;我们使用它们通知 inputDelegate ，您已经通过除键盘输入之外的方式更改了您的文本或选择。

The implication of the above is that we don't implement these delegate methods; we use them to inform the inputDelegate that you have changed your text or selection via means other than keyboard input.

以下是方法，说明了这一点：

Here is an example method that illustrates this:

- (void)delete:(id)sender;
{
    if (selection && ![selection isEmpty]) {
        [inputDelegate textWillChange:self];
        [inputDelegate selectionWillChange:self];
        [self replaceRange:selection withText:@""];
        [inputDelegate selectionDidChange:self];
        [inputDelegate textDidChange:self];
    }
}

具有更多示例的示例代码。

Sample code with more examples here.

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