UITextInputDelegate方法无法正常运行 [英] UITextInputDelegate methods not functioning correctly

问题描述

我现在正在开发iOS 8自定义键盘扩展程序，使用 UITextInputDelegate 方法存在一些问题。

I'm working on iOS 8 custom keyboard extension right now, and there are some issues in using UITextInputDelegate Methods.

这是否右：当用户长按打字区域时，应该调用 selectionWillChange：和 selectionDidChange：方法？只要文本字面改变，就应该调用 textWillChange：和 textDidChange：方法吗？

Does this right: selectionWillChange: and selectionDidChange: methods should be called when user long-presses typing area? And textWillChange: and textDidChange: methods should be called whenever the text is literally changing?

实际上，我是什么观察到的是，当我在文本输入区域中更改选择时，会调用textWillChange：和textDidChange：，并且我无法得到其他两个方法在什么条件下被调用的线索。如果有人知道这些委托方法的用法，请告诉我。

Actually, what I observed is that, when I changed selection in text input area, textWillChange: and textDidChange: are called, and I cannot get a clue that the other two methods are called in what condition. If anyone knows about the usage of these delegate methods, please let me know.

推荐答案

这对我不起作用......我目前正在做的只是使用 textWillChange 和 textDidChange 如你所说，当你改变选择...（他们被称为 BEFORE 和 AFTER ）

然后比较：
self.textDocumentProxy。 documentContextBeforeInput
self.textDocumentProxy.documentContextAfterInput

从 BEFORE （textWillChange）到 AFTER （textDidChange）查看选择范围或长度是否完全改变。

It's not working for me either... what I am currently doing is just using textWillChange and textDidChange which does get called, as you mentioned, when you change your selection... (they get called BEFORE and AFTER)

And then comparing the:
self.textDocumentProxy.documentContextBeforeInput
self.textDocumentProxy.documentContextAfterInput

From BEFORE (textWillChange) to the AFTER (textDidChange) to see if selection range or length changed at all.

这样的东西（在你的.h文件中设置下面的4个NSStrings ...当然没有测试过这个完整的片段，因为我刚才在SO.com上从头开始编写它，但我确信如果我犯了任何错误，原理是否有效） / p>

Something like this (set the 4 NSStrings below in your .h file of course... haven't tested this exact snippet because I wrote it from scratch just now on SO.com but I'm sure the principle works if I made any errors)

- (void)textWillChange:(id<UITextInput>)textInput {
    beforeStringOfTextBehindCursor = self.textDocumentProxy.documentContextBeforeInput;
    beforeStringOfTextAfterCursor = self.textDocumentProxy.documentContextAfterInput;
}

- (void)textDidChange:(id<UITextInput>)textInput {
    afterStringOfTextBehindCursor = self.textDocumentProxy.documentContextBeforeInput;
    afterStringOfTextAfterCursor = self.textDocumentProxy.documentContextAfterInput;

    BOOL didSelectionChange = NO;

    if (![beforeStringOfTextBehindCursor isEqualToString:afterStringOfTextBehindCursor]) {
        didSelectionChange = YES;
    }

    if (![beforeStringOfTextAfterCursor isEqualToString:afterStringOfTextAfterCursor]) {
        didSelectionChange = YES;
    }

    if (didSelectionChange) {
        NSLog(@"Selection Changed!");
    }   
}

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