有没有一种方法可以动态更改Flutter TextField的maxLines? [英] Is there a way to dynamically change the Flutter TextField's maxLines?

问题描述

我有一个像这样的TextField:

I have a TextField like this:

new Flexible(
    fit: FlexFit.loose,
    child: new Container(
        alignment: FractionalOffset.topLeft,
        child: new TextField(
            decoration: new InputDecoration(
                  hintText: 'Add a note',
            ),
            maxLines: 1,
            onChanged: (value) => _showSaveOptions(value),
        ),
    ),
),

我想将我的TextField从maxLines设置为1开始，但是在键入时，我希望maxLines增加，以便所有文本都保留在页面上，而我没有向上滚动.但是，我也不想将maxLines设置为5或10，因为空的TextField占用了必要的更多空间.我要实现的行为的一个示例是在Google表单的长答案文本"选项中，该选项以一行开头: 并随着我的输入而扩展:

I'd like to have my TextField to start out with maxLines set to 1, but as I type, I would like the maxLines to increase, so that all the text remains on the page and I don't have to scroll up. However, I also don't want to start off with maxLines set to say, 5 or 10, because the empty TextField takes up more space that necessary. An example of the behavior I want to implement is in the Long Answer Text option in Google Forms, where it starts with one line: and expands as I type:

我已经考虑过将maxLines设置为一个计数器，该计数器在用户每次换行时都会增加，但是如何确定用户何时填满行?

I've considered setting maxLines to a counter that increments every time the user hits a newline, but how do I determine when the user has filled up a line?

推荐答案

Flutter在TextField中落后于多行支持.在针对同一问题提出了问题之后，在 0.0.16 版本.

Flutter was lagging multiline support in TextField. After an issue was raised regarding the same, the multiline feature has been added in the 0.0.16 release.

确保将flutter升级到最新版本.要获取多行TextField，请使用:

Make sure you upgrade flutter to the latest release. To get multiline TextField use:

new TextField(
    maxLines: null,
    keyboardType: TextInputType.multiline,
) 

希望这对您有帮助！

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