当输入文本时自动展开的Flutter文本字段，当达到一定高度时开始滚动文本 [英] Flutter textfield that auto expands when text is entered and then starts scrolling the text when a certain height is reached

问题描述

我尝试了Flutter TextField的许多配置，但不知道如何构建它。

I've tried many configurations of the Flutter TextField but can't figure out how to build this one.

我正在寻找一个文本框，它是一个

I'm looking for a textfield that is a single line initially and it auto expands as the text is entered into it and then at some point begins scrolling itself.

这可以通过使用maxLines：null属性部分实现，并在输入文本时自动扩展。 。但是，当输入大量文本时，文本字段中的文本本身就会溢出。

This can be achieved partially by using the maxLines: null attribute. But then when a lot of text is entered the Text in the textfield itself overflows.

如果将maxLines设置为一个值，则整个文本字段本身都会扩展为那些

And if the maxLines is set to a value then the whole textfield itself gets expanded to those many lines to start off with rather than beginning with a single line.

是否有一种方法可以限制文本字段的高度，就像在某些聊天应用程序（如WhatsApp）中所做的那样

Is there a way to limit the height of textfield at some point like done in many chat apps like WhatsApp and telegram.

推荐答案

Container(
    child: new ConstrainedBox(
        constraints: BoxConstraints(
            maxHeight: 300.0,
        ),
        child: TextField(
                    maxLines: null,
                ),
            ),
        ),
    ),
)

在较旧的Flutter中

In older Flutter versions it was

Container(
    child: new ConstrainedBox(
        constraints: BoxConstraints(
            maxHeight: 300.0,
        ),
        child: new Scrollbar(
            child: new SingleChildScrollView(
                scrollDirection: Axis.vertical,
                reverse: true,
                child: new TextField(
                    maxLines: null,
                ),
            ),
        ),
    ),
)

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