这将在用户按下返回键时为您提供一个可调用的函数。

fun EditText.setLineBreakListener(onLineBreak: () -> Unit) {
    val lineBreak = "\n"
    doOnTextChanged { text, _, _, _ ->
        val currentText = text.toString()

        // Check if text contains a line break
        if (currentText.contains(lineBreak)) {

            // Uncommenting the lines below will remove the line break from the string
            // and set the cursor back to the end of the line

            // val cleanedString = currentText.replace(lineBreak, "")
            // setText(cleanedString)
            // setSelection(cleanedString.length)

            onLineBreak()
        }
    }
}

使用

editText.setLineBreakListener {
    doSomething()
}

检测回车键被按下的最简单的方法是:

mPasswordField.setOnEditorActionListener(new TextView.OnEditorActionListener() {
            @Override
            public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
                if (event!= null) {   // KeyEvent: If triggered by an enter key, this is the event; otherwise, this is null.
                    signIn(mEmailField.getText().toString(), mPasswordField.getText().toString());
                    return true;
                } else {
                    return false;
                }
            }
        });

我使用Kotlin创建了一个函数，它可以处理EditText的所有“完成”动作，包括键盘，并且可以修改它，也可以处理其他按键:

private val DEFAULT_ACTIONS_TO_HANDLE_AS_DONE_FOR_EDIT_TEXT = arrayListOf(EditorInfo.IME_ACTION_SEND, EditorInfo.IME_ACTION_GO, EditorInfo.IME_ACTION_SEARCH, EditorInfo.IME_ACTION_DONE)
private val DEFAULT_KEYS_TO_HANDLE_AS_DONE_FOR_EDIT_TEXT = arrayListOf(KeyEvent.KEYCODE_ENTER, KeyEvent.KEYCODE_NUMPAD_ENTER)

fun EditText.setOnDoneListener(function: () -> Unit, onKeyListener: OnKeyListener? = null, onEditorActionListener: TextView.OnEditorActionListener? = null,
                               actionsToHandle: Collection<Int> = DEFAULT_ACTIONS_TO_HANDLE_AS_DONE_FOR_EDIT_TEXT,
                               keysToHandle: Collection<Int> = DEFAULT_KEYS_TO_HANDLE_AS_DONE_FOR_EDIT_TEXT) {
    setOnEditorActionListener { v, actionId, event ->
        if (onEditorActionListener?.onEditorAction(v, actionId, event) == true)
            return@setOnEditorActionListener true
        if (actionsToHandle.contains(actionId)) {
            function.invoke()
            return@setOnEditorActionListener true
        }
        return@setOnEditorActionListener false
    }
    setOnKeyListener { v, keyCode, event ->
        if (onKeyListener?.onKey(v, keyCode, event) == true)
            return@setOnKeyListener true
        if (event.action == KeyEvent.ACTION_DOWN && keysToHandle.contains(keyCode)) {
            function.invoke()
            return@setOnKeyListener true
        }
        return@setOnKeyListener false
    }
}

那么，示例用法:

        editText.setOnDoneListener({
            //do something
        })

至于改变标签，我认为这取决于键盘应用，它通常只在横屏上改变，就像这里写的那样。总之，这个的用法示例:

        editText.imeOptions = EditorInfo.IME_ACTION_DONE
        editText.setImeActionLabel("ASD", editText.imeOptions)

或者，如果你想用XML:

    <EditText
        android:id="@+id/editText" android:layout_width="wrap_content" android:layout_height="wrap_content"
        android:imeActionLabel="ZZZ" android:imeOptions="actionDone" />

结果(横屏显示):

我想知道是否有办法 处理用户按Enter键时 输入EditText之类的 onSubmit HTML事件。

是的。

也在想有没有办法 操作虚拟键盘 就像“完成”按钮一样 标记其他东西(例如 “Go”)并执行某个动作 当点击(再次，像onSubmit)。

也没错。

你会想看看android:imeActionId和android:imeOptions属性，加上setOnEditorActionListener()方法，所有的TextView。

要将“Done”按钮的文本更改为自定义字符串，请使用:

mEditText.setImeActionLabel("Custom text", KeyEvent.KEYCODE_ENTER);

你应该这样做。它也隐藏在Android开发者的样例代码“蓝牙聊天”中。用你自己的变量和方法替换“example”的粗体部分。

首先，把你需要的东西导入到主Activity中，你想让返回按钮做一些特殊的事情:

import android.view.inputmethod.EditorInfo;
import android.widget.TextView;
import android.view.KeyEvent;

现在，创建一个类型为TextView的变量。OnEditorActionListener作为返回键(这里我使用exampleListener);

TextView.OnEditorActionListener exampleListener = new TextView.OnEditorActionListener(){

然后，您需要告诉侦听器当按下返回按钮时该做什么。它需要知道我们谈论的EditText是什么(这里我使用exampleView)，然后它需要知道当按下Enter键时要做什么(这里是example_confirm())。如果这是活动中最后一个或唯一一个EditText，它应该做与提交(或确定，确认，发送，保存等)按钮的onClick方法相同的事情。

public boolean onEditorAction(TextView exampleView, int actionId, KeyEvent event) {
   if (actionId == EditorInfo.IME_NULL  
      && event.getAction() == KeyEvent.ACTION_DOWN) { 
      example_confirm();//match this behavior to your 'Send' (or Confirm) button
   }
   return true;
}

最后，设置监听器(很可能在你的onCreate方法中);

exampleView.setOnEditorActionListener(exampleListener);

硬件键盘总是产生输入事件，但是软件键盘在单个的lineedittext中返回不同的actionid和null。每当用户在已设置此侦听器的EditText中按下enter键时，此代码就会响应，而不管EditText或键盘类型是什么。

import android.view.inputmethod.EditorInfo;
import android.view.KeyEvent;
import android.widget.TextView.OnEditorActionListener;

listener=new TextView.OnEditorActionListener() {
  @Override
  public boolean onEditorAction(TextView view, int actionId, KeyEvent event) {
    if (event==null) {
      if (actionId==EditorInfo.IME_ACTION_DONE);
      // Capture soft enters in a singleLine EditText that is the last EditText.
      else if (actionId==EditorInfo.IME_ACTION_NEXT);
      // Capture soft enters in other singleLine EditTexts
      else return false;  // Let system handle all other null KeyEvents
    }
    else if (actionId==EditorInfo.IME_NULL) { 
    // Capture most soft enters in multi-line EditTexts and all hard enters.
    // They supply a zero actionId and a valid KeyEvent rather than
    // a non-zero actionId and a null event like the previous cases.
      if (event.getAction()==KeyEvent.ACTION_DOWN); 
      // We capture the event when key is first pressed.
      else  return true;   // We consume the event when the key is released.  
    }
    else  return false; 
    // We let the system handle it when the listener
    // is triggered by something that wasn't an enter.


    // Code from this point on will execute whenever the user
    // presses enter in an attached view, regardless of position, 
    // keyboard, or singleLine status.

    if (view==multiLineEditText)  multiLineEditText.setText("You pressed enter");
    if (view==singleLineEditText)  singleLineEditText.setText("You pressed next");
    if (view==lastSingleLineEditText)  lastSingleLineEditText.setText("You pressed done");
    return true;   // Consume the event
  }
};

The default appearance of the enter key in singleLine=false gives a bent arrow enter keypad. When singleLine=true in the last EditText the key says DONE, and on the EditTexts before it it says NEXT. By default, this behavior is consistent across all vanilla, android, and google emulators. The scrollHorizontal attribute doesn't make any difference. The null test is important because the response of phones to soft enters is left to the manufacturer and even in the emulators, the vanilla Level 16 emulators respond to long soft enters in multi-line and scrollHorizontal EditTexts with an actionId of NEXT and a null for the event.