我想知道是否有一种方法来处理用户在输入EditText时按下Enter,就像onSubmit HTML事件。

还想知道是否有一种方法来操纵虚拟键盘,以这样的方式,“完成”按钮被标记为其他的东西(例如“Go”),并在单击时执行特定的动作(再次,像onSubmit)。


当前回答

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()
}

其他回答

作为Chad响应的补充(对我来说几乎完美),我发现我需要在KeyEvent操作类型上添加一个检查,以防止代码执行两次(一次在key-up事件上执行,一次在key-down事件上执行)。

if (actionId == EditorInfo.IME_NULL && event.getAction() == KeyEvent.ACTION_DOWN)
{
    // your code here
}

有关重复动作事件(按住enter键)的信息,请参见http://developer.android.com/reference/android/view/KeyEvent.html。

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.

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);
final EditText edittext = (EditText) findViewById(R.id.edittext);
edittext.setOnKeyListener(new OnKeyListener() {
    public boolean onKey(View v, int keyCode, KeyEvent event) {
        // If the event is a key-down event on the "enter" button
        if ((event.getAction() == KeyEvent.ACTION_DOWN) &&
            (keyCode == KeyEvent.KEYCODE_ENTER)) {
          // Perform action on key press
          Toast.makeText(HelloFormStuff.this, edittext.getText(), Toast.LENGTH_SHORT).show();
          return true;
        }
        return false;
    }
});

如果使用DataBinding,请参见https://stackoverflow.com/a/52902266/2914140和https://stackoverflow.com/a/67933283/2914140。

Bindings.kt:

@BindingAdapter("onEditorEnterAction")
fun EditText.onEditorEnterAction(callback: OnActionListener?) {
    if (callback == null) setOnEditorActionListener(null)
    else setOnEditorActionListener { v, actionId, event ->
        val imeAction = when (actionId) {
            EditorInfo.IME_ACTION_DONE,
            EditorInfo.IME_ACTION_SEND,
            EditorInfo.IME_ACTION_GO -> true
            else -> false
        }

        val keydownEvent = event?.keyCode == KeyEvent.KEYCODE_ENTER 
            && event.action == KeyEvent.ACTION_DOWN

        if (imeAction or keydownEvent) {
            callback.enterPressed()
            return@setOnEditorActionListener true
        }
        return@setOnEditorActionListener false
    }
}

interface OnActionListener {
    fun enterPressed()
}

layout.xml:

<data>
    <variable
        name="viewModel"
        type="YourViewModel" />
</data>    

<EditText
    android:imeOptions="actionDone|actionSend|actionGo"
    android:singleLine="true"
    android:text="@={viewModel.message}"
    app:onEditorEnterAction="@{() -> viewModel.send()}" />