完美的工作

public class MainActivity extends AppCompatActivity {  
TextView t;
Button b;
EditText e;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    b = (Button) findViewById(R.id.b);
    e = (EditText) findViewById(R.id.e);

    e.addTextChangedListener(new TextWatcher() {

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {

            if (before == 0 && count == 1 && s.charAt(start) == '\n') {

                b.performClick();
                e.getText().replace(start, start + 1, ""); //remove the <enter>
            }

        }
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
        @Override
        public void afterTextChanged(Editable s) {}
    });

    b.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            b.setText("ok");

        }
    });
}

}

完美的工作

在xml中，将imeOptions属性添加到editText中

<EditText
    android:id="@+id/edittext_additem"
    ...
    android:imeOptions="actionDone"
    />

然后，在Java代码中，将OnEditorActionListener添加到相同的EditText中

mAddItemEditText.setOnEditorActionListener(new TextView.OnEditorActionListener() {
        @Override
        public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
            if(actionId == EditorInfo.IME_ACTION_DONE){
                //do stuff
                return true;
            }
            return false;
        }
    });

下面是解释 imeOptions=actionDone将“actionDone”分配给EnterKey。键盘上的EnterKey将从“Enter”变为“Done”。因此，当按下回车键时，它将触发这个动作，因此您将处理它。

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.

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()}" />

将“txtid”替换为您的EditText ID。

EditText txtinput;
txtinput=findViewById(R.id.txtid)    
txtinput.setOnEditorActionListener(new TextView.OnEditorActionListener() {
        @Override
        public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
            if ((event != null && (event.getKeyCode() == KeyEvent.KEYCODE_ENTER))     || (actionId == EditorInfo.IME_ACTION_DONE)) {
                
                //Code for the action you want to proceed with.

                InputMethodManager inputManager = (InputMethodManager)
                        getSystemService(Context.INPUT_METHOD_SERVICE);

                 inputManager.hideSoftInputFromWindow(getCurrentFocus().getWindowToken(),
                        InputMethodManager.HIDE_NOT_ALWAYS);
            }
            return false;
        }
    });