首先，您必须设置EditText监听按键

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

    // Set the EditText listens to key press
    EditText edittextproductnumber = (EditText) findViewById(R.id.editTextproductnumber);
    edittextproductnumber.setOnKeyListener(this);

}

其次，定义按键时的事件，例如，设置TextView的文本的event:

@Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
    // TODO Auto-generated method stub

 // Listen to "Enter" key press
 if ((event.getAction() == KeyEvent.ACTION_DOWN) && (keyCode == KeyEvent.KEYCODE_ENTER))
 {
     TextView textviewmessage = (TextView) findViewById(R.id.textViewmessage);
     textviewmessage.setText("You hit 'Enter' key");
     return true;
 }

return false;   

}

最后，不要忘记在顶部导入EditText,TextView,OnKeyListener,KeyEvent:

import android.view.KeyEvent;
import android.view.View.OnKeyListener;
import android.widget.EditText;
import android.widget.TextView;

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);

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;
        }
    });

这在LG安卓手机上运行良好。它防止ENTER和其他特殊字符被解释为普通字符。“下一步”或“完成”按钮自动出现，“ENTER”按预期工作。

edit.setInputType(InputType.TYPE_CLASS_TEXT);

下面是一个简单的静态函数，您可以将它扔到Utils或keyboard类中，当用户敲击硬件或软件键盘上的返回键时，它将执行代码。这是@earlcasper精彩回答的修改版

 /**
 * Return a TextView.OnEditorActionListener that will execute code when an enter is pressed on
 * the keyboard.<br>
 * <code>
 *     myTextView.setOnEditorActionListener(Keyboards.onEnterEditorActionListener(new Runnable()->{
 *         Toast.makeText(context,"Enter Pressed",Toast.LENGTH_SHORT).show();
 *     }));
 * </code>
 * @param doOnEnter A Runnable for what to do when the user hits enter
 * @return the TextView.OnEditorActionListener
 */
public static TextView.OnEditorActionListener onEnterEditorActionListener(final Runnable doOnEnter){
    return (__, actionId, event) -> {
        if (event==null) {
            if (actionId == EditorInfo.IME_ACTION_DONE) {
                // Capture soft enters in a singleLine EditText that is the last EditText.
                doOnEnter.run();
                return true;
            } else if (actionId==EditorInfo.IME_ACTION_NEXT) {
                // Capture soft enters in other singleLine EditTexts
                doOnEnter.run();
                return true;
            } 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.
                return true;
            } else {
                doOnEnter.run();
                return true;   // We consume the event when the key is released.
            }
        } else {
            // We let the system handle it when the listener
            // is triggered by something that wasn't an enter.
            return false;
        }
    };
}

我通过扩展新的MaterialAlertDialogBuilder创建了一个辅助类

使用

new InputPopupBuilder(context)
        .setInput(R.string.send, 
                R.string.enter_your_message, 
                text -> sendFeedback(text, activity))
        .setTitle(R.string.contact_us)
        .show();

Code

public class InputPopupBuilder extends MaterialAlertDialogBuilder {

    private final Context context;
    private final AppCompatEditText input;

    public InputPopupBuilder(Context context) {
        super(context);
        this.context = context;
        input = new AppCompatEditText(context);
        input.setInputType(InputType.TYPE_CLASS_TEXT);
        setView(input);
    }

    public InputPopupBuilder setInput(int actionLabel, int hint, Callback callback) {
        input.setHint(hint);
        input.setImeActionLabel(context.getString(actionLabel), KeyEvent.KEYCODE_ENTER);
        input.setOnEditorActionListener((TextView.OnEditorActionListener) (v, actionId, event) -> {
            if (actionId == EditorInfo.IME_NULL
                    && event.getAction() == KeyEvent.ACTION_DOWN) {
                Editable text = input.getText();
                if (text != null) {
                    callback.onClick(text.toString());
                    return true;
                }
            }
            return false;
        });

        setPositiveButton(actionLabel, (dialog, which) -> {
            Editable text = input.getText();
            if (text != null) {
                callback.onClick(text.toString());
            }
        });

        return this;
    }

    public InputPopupBuilder setText(String text){
        input.setText(text);
        return this;
    }

    public InputPopupBuilder setInputType(int inputType){
        input.setInputType(inputType);
        return this;
    }

    public interface Callback {
        void onClick(String text);
    }
}

需要

implementation 'com.google.android.material:material:1.3.0-alpha04'