496
votes

I am wondering if there is a way to handle the user pressing Enter while typing in an EditText, something like the onSubmit HTML event.

Also wondering if there is a way to manipulate the virtual keyboard in such a way that the "Done" button is labeled something else (for example "Go") and performs a certain action when clicked (again, like onSubmit).

30
Kotlin & Extensions: have a look here: stackoverflow.com/a/48810268/1912924Francesco Donzello

30 Answers

402
votes

I am wondering if there is a way to handle the user pressing Enter while typing in an EditText, something like the onSubmit HTML event.

Yes.

Also wondering if there is a way to manipulate the virtual keyboard in such a way that the "Done" button is labeled something else (for example "Go") and performs a certain action when clicked (again, like onSubmit).

Also yes.

You will want to look at the android:imeActionId and android:imeOptions attributes, plus the setOnEditorActionListener() method, all on TextView.

For changing the text of the "Done" button to a custom string, use:

mEditText.setImeActionLabel("Custom text", KeyEvent.KEYCODE_ENTER);
298
votes
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;
    }
});
218
votes

Here's what you do. It's also hidden in the Android Developer's sample code 'Bluetooth Chat'. Replace the bold parts that say "example" with your own variables and methods.

First, import what you need into the main Activity where you want the return button to do something special:

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

Now, make a variable of type TextView.OnEditorActionListener for your return key (here I use exampleListener);

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

Then you need to tell the listener two things about what to do when the return button is pressed. It needs to know what EditText we're talking about (here I use exampleView), and then it needs to know what to do when the Enter key is pressed (here, example_confirm()). If this is the last or only EditText in your Activity, it should do the same thing as the onClick method for your Submit (or OK, Confirm, Send, Save, etc) button.

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;
}

Finally, set the listener (most likely in your onCreate method);

exampleView.setOnEditorActionListener(exampleListener);
42
votes

Hardware keyboards always yield enter events, but software keyboards return different actionIDs and nulls in singleLine EditTexts. This code responds every time the user presses enter in an EditText that this listener has been set to, regardless of EditText or keyboard type.

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.

37
votes

This page describes exactly how to do this.

https://developer.android.com/training/keyboard-input/style.html

Set the android:imeOptions then you just check the actionId in onEditorAction. So if you set imeOptions to 'actionDone' then you would check for 'actionId == EditorInfo.IME_ACTION_DONE' in onEditorAction. Also, make sure to set the android:inputType.

If using Material Design put code in TextInputEditText.

Here's the EditText from the example linked above:

<EditText
    android:id="@+id/search"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:hint="@string/search_hint"
    android:inputType="text"
    android:imeOptions="actionSend" />

You can also set this programmatically using the setImeOptions(int) function. Here's the OnEditorActionListener from the example linked above:

EditText editText = (EditText) findViewById(R.id.search);
editText.setOnEditorActionListener(new OnEditorActionListener() {
    @Override
    public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
        boolean handled = false;
        if (actionId == EditorInfo.IME_ACTION_SEND) {
            sendMessage();
            handled = true;
        }
        return handled;
    }
});
22
votes

I know this is a year old, but I just discovered this works perfectly for an EditText.

EditText textin = (EditText) findViewById(R.id.editText1);
textin.setInputType(InputType.TYPE_CLASS_TEXT);

It prevents anything but text and space. I could not tab, "return" ("\n"), or anything.

16
votes

Just as an addendum to Chad's response (which worked almost perfectly for me), I found that I needed to add a check on the KeyEvent action type to prevent my code executing twice (once on the key-up and once on the key-down event).

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

See http://developer.android.com/reference/android/view/KeyEvent.html for info about repeating action events (holding the enter key) etc.

16
votes

In your xml, add the imeOptions attribute to the editText

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

Then, in your Java code, add the OnEditorActionListener to the same EditText

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;
        }
    });

Here is the explanation- The imeOptions=actionDone will assign "actionDone" to the EnterKey. The EnterKey in the keyboard will change from "Enter" to "Done". So when Enter Key is pressed, it will trigger this action and thus you will handle it.

16
votes

I had a similar purpose. I wanted to resolve pressing the "Enter" key on the keyboard (which I wanted to customize) in an AutoCompleteTextView which extends TextView. I tried different solutions from above and they seemed to work. BUT I experienced some problems when I switched the input type on my device (Nexus 4 with AOKP ROM) from SwiftKey 3 (where it worked perfectly) to the standard Android keyboard (where instead of handling my code from the listener, a new line was entered after pressing the "Enter" key. It took me a while to handle this problem, but I don't know if it will work under all circumstances no matter which input type you use.

So here's my solution:

Set the input type attribute of the TextView in the xml to "text":

android:inputType="text"

Customize the label of the "Enter" key on the keyboard:

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

Set an OnEditorActionListener to the TextView:

myTextView.setOnEditorActionListener(new OnEditorActionListener()
{
    @Override
    public boolean onEditorAction(TextView v, int actionId,
        KeyEvent event)
    {
    boolean handled = false;
    if (event.getAction() == KeyEvent.KEYCODE_ENTER)
    {
        // Handle pressing "Enter" key here

        handled = true;
    }
    return handled;
    }
});

I hope this can help others to avoid the problems I had, because they almost drove me nuts.

10
votes

You can also do it..

editText.setOnKeyListener(new OnKeyListener() {

            @Override
            public boolean onKey(View v, int keyCode, KeyEvent event)
            {
                if (event.getAction() == KeyEvent.ACTION_DOWN
                        && event.getKeyCode() ==       KeyEvent.KEYCODE_ENTER) 
                {
                    Log.i("event", "captured");

                    return false;
                } 

            return false;
        }
    });
6
votes

First, you have to set EditText listen to key press

@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);

}

Second, define the event upon the key press, for example, event to set TextView's text:

@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;   

}

And finally, do not forget to import EditText,TextView,OnKeyListener,KeyEvent at top:

import android.view.KeyEvent;
import android.view.View.OnKeyListener;
import android.widget.EditText;
import android.widget.TextView;
6
votes
     password.setOnEditorActionListener(new TextView.OnEditorActionListener() {
        public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
            if(event != null && event.getKeyCode() == KeyEvent.KEYCODE_ENTER && event.getAction() == KeyEvent.ACTION_DOWN) {
                InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
                imm.toggleSoftInput(InputMethodManager.SHOW_IMPLICIT, 0);
                submit.performClick();
                return true;
            }
            return false;
        }
    });

Works very fine for me
In addition hide keyboard

6
votes

working perfectly

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");

        }
    });
}

}

working perfectly

5
votes
editText.setOnEditorActionListener(new TextView.OnEditorActionListener() {
        @Override
        public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
            if (actionId != 0 || event.getAction() == KeyEvent.ACTION_DOWN) {
                // Action
                return true;
            } else {
                return false;
            }
        }
    });

Xml

<EditText
        android:id="@+id/editText2"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:hint="@string/password"
        android:imeOptions="actionGo|flagNoFullscreen"
        android:inputType="textPassword"
        android:maxLines="1" />
4
votes

This should work

input.addTextChangedListener(new TextWatcher() {

           @Override
           public void afterTextChanged(Editable s) {}

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

           @Override    
           public void onTextChanged(CharSequence s, int start,
             int before, int count) {
               if( -1 != input.getText().toString().indexOf( "\n" ) ){
                   input.setText("Enter was pressed!");
                    }
           }
          });
4
votes

Type this code in your editor so that it can import necessary modules.

 query.setOnEditorActionListener(new TextView.OnEditorActionListener() {
        @Override
        public boolean onEditorAction(TextView textView, int actionId, KeyEvent keyEvent) {
            if(actionId == EditorInfo.IME_ACTION_DONE
                    || keyEvent.getAction() == KeyEvent.ACTION_DOWN
                        || keyEvent.getAction() == KeyEvent.KEYCODE_ENTER) {

                // Put your function here ---!

                return true;

            }
            return false;
        }
    });
4
votes

you can use this way

editText.setOnEditorActionListener((v, actionId, event) -> {
       if (actionId == EditorInfo.IME_ACTION_DONE) {
          // Do some things      
          return true;
       }
       return false;
});

you can see list of action there.

For example:

IME_ACTION_GO

IME_ACTION_SEARCH

IME_ACTION_SEND

3
votes

This works fine on LG Android phones. It prevents ENTER and other special characters to be interpreted as normal character. Next or Done button appears automatically and ENTER works as expected.

edit.setInputType(InputType.TYPE_CLASS_TEXT);
2
votes

Here's a simple static function that you can throw into your Utils or Keyboards class that will execute code when the user hits the return key on a hardware or software keyboard. It's a modified version of @earlcasper's excellent answer

 /**
 * 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;
        }
    };
}
2
votes

InputType on the textfield must be text in order for what CommonsWare said to work. Just tried all of this, no inputType before the trial and nothing worked, Enter kept registering as soft enter. After inputType = text, everything including the setImeLabel worked.

Example : android:inputType="text"

2
votes
   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;
        }
    });
2
votes

Using Kotlin I've made a function that handles all kinds of "done"-like actions for EditText, including the keyboard, and it's possible to modify it and also handle other keys as you wish, too :

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
    }
}

So, sample usage:

        editText.setOnDoneListener({
            //do something
        })

As for changing the label, I think it depends on the keyboard app, and that it usually change only on landscape, as written here. Anyway, example usage for this:

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

Or, if you want in XML:

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

And the result (shown in landscape) :

enter image description here

1
votes

A dependable way to respond to an <enter> in an EditText is with a TextWatcher, a LocalBroadcastManager, and a BroadcastReceiver. You need to add the v4 support library to use the LocalBroadcastManager. I use the tutorial at vogella.com: 7.3 "Local broadcast events with LocalBroadcastManager" because of its complete concise code Example. In onTextChanged before is the index of the end of the change before the change>;minus start. When in the TextWatcher the UI thread is busy updating editText's editable, so we send an Intent to wake up the BroadcastReceiver when the UI thread is done updating editText.

import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.text.Editable;
//in onCreate:
editText.addTextChangedListener(new TextWatcher() {
  public void onTextChanged
  (CharSequence s, int start, int before, int count) {
    //check if exactly one char was added and it was an <enter>
    if (before==0 && count==1 && s.charAt(start)=='\n') {
    Intent intent=new Intent("enter")
    Integer startInteger=new Integer(start);
    intent.putExtra("Start", startInteger.toString()); // Add data
    mySendBroadcast(intent);
//in the BroadcastReceiver's onReceive:
int start=Integer.parseInt(intent.getStringExtra("Start"));
editText.getText().replace(start, start+1,""); //remove the <enter>
//respond to the <enter> here
1
votes

This question hasn't been answered yet with Butterknife

LAYOUT XML

<android.support.design.widget.TextInputLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="@string/some_input_hint">

        <android.support.design.widget.TextInputEditText
            android:id="@+id/textinput"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:imeOptions="actionSend"
            android:inputType="text|textCapSentences|textAutoComplete|textAutoCorrect"/>
    </android.support.design.widget.TextInputLayout>

JAVA APP

@OnEditorAction(R.id.textinput)
boolean onEditorAction(int actionId, KeyEvent key){
    boolean handled = false;
    if (actionId == EditorInfo.IME_ACTION_SEND || (key.getKeyCode() == KeyEvent.KEYCODE_ENTER)) {
        //do whatever you want
        handled = true;
    }
    return handled;
}
1
votes

Replace "txtid" with your 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;
        }
    });
1
votes

Kotlin solution to react to enter press using Lambda expression:

        editText.setOnKeyListener { _, keyCode, event ->
            if(keyCode == KeyEvent.KEYCODE_ENTER && event.action==KeyEvent.ACTION_DOWN){
            //react to enter press here
            }
            true
        }

not doing the additional check for the type of event will cause this listener to be called twice when pressed once (once for ACTION_DOWN, once for ACTION_UP)

1
votes

If you use DataBinding, see https://stackoverflow.com/a/52902266/2914140 and https://stackoverflow.com/a/67933283/2914140.

Bindings.kt:

@BindingAdapter("onEditorEnterAction")
fun EditText.onEditorEnterAction(callback: OnActionListener?) {
    if (f == 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()}" />
0
votes

Add these depencendy, and it should work:

import android.view.KeyEvent;
import android.view.View;
import android.widget.EditText;
0
votes

This will give you a callable function when the user presses the return key.

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()
        }
    }
}

Usage

editText.setLineBreakListener {
    doSomething()
}
0
votes

Easiest way to detect Enter key being pressed is:

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;
                }
            }
        });