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error in key event handler

I tried to capture key event for android. Here is the source code i tried:
text.setOnKeyListener(new OnKeyListener() {
#Override
public boolean onKey(View view, int keyCode, KeyEvent event) {
if(keyCode==KeyEvent.KEYCODE_A){
Toast.makeText(MainActivity.this, "A Pressed!!", Toast.LENGTH_LONG).show();
}
return false;
}
});
But it's doesn't work or show any error.
How can i handle the key event for android keyboard?

Software keyboards don't generate onKey events. Only hardware keyboards do. If you want to see changes from a software keyboard, use a TextWatcher on the view.

So you need to use TextChangedListener, Refer here, based on the text, do your work.

Space Key event behaviour on Numeric Input field?

I created two EditText with "android:inputType="number" property.
here I am using hardware Keyboard, so when I perform Space Key event on textField, focus control directly shift from editText view to some other random view of screen. In normal text field type it took it as an another character, that's fine.
Any one have idea how can use Space key event to retain focus on same field.

Using editText.setInputType(InputType.TYPE_CLASS_NUMBER) may probably solve your problem.

Change/Add your EditText Property with android:imeOptions="actionNext" like as follows
<EditText
android:id="#+id/edit_text"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:imeOptions="actionNext"
android:inputType="text" />
Or with android:imeOptions="actionNone" for default behavior of EditText
<EditText
android:id="#+id/edit_text"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:imeOptions="actionNone"
android:inputType="text" />

So it looks like your problem doesn't have to do with the 'input' type of your EditText, but rather the key press events coming from the keyboard....
So 'hopefully' this should fix your problem for you (by 'skipping over' the 'next' event from the 'space' button being pressed.)
// do for both EditText(s)
editText1.setOnEditorActionListener(new TextView.OnEditorActionListener() {
#Override
public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
log.d("main","KeyPress:"+ actionID);
if (event != null ) { log.d("main","KeyPress:" + event.getKeyCode() ); }
if ( actionId == EditorInfo.IME_ACTION_NEXT) {
// do 'nothing' or 'add a space' if you want that
return true;
}
return false;
}
});
This is likely what is happening (hard to tell without your XML)
So I found something that should help you figure out the pattern + possibly lead to solving it... from https://stackoverflow.com/a/17990096
if there is a android:nextFocus.... setting in your XML (or equivalent in code) and/or the physical keyboard 'space' is also signalling IME_ACTION_NEXT (or another IME action similar to it)
If the EditorInfo.IME_ACTION_NEXT isn't the IME action that is causing your problems, then you can try this... to determine WHAT is.
from: https://stackoverflow.com/a/4171427
if you have PHYSICAL keyboard you can use to detect keyDown events and handle them appropriately,
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
log.d("main","KeyPress:" + keyCode);
if (event != null ) { log.d("main","KeyPress:" + event.getKeyCode() ); }
// if you want to 'handle' the keyPess here, best to use switch like below
// switch (keyCode) {
// case KeyEvent.KEYCODE_A:
// {
// //your Action code
// return true;
// }
/// }
return super.onKeyDown(keyCode, event);
}
BUT... if you have software keyboard You need to use addTextChangedListener/TextWatcher Because the physical key press is 'eaten' by the EditText (from what I saw in another post, but seems to be correct from my testing.)
mMyEditText.addTextChangedListener(new TextWatcher()
{
public void afterTextChanged(Editable s)
{
}
public void beforeTextChanged(CharSequence s, int start, int count, int after)
{
/*This method is called to notify you that, within s, the count characters beginning at start are about to be replaced by new text with length after. It is an error to attempt to make changes to s from this callback.*/
}
public void onTextChanged(CharSequence s, int start, int before, int count)
{
}
);
You can override what the EditText does when a 'space' is entered.
This seems pretty easy when in 'software keyboard', but physical keyboard seems to be a bit more difficult.
https://developer.android.com/reference/android/widget/TextView.OnEditorActionListener.html
Similar to this question (but 'space' instead of 'enter') Android - Handle "Enter" in an EditText
This could help you determine the 'pattern' of the focus being changed. if it is random or not (most likely -not- random, but possibly 'interesting' to look into)
http://developer.android.com/reference/android/view/View.OnFocusChangeListener.html
// try this to see
View.OnFocusChangeListener changeListener = new View.OnFocusChangeListener()
{
#Override
public void onFocusChange(View v, boolean hasFocus) {
log.d("YourClassName", "FocusChanged" + hasFocus)
}
};
EditText1.setOnFocusChangeListener(changeListener);
EditText2.setOnFocusChangeListener(changeListener);
Button.setOnFocusChangeListener(changeListener);
// ... etc... (add to views to see if there is pattern)

Prevent ' Enter key ' to trigger TextWatcher

I was making an application to act as remote keyboard where user will click on an edittext and type and corresponding alphabets will b typed in computer.
I have detected variaous alphabets and numbers with the help of TextWatcher and sent them to my server successfully.
Problem comes when user presses enter key. This also triggers TextWatcher . and since i am sending the latest entered changes , error shows up on server side.
As a solution what i did is , set one onkeylistener as well which will detect the enter key and perform action and CONSUME it , but unfortunately in that case also first textwatcher gets triggered and then onkeylistener.
Here is the code of my onkeylistener
keyboard.setOnKeyListener(new OnKeyListener() {
public boolean onKey(View v, int keyCode, KeyEvent event) {
if(keyCode == KeyEvent.KEYCODE_ENTER&&event.getAction()==KeyEvent.ACTION_UP){
out.println("enter");
return true;
}
return false;
}
});
Code of TextWatcher :
private TextWatcher watcher = new TextWatcher() {
public void onTextChanged(CharSequence s, int start, int before, int count) {
if(count>0){
out.println(":"+s.subSequence(start, start+count).toString());
}
}
.
.
.
Problem is on pressing enter key it fires TextWatcher's onTextChanged as well as onkeylistener. whereas i want only on key listener to fire.
I want to fire Textwatcher only in case of alphabets , numbers , some symbols etc.
Also if you can suggest different approach for detecting and sending characters ( soft ) will be great .

Ok i think i solved it. in Textwatcher add this if statement:
if(s.toString().substring(start).contains("\n"))
in that way if last key entered was 'enter' then it would go into this is and then u can perform whatever u want.

Event when user select back?

How can I catch the event when the user, after he entered the text on an EditText, select Back and the keyboard disappear?

Override onBackPressed at your Activity class:
#Override
public void onBackPressed() {
//If keyboard is on, do what you want
super.onBackPressed();
}

If you want to catch the back key when user has finished entering text in EditText and he presses back key then you should use:
EditText edit = (EditText)findViewById(R.id.yourId);
edit.setOnKeyListener(new EditText.OnKeyListener(){
public boolean onKey(View v, int keyCode, KeyEvent event) {
if(keyCode == KeyEvent.KEYCODE_BACK){
System.out.println("******back key caught in edit.setOnKeyListener");
}
return false;
}
});

I had the same problem. Vineet Shukla's answer was not working, until I made sure that the delegate was a EditText.OnKeyListener. Prior to that it was a View.OnKeyListener and I was not seeing KeyEvent.KEYCODE_BACK == keyCode, for was I even seeing onKey ever called. I hope this is helpful to someone having a similar problem, although this post is a year old. Cheers.

How to watch multiple edittext boxes for a softkey enter or done press?

I have 14 edittext boxes that a user can change at will. When the text is changed in one of them, a softpad key press on the 'enter/next/done' key should re-run a calculation using the new text. I've tried onKey listener but it doesn't work on the soft keyboard, on;y the hard keypad. I've tried a textwatcher like onTextChanged but it reacts and runs the calculation when only a single digit is entered, before the user can input a two or more digit number. So... I hear the onEditorActionListener works on soft keypads to watch for the keypress, but I can't get the syntax right. Here's what I have:
In the onCreate method:
myEdittext1.setOnEditorActionListener(this);
...
myEdittext14.setOnEditorActionListener(this);
Then, outside the onCreate method, I have:
#Override
public boolean onEditorAction(TextView v, int actionId, KeyEvent event)
{ if (event.getKeyCode() == KeyEvent.FLAG_EDITOR_ACTION)
{ //do my calcs}
}
return(true);
}
The code gives me the foreced-close business. Any help would be greatly appreciated.

KeyEvent can be null. You need to check for this situation in your listener.
v The view that was clicked.
actionId Identifier of the action. This will be either the identifier you supplied, or EditorInfo.IME_NULL if being called due to the enter key being pressed.
event If triggered by an enter key, this is the event; otherwise, this is null.
onEditorAction is the appropriate way to listen for finish and Done soft keyboard actions.

so here's a working version:
#Override
public boolean onEditorAction(TextView v, int actionId, KeyEvent event)
{ if (event == null || event.getAction()==KeyEvent.ACTION_UP)
{ //do my calcs
return(true);//reset key event for next press
}
}
The enter key returns a 'null' in the event variable, thats why my version at the top of this post crashed.
Nick's code above worked well too, just remember to set the xml property android:imeOptions=actionDone" for all of the edittext boxes.