[android] How can I know when an EditText loses focus?

I need to catch when an EditText loses focus, I've searched other questions but I didn't find an answer.

I used OnFocusChangeListener like this

OnFocusChangeListener foco = new OnFocusChangeListener() {

    @Override
    public void onFocusChange(View v, boolean hasFocus) {
        // TODO Auto-generated method stub

    }
};

But, it doesn't work for me.

Have your Activity implement OnFocusChangeListener() if you want a factorized use of this interface, example:

public class Shops extends AppCompatActivity implements View.OnFocusChangeListener{

In your OnCreate you can add a listener for example:

editTextResearch.setOnFocusChangeListener(this);
editTextMyWords.setOnFocusChangeListener(this);
editTextPhone.setOnFocusChangeListener(this);

then android studio will prompt you to add the method from the interface, accept it... it will be like:

@Override
public void onFocusChange(View v, boolean hasFocus) {
// todo your code here...
}

and as you've got a factorized code, you'll just have to do that:

@Override
public void onFocusChange(View v, boolean hasFocus) {
   if (hasFocus) {
        editTextResearch.setText("");
        editTextMyWords.setText("");
        editTextPhone.setText("");
    }
    if (!hasFocus){
        editTextResearch.setText("BlaBlaBla");
        editTextMyWords.setText(" One Two Tree!");
        editTextPhone.setText("\"your phone here:\"");
    }
}

anything you code in the !hasFocus is for the behavior of the item that loses focus, that should do the trick! But beware that in such state, the change of focus might overwrite the user's entries!

Its Working Properly

EditText et_mobile= (EditText) findViewById(R.id.edittxt);

et_mobile.setOnFocusChangeListener(new OnFocusChangeListener() {          
    @Override
    public void onFocusChange(View v, boolean hasFocus) {
        if (!hasFocus) {
            // code to execute when EditText loses focus
            if (et_mobile.getText().toString().trim().length() == 0) {
                CommonMethod.showAlert("Please enter name", FeedbackSubmtActivity.this);
            }
        }
    }
});



public static void showAlert(String message, Activity context) {

    final AlertDialog.Builder builder = new AlertDialog.Builder(context);
    builder.setMessage(message).setCancelable(false)
            .setPositiveButton("OK", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int id) {

                }
            });
    try {
        builder.show();
    } catch (Exception e) {
        e.printStackTrace();
    }

}

Using Java 8 lambda expression:

editText.setOnFocusChangeListener((v, hasFocus) -> {
    if(!hasFocus) {
        String value = String.valueOf( editText.getText() );
    }        
});

Kotlin way

editText.setOnFocusChangeListener { _, hasFocus ->
    if (!hasFocus) {  }
}