How can I know when an EditText loses focus?

Implement onFocusChange of setOnFocusChangeListener and there's a boolean parameter for hasFocus. When this is false, you've lost focus to another control.

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

 txtEdit.setOnFocusChangeListener(new OnFocusChangeListener() {          
        @Override
        public void onFocusChange(View v, boolean hasFocus) {
            if (!hasFocus) {
               // code to execute when EditText loses focus
            }
        }
    });

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){
    doSomethingWith(editTextResearch.getText(),
      editTextMyWords.getText(),
      editTextPhone.getText());
  }
}

That should do the trick!

Kotlin way

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