This should help you out. I've created a textwatcher and the simple method inputValidation
which returns a boolean whether the editable is empty or not. If the edittext is blank when the validation label is displayed.
TextView input_validation;
EditText input;
int final_input_value;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
setupViews();
}
public void setupViews() {
input_validation = (TextView) findViewById(R.id.input_validation);
input_validation.setVisibility(View.GONE);
input = (EditText) findViewById(R.id.input);
input.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence charSequence, int i, int i2, int i3) {
}
@Override
public void onTextChanged(CharSequence charSequence, int i, int i2, int i3) {
}
@Override
public void afterTextChanged(Editable editable) {
if (inputValidation(editable)) {
input_validation.setVisibility(View.VISIBLE);
input_validation.setText("You must enter your Age");
} else {
input_validation.setVisibility(View.GONE);
final_input_value = Integer.parseInt(editable.toString());
}
}
});
}
public boolean inputValidation(Editable inputText) {
return inputText.toString().isEmpty();
}
Layout
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/input_label"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Your Age"
android:textStyle="bold"
android:textColor="@android:color/holo_blue_dark"
android:paddingBottom="16dp" />
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/input"
android:inputType="number"
android:layout_below="@+id/input_label"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/input_validation"
android:textStyle="italic"
android:textColor="@android:color/holo_red_dark"
android:layout_below="@+id/input"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
The output looks like this.
