The following code shows how to implement TextWatcher interface from Activity class.
Main layout xml file
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="@string/hello" /> </LinearLayout>
Main activity Java code
package com.java2s.myapplication3.app; /* w ww . ja v a 2 s.c o m*/ import android.app.Activity; import android.os.Bundle; import android.text.Editable; import android.text.TextWatcher; import android.widget.EditText; public class MainActivity extends Activity implements TextWatcher { EditText text; int textCount; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); //Create an EditText widget and add the watcher text = new EditText(this); text.addTextChangedListener(this); setContentView(text); } /* TextWatcher Implementation Methods */ public void beforeTextChanged(CharSequence s, int start, int count, int after) { } public void onTextChanged(CharSequence s, int start, int before, int end) { textCount = text.getText().length(); setTitle(String.valueOf(textCount)); } public void afterTextChanged(Editable s) { } }