Android EditText文本内容变化监听方法

package com.google;

import android.app.Activity;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.widget.EditText;

public class ActMain extends Activity {

private EditText et_search;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

et_search = (EditText) findViewById(R.id.et_search);

et_search.addTextChangedListener(textWatcher);
}

private TextWatcher textWatcher = new TextWatcher() {

@Override
public void onTextChanged(CharSequence s, int start, int before,
int count) {
//  
System.out.println("-1-onTextChanged-->"
+ et_search.getText().toString() + "<--");
}

@Override
public void beforeTextChanged(CharSequence s, int start, int count,
int after) {
//  
System.out.println("-2-beforeTextChanged-->"
+ et_search.getText().toString() + "<--");

}

@Override
public void afterTextChanged(Editable s) {
//  
System.out.println("-3-afterTextChanged-->"
+ et_search.getText().toString() + "<--");

}
};
}