Try following TextWatcher:
TextWatcher t = new TextWatcher() {
long lastChange = 0;
@Override
public void onTextChanged(CharSequence s, int start, int before,
int count) {
// TODO Auto-generated method stub
if (s.length() > 3) {
new Handler().postDelayed(new Runnable() {
public void run() {
if (System.currentTimeMillis() - lastChange >= 300) {
//send request
}
}
}, 300);
lastChange = System.currentTimeMillis();
}
}
@Override
public void beforeTextChanged(CharSequence s, int start, int count,
int after) {
// TODO Auto-generated method stub
}
@Override
public void afterTextChanged(Editable s) {
// TODO Auto-generated method stub
}
};