etExchangeRateEn = (EditText) findViewById(R.id.etExchangeRateEn);
etExchangeRateCn = (EditText) findViewById(R.id.etExchangeRateCn);

twEN = new TextWatcher()
{

@Override
public void afterTextChanged(Editable s)
{
etExchangeRateCn.addTextChangedListener(twCN);
}

@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after)
{

}

@Override
public void onTextChanged(CharSequence s, int start, int before, int count)
{

etExchangeRateCn.setText( "CN");

}

};

twCN = new TextWatcher()
{

@Override
public void afterTextChanged(Editable s)
{
etExchangeRateEn.addTextChangedListener(twEN);

}

@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after)
{
}

@Override
public void onTextChanged(CharSequence s, int start, int before, int count)
{

etExchangeRateEn.setText("EN");

}
};
etExchangeRateEn.addTextChangedListener(twEN);
etExchangeRateCn.addTextChangedListener(twCN);