密码框显示和隐藏

import android.app.Activity;
import android.graphics.Rect;
import android.os.Bundle;
import android.text.method.HideReturnsTransformationMethod;
import android.text.method.PasswordTransformationMethod;
import android.text.method.TransformationMethod;
import android.view.View;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.CompoundButton.OnCheckedChangeListener;
import android.widget.EditText;


public class PasswordIsShowTestActivity extends Activity {

    private EditText username;
    private EditText password;
    private CheckBox cbBox ;

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

        username = (EditText)findViewById(R.id.editText1);
        password = (EditText)findViewById(R.id.editText2);
        cbBox = (CheckBox)findViewById(R.id.checkBox1);
        cbBox.setOnCheckedChangeListener(new OnCheckedChangeListener() {

            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if(cbBox.isChecked()){
                                     password.setTransformationMethod(
                            HideReturnsTransformationMethod.getInstance());
                }else{
                               password.setTransformationMethod(
                            PasswordTransformationMethod.getInstance());
                }
            }
        });
    }
}