private Button mBtnPassword;private EditText mEtPassword;private boolean mbDisplayFlg = false; /** Called when the activity is first created. */@Overridepublic void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.main);  mEtPassword = (EditText)findViewById(R.id.password);  mBtnPassword = (Button)findViewById(R.id.btnPassword);  mBtnPassword.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub Log.d("AndroidTest", "mbDisplayFlg = " + mbDisplayFlg); if (!mbDisplayFlg) {  // display password text, for example "123456"  mEtPassword.setTransformationMethod(HideReturnsTransformationMethod.getInstance()); } else {  // hide password, display "."  mEtPassword.setTransformationMethod(PasswordTransformationMethod.getInstance()); } mbDisplayFlg = !mbDisplayFlg; mEtPassword.postInvalidate(); }  });}

<?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"> <Button android:id="@+id/btnPassword" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="密碼" /> <EditText android:id="@+id/password" android:layout_width="fill_parent" android:layout_height="wrap_content" android:password="true" android:textSize="18sp" android:text="123456"> </EditText></LinearLayout>