您必须询问当前文本是否已经显示了圆点，函数PasswordTransformationMethod.getInstance()允许您这样做。

这是我在kotlin中的函数:

        fun hideAndShowPassword(editText: EditText, indicator: ImageView) {

        if (editText.transformationMethod == PasswordTransformationMethod.getInstance()) {
            editText.transformationMethod = HideReturnsTransformationMethod.getInstance()
            indicator.setImageDrawable(
                ContextCompat.getDrawable(
                    editText.context,
                    R.drawable.eye
                )
            )
            indicator.imageTintList =
                ContextCompat.getColorStateList(editText.context, R.color.colorTintIcons)
        } else {
            editText.transformationMethod = PasswordTransformationMethod.getInstance()
            indicator.setImageDrawable(
                ContextCompat.getDrawable(
                    editText.context,
                    R.drawable.eye_off
                )
            )
            indicator.imageTintList =
                ContextCompat.getColorStateList(editText.context, R.color.colorTintIcons)
        }

        editText.setSelection(editText.text.length)
    }

使用复选框并相应地更改输入类型。

public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
    int start,end;
    Log.i("inside checkbox chnge",""+isChecked);
    if(!isChecked){
        start=passWordEditText.getSelectionStart();
        end=passWordEditText.getSelectionEnd();
        passWordEditText.setTransformationMethod(new PasswordTransformationMethod());;
        passWordEditText.setSelection(start,end);
    }else{
        start=passWordEditText.getSelectionStart();
        end=passWordEditText.getSelectionEnd();
        passWordEditText.setTransformationMethod(null);
        passWordEditText.setSelection(start,end);
    }
}

我可以添加ShowPassword / HidePassword代码，只需几行，在一个块中独立:

protected void onCreate(Bundle savedInstanceState) {
    ...
    etPassword = (EditText)findViewById(R.id.password);
    etPassword.setTransformationMethod(new PasswordTransformationMethod()); // Hide password initially

    checkBoxShowPwd = (CheckBox)findViewById(R.id.checkBoxShowPwd);
    checkBoxShowPwd.setText(getString(R.string.label_show_password)); // Hide initially, but prompting "Show Password"
    checkBoxShowPwd.setOnCheckedChangeListener( new CompoundButton.OnCheckedChangeListener() {
        public void onCheckedChanged(CompoundButton arg0, boolean isChecked) {
            if (isChecked) {
                etPassword.setTransformationMethod(null); // Show password when box checked
                checkBoxShowPwd.setText(getString(R.string.label_hide_password)); // Prompting "Hide Password"
            } else {
                etPassword.setTransformationMethod(new PasswordTransformationMethod()); // Hide password when box not checked
                checkBoxShowPwd.setText(getString(R.string.label_show_password)); // Prompting "Show Password"
            }
        }
    } );
    ...

在XML中这样做

    <LinearLayout
          android:layout_height="wrap_content"
          android:layout_width="fill_parent"
          android:orientation="vertical"
          >
          <RelativeLayout
              android:id="@+id/REFReLayTellFriend"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:orientation="horizontal"
              >
          <EditText
              android:id="@+id/etpass1"
              android:layout_width="fill_parent"
              android:layout_height="wrap_content"
              android:background="@android:color/transparent"
              android:bottomLeftRadius="10dp"
              android:bottomRightRadius="50dp"
              android:fontFamily="@font/frutiger"
              android:gravity="start"
              android:inputType="textPassword"
              android:hint="@string/regpass_pass1"
              android:padding="20dp"
              android:paddingBottom="10dp"
              android:textColor="#000000"
              android:textColorHint="#d3d3d3"
              android:textSize="14sp"
              android:topLeftRadius="10dp"
              android:topRightRadius="10dp"/>
              <ImageButton
                  android:id="@+id/imgshowhide1"
                  android:layout_width="40dp"
                  android:layout_height="20dp"
                  android:layout_marginTop="20dp"
                  android:layout_marginRight="10dp"
                  android:background="@drawable/showpass"
                  android:layout_alignRight="@+id/etpass1"/>
          </RelativeLayout>    

 boolean show=true;
 //on image click inside password do this
 if(show){
                imgshowhide2.setBackgroundResource(0);
                imgshowhide2.setBackgroundResource(R.drawable.hide);
                etpass2.setInputType(InputType.TYPE_TEXT_VARIATION_VISIBLE_PASSWORD);
                etpass2.setSelection(etpass2.getText().length());

                show=false;
            }else{
                imgshowhide2.setBackgroundResource(0);
                imgshowhide2.setBackgroundResource(R.drawable.showpass);
                //etpass1.setInputType(InputType.TYPE_TEXT);
                etpass2.setInputType(InputType.TYPE_CLASS_TEXT |
                        InputType.TYPE_TEXT_VARIATION_PASSWORD);
                etpass2.setSelection(etpass2.getText().length());
                show=true;
            }

使用下面的代码

    val hidePasswordMethod = PasswordTransformationMethod()
    showOrHidePasswordButton.setOnClickListener {
        passwordEditText.apply {
            transformationMethod =
                if (transformationMethod is PasswordTransformationMethod) 
                   null //shows password
               else 
                   hidePasswordMethod //hides password
        }
    }

并确保你把它添加到你的密码编辑文本在布局

    android:inputType="textPassword"

我使用了一个OnClickListener()，它与我想用作toogle的按钮相关联。

private EditText email_et, contraseña_et;
protected void onCreate(Bundle savedInstanceState) {
....
contraseña_et = (EditText) findViewById(R.id.contraseña_et);
....
vercontra_btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            int inputType = contraseña_et.getInputType();
            if (inputType == 129){
                contraseña_et.setInputType(1);
            } else {
                contraseña_et.setInputType(129);
            }
            contraseña_et.setSelection(contraseña_et.getText().length());
        }
    });

阅读文档，int值似乎是不同的，所以我调试找到正确的值，它的工作棒极了，这是一个更容易一点的方式。

[顺便说一下，Contraseña是西班牙语的密码]