1 -创建一个选择器文件"show_password_selector.xml"

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/pwd_hide"
          android:state_selected="true"/>
    <item android:drawable="@drawable/pwd_show"
          android:state_selected="false" />
 </selector>

2 -将“show_password_selector”文件放入imageview。

<ImageView
    android:id="@+id/iv_pwd"
    android:layout_width="@dimen/_35sdp"
    android:layout_height="@dimen/_25sdp"
    android:layout_alignParentRight="true"
    android:layout_centerVertical="true"
    android:layout_marginRight="@dimen/_15sdp"
    android:src="@drawable/show_password_selector" />

3 -把下面的代码在java文件。

iv_new_pwd.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        if (iv_new_pwd.isSelected()) {
            iv_new_pwd.setSelected(false);
            Log.d("mytag", "in case 1");
            edt_new_pwd.setInputType(InputType.TYPE_CLASS_TEXT);
        } else {
            Log.d("mytag", "in case 1");
            iv_new_pwd.setSelected(true);
            edt_new_pwd.setInputType(InputType.TYPE_CLASS_TEXT | InputType.TYPE_TEXT_VARIATION_PASSWORD);
        }
    }
});

显示:

editText.setInputType(InputType.TYPE_TEXT_VARIATION_VISIBLE_PASSWORD);

隐藏:

editText.setInputType(InputType.TYPE_CLASS_TEXT | InputType.TYPE_TEXT_VARIATION_PASSWORD);

在这些之后，光标被重置，所以:

editText.setSelection(editText.length());

要显示圆点而不是密码，请设置PasswordTransformationMethod:

yourEditText.setTransformationMethod(new PasswordTransformationMethod());

当然，您可以在XML布局中的edittext元素中默认设置此选项

android:password

要重新显示可读密码，只需传递null作为转换方法:

yourEditText.setTransformationMethod(null);

private boolean isPasswordVisible;

private TextInputEditText firstEditText;

...

firstEditText = findViewById(R.id.et_first);

...

    private void togglePassVisability() {
    if (isPasswordVisible) {
        String pass = firstEditText.getText().toString();
        firstEditText.setTransformationMethod(PasswordTransformationMethod.getInstance());
        firstEditText.setInputType(InputType.TYPE_CLASS_TEXT | InputType.TYPE_TEXT_VARIATION_PASSWORD);
        firstEditText.setText(pass);
        firstEditText.setSelection(pass.length());           
    } else {
        String pass = firstEditText.getText().toString();
        firstEditText.setTransformationMethod(HideReturnsTransformationMethod.getInstance());
        firstEditText.setInputType(InputType.TYPE_CLASS_TEXT);
        firstEditText.setText(pass);
        firstEditText.setSelection(pass.length());
    }
    isPasswordVisible= !isPasswordVisible;
}

根据这个来源，如果你已经将你的项目迁移到AndroidX，那么你可以替换

编译”com.android.support:设计:24.2.0”

与

实现“com.google.android.material:材料:1.0.0”

然后你所要做的就是把下面的代码放到你的布局文件中:

<com.google.android.material.textfield.TextInputLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:passwordToggleEnabled="true"
    android:hint="@string/hint_text">

  <com.google.android.material.textfield.TextInputEditText
      android:layout_width="match_parent"
      android:layout_height="wrap_content"/>

</com.google.android.material.textfield.TextInputLayout>

关于材质TextInputLayout的更多信息可以在这里找到。

对于这个源码，建议从Android支持库迁移到AndroidX:

AndroidX is the open-source project that the Android team uses to develop, test, package, version and release libraries within Jetpack. AndroidX is a major improvement to the original Android Support Library. Like the Support Library, AndroidX ships separately from the Android OS and provides backwards-compatibility across Android releases. AndroidX fully replaces the Support Library by providing feature parity and new libraries. In addition AndroidX includes the following features: All packages in AndroidX live in a consistent namespace starting with the string androidx. The Support Library packages have been mapped into corresponding androidx.* packages. For a full mapping of all the old classes and build artifacts to the new ones, see the Package Refactoring page. Unlike the Support Library, AndroidX packages are separately maintained and updated. The androidx packages use strict Semantic Versioning starting with version 1.0.0. You can update AndroidX libraries in your project independently. All new Support Library development will occur in the AndroidX library. This includes maintenance of the original Support Library artifacts and introduction of new Jetpack components.

TextInputLayout的更新代码:

   <androidx.cardview.widget.CardView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:layout_constraintBottom_toTopOf="@+id/lg_forget_password"
    app:layout_constraintTop_toBottomOf="@+id/lg_name"
    app:cardElevation="@dimen/dp20"
    android:layout_marginStart="@dimen/dp20"
    app:cardCornerRadius="@dimen/dp10"
    android:layout_marginEnd="@dimen/dp20"
    android:id="@+id/textField">

    <com.google.android.material.textfield.TextInputLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:backgroundTint="@android:color/transparent"
        app:boxStrokeWidth="0dp"
        app:boxStrokeWidthFocused="0dp"
        app:endIconMode="password_toggle"
        app:hintEnabled="false"
      >

        <com.google.android.material.textfield.TextInputEditText
            android:id="@+id/lg_password"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@drawable/input_bg"
            android:drawableStart="@drawable/ic_baseline_lock_24"
            android:drawablePadding="@dimen/dp10"
            android:fontFamily="@font/roboto_flex"
            android:hint="@string/password"
            android:inputType="textPassword"
            android:padding="@dimen/dp15"
            android:singleLine="true" />

    </com.google.android.material.textfield.TextInputLayout>
</androidx.cardview.widget.CardView>

结果: