专注于TextInputEditText时自动向下滚动

Question

到目前为止，我已经完成了：

MainActivity：

class MainActivity : AppCompatActivity() {

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    val email: EditText = this.findViewById(R.id.edt_mail)
    val pass: EditText = this.findViewById(R.id.edt_password)
    val scrollView = findViewById<View>(R.id.nestedScrollView) as ScrollView
    email.setOnFocusChangeListener { v, hasFocus ->
        if (hasFocus) {
            scrollView.postDelayed({
                scrollView.fullScroll(View.FOCUS_DOWN)
            }, 1200)
        }
    }
    pass.setOnFocusChangeListener { v, hasFocus ->
        if (hasFocus) {
            scrollView.postDelayed({
                scrollView.fullScroll(View.FOCUS_DOWN)
            }, 1200)
        }
    }}}

activity_main.xml中

<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/nestedScrollView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true"
android:focusable="true"
android:focusableInTouchMode="true">

<android.support.constraint.ConstraintLayout
    android:id="@+id/main"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <ImageView
        android:id="@+id/logo"
        android:layout_width="258dp"
        android:layout_height="47dp"
        android:layout_marginTop="164dp"
        android:contentDescription="@string/companyLogo"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.515"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@drawable/logo" />

    <TextView
        android:id="@+id/LoginGuideLine"
        style="@style/LoginGuideLine"
        android:layout_width="295dp"
        android:layout_height="100dp"
        android:layout_marginTop="20dp"
        android:padding="20dp"
        android:text="@string/LoginGuideLine"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.518"
        app:layout_constraintStart_toStartOf="parent"

        app:layout_constraintTop_toBottomOf="@+id/logo" />

    <android.support.design.widget.TextInputLayout
        android:id="@+id/edtl_login"
        style="@style/TextInput"
        android:layout_width="295dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:inputType="textEmailAddress"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.518"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/LoginGuideLine">

        <android.support.design.widget.TextInputEditText
            android:id="@+id/edt_mail"
            android:layout_width="295dp"
            android:layout_height="wrap_content"
            android:focusable="true"
            android:hint="@string/EmailHint"
            android:inputType="textEmailAddress" />
    </android.support.design.widget.TextInputLayout>

    <android.support.design.widget.TextInputLayout
        android:id="@+id/edtl_password"
        style="@style/TextInput"
        android:layout_width="295dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:inputType="textPassword"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.518"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/edtl_login">

        <android.support.design.widget.TextInputEditText
            android:id="@+id/edt_password"
            android:layout_width="295dp"
            android:layout_height="wrap_content"
            android:focusable="true"
            android:hint="@string/PasswordHint"
            android:inputType="textPassword" />
    </android.support.design.widget.TextInputLayout>

    <Button
        android:id="@+id/LoginBtn"
        style="@style/PrimaryBtn"
        android:layout_width="295dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="56dp"
        android:text="@string/BtnTxt"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.518"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/edtl_password" />
</android.support.constraint.ConstraintLayout>

的AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest 
 xmlns:android="http://schemas.android.com/apk/res/android"
package="constraints">
<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity
        android:name=".MainActivity"
        android:screenOrientation="landscape">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <meta-data
        android:name="preloaded_fonts"
        android:resource="@array/preloaded_fonts" />
</application>

这基本上是我正在制作的登录页面UI，我希望屏幕在关注电子邮件或密码字段时自动向下滚动。在电子邮件领域，它完成工作，但在密码字段，它将焦点自动切换回电子邮件字段，我试图重置焦点，但似乎没有工作，所以我不知道问题出在哪里