Google Android - это несложно

Код: Выделить всё

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TextView 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:text="Enter your passcode" />
    
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:orientation="horizontal" >

        <EditText
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:cursorVisible="false"
            android:inputType="numberPassword"
            android:maxLength="1" />

        <EditText
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:cursorVisible="false"
            android:inputType="numberPassword"
            android:maxLength="1" />

        <EditText
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:cursorVisible="false"
            android:inputType="numberPassword"
            android:maxLength="1" />

        <EditText
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:cursorVisible="false"
            android:inputType="numberPassword"
            android:maxLength="1" />
    </LinearLayout>
    
    <GridLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:columnCount="3"
        android:orientation="horizontal" >

        <Button android:text="1" />
        <Button android:text="2" />
        <Button android:text="3" />
        <Button android:text="4" />
        <Button android:text="5" />
        <Button android:text="6" />
        <Button android:text="7" />
        <Button android:text="8" />
        <Button android:text="9" />
        <Button
            android:layout_column="1" 
            android:text="0" />
        <Button android:text="d" />
        
    </GridLayout>

</LinearLayout>