<LinearLayout 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:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical" android:gravity="center" android:layout_centerHorizontal="true"

tools:context="com.example.android.practice.MainActivity">


<TextView

    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:textStyle="bold"
    android:textColor="#000000"
    android:text="@string/Constraint_Layout"
    android:textSize="30sp"

    android:layout_marginTop="10dp"
    />
<TextView

    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:textStyle="bold"
    android:textColor="#000000"
    android:text="@string/Linear_Layout"
    android:textSize="30sp"

    android:layout_marginTop="10dp"
    />
<TextView

    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:textStyle="bold"
    android:textColor="#000000"
    android:text="@string/Relative_Layout"
    android:textSize="30sp"

    android:layout_marginTop="10dp"
    />
<TextView

    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:textStyle="bold"
    android:textColor="#000000"
    android:text="@string/Card_View"
    android:textSize="30sp"

    android:layout_marginTop="10dp"
    />
<TextView

    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:textStyle="bold"
    android:textColor="#000000"
    android:text="@string/Scroll_View"
    android:textSize="30sp"

    android:layout_marginTop="10dp"
    />

<TextView

    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:textStyle="bold"
    android:textColor="#000000"

    android:text="@string/Grid_View"
    android:textSize="30sp"

    android:layout_marginTop="10dp"
    />

//for main.xml package com.example.android.practice;

import android.support.v7.app.AppCompatActivity; import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


}

}