flag

Activityl.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:layout_weight="1"
        android:background="#000fe5"
        android:id="@+id/flag1"/>


        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical"
            android:layout_weight="1"
            android:background="#ffffff"
            android:id="@+id/flag2"/>

            <LinearLayout

                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:orientation="vertical"
                android:layout_weight="1"
                android:background="#000fe6"
                android:id="@+id/flag3"/>


</LinearLayout>

----------------------
Main activity java

package com.example.hackeru.myflag;

import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.LinearLayout;

public class MainActivity extends AppCompatActivity {

    LinearLayout flag1,flag2,flag3;

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

    private void setPointer() {
        flag1 = findViewById(R.id.flag1);
        flag2 = findViewById(R.id.flag2);
        flag3 = findViewById(R.id.flag3);

        flag1.setBackgroundColor(Color.RED);
        flag2.setBackgroundColor(Color.YELLOW);
        flag3.setBackgroundColor(Color.RED);
    }
}