Question

Create an app that has two DatePicker components. The user should select his or her birthdate with the first DatePicker and some date in the future with the second DatePicker. The app should display how old the user will be on the second date.

Answer 1

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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="match_parent"
    tools:context=".MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Enter your date of birth:"
            android:textSize="20sp"/>

        <DatePicker
            android:id="@+id/PickDateOfBirth"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="#4BE226"
            android:datePickerMode="spinner"
            android:layout_marginTop="15dp"/>

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Enter today's date:"
            android:textSize="20sp"
            android:layout_marginTop="15dp"/>

        <DatePicker
            android:id="@+id/PickTodaysDate"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="#E9AC2F"
            android:datePickerMode="spinner"
            android:layout_marginTop="15dp"/>

        <Button
            android:id="@+id/Findage"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Find my age"
            android:textAllCaps="false"
            android:layout_gravity="center"
            android:layout_marginTop="15dp"/>

        <TextView
            android:id="@+id/age"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="15sp"/>


    </LinearLayout>


</RelativeLayout>

MainActivity.java

package com.example.datepicker;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final TextView age = (TextView)findViewById(R.id.age);
        Button findage = (Button)findViewById(R.id.Findage);
        final DatePicker dateOfBirth = (DatePicker)findViewById(R.id.PickDateOfBirth);
        final DatePicker TodaysDate = (DatePicker)findViewById(R.id.PickTodaysDate);

        findage.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                int years = TodaysDate.getYear() - dateOfBirth.getYear();
                age.setText("Your age is: "+years);
            }
        });

    }
}