Question

Using Android Studio, create a one java android app that has 4 buttons:-

Change Color Button - When the Change Color button is clicked, it changes the current activity background to a randomly selected color

Speak Button - When the Speak button is clicked, it opens a new activity named SpeakActivity. On the SpeakActivity there are three controls: EditText, Button (Speak) and Button (Back). The Speak button uses the Text to Speech service to say the text entered in EditText. The Back button returns the user to the main/parent activity.

API Version Button - When the API Version button is clicked, display the Android API Version of the phone on a Toast in the current activity.

Serial Number Button - When the Serial Number button is clicked, send the serial number of your device to an email app as an implicit intent.

Layout

Best practices & layout all your screens look professional all variables have meaningful names all static strings are placed in the strings.xml file

Please show screenshots of your .xml and .java and the validated program.

Answer 1

/*this android code is developed in android API 26*/

//Menifest.xm

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.simpleactivity">

    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
    <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=".SpeakActivity"></activity>
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

//Colors.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="colorPrimary">#008577</color>
    <color name="colorPrimaryDark">#00574B</color>
    <color name="colorAccent">#D81B60</color>
    <item name="blue" type="color">#FF33B5E5</item>
    <item name="purple" type="color">#FFAA66CC</item>
    <item name="green" type="color">#FF99CC00</item>
    <item name="orange" type="color">#FFFFBB33</item>
    <item name="red" type="color">#FFFF4444</item>
    <item name="darkblue" type="color">#FF0099CC</item>
    <item name="darkpurple" type="color">#FF9933CC</item>
    <item name="darkgreen" type="color">#FF669900</item>
    <item name="darkorange" type="color">#FFFF8800</item>
    <item name="darkred" type="color">#FFCC0000</item>

    <integer-array name="androidcolors">
        <item>@color/blue</item>
        <item>@color/purple</item>
        <item>@color/green</item>
        <item>@color/orange</item>
        <item>@color/red</item>
        <item>@color/darkblue</item>
        <item>@color/darkpurple</item>
        <item>@color/darkgreen</item>
        <item>@color/darkorange</item>
        <item>@color/darkred</item>
    </integer-array>
</resources>

//============================= strings.xml

<resources>
    <string name="app_name">SimpleActivity</string>
    <string name="str_color">Change Color</string>
    <string name="str_speak">Speak</string>
    <string name="str_API">API Version</string>
    <string name="str_number">Serial Number</string>
    <string name="str_back">Back</string>
</resources>

//activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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:id ="@+id/layout"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/button4"
        android:onClick="btnSerialNumber"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/str_number"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.832"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.437" />

    <Button
        android:id="@+id/button3"
        android:onClick="btnAPI_VERSION"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/str_API"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.266"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.437" />

    <Button
        android:id="@+id/button"

        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="btnSpeakClick"
        android:text="@string/str_speak"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.266"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.247" />

    <Button
        android:id="@+id/button2"
        android:onClick="btnChangeColor"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/str_color"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.832"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.247" />
</androidx.constraintlayout.widget.ConstraintLayout>

//========================= MainActivity.java

package com.example.simpleactivity;

import androidx.appcompat.app.AppCompatActivity;
import androidx.constraintlayout.widget.ConstraintLayout;
import androidx.core.app.ActivityCompat;

import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Color;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;

import java.util.Random;

public class MainActivity extends AppCompatActivity {

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

    public void btnChangeColor(View view) {
        int[] androidColors = getResources().getIntArray(R.array.androidcolors);
        int randomAndroidColor = androidColors[new Random().nextInt(androidColors.length)];
        ConstraintLayout constraintLayout = findViewById(R.id.layout);
        constraintLayout.setBackgroundColor(randomAndroidColor);
    }

    public void btnSpeakClick(View view) {
        Intent intent = new Intent(this, SpeakActivity.class);
        startActivity(intent);
    }

    public void btnAPI_VERSION(View view) {
        String api = Build.VERSION.RELEASE;
        Toast.makeText(this, api, Toast.LENGTH_LONG).show();
    }

    public void btnSerialNumber(View view) {
        //Require permissions for API >=23
        if (checkSelfPermission(Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) {
            // TODO: Consider calling
            //    Activity#requestPermissions
            // here to request the missing permissions, and then overriding
            //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
            //                                          int[] grantResults)
            // to handle the case where the user grants the permission. See the documentation
            // for Activity#requestPermissions for more details.
            requestPermissions(new String[]{Manifest.permission.READ_PHONE_STATE},PackageManager.PERMISSION_GRANTED);
            return;
        }

       String serial_number = Build.getSerial().toString();
        Toast.makeText(this,serial_number,Toast.LENGTH_LONG).show();
        Intent emailIntent = new Intent(Intent.ACTION_SEND);
        emailIntent.setData(Uri.parse("mailto:"));
        emailIntent.setType("text/plain");
        emailIntent.putExtra(emailIntent.EXTRA_TEXT, serial_number);
        try {
            startActivity(Intent.createChooser(emailIntent, "Email"));
            finish();

        } catch (android.content.ActivityNotFoundException ex) {
            Toast.makeText(MainActivity.this, "ERROR ....NO EMAIL CLIENT FOUND.", Toast.LENGTH_SHORT).show();
        }
    }
}

//=========================activity_speak.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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=".SpeakActivity">

    <EditText
        android:id="@+id/editText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:ems="10"
        android:inputType="text"
        android:text=""
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.434"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.173" />

    <Button
        android:id="@+id/button5"
        android:onClick="btnNowSpeak"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/str_speak"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.198"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.499" />

    <Button
        android:id="@+id/button6"
        android:onClick="btnBack"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/str_back"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.808"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.499" />
</androidx.constraintlayout.widget.ConstraintLayout>

//==================================SpeakActivity.java

package com.example.simpleactivity;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.speech.tts.TextToSpeech;
import android.speech.tts.TextToSpeechService;
import android.view.View;
import android.widget.EditText;

import java.util.Locale;

public class SpeakActivity extends AppCompatActivity {
    TextToSpeech textToSpeech;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_speak);
         textToSpeech=new TextToSpeech(getApplicationContext(), new TextToSpeech.OnInitListener() {
            @Override
            public void onInit(int status) {
                if(status != TextToSpeech.ERROR) {
                    textToSpeech.setLanguage(Locale.US);
                }
            }
        });
    }

    public void btnNowSpeak(View view)
    {
        EditText ed = findViewById(R.id.editText);
        String sentence = ed.getText().toString();
        textToSpeech.speak(sentence,TextToSpeech.QUEUE_FLUSH,null,UI_MODE_SERVICE);
    }
    public void btnBack(View view)
    {
        Intent intent = new Intent(this,MainActivity.class);
        startActivity(intent);
    }
    public void onPause() {
        if (textToSpeech != null) {
            textToSpeech.stop();
            textToSpeech.shutdown();
        }
        super.onPause();
    }
}

//Outputs

//If you need any help regarding this solution ........... please leave a comment .......... thanks