Implement Gestures In Android Apps

Introduction

Android is one of the most popular operating systems for mobile. Nowadays, gestures are an important element of Android apps. Gestures make it easy to access the apps and makes things convenient for the user.

In this article, I will show you how to implement gestures in Android applications using Android Studio. Android is a kernel based operating system. In Android, users can modify the GUI components and source code.

Requirements

• Android Studio
• A little knowledge of XML and JAVA 
• Android Emulator (or) Android mobile

Steps to be followed

Carefully follow my steps to implement gestures in Android applications using Android Studio. I have included the source code too.

Step 1

Open Android Studio and start a new project.



Step 2

Put the application name and company domain. If you wish to use C++ for coding this project, mark the "Include C++ support" checkbox and click Next.



Step 3

Select the Android minimum SDK and click Next.



Step 4

Choose "Basic Activity" and click Next.



Step 5

Put the activity name and layout name. Android Studio basically takes Java class nameas  what you provide for activity name. Now, click Finish.



Step 6

Go to activity_main.xml and click the text botton. This xml file contains the designing code for Android app. In the activity_main.xml file, copy and paste the below code.

Activity_main.xml code

<?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="ganeshannt.gesturesample.MainActivity">


    <TextView
        android:id="@+id/ganimsg"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="230dp"
        android:text="TextView"
        android:textAppearance="@style/TextAppearance.AppCompat.Body2" />
</RelativeLayout>

User interface



Step 7

In the MainActivity.java file, copy and paste the below code. Java is back-end language for Android. Do not replace your package name otherwise the app will not run.

MainActivity.java code

package ganeshannt.gesturesample;

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
import android.view.MotionEvent;
import android.view.GestureDetector;
import android.support.v4.view.GestureDetectorCompat;


public class MainActivity extends ActionBarActivity implements GestureDetector.OnGestureListener,
        GestureDetector.OnDoubleTapListener {
    private TextView ganeshMessage;
    private GestureDetectorCompat gestureDetector;

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

        ganeshMessage = (TextView) findViewById(R.id.ganimsg);
        this.gestureDetector = new GestureDetectorCompat(this, this);
        gestureDetector.setOnDoubleTapListener(this);
    }

    ///////// GESTURE METHODS //////////
    @Override
    public boolean onSingleTapConfirmed(MotionEvent e) {
        ganeshMessage.setText("onSingleTapConfirmed");
        return true;
    }

    @Override
    public boolean onDoubleTap(MotionEvent e) {
        ganeshMessage.setText("onDoubleTap");
        return true;
    }

    @Override
    public boolean onDoubleTapEvent(MotionEvent e) {
        ganeshMessage.setText("onDoubleTapEvent");
        return true;
    }

    @Override
    public boolean onDown(MotionEvent e) {
        ganeshMessage.setText("onDown");
        return true;
    }

    @Override
    public void onShowPress(MotionEvent e) {
        ganeshMessage.setText("onShowPress");

    }

    @Override
    public boolean onSingleTapUp(MotionEvent e) {
        ganeshMessage.setText("onSingleTapUp");
        return true;
    }

    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
        ganeshMessage.setText("onScroll");
        return true;
    }

    @Override
    public void onLongPress(MotionEvent e) {
        ganeshMessage.setText("onLongPress");

    }

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
        ganeshMessage.setText("onFling");
        return true;
    }

    ///////// GESTURE METHODS //////////


    @Override
    public boolean onTouchEvent(MotionEvent event) {
        this.gestureDetector.onTouchEvent(event);
        return super.onTouchEvent(event);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

Step 8

As we need to perform each java activity change in AndroidManifest, add the below code in AndroidManifest.xml file. 

AndroidManifest.xml code

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

    <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=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>

Step 9

This is our user interface of the application. Click the "Make Project" option.

Step 10

Run the application >> select virtual machine >> click OK.



Deliverables

Here, we have successfully implemented gestures in an Android application.










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Source code - https://github.com/GaneshanNT/GestureSample