Tukukkk

I'm trying to build an Android Studio game for a college project and so far I was able to follow a nice tutorial on it. However, I've reached a concrete wall. My idea is to move the character that's currently positioned in the middle of the screen - horizontally when dragging and holding left or right on the screen. My knowledge on java and android development is very limited and therefore I really don't know how to handle this situation. Currently I have a if(action == MotionEvent.ACTION_DOWN) when tapping the character he shoots a cannon ball out of his cannon. The bitmap drawable in question is called "deerstroyer" in the code.

Here's the code of my GameView class

package com.example.moostauche.reindeerrage;



import android.app.Activity;

import android.content.Context;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.graphics.Canvas;

import android.graphics.Point;

import android.graphics.Rect;

import android.os.Handler;

import android.view.Display;

import android.view.MotionEvent;

import android.view.View;



import java.util.ArrayList;



//constructor

public class GameView extends View

{

    //in the GameView set the background to the gameBackground

    //variables

    Bitmap background, deerstroyer;

    Rect rect;



    static int displayWidth, displayHeight;

    ArrayList<Enemy1> enemies;

    ArrayList<Enemy2> enemies2;

    ArrayList<Santa> santas;

    ArrayList<Snow> snowing;

    ArrayList<Cloud> clouds;

    ArrayList<Cloud2> clouds2;

    ArrayList<Bullet> bullets;

    //import the handler

    Handler handler;

    //import runnable

    Runnable runnable;

    //how often do we want to update frames in ms

    final long UPDATE_MILLIS = 80;

    long start = System.currentTimeMillis();

    long end = start + 10 * 1000;



    static int deerstroyerWidth, deerstroyerHeight;

    Context context;

    int count = 0;



    public GameView( Context context )

    {

        super( context );

        this.context = context;

        //setting the background as our background image from drawable

        background = BitmapFactory.decodeResource( getResources(), R.drawable.christmasbackground );

        deerstroyer = BitmapFactory.decodeResource( getResources(), R.drawable.deerstroyer );



        //All the code below is to set the background image to fit the screen of the phone

        Display display = ( ( Activity ) getContext() ).getWindowManager().getDefaultDisplay();

        Point size = new Point();

        display.getSize( size );

        displayWidth = size.x;

        displayHeight = size.y;

        rect = new Rect( 0, 0, displayWidth, displayHeight );

        enemies = new ArrayList<>();

        enemies2 = new ArrayList<>();

        santas = new ArrayList<>();

        snowing = new ArrayList<>();

        clouds = new ArrayList<>();

        clouds2 = new ArrayList<>();

        bullets = new ArrayList<>();



        for ( int i = 0; i < 1; i++ )

        {

            Enemy1 enemy = new Enemy1( context );

            enemies.add( enemy );

            Enemy2 enemy2 = new Enemy2( context );

            enemies2.add( enemy2 );

        }



        for ( int i = 0; i < 1; i++ )

        {

            Snow snow = new Snow( context );

            snowing.add( snow );

        }



        for ( int i = 0; i < 1; i++ )

        {

            Cloud cloud = new Cloud( context );

            clouds.add( cloud );

            Cloud2 cloud2 = new Cloud2( context );

            clouds2.add( cloud2 );

        }



        for ( int i = 0; i < 1; i++ )

        {

            Santa santa = new Santa( context );

            santas.add( santa );

        }



        //instantiate the handler

        handler = new Handler();



        //instantiate runnable - for redrawing the view

        runnable = new Runnable()

        {

            @Override

            public void run()

            {

                invalidate();

            }

        };



        deerstroyerWidth = deerstroyer.getWidth();

        deerstroyerHeight = deerstroyer.getHeight();

    }



    @Override

    protected void onDraw( Canvas canvas )

    {

        super.onDraw( canvas );



        //draw the background on the canvas

        canvas.drawBitmap( background, null, rect, null );



        for ( int i = 0; i < enemies.size(); i++ )

        {

            //draw enemy 1 and count the frames, if the enemy frames are greater than 3, reset the frames

            canvas.drawBitmap( enemies.get( i ).getBitmap(), enemies.get( i ).enemyX, enemies.get( i ).enemyY, null );

            enemies.get( i ).enemyFrame++;

            if ( enemies.get( i ).enemyFrame > 3 )

            {

                enemies.get( i ).enemyFrame = 0;

            }



            //enemy 1 moves from right to left

            enemies.get( i ).enemyX -= enemies.get( i ).movementSpeed;

            if ( enemies.get( i ).enemyX < -enemies.get( i ).getWidth() )

            {

                enemies.get( i ).resetPosition();

            }



            //draw enemy 2 and count the frames, if the enemy frames are greater than 3, reset the frames

            canvas.drawBitmap( enemies2.get( i ).getBitmap(), enemies2.get( i ).enemyX, enemies2.get( i ).enemyY, null );

            enemies2.get( i ).enemyFrame++;

            if ( enemies2.get( i ).enemyFrame > 3 )

            {

                enemies2.get( i ).enemyFrame = 0;

            }



            //enemy 2 moves from Up to Down

            enemies2.get( i ).enemyY += enemies2.get( i ).movementSpeed;

            if ( enemies2.get( i ).enemyY > ( displayHeight + enemies2.get( i ).getHeight() ) )

            {

                enemies2.get( i ).resetPosition();

            }

        }



        for ( int i = 0; i < santas.size(); i++ )

        {

            //draw Santa and count the frames, if the santa frames are greater than 3, reset the frames

            canvas.drawBitmap( santas.get( i ).getBitmap(), santas.get( i ).enemyX, santas.get( i ).enemyY, null );

            santas.get( i ).enemyFrame++;

            if ( santas.get( i ).enemyFrame > 3 )

            {

                santas.get( i ).enemyFrame = 0;

            }



            //Santa 1 moves from left to right

            santas.get( i ).enemyX -= santas.get( i ).movementSpeed;

            if ( santas.get( i ).enemyX < -santas.get( i ).getWidth() )

            {

                santas.get( i ).resetPosition();

            }

        }



        for ( int i = 0; i < snowing.size(); i++ )

        {

            //draw enemy 2 and count the frames, if the enemy frames are greater than 3, reset the frames

            canvas.drawBitmap( snowing.get( i ).getBitmap(), snowing.get( i ).enemyX, snowing.get( i ).enemyY, null );

            snowing.get( i ).enemyFrame++;

            if ( snowing.get( i ).enemyFrame > 3 )

            {

                snowing.get( i ).enemyFrame = 0;

            }

        }



        for ( int i = 0; i < clouds.size(); i++ )

        {

            //draw enemy 1 and count the frames, if the enemy frames are greater than 3, reset the frames

            canvas.drawBitmap( clouds.get( i ).getBitmap(), clouds.get( i ).enemyX, clouds.get( i ).enemyY, null );

            clouds.get( i ).enemyFrame++;

            if ( clouds.get( i ).enemyFrame > 3 )

            {

                clouds.get( i ).enemyFrame = 0;

            }



            //enemy 1 moves from right to left

            clouds.get( i ).enemyX -= clouds.get( i ).movementSpeed;

            if ( clouds.get( i ).enemyX < -clouds.get( i ).getWidth() )

            {

                clouds.get( i ).resetPosition();

            }

        }



        for ( int i = 0; i < clouds2.size(); i++ )

        {

            //draw enemy 1 and count the frames, if the enemy frames are greater than 3, reset the frames

            canvas.drawBitmap( clouds2.get( i ).getBitmap(), clouds2.get( i ).enemyX, clouds2.get( i ).enemyY, null );

            clouds2.get( i ).enemyFrame++;

            if ( clouds2.get( i ).enemyFrame > 3 )

            {

                clouds2.get( i ).enemyFrame = 0;

            }



            //enemy 1 moves from right to left

            clouds2.get( i ).enemyX += clouds2.get( i ).movementSpeed;

            if ( clouds2.get( i ).enemyX > ( displayWidth + clouds2.get( i ).getWidth() ) )

            {

                clouds2.get( i ).resetPosition();

            }

        }



        //bullet logic and destruction of different enemies

        for ( int i = 0; i < bullets.size(); i++ )

        {

            if ( bullets.get( i ).y > -bullets.get( i ).getBulletHeight() )

            {

                bullets.get( i ).y -= bullets.get( i ).bulletSpeed;

                canvas.drawBitmap( bullets.get( i ).bullet, bullets.get( i ).x, bullets.get( i ).y, null );

            }

            else

            {

                bullets.remove( i );

            }

        }



        //draw the deerstroyer elf and center him

        canvas.drawBitmap( deerstroyer, ( displayWidth / 2 - deerstroyerWidth / 2 ), displayHeight - deerstroyerHeight, null );



        //update the milliseconds

        handler.postDelayed( runnable, UPDATE_MILLIS );

    }

    //on touch event, shoot the bullet

    **



    @Override

    public boolean onTouchEvent( MotionEvent event )

    {

        float touchX = event.getX();

        float touchY = event.getY();

        int action = event.getAction();

        if ( action == MotionEvent.ACTION_DOWN )

        {

            //if you tap on the deerstroyer elf, he will shoot a bullet

            if ( touchX >= ( displayWidth / 2 - deerstroyerWidth / 2 ) 

                 && touchX <= ( displayWidth / 2 + deerstroyerWidth / 2 ) 

                 && touchY >= ( displayHeight - deerstroyerHeight ) )

            {

                //there can only be two bullets present on the screen at a time

                if ( bullets.size() < 3 )

                {

                    Bullet b = new Bullet( context );

                    bullets.add( b );

                }

            }

        }

        return true;

    }

    **

}