Hello friends, here comes the part 2 of Simple 2D Android Game Development Tutorial. Before we get started, let me do a quick recap of what we went through in part 1 of this project.
So we began with designing the StartScreen. Then we created the class GameView.java in which we drew the Player, Enemy and the Stars in background. Also, we created methods to update the position of the the player and all so that it looked like it was moving in GameView.java. GameView.java was finally added to the GameActivity.java. Then we wrote conditions to detect the collision between the player and the enemy and also added controls. This is where we drew the Boom in the GameView.java. I guess that was enough to sum up of what we did in part 1. You can also visit the part 1 from the below given link.
Android Game Development Tutorial – Simple 2d Game Part 1
You can also download the finished apk from the below link to test the game in your device.
[download id=”3641″]
In part 2, we shall begin with the following objectives in mind:
- Drawing the friendly spaceships and setting motion to them.
- Detecting their collision and configuring the game over condition.
- Adding the gameOver condition due to the miss of 3 enemies.
- Drawing the “Game Over ” text in GameView.java
- Adding a parameter score to calculate the score.
- Adding the HighScore activity to view the the four highest scores in the history of game.
- Adding background music to the game
We have the above seven objectives in this final part of Android Game Development Tutorial. So lets begin.
Android Game Development Tutorial Part 2
Contents
Adding Friend
Let us begin with the addition of friendly ships on the GameScreen. According to the game story we decided in part 1, we would have a friendly ship in the game. If the player collides with the friendly ship then GAME OVER. So lets add a friendly ship in our game.
- Download the image below add it to the drawables which will be used as the image for friend ship.
- Now, create a class Friend.java and add the following code.
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 |
package net.simplifiedcoding.spacefighter; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Rect; import java.util.Random; /** * Created by Manish on 10/24/2016. */ public class Friend { private Bitmap bitmap; private int x; private int y; private int speed = 1; private int maxX; private int minX; private int maxY; private int minY; public Friend(Context context, int screenX, int screenY) { bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.friend); maxX = screenX; maxY = screenY; minX = 0; minY = 0; Random generator = new Random(); speed = generator.nextInt(6) + 10; x = screenX; y = generator.nextInt(maxY) - bitmap.getHeight(); } public void update(int playerSpeed) { x -= playerSpeed; x -= speed; if (x < minX - bitmap.getWidth()) { Random generator = new Random(); speed = generator.nextInt(10) + 10; x = maxX; y = generator.nextInt(maxY) - bitmap.getHeight(); } } //one more getter for getting the rect object public Rect getDetectCollision() { return detectCollision; } //getters public Bitmap getBitmap() { return bitmap; } public int getX() { return x; } public int getY() { return y; } } |
- As we added the above class, now we need to add the friend ships to GameView.
- Hence, update your class GameView.java with the code given below. To lower the difficulty of the game, the number of enemies entering the GameScreen at a time has been changed from three to one which can be noticed as the enemies are added to GameView below.
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 |
package net.simplifiedcoding.spacefighter; import android.app.Activity; import android.app.AlertDialog; import android.app.Service; import android.content.ComponentName; import android.content.Context; import android.content.DialogInterface; import android.content.Intent; import android.content.ServiceConnection; import android.content.SharedPreferences; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.Rect; import android.media.MediaPlayer; import android.os.IBinder; import android.view.MotionEvent; import android.view.SurfaceHolder; import android.view.SurfaceView; import android.widget.Toast; import java.util.ArrayList; public class GameView extends SurfaceView implements Runnable { volatile boolean playing; private Thread gameThread = null; private Player player; private Paint paint; private Canvas canvas; private SurfaceHolder surfaceHolder; private Enemy enemies; //created a reference of the class Friend private Friend friend; private ArrayList<Star> stars = new ArrayList<Star>(); //defining a boom object to display blast private Boom boom; public GameView(Context context, int screenX, int screenY) { super(context); player = new Player(context, screenX, screenY); surfaceHolder = getHolder(); paint = new Paint(); int starNums = 100; for (int i = 0; i < starNums; i++) { Star s = new Star(screenX, screenY); stars.add(s); } //single enemy initialization enemies = new Enemy(context, screenX, screenY); //initializing boom object boom = new Boom(context); //initializing the Friend class object friend = new Friend(context, screenX, screenY); } @Override public void run() { while (playing) { update(); draw(); control(); } } private void update() { player.update(); //setting boom outside the screen boom.setX(-250); boom.setY(-250); for (Star s : stars) { s.update(player.getSpeed()); } enemies.update(player.getSpeed()); //if collision occurs with player if (Rect.intersects(player.getDetectCollision(), enemies.getDetectCollision())) { //displaying boom at that location boom.setX(enemies.getX()); boom.setY(enemies.getY()); //will play a sound at the collision between player and the enemy enemies.setX(-200); } //updating the friend ships coordinates friend.update(player.getSpeed()); } private void draw() { if (surfaceHolder.getSurface().isValid()) { canvas = surfaceHolder.lockCanvas(); canvas.drawColor(Color.BLACK); paint.setColor(Color.WHITE); paint.setTextSize(20); for (Star s : stars) { paint.setStrokeWidth(s.getStarWidth()); canvas.drawPoint(s.getX(), s.getY(), paint); } canvas.drawBitmap( player.getBitmap(), player.getX(), player.getY(), paint); canvas.drawBitmap( enemies.getBitmap(), enemies.getX(), enemies.getY(), paint ); //drawing boom image canvas.drawBitmap( boom.getBitmap(), boom.getX(), boom.getY(), paint ); //drawing friends image canvas.drawBitmap( friend.getBitmap(), friend.getX(), friend.getY(), paint ); surfaceHolder.unlockCanvasAndPost(canvas); } } private void control() { try { gameThread.sleep(17); } catch (InterruptedException e) { e.printStackTrace(); } } public void pause() { playing = false; try { gameThread.join(); } catch (InterruptedException e) { } } public void resume() { playing = true; gameThread = new Thread(this); gameThread.start(); } @Override public boolean onTouchEvent(MotionEvent motionEvent) { switch (motionEvent.getAction() & MotionEvent.ACTION_MASK) { case MotionEvent.ACTION_UP: player.stopBoosting(); break; case MotionEvent.ACTION_DOWN: player.setBoosting(); break; } return true; } } |
Detecting Collision
Again we need to detect collision between Player and Friend ships to make our Game Over.
- To detect collision betweeen Player and Friend, we will again use Rect Object. To do so, update the code of Friend class as follows.
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 |
package net.simplifiedcoding.spacefighter; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Rect; import java.util.Random; /** * Created by Manish on 10/24/2016. */ public class Friend { private Bitmap bitmap; private int x; private int y; private int speed = 1; private int maxX; private int minX; private int maxY; private int minY; //creating a rect object for a friendly ship private Rect detectCollision; public Friend(Context context, int screenX, int screenY) { bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.friend); maxX = screenX; maxY = screenY; minX = 0; minY = 0; Random generator = new Random(); speed = generator.nextInt(6) + 10; x = screenX; y = generator.nextInt(maxY) - bitmap.getHeight(); //initializing rect object detectCollision = new Rect(x, y, bitmap.getWidth(), bitmap.getHeight()); } public void update(int playerSpeed) { x -= playerSpeed; x -= speed; if (x < minX - bitmap.getWidth()) { Random generator = new Random(); speed = generator.nextInt(10) + 10; x = maxX; y = generator.nextInt(maxY) - bitmap.getHeight(); } //Adding the top, left, bottom and right to the rect object detectCollision.left = x; detectCollision.top = y; detectCollision.right = x + bitmap.getWidth(); detectCollision.bottom = y + bitmap.getHeight(); } //one more getter for getting the rect object public Rect getDetectCollision() { return detectCollision; } //getters public Bitmap getBitmap() { return bitmap; } public int getX() { return x; } public int getY() { return y; } } |
Making Game Over Condition
As per the story of this project, this game can get over in two ways. Either the player misses a total number of 3 enemies or the player collides with friend. So lets make this condition working in our game.
- To make the above two conditions of game over, update the GameView.java as follows.
- First declare the following parameters in GameView.java as follows:-
|
1 2 3 4 5 6 7 8 9 10 11 |
//a screenX holder int screenX; //to count the number of Misses int countMisses; //indicator that the enemy has just entered the game screen boolean flag ; //an indicator if the game is Over private boolean isGameOver ; |
- Now initialize the above parameters in the GameView constructor as follows.
|
1 2 3 4 5 |
this.screenX = screenX; countMisses = 0; isGameOver = false; |
- flag will be initialized later.
- Now, Update the update() method in GameView.java as follows:-
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 |
private void update() { player.update(); //setting boom outside the screen boom.setX(-250); boom.setY(-250); for (Star s : stars) { s.update(player.getSpeed()); } //setting the flag true when the enemy just enters the screen if(enemies.getX()==screenX){ flag = true; } enemies.update(player.getSpeed()); //if collision occurs with player if (Rect.intersects(player.getDetectCollision(), enemies.getDetectCollision())) { //displaying boom at that location boom.setX(enemies.getX()); boom.setY(enemies.getY()); //will play a sound at the collision between player and the enemy enemies.setX(-200); }// the condition where player misses the enemy else{ //if the enemy has just entered if(flag){ //if player's x coordinate is more than the enemies's x coordinate.i.e. enemy has just passed across the player if(player.getDetectCollision().exactCenterX() >= enemies.getDetectCollision().exactCenterX()){ //increment countMisses countMisses++; //setting the flag false so that the else part is executed only when new enemy enters the screen flag = false; //if no of Misses is equal to 3, then game is over. if(countMisses==3){ //setting playing false to stop the game. playing = false; isGameOver = true; } } } } //updating the friend ships coordinates friend.update(player.getSpeed()); //checking for a collision between player and a friend if(Rect.intersects(player.getDetectCollision(),friend.getDetectCollision())){ //displaying the boom at the collision boom.setX(friend.getX()); boom.setY(friend.getY()); //setting playing false to stop the game playing = false; //setting the isGameOver true as the game is over isGameOver = true; } } |
- As the game Over gets over, we need to draw a big Game Over text in the draw() method of GameView.java. To do so, update the draw() method in GameView.java as follows.
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 |
private void draw() { if (surfaceHolder.getSurface().isValid()) { canvas = surfaceHolder.lockCanvas(); canvas.drawColor(Color.BLACK); paint.setColor(Color.WHITE); paint.setTextSize(20); for (Star s : stars) { paint.setStrokeWidth(s.getStarWidth()); canvas.drawPoint(s.getX(), s.getY(), paint); } canvas.drawBitmap( player.getBitmap(), player.getX(), player.getY(), paint); canvas.drawBitmap( enemies.getBitmap(), enemies.getX(), enemies.getY(), paint ); //drawing boom image canvas.drawBitmap( boom.getBitmap(), boom.getX(), boom.getY(), paint ); //drawing friends image canvas.drawBitmap( friend.getBitmap(), friend.getX(), friend.getY(), paint ); //draw game Over when the game is over if(isGameOver){ paint.setTextSize(150); paint.setTextAlign(Paint.Align.CENTER); int yPos=(int) ((canvas.getHeight() / 2) - ((paint.descent() + paint.ascent()) / 2)); canvas.drawText("Game Over",canvas.getWidth()/2,yPos,paint); } surfaceHolder.unlockCanvasAndPost(canvas); } } |
- After this the Game Over screen would appear as follows.
Game Over
Adding Scores
- Now as the GameOver has been configured, its time to configure the scores achieved. To do so, begin with declaring the following variables in GameView.java
|
1 2 3 4 5 6 7 8 |
//the score holder int score; //the high Scores Holder int highScore[] = new int[4]; //Shared Prefernces to store the High Scores SharedPreferences sharedPreferences; |
Next, initialize the above parameters in the GameView constructor as follows:-
|
1 2 3 4 5 6 7 8 9 10 |
//setting the score to 0 initially score = 0; sharedPreferences = context.getSharedPreferences("SHAR_PREF_NAME",Context.MODE_PRIVATE); //initializing the array high scores with the previous values highScore[0] = sharedPreferences.getInt("score1",0); highScore[1] = sharedPreferences.getInt("score2",0); highScore[2] = sharedPreferences.getInt("score3",0); highScore[3] = sharedPreferences.getInt("score4",0); |
- Next, update the update() method in GameView.java as follows.
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 |
private void update() { //incrementing score as time passes score++; player.update(); //setting boom outside the screen boom.setX(-250); boom.setY(-250); for (Star s : stars) { s.update(player.getSpeed()); } //setting the flag true when the enemy just enters the screen if(enemies.getX()==screenX){ flag = true; } enemies.update(player.getSpeed()); //if collision occurs with player if (Rect.intersects(player.getDetectCollision(), enemies.getDetectCollision())) { //displaying boom at that location boom.setX(enemies.getX()); boom.setY(enemies.getY()); //playing a sound at the collision between player and the enemy enemies.setX(-200); }// the condition where player misses the enemy else{ //if the enemy has just entered if(flag){ //if player's x coordinate is more than the enemies's x coordinate.i.e. enemy has just passed across the player if(player.getDetectCollision().exactCenterX()>=enemies.getDetectCollision().exactCenterX()){ //increment countMisses countMisses++; //setting the flag false so that the else part is executed only when new enemy enters the screen flag = false; //if no of Misses is equal to 3, then game is over. if(countMisses==3){ //setting playing false to stop the game. playing = false; isGameOver = true; //Assigning the scores to the highscore integer array for(int i=0;i<4;i++){ if(highScore[i]<score){ final int finalI = i; highScore[i] = score; break; } } //storing the scores through shared Preferences SharedPreferences.Editor e = sharedPreferences.edit(); for(int i=0;i<4;i++){ int j = i+1; e.putInt("score"+j,highScore[i]); } e.apply(); } } } } //updating the friend ships coordinates friend.update(player.getSpeed()); //checking for a collision between player and a friend if(Rect.intersects(player.getDetectCollision(),friend.getDetectCollision())){ //displaying the boom at the collision boom.setX(friend.getX()); boom.setY(friend.getY()); //setting playing false to stop the game playing = false; //setting the isGameOver true as the game is over isGameOver = true; //Assigning the scores to the highscore integer array for(int i=0;i<4;i++){ if(highScore[i]<score){ final int finalI = i; highScore[i] = score; break; } } //storing the scores through shared Preferences SharedPreferences.Editor e = sharedPreferences.edit(); for(int i=0;i<4;i++){ int j = i+1; e.putInt("score"+j,highScore[i]); } e.apply(); } } |
- By now, the score is being the calculated and being score into the high scores. Now, to see the increment of score live on the game screen, update the draw() method in GameView.java as follows.
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 |
private void draw() { if (surfaceHolder.getSurface().isValid()) { canvas = surfaceHolder.lockCanvas(); canvas.drawColor(Color.BLACK); paint.setColor(Color.WHITE); paint.setTextSize(20); for (Star s : stars) { paint.setStrokeWidth(s.getStarWidth()); canvas.drawPoint(s.getX(), s.getY(), paint); } //drawing the score on the game screen paint.setTextSize(30); canvas.drawText("Score:"+score,100,50,paint); canvas.drawBitmap( player.getBitmap(), player.getX(), player.getY(), paint); canvas.drawBitmap( enemies.getBitmap(), enemies.getX(), enemies.getY(), paint ); //drawing boom image canvas.drawBitmap( boom.getBitmap(), boom.getX(), boom.getY(), paint ); //drawing friends image canvas.drawBitmap( friend.getBitmap(), friend.getX(), friend.getY(), paint ); //draw game Over when the game is over if(isGameOver){ paint.setTextSize(150); paint.setTextAlign(Paint.Align.CENTER); int yPos=(int) ((canvas.getHeight() / 2) - ((paint.descent() + paint.ascent()) / 2)); canvas.drawText("Game Over",canvas.getWidth()/2,yPos,paint); } surfaceHolder.unlockCanvasAndPost(canvas); } } |
- The preview of score being shown on the game screen can be seen as follows:-
Making High Scores
- Now that we have all the high scores set in shared Preferences, its time to configure the high score button in MainActivity.java. Its click should should take the game to another activity where the highest four scores would be listed.
- To do so, begin with creating a new activity called HighScore. As the new activity is loaded, configure the HighScore.java and activity_high_score.xml as follows.
- Here’s the activity_high_score.xml. It consistes of four textViews showing the highest four scores in the history of game. So, go ahead and add the following code to the activity_high_score.xml.
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 |
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_high_score" android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="center_horizontal" android:paddingTop="150dp" android:orientation="vertical" tools:context="net.simplifiedcoding.spacefighter.HighScore" android:background="@drawable/splash"> <TextView android:textAlignment="center" android:textColor="@android:color/white" android:layout_width="wrap_content" android:layout_height="wrap_content" android:gravity="center" android:textSize="30dp" android:id="@+id/textView" /> <TextView android:textColor="@android:color/white" android:textSize="30dp" android:layout_width="wrap_content" android:layout_height="wrap_content" android:gravity="center" android:id="@+id/textView2" /> <TextView android:textColor="@android:color/white" android:gravity="center" android:textAlignment="center" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="30dp" android:id="@+id/textView3" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="30dp" android:textColor="@android:color/white" android:gravity="center" android:textAlignment="center" android:id="@+id/textView4" /> </LinearLayout> |
- The above code will generate the following preview.
- Here’s the HighScore.java. It simply fetches the scores through shared Preferences and sets them to the textViews. So, go ahead and add the following code to the HighScore.java.
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 |
package net.simplifiedcoding.spacefighter; import android.content.Context; import android.content.SharedPreferences; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.widget.TextView; import org.w3c.dom.Text; public class HighScore extends AppCompatActivity { TextView textView,textView2,textView3,textView4; SharedPreferences sharedPreferences; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_high_score); //initializing the textViews textView = (TextView) findViewById(R.id.textView); textView2 = (TextView) findViewById(R.id.textView2); textView3 = (TextView) findViewById(R.id.textView3); textView4 = (TextView) findViewById(R.id.textView4); sharedPreferences = getSharedPreferences("SHAR_PREF_NAME", Context.MODE_PRIVATE); //setting the values to the textViews textView.setText("1."+sharedPreferences.getInt("score1",0)); textView2.setText("2."+sharedPreferences.getInt("score2",0)); textView3.setText("3."+sharedPreferences.getInt("score3",0)); textView4.setText("4."+sharedPreferences.getInt("score4",0)); } } |
- Now that our HighScore activity is ready, define the onClick method of highscore button in MainActivity.java as follows:-
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 |
package net.simplifiedcoding.spacefighter; import android.app.Activity; import android.app.AlertDialog; import android.content.DialogInterface; import android.content.Intent; import android.content.pm.ActivityInfo; import android.media.Image; import android.media.MediaPlayer; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.ImageButton; import android.widget.Toast; public class MainActivity extends Activity implements View.OnClickListener { // play image button private ImageButton buttonPlay; //high score button private ImageButton buttonScore; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //setting the orientation to landscape setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE); //getting the button buttonPlay = (ImageButton) findViewById(R.id.buttonPlay); //initializing the highscore button buttonScore = (ImageButton) findViewById(R.id.buttonScore); //setting the on click listener to high score button buttonScore.setOnClickListener(this); //setting the on click listener to play now button buttonPlay.setOnClickListener(this); } // the onclick methods @Override public void onClick(View v) { if (v == buttonPlay) { //the transition from MainActivity to GameActivity startActivity(new Intent(MainActivity.this, GameActivity.class)); } if (v == buttonScore) { //the transition from MainActivity to HighScore activity startActivity(new Intent(MainActivity.this, HighScore.class)); } } } |
- By now, we have drawn the friends onto the game screen, configured the game Over, configured the score and the HighScore Activity.
- The game is playable but is yet boring without any sound. It calls for some backgroung music as the game is played.
Adding Sounds
- To add sounds, firstly download the audio tracks from the link given below and add them to the raw folder(create it first) in resources.
- Next, declare the following MediaPlayer objects in GameView.java as follows:-
|
1 2 3 4 |
//the mediaplayer objects to configure the background music static MediaPlayer gameOnsound; final MediaPlayer killedEnemysound; final MediaPlayer gameOversound; |
Next, intialize the above objects in GameView constructor and start the game music method as shown below:-
|
1 2 3 4 5 6 7 |
//initializing the media players for the game sounds gameOnsound = MediaPlayer.create(context,R.raw.gameon); killedEnemysound = MediaPlayer.create(context,R.raw.killedenemy); gameOversound = MediaPlayer.create(context,R.raw.gameover); //starting the game music as the game starts gameOnsound.start(); |
- Now, we need to manipulate the above MediaPlayer objects to start and stop the sounds as per required. To do so, update the update() method in GameView.java as follows
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 |
private void update() { //incrementing score as time passes score++; player.update(); //setting boom outside the screen boom.setX(-250); boom.setY(-250); for (Star s : stars) { s.update(player.getSpeed()); } //setting the flag true when the enemy just enters the screen if(enemies.getX()==screenX){ flag = true; } enemies.update(player.getSpeed()); //if collision occurs with player if (Rect.intersects(player.getDetectCollision(), enemies.getDetectCollision())) { //displaying boom at that location boom.setX(enemies.getX()); boom.setY(enemies.getY()); //playing a sound at the collision between player and the enemy killedEnemysound.start(); enemies.setX(-200); } else{// the condition where player misses the enemy //if the enemy has just entered if(flag){ //if player's x coordinate is equal to enemies's y coordinate if(player.getDetectCollision().exactCenterX()>=enemies.getDetectCollision().exactCenterX()){ //increment countMisses countMisses++; //setting the flag false so that the else part is executed only when new enemy enters the screen flag = false; //if no of Misses is equal to 3, then game is over. if(countMisses==3){ //setting playing false to stop the game. playing = false; isGameOver = true; //stopping the gameon music gameOnsound.stop(); //play the game over sound gameOversound.start(); //Assigning the scores to the highscore integer array for(int i=0;i<4;i++){ if(highScore[i]<score){ final int finalI = i; highScore[i] = score; break; } } //storing the scores through shared Preferences SharedPreferences.Editor e = sharedPreferences.edit(); for(int i=0;i<4;i++){ int j = i+1; e.putInt("score"+j,highScore[i]); } e.apply(); } } } } //updating the friend ships coordinates friend.update(player.getSpeed()); //checking for a collision between player and a friend if(Rect.intersects(player.getDetectCollision(),friend.getDetectCollision())){ //displaying the boom at the collision boom.setX(friend.getX()); boom.setY(friend.getY()); //setting playing false to stop the game playing = false; //setting the isGameOver true as the game is over isGameOver = true; //stopping the gameon music gameOnsound.stop(); //play the game over sound gameOversound.start(); //Assigning the scores to the highscore integer array for(int i=0;i<4;i++){ if(highScore[i]<score){ final int finalI = i; highScore[i] = score; break; } } //storing the scores through shared Preferences SharedPreferences.Editor e = sharedPreferences.edit(); for(int i=0;i<4;i++){ int j = i+1; e.putInt("score"+j,highScore[i]); } e.apply(); } } |
- We are almost done with this Android Game Development Tutorial. Just a few things remain to be configured.
- One of which is to add a static method to the class GameView.java which will be used later in the MainActivity.java.
- So, go ahead and add a method named stopMusic() to the class GameView.java as shown below:-
|
1 2 3 4 |
//stop the music on exit public static void stopMusic(){ gameOnsound.stop(); } |
- Next, we need to configure the tap on the GameOver screen such that it takes you to MainActivity. To do so, declare a variable context of the type Context in the class GameView.java as follows:-
|
1 2 |
//context to be used in onTouchEvent to cause the activity transition from GameAvtivity to MainActivity. Context context; |
- Further, initialize it in the GameView constructor as follows:-
|
1 2 |
//initializing context this.context = context; |
- Now, update the onTouchEvent() method in GameView.java as follows:-
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 |
@Override public boolean onTouchEvent(MotionEvent motionEvent) { switch (motionEvent.getAction() & MotionEvent.ACTION_MASK) { case MotionEvent.ACTION_UP: player.stopBoosting(); break; case MotionEvent.ACTION_DOWN: player.setBoosting(); break; } //if the game's over, tappin on game Over screen sends you to MainActivity if(isGameOver){ if(motionEvent.getAction()==MotionEvent.ACTION_DOWN){ context.startActivity(new Intent(context,MainActivity.class)); } } return true; } |
- Finally, we need to add exit confirmation dialog boxes to the MainActivity and GameActivity.java. To do so, add the following method to both the above mentioned classes.
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 |
@Override public void onBackPressed() { AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setMessage("Are you sure you want to exit?") .setCancelable(false) .setPositiveButton("Yes", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { GameView.stopMusic(); Intent startMain = new Intent(Intent.ACTION_MAIN); startMain.addCategory(Intent.CATEGORY_HOME); startMain.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); startActivity(startMain); finish(); } }) .setNegativeButton("No", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { dialog.cancel(); } }); AlertDialog alert = builder.create(); alert.show(); } |
- And you did it. You finally developed a fully functional 2d game in android. Play the game and have fun. If you find something fishy or you are stuck at something, feel free to tell me in the comments section.
- And yes the source code is available of this Android Game Development Tutorial, in GitHub repository and you can get it from the below link.
So thats all for this Android Game Development Tutorial Series. Stay tuned and we will publish more interesting Android Game Development Tutorials. Thank You 🙂
Good job thank you
Bug on checking if three enemies were missed.
Checking for if the center was met is a bad idea, as a hit can occur on the enemy after the player crosses the center lines.
A better way to check if a miss occured could be to either:
A) Insert a miss coutner increment for when the enemy goes off screen
B) For when the right box of the enemy collision box passes/exceeds the left edge of the player collision box.
I’m starting now with games, how to fix this bug
I want to ask a question. Do highscores reset when i close the app and open it again ?? or are they permanent
Closing app will not reset your highscores. However, clearing app data from Settings will reset your highscores.
Please give more tutorial of gaming Application
thank you…keep it up
your update method having errors u r using gt; for >= symbol and amp for &
u also said to add on back pressed method to both main activity and gavmeview its giving erros
How can we add textview to GameView class
Plz explain.
where highscores are stored is there a database???
for(int i=0;i<4;i++){
//…
}
What is this? I have compile errors. Is this java?
Please help. Are there any alternatives for write this?
Thanks a lot for writing this tutorial. Really a good job. Keep writing.
Hello, thanks before. But can you reupload the finished apk, please?
Excellent work
Awesome tutorial. Thank you so very much!
very nice tutorial but i am getting an unexpected error.
The game is automatically over after some seconds not by the rules.
Please help me
Thanks for the tutorial really helpful,can you post some more tutorials on game
How to identify the collision at the exact touch of the incoming Friend or enemy? I am using my own image for this and the collision is happening as soon as the rectangular side of the image is being touched..and that looks like collision has happened even before actually touching the incoming object.
How can i rectify this ? Or Do I need to use some specific kind of image ?
Game is excellent. But the enemy and friend are out of the screen which makes it impossible to know how many we have missed. Can we adjust them inside the device’s screen? Please do reply. 🙂
in frist tutorial in GameView.java you used
for (int i = 0; i < enemyCount; i++) {
enemies[i].update(player.getSpeed());
in second tutorial it's removed
?
works like charm, I got it in my first run, previous and this tutorial is awesome … you are great
I forgot to mention I changed the code little bit to stop and start music on pressing home button of user phone..
and manage to add enemy and friends within the screen, cause with your great tutorial code sometime enemies and friends are getting half part on screen and half hidden into screen….
although really enjoyed your tutorial… thanks a 101 times…. (y)
please keep up the good work.
This was such a smooth install, thanks so much! This was my first Android project. I installed java, Android Studio, and got your code from GitHub. It had one error in compiling, and I had to add the google() line in 2 places in build.gradle
:
buildscript {
repositories {
jcenter()
google()
}
dependencies {
classpath ‘com.android.tools.build:gradle:3.2.1’
// NOTE: Do not place your application dependencies here; they belong
// in the individual module build.gradle files
}
}
allprojects {
repositories {
jcenter()
google()
maven { url “https://jitpack.io” }
}
}
After that it compiled and runs on both the emulator and on my physical phone. It’s so encouraging to have something actually work so quick. I’ve had many experiences on other platforms where nothing works and it gets very frustrating. You made this super easy. Thanks!
Mike
//if player’s x coordinate is equal to enemies’s y coordinate
if(player.getDetectCollision().exactCenterX()>=enemies.getDetectCollision().exactCenterX())
ERRORS:-
1) at p (of player) it is showing expression expected
2) cannot resolve symbol gt
3) at = it is showing unexpected token
4) after closing if parenthesis it is showing ; expected
//Assigning the scores to the highscore integer array
for(int i=0;i<4;i++){
if(highScore[i]<score){
final int finalI = i;
highScore[i] = score;
break;
}
}
ERRORS:-
1) cannot resolve symbol lt
2) at 4; it is showing Not a statement ‘)’ expected
3) after closing for loop parenthesis ( for()) it is showing ; expected
4) inside parenthesis of if at h (of highScore) it is showing expression expected
5) after closing parenthesis of if it is showing ; expected
6) break outside switch or loop
@Override
public boolean onTouchEvent(MotionEvent motionEvent) {
switch (motionEvent.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_UP:
player.stopBoosting();
break;
case MotionEvent.ACTION_DOWN:android.view.MotionEvent
player.setBoosting();
break;
}
ERRORS:-
1) inside parenthesis of switch at m (of motionEvent) it is showing expression expected
2) cannot resolve symbol amp
3) after closing parenthesis of switch it is showing ; expected
5) at both case MotionEvent.ACTION_UP: and case MotionEvent.ACTION_DOWN: it is showing case
statement outside switch
6) break outside switch or loop