SnakeGame Main Activity

SnakeGame_MainActivity.java

package com.mjuaji.snake1720;


import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Point;
import android.graphics.Rect;
import android.os.Bundle;
import android.view.Display;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class MainActivity extends Activity {
    Canvas canvas;
    SnakeAnimView snakeAnimView;
    //snake head sprite sheet
    Bitmap headAnimBitmap;
    //The portion of the bitmap to be drawn in the current frame
    Rect rectToBeDrawn;
    int frameHeight = 64;
    int frameWidth = 64;
    int numFrames = 6;
    int frameNumber;

    int screenWidth;
    int screenHeight;

    //stats
    long lastFrameTime;
    int fps;
    int hi;

    //start the game from on touch event
    Intent i;

    @Override
    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        //find out the width and height of the Screen
        Display display = getWindowManager().getDefaultDisplay();
        Point size = new Point();
        display.getSize(size);
        screenWidth = size.x;
        screenHeight = size.y;
        headAnimBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.head_sprite_sheet);
        snakeAnimView = new SnakeAnimView(this);
        setContentView(snakeAnimView);

        i = new Intent(this, GameActivity.class);
    }

    class SnakeAnimView extends SurfaceView implements Runnable{
        Thread ourThread = null;
        SurfaceHolder ourHolder;
        volatile boolean playingSnake;
        Paint paint;

        public SnakeAnimView(Context context){
            super(context);
            ourHolder = getHolder();
            paint = new Paint();
            frameWidth = headAnimBitmap.getWidth()/numFrames;
            frameHeight = headAnimBitmap.getHeight();
        }

        @Override
        public void run(){
            while(playingSnake){
                update();
                draw();
                controlFPS();
            }
        }

        public void update(){
            //which frame should we draw
            rectToBeDrawn = new Rect((frameNumber*frameWidth)-1, 0, (frameNumber*frameWidth+frameWidth)-1,frameHeight);
            //now the next frame
            frameNumber++;
            //dont try and draw frames that dont exist
            if(frameNumber == numFrames){
                frameNumber = 0; //back to the first frame
            }
        }

        public void draw(){
            if(ourHolder.getSurface().isValid()){
                canvas = ourHolder.lockCanvas();
                //the background
                canvas.drawColor(Color.BLACK);
                paint.setColor(Color.argb(255,255,255,255));
                paint.setTextSize(150);

                canvas.drawText("Snake",10,150,paint);
                paint.setTextSize(25);
                canvas.drawText(" Hi score: " + hi, 10, screenHeight - 50, paint);

                //draw the snake head make this Rect whatever size and location you like(startX, startY, endX, endY)
                Rect destRect = new Rect(screenWidth/2 - 100, screenHeight/2-100, screenWidth/2+100, screenHeight/2+100);

                canvas.drawBitmap(headAnimBitmap, rectToBeDrawn, destRect, paint);
                ourHolder.unlockCanvasAndPost(canvas);
            }
        }

        public void controlFPS(){
            long timeThisFrame = (System.currentTimeMillis() - lastFrameTime);
            long timeToSleep = 500 - timeThisFrame;
            if(timeThisFrame > 0){
                fps = (int)(1000/timeThisFrame);
            }
            if(timeToSleep > 0){
                try{
                    ourThread.sleep(timeToSleep);
                }catch(InterruptedException e){

                }
            }
            lastFrameTime = System.currentTimeMillis();
        }


        public void pause(){
            playingSnake = false;
            try{
                ourThread.join();
            }catch(InterruptedException e){

            }
        }

        public void resume(){
            playingSnake = true;
            ourThread = new Thread(this);
            ourThread.start();
        }

        @Override
        public boolean onTouchEvent(MotionEvent motionEvent){
            startActivity(i);
            return true;
        }
    }
    @Override
    protected void onStop(){
        super.onStop();
        while(true){
            snakeAnimView.pause();
            break;
        }
        finish();
    }

    @Override
    protected void onResume(){
        super.onResume();
        snakeAnimView.resume();
    }

    @Override
    protected void onPause(){
        super.onPause();
        snakeAnimView.pause();
    }

    public boolean onKeyDown(int keyCode, KeyEvent event){
        if(keyCode == KeyEvent.KEYCODE_BACK){
            snakeAnimView.pause();
            finish();
            return true;
        }
        return false;
    }

}