Question

好的，所以我需要开始另一个关于碰撞检测的活动，我是一个尝试制作这个简单游戏的初学者，我只是想不出来...它标记为//这是我想要的地方启动另一个活动，我想要启动它，当前代码给我错误

我需要启动活动的GameView.java文件

    package fi.itsn.jetfighter;

import android.content.Context;
import android.content.Intent;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

import java.util.ArrayList;

import static android.support.v4.app.ActivityCompat.startActivity;

/**
 * Created by h on 21.9.2016.
 */

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;
    private Broccoli[] broccolis;

    private int enemyCount = 3;
    private int broccoliCount = 1;

    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);
        }

        enemies = new Enemy[enemyCount];
        for (int i = 0; i < enemyCount; i++) {
            enemies[i] = new Enemy(context, screenX, screenY);
        }

        //initializing boom object
        boom = new Boom(context);

        broccolis = new Broccoli[broccoliCount];
        for (int i = 0; i < broccoliCount; i++) {
            broccolis[i] = new Broccoli(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());
        }

        for (int i = 0; i < enemyCount; i++) {
            enemies[i].update(player.getSpeed());

            //if collision occurrs with player
            if (Rect.intersects(player.getDetectCollision(), enemies[i].getDetectCollision())) {

                //displaying boom at that location
                boom.setX(enemies[i].getX());
                boom.setY(enemies[i].getY());

                enemies[i].setX(-200);

            }
        }

        for (int i = 0; i < broccoliCount; i++) {
            broccolis[i].update(player.getSpeed());

            if (Rect.intersects(player.getDetectCollision(), broccolis[i].getDetectCollision())) {

                startActivity(new Intent(this, end.class));
//This is the place I am trying to start another activity
            }
        }
    }




    private void draw() {
        if (surfaceHolder.getSurface().isValid()) {
            canvas = surfaceHolder.lockCanvas();
            canvas.drawColor(Color.BLUE);

            paint.setColor(Color.WHITE);

            for (Star s : stars) {
                paint.setStrokeWidth(s.getStarWidth());
                canvas.drawPoint(s.getX(), s.getY(), paint);
            }

            canvas.drawBitmap(
                    player.getBitmap(),
                    player.getX(),
                    player.getY(),
                    paint);

            for (int i = 0; i < enemyCount; i++) {
                canvas.drawBitmap(
                        enemies[i].getBitmap(),
                        enemies[i].getX(),
                        enemies[i].getY(),
                        paint
                );
            }

            for (int i = 0; i < broccoliCount; i++) {
                canvas.drawBitmap(
                        broccolis[i].getBitmap(),
                        broccolis[i].getX(),
                        broccolis[i].getY(),
                        paint
                );
            }

            //drawing boom image
            canvas.drawBitmap(
                    boom.getBitmap(),
                    boom.getX(),
                    boom.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;
    }

}

这是Broccoli.java文件

    package fi.itsn.jetfighter;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Rect;

import java.util.Random;

/**
 * Created by h on 22.9.2016.
 */

public class Broccoli {

    //bitmap for the enemy
    //we have already pasted the bitmap in the drawable folder
    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
    private Rect detectCollision;

    public Broccoli(Context context, int screenX, int screenY) {
        bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.broccoli);
        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();
    }

    //adding a setter to x coordinate so that we can change it after collision
    public void setX(int x){
        this.x = x;
    }

    //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;
    }

    public int getSpeed() {
        return speed;
    }


}

Answer 1

尝试

 startActivity(new Intent(getContext(), end.class));

您需要传递上下文this。在这里，您正在使用SurfaceView而不是Activity来扩展课程，因此this无法为您提供Activity中提供的上下文

OR

因为您在构造函数中传递上下文，所以您也可以像

那样执行

public GameView(Context context, int screenX, int screenY) {{
   super(context);
   this.mContext = context;
 }

并在mContext

中传递此Intent

startActivity(new Intent(mContext, end.class));

在碰撞检测上开始另一项活动

1 个答案: