Android Studio-游戏（开发中）运行时间越长，速度越慢

Question

I am designing a game on android studio and the game slows to a crawl the longer I run the code. The game so far is just blue balls flying across the screen. There is no interaction there yet.

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

import java.util.ArrayList;
import java.util.Random;

public class GamePanel extends SurfaceView implements SurfaceHolder.Callback {

public static final int WIDTH = 1600;
public static final int HEIGHT = 2560;

private FirstThread fT;
private Background logo;
private ArrayList<SugarFlake> sF;

private long sugarTime;
Random rm = new Random();


public int movement = -5;

public GamePanel(Context context) {
    super(context);
    getHolder().addCallback(this);
    setFocusable(true);// definition: Set whether this view can receive the focus. Setting this to false will also ensure that this view is not focusable in touch mode.

}

@Override
public void surfaceCreated(SurfaceHolder holder) {
    logo = new Background(BitmapFactory.decodeResource(getResources(), R.drawable.company_name));
    sF = new ArrayList<SugarFlake>();
    fT = new FirstThread(getHolder(), this);
    numOfflakes = 15;
    sugarTime = System.nanoTime();
    fT.setRunning(true);
    fT.start();
}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
    boolean retry = true;
    int counter = 0;
    while (retry && counter < 1000) {
        counter++;
        try {
            fT.setRunning(false);
            fT.join();
            retry = false;
            fT = null;
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}


public void update() {
    long currentTime = System.nanoTime();
    int sugarPosition;

    int t = 1;

    while (t < 200) {
        if (sF.size() == 0) {

            sF.add(new SugarFlake(WIDTH / 2 + 8, -25));

        }

        if (currentTime > sugarTime) {
            sugarPosition = (int) (rm.nextDouble() * 10 + (WIDTH / 4 * rm.nextDouble() * 10));


            if (sugarPosition < WIDTH && sugarPosition > 25)
                sF.add(new SugarFlake(sugarPosition, 0));

        }
        sugarTime = System.nanoTime();
        for (int i = 0; i < 1; i++) {
            sF.get(i).update();

            if (sF.get(i).getY() > HEIGHT -20) {
                sF.remove(i);
            }
        }
        t++;

    }
}
public void draw(Canvas canvas) {
    super.draw(canvas);
    final float scaleFactorX = getWidth() / (WIDTH * 1.f);
    final float scaleFactorY = getHeight() / (HEIGHT * 1.f);

    if (canvas != null) {
        final int savedState = canvas.save();// canvas.save definition: Saves the current matrix and clip onto a private stack.
        canvas.scale(scaleFactorX, scaleFactorY);
        logo.draw(canvas);
        Paint p = new Paint();
        p.setColor(Color.BLUE);
        p.setStyle(Paint.Style.FILL);
        canvas.drawRect((WIDTH / 2 - 5), HEIGHT, (WIDTH / 2 + 5), 0, p);
        for (SugarFlake sugarFlake : sF) {
            sugarFlake.draw(canvas);
            // System.out.println("this is che draw method, blah");
        }


        canvas.restoreToCount(savedState); // definition: Efficient way to pop any calls to save() that happened after the save count reached saveCount. It is an error for saveCount to be less than 1.

    }

}

}

this is the main code.

Below is what pops up in the logcat after running the app for about a minute. The number that prints out with System..out is the frames per second programmed in another class which I am adding below this readout. THe arraylist sugarflake is

public void oneFlake(Canvas canvas){
        Paint p = new Paint();
        p.setColor(Color.BLUE);
        p.setStyle(Paint.Style.FILL);

        canvas.drawCircle(x - r, y - r, r, p);
    }

This moves down the screen as the app runs.

08-17 10:44:53.073 15757-15765/com.example.vitaliy_2.thegame W/art: Suspending all threads took: 33.752ms
08-17 10:44:53.083 15757-15772/com.example.vitaliy_2.thegame I/art: Background sticky concurrent mark sweep GC freed 2767(92KB) AllocSpace objects, 0(0B) LOS objects, 0% free, 64MB/64MB, paused 1.708ms total 255.645ms
08-17 10:44:53.253 15757-15772/com.example.vitaliy_2.thegame I/art: Background partial concurrent mark sweep GC freed 231598(15MB) AllocSpace objects, 0(0B) LOS objects, 24% free, 48MB/64MB, paused 1.983ms total 139.678ms
08-17 10:44:53.583 15757-15927/com.example.vitaliy_2.thegame I/System.out: 16.0
08-17 10:44:55.615 15757-15927/com.example.vitaliy_2.thegame I/System.out: 14.0
08-17 10:44:57.637 15757-15927/com.example.vitaliy_2.thegame I/System.out: 14.0
08-17 10:44:59.409 15757-15927/com.example.vitaliy_2.thegame I/System.out: 17.0
08-17 10:45:01.301 15757-15927/com.example.vitaliy_2.thegame I/System.out: 15.0
08-17 10:45:03.123 15757-15927/com.example.vitaliy_2.thegame I/System.out: 16.0
08-17 10:45:05.005 15757-15927/com.example.vitaliy_2.thegame I/System.out: 16.0
08-17 10:45:07.057 15757-15927/com.example.vitaliy_2.thegame I/System.out: 14.0
08-17 10:45:09.129 15757-15927/com.example.vitaliy_2.thegame I/System.out: 14.0
08-17 10:45:11.441 15757-15927/com.example.vitaliy_2.thegame I/System.out: 12.0
08-17 10:45:12.091 15757-15765/com.example.vitaliy_2.thegame W/art: Suspending all threads took: 6.225ms
08-17 10:45:12.091 15757-15772/com.example.vitaliy_2.thegame W/art: Suspending all threads took: 6.195ms
08-17 10:45:12.182 15757-15772/com.example.vitaliy_2.thegame I/art: Background sticky concurrent mark sweep GC freed 2156(72KB) AllocSpace objects, 0(0B) LOS objects, 0% free, 64MB/64MB, paused 8.361ms total 275.787ms
08-17 10:45:12.292 15757-15772/com.example.vitaliy_2.thegame I/art: Background partial concurrent mark sweep GC freed 232889(15MB) AllocSpace objects, 0(0B) LOS objects, 24% free, 48MB/64MB, paused 1.251ms total 110.168ms
08-17 10:45:13.673 15757-15927/com.example.vitaliy_2.thegame I/System.out: 13.0
08-17 10:45:15.785 15757-15927/com.example.vitaliy_2.thegame I/System.out: 14.0
08-17 10:45:18.268 15757-15927/com.example.vitaliy_2.thegame I/System.out: 12.0
08-17 10:45:20.540 15757-15927/com.example.vitaliy_2.thegame I/System.out: 13.0
08-17 10:45:22.902 15757-15927/com.example.vitaliy_2.thegame I/System.out: 12.0
08-17 10:45:25.064 15757-15927/com.example.vitaliy_2.thegame I/System.out: 14.0
08-17 10:45:27.206 15757-15927/com.example.vitaliy_2.thegame I/System.out: 14.0
08-17 10:45:27.987 15757-15757/com.example.vitaliy_2.thegame I/Timeline: Timeline: Activity_idle id: android.os.BinderProxy@ecdb605 time:47113609

This the frame rate simulator

import android.graphics.Canvas;
import android.view.SurfaceHolder;

public class FirstThread extends Thread{
    private final SurfaceHolder surfaceHolder;
    private GamePanel gP;
    private boolean running;
    public static Canvas canvas;
    public FirstThread(SurfaceHolder surfaceHolder, GamePanel gP){
        super();
        this.surfaceHolder = surfaceHolder;
        this.gP = gP;
    }

    @Override
    public void run() {
        long startTime;
        long timeMillis;
        long waitTime;
        long totalTime = 0;
        int frameCount = 0;
        final int FPS = 30;
        long targetTime = 1000/FPS;

        while(running){
            startTime = System.nanoTime();
            canvas = null;

            try{
                canvas = this.surfaceHolder.lockCanvas();
                synchronized (surfaceHolder){
                    this.gP.update();
                    this.gP.draw(canvas);
                }
            }catch(Exception ignored){}finally{
                if(canvas != null){
                    try{surfaceHolder.unlockCanvasAndPost(canvas);}catch(Exception e){e.printStackTrace();}
                }
            }
            timeMillis = (System.nanoTime() - startTime) / 100000;
            waitTime = targetTime - timeMillis;
            try {sleep(waitTime);} catch (Exception ignored){}
            totalTime += System.nanoTime() - startTime;
            frameCount++;
            if(frameCount == FPS){
                double averageFPS = 1000 / ((totalTime / frameCount) /1000000);
                frameCount = 0;
                totalTime = 0;
                System.out.println(averageFPS);
            }
        }
    }
    public void setRunning(boolean b){running = b;}
}

Let me know if any more information is needed. Thank you.

Answer 1

Looks like you're creating new instances of SugarFlake repeatedly, and adding and removing them from the ArrayList every call to 'update'.

I'd recommend allocating all of those objects at the start, and just recycling them as needed. Relying on the garbage collector to get rid of them is probably causing the performance problem.

Check out ' object pooling ' for more on this.

Answer 2

maybe it's all those

sF.add(new SugarFlake(sugarPosition, 0));

and

sF.add(new SugarFlake(WIDTH / 2 + 8, -25));

you have in the code that cause the slowness..

You are allocating memory and never releasing it, those are memory leaks

You should just move the SugarFlake to new positions instead of create new one everytime. Reuse them and set an upper limit on the number of SugarFlakes