java - 当我尝试在 android studio 中调试时卡在收集数据中

Question

我正在尝试通过单例模式编写代码。

这是我的 MainActivity。

public class MainActivity extends AppCompatActivity {

public static MainActivity activity;
public TouchSensor touchSensor;
public SurfaceViewThread surfaceViewThread;
public TriggerChecker triggerChecker;

public Physics physics;

//public static Handler mHandler = new Handler();

@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);

    activity = this;
    surfaceViewThread = SurfaceViewThread.getInstance();
    touchSensor = TouchSensor.getInstance();
    triggerChecker = TriggerChecker.getInstance();
    physics = Physics.getInstance();

    touchSensor.start();
    triggerChecker.start();
    physics.start();
    //surfaceViewThread is already started.

    activity.setContentView(surfaceViewThread);
}

这是我尝试通过单例模式编写的代码。

public class SurfaceViewThread extends SurfaceView implements Runnable, SurfaceHolder.Callback {

private static SurfaceViewThread surfaceViewThread = new SurfaceViewThread();

private static Camera camera;
private SurfaceHolder holder;
private Thread thread;
private boolean run;

private Vector<ObjectGraphic> objects;
private Vector<Graphic> UIs;
private ObjectGraphic field;

private Vector<ObjectGraphic> draws;
private ComponentMessage componentMessage;

public static SurfaceViewThread getInstance()
{
    if(surfaceViewThread == null)
        surfaceViewThread = new SurfaceViewThread();
    return surfaceViewThread;
}
private SurfaceViewThread()
{
    super(activity.getApplicationContext());
    camera = new Camera();
    getHolder().addCallback(this);
    holder = getHolder();
    objects = new Vector<>();
    UIs = new Vector<>();

    draws = new Vector<>();

    run = false;

    componentMessage = new ComponentMessage();
}

当我构建这段代码时，Camera 类因 NullPointException 而崩溃。

public class Camera extends GameObject {

private Rect area;
private int sight;
private int maxSight = 50;
private int minSight = 10;
private int[] fieldOfView;//{vertical, horizontal}
private int[] maxFieldOfView = new int[] { 60, 45 };
private int[] minFieldOfView = new int[] { 10, 10 };

public Camera()
{
    super();
    area = new Rect();
    this.fieldOfView = new int[] { 60, 45 };
    objectMatrix.Rotate(objectMatrix.xVector(), Math.toRadians(-45));

    setDisplayVector();
}
private void setSight()
{
    double angle = Math.PI/2 - Math.acos(new Common_Math.Matrix1X4(0, 1, 0, 0).Inner(objectMatrix.zVector().Invert()));
    if(angle < 0 && angle > - Math.PI/2) {
        double t = -objectMatrix.qVector().getY() / objectMatrix.zVector().getY();
        int x = (int) (objectMatrix.zVector().getX() * t + objectMatrix.qVector().getX());
        int z = (int) (objectMatrix.zVector().getZ() * t + objectMatrix.qVector().getZ());

        sight = (int)Math.sqrt(Math.pow((x - objectMatrix.qVector().getX()), 2) + Math.pow((objectMatrix.qVector().getY()), 2) + Math.pow((z - objectMatrix.qVector().getZ()), 2));
        if(sight < minSight)
            sight = minSight;
    }
    else
    {
        sight = maxSight;
    }
}
private void setDisplayVector()
{
    setSight();
    Common_Math.Matrix1X4 upVector, downVector, leftVector, rightVector;
    Common_Math.Matrix1X4 zVector = objectMatrix.zVector();

    upVector = zVector.Rotate(objectMatrix.xVector(), fieldOfView[0]);
    downVector = zVector.Rotate(objectMatrix.xVector(), -fieldOfView[0]);
    leftVector = zVector.Rotate(objectMatrix.yVector(), fieldOfView[1]);
    rightVector = zVector.Rotate(objectMatrix.yVector(), -fieldOfView[1]);

    double angle = Math.PI/2 - Math.acos(new Common_Math.Matrix1X4(0, 1, 0, 0).Inner(objectMatrix.zVector().Invert()));
    upVector = upVector.Scaled((int)(Math.abs(objectMatrix.qVector().getY() * Math.tan(angle + fieldOfView[0]))));
    downVector = downVector.Scaled((int)(Math.abs(objectMatrix.qVector().getY() * Math.tan(angle - fieldOfView[0]))));
    leftVector = leftVector.Scaled((int)(sight * Math.asin(fieldOfView[1])));
    rightVector = rightVector.Scaled((int)(sight * Math.asin(fieldOfView[1])));

    area.left = (int) objectMatrix.qVector().Add(leftVector).getX();
    area.top = (int) objectMatrix.qVector().Add(upVector).getY();
    area.right = (int) objectMatrix.qVector().Add(rightVector).getX();
    area.bottom = (int) objectMatrix.qVector().Add(downVector).getY();
}

这是GameObject类

public class GameObject {

protected GameObject upperGameObject;//if upperGameObject is null, this GameObject is parent GameObject.

protected Common_Math.Matrix4X4 objectMatrix;
private Vector<SeaWeedComponent> componentVector;

public GameObject()
{
    objectMatrix = new Common_Math.Matrix4X4();
    AllocatePhysicsSpace();
    componentVector = new Vector<>();
}

和 Matrix4x4 类

public static class Matrix4X4
{
    private Matrix1X4 xVector, yVector, zVector, qVector;

    public Matrix4X4() {
        xVector = new Matrix1X4(1, 0, 0, 0);
        yVector = new Matrix1X4(0, 1, 0, 0);
        zVector = new Matrix1X4(0, 0, 1, 0);
        qVector = new Matrix1X4(0, 0, 0, 1);
    }

所以我检查了一个断点以查看为什么会发生这种情况，但是当我调试它时，每个变量都停留在“收集数据..”并且没有任何反应。甚至调试器的响应速度也变慢了。

我猜不出为什么会这样。我的代码有什么问题吗？如何查看变量？

Answer 1

不确定这应该是评论还是答案...

我在完全不同的上下文中看到了同样的问题，它“以某种方式”与使用线程有关。 似乎当调试器试图获取一个值并且需要运行与另一个线程关联的东西时，它会死锁。

在我的例子中，我有一个 javascript 引擎，当我需要执行 JS 时，它会在非 ui 线程上调用。如果我在任何地方都有变量，例如JSObject 的子类，调试器锁定。

我发现解决此问题的唯一方法是明智地进行日志记录和设置断点。

检查您的代码在访问变量时是否遇到任何锁或同步语句，这可能是您的情况的原因。

在修复此问题之前，您可以在使用“Gson().toJson(yourObject)”作为 json 字符串调试时看到您的对象。