Question

在我在两个不同的矩形上的两个固定点之间绘制线之后我需要旋转它们。问题是我的线没有更新，它保持在相同的x1，y1 x2，y2。如何使线条跟随这个矩形？

如果您有任何示例代码或可以提供帮助的内容，那就太棒了！谢谢！

我不认为我需要OnValidateUpdate来解决这个问题。这是我演示此问题的示例代码：

我想画的对象：

public class Object {
    private int xPos;
    private int yPos;
    private int width;
    private int height;        
    float xDistance = 0f;
    float yDistance = 0f;
    double angleToTurn = 0.0;       
    Matrix matrix = new Matrix();
    private Rect rect;
    private Paint paint;
    private Point point;
    Paint p = null;



public Object(int xPos, int yPos){          
        this.xPos = xPos;
        this.yPos = yPos;          
        this.width = 300;
        this.height = 100;          
        matrix = new Matrix();          
        rect = new Rect(xPos,yPos,xPos + width,yPos + height);          
        paint = new Paint();
        paint.setStyle(Style.FILL); 
        paint.setColor(Color.BLUE);

        p = new Paint();
        p.setStyle(Style.FILL); 
        p.setStrokeWidth(15); 
        p.setColor(Color.BLACK);

        point = new Point(this.getxPos(), this.getyPos()+this.getHeight());

    }    
    public void rotate(float xEvent, float yEvent){         
         xDistance = xEvent - this.xPos;
         yDistance = yEvent - this.yPos;
         int angleToTurn = ((int)Math.toDegrees(Math.atan2(yDistance, xDistance)));
         matrix.setRotate((int)(angleToTurn),xPos,yPos + height/2);     

    }       
    public void draw(Canvas c){         
        c.save();
        c.setMatrix(matrix);

        c.drawRect(rect, paint);            
        c.drawPoint(point.x,point.y,p);

        c.restore();            
    }

    public Point getPoint() {
        return point;
    }
    public void setPoint(Point point) {
        this.point = point;
    }
    public Matrix getMatrix() {
        return matrix;
    }
    public void setMatrix(Matrix matrix) {
        this.matrix = matrix;
    }
    public int getxPos() {
        return xPos;
    }
    public void setxPos(int xPos) {
        this.xPos = xPos;
    }
    public int getyPos() {
        return yPos;
    }
    public void setyPos(int yPos) {
        this.yPos = yPos;
    }
    public int getWidth() {
        return width;
    }
    public void setWidth(int width) {
        this.width = width;
    }
    public int getHeight() {
        return height;
    }
    public void setHeight(int height) {
        this.height = height;
    }

GameView类，我在其中绘制2个rects：

 public class GameView extends SurfaceView implements SurfaceHolder.Callback{

    private SurfaceHolder surfaceHolder;
    private GameloopThread gameloopThread;     
    float downx,downy,upx,upy;
    private Object object,object1;
    Line line; 


    public GameView(Context context) {
        super(context);
        gameloopThread = new GameloopThread(this);
        surfaceHolder = getHolder();
        surfaceHolder.addCallback(this);

        object = new Object(500,500);
        object1 = new Object(800,700);

        line = new Line(object.getPoint(),object1.getPoint());
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        Canvas canvas  = surfaceHolder.lockCanvas();
        onDraw(canvas);
        surfaceHolder.unlockCanvasAndPost(canvas);
        gameloopThread.setRunning(true);
        gameloopThread.start();
    }
    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        boolean retry = true;
        gameloopThread.setRunning(false);
        while(retry){
            try {
                gameloopThread.join();
                retry=false;
            }catch(InterruptedException e){

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

    }

    @SuppressLint("ClickableViewAccessibility")
    @Override
    public boolean onTouchEvent( MotionEvent event) {
        float x = 0f,y=0f;
        if(event.getAction() == MotionEvent.ACTION_DOWN){
            downx = event.getX();
            downy = event.getY();

        }
        if (event.getAction() == MotionEvent.ACTION_MOVE) { 
            x = event.getX();
            y = event.getY();
            object.rotate(x, y); 
            object1.rotate(x, y);          
        }
        if (event.getAction() == MotionEvent.ACTION_UP) {

        }                       
        return true;
    }
    @Override
    public void onDraw(Canvas canvas){
        super.onDraw(canvas); 
        canvas.drawColor(Color.LTGRAY);
        if(object != null)
            object.draw(canvas);
        if(object1 != null)
            object1.draw(canvas); 

        if(line != null){           
            line._drawLine(canvas);         
        }

    }

 }

应该连接两个矩形的线类（我为它做了类，但不需要它）

 public class Line {

  private Point point1,point2;
  private Paint p;
  Matrix m;
  public Line(Point p1,Point p2){
    this.point1 = p1;
    this.point2 = p2;

    p = new Paint();
    p.setStyle(Style.FILL);    
    p.setColor(Color.RED);

    m = new Matrix();

 }

 public void _drawLine(Canvas c){       
     c.setMatrix(m);
    c.save();       
    c.drawLine(point1.x, point1.y, point2.x, point2.y, p); 
    c.restore();
 }

 public Matrix getMatrix(){
    return m;
 }

 }

我想尽可能使用Matrix对象来实现它。还有MainActivity和Thread类，但我不发布它们因为它与这个问题无关。

Answer 1

您可以使用ValueAnimator为矩形设置动画。每个

onAnimationUpdate(ValueAnimator animation)

您可以使用新位置无效或重新绘制该行。

Answer 2

我找到了解决方案，我可以使用Matrix.mapPoints，保存它们只是重绘线！

两个旋转矩形之间的android-update线

2 个答案: