如何正确比较坐标？

Question

我有带有绘制文本和用户绘制线条的自定义视图。

文本有一些 (x,y) 坐标，线条也有（一旦用户绘制它）。我只是想比较一下，那条线的坐标和文本的坐标是一样的。

但由于很难用手指敲出精确的坐标，所以无法直接比较给用户看，他好像连接了2个文本，但坐标略有不同。

如何正确操作？

这是我的直接比较代码（方法isCorrectConnection）：

public class FingerLineView extends View {
    private final Paint mPaint;
    private final Paint mPaintText;
    private float startX, startY;
    private float endX, endY;

    public FingerLineView(Context context) {
        this(context, null);
    }

    public FingerLineView(Context context, AttributeSet attrs) {
        super(context, attrs);
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setColor(Color.RED);
        mPaintText = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaintText.setColor(Color.BLACK);
        mPaintText.setTextSize(30);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawLine(startX, startY, endX, endY, mPaint);
        canvas.drawText("TEXT", 10, 200, mPaintText);
        canvas.drawText("TEXT", 200, 200, mPaintText);
    }

    @Override
    public boolean onTouchEvent(@NonNull MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                startX = event.getX();
                startY = event.getY();
                // Set the end to prevent initial jump
                endX = event.getX();
                endY = event.getY();
                invalidate();
                break;
            case MotionEvent.ACTION_MOVE:
                endX = event.getX();
                endY = event.getY();
                invalidate();
                break;
            case MotionEvent.ACTION_UP:
                endX = event.getX();
                endY = event.getY();
                isCorrectConnection(startX, startY, endX, endY, 10, 200, 200, 200);
                invalidate();
                break;
        }
        return true;
    }

    public boolean isCorrectConnection(float startX, float startY, float endX, float endY,
                                       float textX1, float textY1, float textX2, float textY2) {
        return startX == textX1 && startY == textY1 && endX == textX2 && endY == textY2;
    }
}

Answer 1

根据我对你的问题的理解，你想检查用户是否点击了第一个文本并移动（拖动）到第二个文本，反之亦然，你应该检查按下整个文本而不仅仅是左上角绘制的文本，所以我有一个答案，这两个文本应该不同，因为知道有像素大小，然后检查这个文本矩形内的触摸，而不仅仅是我描述的左上角点，所以让我们开始吧：首先你应该将您的 isCorrectConnection 函数改为：-

private boolean isCorrectConnection(float startX, float startY, float endX, float endY,
                                   float x1, float y1, float x2, float y2
                                   String text1, String text2) {
    //Measuring text1's size
    Rect textBounds = new Rect();
    mPaint.getTextBounds(text1, 0, text1.length(), textBounds);
    int w1 = textBounds.width();
    int h1 = textBounds.height();

    //Measuring text2's size
    Rect textBounds2 = new Rect();
    mPaint.getTextBounds(text2, 0, text2.length(), textBounds2);
    int w2 = textBounds2.width();
    int h2 = textBounds2.height();

    //Checking for touched and moved from text1 to text2
    if(startX >= x1 && startX <= (x1 + w1) && startY >= y1 && startY <= (y1 + h1) &&
       endX >= x2 && endX <= (x2 + w2) && endY >= y2 && endY <= (y2 + h2))
        return true;

    //Checking for touched and moved from text2 to text1
    if(startX >= x2 && startX <= (x2 + w2) && startY >= y2 && startY <= (y2 + h2) &&
       endX >= x1 && endX <= (x1 + w1) && endY >= y1 && endY <= (y1 + h1))
        return true;

    return false;
}

如果您确定文本相同，请改为执行以下操作：-

private boolean isCorrectConnection(float startX, float startY, float endX, float endY,
                                   float x1, float y1, float x2, float y2
                                   String text) {
    //Measuring text's size
    Rect textBounds = new Rect();
    mPaint.getTextBounds(text, 0, text.length(), textBounds);
    int w1 = textBounds.width(), w2 = w1;
    int h1 = textBounds.height(), h2 = h1;

    //Checking for touched and moved from text1 to text2
    if(startX >= x1 && startX <= (x1 + w1) && startY >= y1 && startY <= (y1 + h1) &&
       endX >= x2 && endX <= (x2 + w2) && endY >= y2 && endY <= (y2 + h2))
        return true;

    //Checking for touched and moved from text2 to text1
    if(startX >= x2 && startX <= (x2 + w2) && startY >= y2 && startY <= (y2 + h2) &&
       endX >= x1 && endX <= (x1 + w1) && endY >= y1 && endY <= (y1 + h1))
        return true;

    return false;
}

如何正确比较坐标？

how to correctly compare coordinates?

java

android

coordinate-systems

android-canvas