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如何正确比较坐标?

coordinate-systems android-canvas android java

-1

Alex · 技术社区 · 7 年前

我有绘制文本和用户绘制线的自定义视图。

文本有一些(x,y)坐标,直线也有它(只要用户绘制它)。我只想比较一下,直线坐标和文本坐标是一样的。

但由于用手指很难找到精确的坐标,所以用户不可能直接比较,看起来他连接了两个文本,但坐标略有不同。

我怎样才能正确地做呢?

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;
    }
}

1 回复 | 直到 7 年前

Azhy 7 年前

根据我对您的问题的理解,如果您想检查用户是否单击第一个文本并移动(拖动)到第二个文本,或者反之亦然,您应该检查是否按下整个文本,而不仅仅是绘制文本的左上角,所以我有一个答案给你,这两个文本的应该是不同的,因为知道有像素大小,然后在这个文本矩形内检查触摸,而不是像我所描述的左上角点,所以让我们开始:首先你应该改变你的 isCorrectConnection 此函数instead:-

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;
}

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;
}