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用画线连接元件

android-drawable android-custom-view android-layout android

Alex · 技术社区 · 7 年前

我试图做一些视图,这将允许用户连接一些元素与绘制的线。

E、 g.在图像上有几个 TextViews ,用户从一条线到另一条线,如果连接正确(text1到text3),线将保持不变。

现在,我已经实现了自定义视图,它绘制了一条线,它跟随您的手指:

public class FingerLineView extends View {
    private final Paint mPaint;
    private float startX;
    private float startY;
    private float endX;
    private float 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(Style.STROKE);
        mPaint.setColor(Color.RED);
    }

    @Override protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawLine(startX, startY, endX, endY, mPaint);
    }

    @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();
                invalidate();
                break;
        }
        return true;
    }
}

工作原理如下:

但我不知道如何正确地将其与视图元素“连接”,比如 TextView .

我应该使用完全自定义视图还是有更好的方法?

1 回复 | 直到 7 年前

Antonio Vlasic 7 年前

画布比你可能知道的更强大。;)
drawText -方法。性能卓越,易于使用,100%可定制。

编辑:

public class FingerLineView extends View {
private final Paint mPaint;
private final Paint mPaintText;
private float startX;
private float startY;
private float endX;
private float 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", startX - mPaintText.measureText("TEXT")/2, startY - 30, mPaintText);
    canvas.drawText("TEXT", endX - mPaintText.measureText("TEXT")/2, endY - 30, 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();
            invalidate();
            break;
    }
    return true;
}

}