Question

DrawView.java

public class DrawView extends View implements OnTouchListener {
private Canvas mCanvas;
private Path mPath;
public Paint mPaint;
ArrayList<Path> paths = new ArrayList<Path>();
private ArrayList<Path> undonePaths = new ArrayList<Path>();

private MaskFilter mEmboss;
private MaskFilter mBlur;

private Bitmap im;

public DrawView(Context context) {
    super(context);
    setFocusable(true);
    setFocusableInTouchMode(true);
    this.setOnTouchListener(this);

    paths.clear();
    undonePaths.clear();

    mPaint = new Paint();
    mPaint.setAntiAlias(true);
    mPaint.setDither(true);
    mPaint.setColor(Color.BLUE);
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setStrokeJoin(Paint.Join.ROUND);
    mPaint.setStrokeCap(Paint.Cap.ROUND);
    mPaint.setStrokeWidth(4);
    mEmboss = new EmbossMaskFilter(new float[] { 1, 1, 1 }, 0.4f, 6, 3.5f);

    mBlur = new BlurMaskFilter(8, BlurMaskFilter.Blur.NORMAL);

    mCanvas = new Canvas();
    mPath = new Path();
    // paths.add(mPath);

    im = BitmapFactory.decodeResource(context.getResources(),
            R.drawable.ic_launcher);

}

@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    super.onSizeChanged(w, h, oldw, oldh);
}

@Override
protected void onDraw(Canvas canvas) {
    canvas.drawColor(Share.cColor);

    for (Path p : paths) {

        canvas.drawPath(p, mPaint);
    }

    canvas.drawPath(mPath, mPaint);

}

private float mX, mY;
private static final float TOUCH_TOLERANCE = 4;

private void touch_start(float x, float y) {

    mPaint.setColor(Share.dColor);
    undonePaths.clear();
    mPath.reset();
    mPath.moveTo(x, y);
    mX = x;
    mY = y;

    Log.e("", "pathsize:::" + paths.size());
    Log.e("", "undonepathsize:::" + undonePaths.size());
}

private void touch_move(float x, float y) {
    float dx = Math.abs(x - mX);
    float dy = Math.abs(y - mY);
    if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) {
        mPath.quadTo(mX, mY, (x + mX) / 2, (y + mY) / 2);
        mX = x;
        mY = y;
    }
}

private void touch_up() {
    mPath.lineTo(mX, mY);
    // commit the path to our offscreen
    mCanvas.drawPath(mPath, mPaint);
    // kill this so we don't double draw
    paths.add(mPath);
    mPath = new Path();

    Log.e("", "pathsize:::" + paths.size());
    Log.e("", "undonepathsize:::" + undonePaths.size());
}

public void onClickUndo() {

    Log.e("", "pathsize:::" + paths.size());
    Log.e("", "undonepathsize:::" + undonePaths.size());
    if (paths.size() > 0) {
        undonePaths.add(paths.remove(paths.size() - 1));
        invalidate();
    } else {

    }
    // toast the user
}

public void onClickRedo() {

    Log.e("", "pathsize:::" + paths.size());
    Log.e("", "undonepathsize:::" + undonePaths.size());
    if (undonePaths.size() > 0) {
        paths.add(undonePaths.remove(undonePaths.size() - 1));
        invalidate();
    } else {

    }
    // toast the user
}

@Override
public boolean onTouch(View arg0, MotionEvent event) {
    float x = event.getX();
    float y = event.getY();

    switch (event.getAction()) {
    case MotionEvent.ACTION_DOWN:
        touch_start(x, y);
        invalidate();
        break;
    case MotionEvent.ACTION_MOVE:
        touch_move(x, y);
        invalidate();
        break;
    case MotionEvent.ACTION_UP:
        touch_up();
        invalidate();
        break;
    }
    return true;
}

}

我正在尝试绘制不同颜色的手指画颜，但每当我改变颜色的颜色，然后所有以前的路径或绘图得到和绘制更新的颜色我想用不同的颜色绘制我该怎么办？请给我一些解决方案。

Answer 1

为此，您必须为每个绘制的对象创建一个新的Paint。这是因为当Canvas重绘时，它每次引用相同的Paint对象，因此所有路径都将使用此绘制。

首先，我会将您的paths数组更改为包含Paint和Path。您可以使用Android类型Pair实现此目的。

ArrayList<Pair<Path, Paint>> paths = new ArrayList<Pair<Path, Paint>>();

您还必须以这种方式转换undonePaths变量。

然后，在您的touch_up()方法中，您需要添加这个新的Paint对象。

Paint newPaint = new Paint(mPaint); // Clones the mPaint object
paths.add(new Pair<Path, Paint>(mPath, newPaint));

最后，您的循环也必须为此进行调整：

for (Pair<Path, Paint> p : paths) {
    canvas.drawPath(p.first, p.second);
}

这是相当大的内存密集型，所以当它们不再使用时你必须小心重置这些项目，但要有这么多不同的颜色，你必须全部这些不同的Paint对象。

关于Android Paint绘图颜色

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