android - 关于Android Paint绘图颜色

Question

绘图 View .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;
}

我正在尝试用不同的颜色绘制手指画，但每当我更改油漆的颜色时，所有以前的路径或绘图都会获取并使用更新的颜色绘制我想用不同的颜色绘制我该怎么做？请给我一些解决方案。

Answer 1

为此，您必须为绘制的每个对象创建一个新的Paint。这是因为当 Canvas 重绘时，它每次都引用同一个 Paint 对象，所以所有路径都将使用这个 paint。

首先，我会更改您的 paths 数组以同时包含 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您的 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);
}

这非常占用内存，所以当这些项目不再使用时，您必须非常小心地重置它们，但是要有这么多不同的颜色，您必须拥有所有这些不同的 Paint 对象。