【发布时间】：2014-06-26 15:09:41
【问题描述】：
嘿，我在我的应用程序中实现了涂鸦功能。绘制线条时，移动手指时看不到线条路径。我可以在启动时看到线，即 TouchUp，有人可以帮助我，以便我可以在沿着路径移动手指时看到绘制的线。
public class DoodleImageView extends View {
// drawing path
private Path drawPath;
// drawing point
private boolean drawPoint;
// drawing and canvas paint
public Paint drawPaint;
public Paint tempPaint;
private Paint canvasPaint;
// initial color
private int paintColor;
// canvas
private Canvas drawCanvas;
// canvas bitmap
private Bitmap canvasBitmap;
private ArrayList<Path> paths = new ArrayList<Path>();
private ArrayList<Integer> pathscolor = new ArrayList<Integer>();
private ArrayList<Integer> pointcolor = new ArrayList<Integer>();
private ArrayList<Integer> marker = new ArrayList<Integer>();
private ArrayList<Point> points = new ArrayList<Point>();
private float mX, mY;
private final float TOUCH_TOLERANCE = 1;
public DoodleImageView(Context context, AttributeSet attrs) {
super(context, attrs);
setupDrawing();
// TODO Auto-generated constructor stub
}
private void setupDrawing() {
// get drawing area setup for interaction
drawPath = new Path();
drawPaint = new Paint();
// drawPaint.setColor(paintColor);
drawPaint.setAntiAlias(true);
drawPaint.setStrokeWidth(20);
drawPaint.setStyle(Paint.Style.STROKE);
drawPaint.setStrokeJoin(Paint.Join.ROUND);
drawPaint.setStrokeCap(Paint.Cap.ROUND);
canvasPaint = new Paint(Paint.DITHER_FLAG);
}
private Paint setUpPaint(int color) {
tempPaint = new Paint();
tempPaint.setColor(color);
tempPaint.setAntiAlias(true);
tempPaint.setStrokeWidth(20);
tempPaint.setStyle(Paint.Style.STROKE);
tempPaint.setStrokeJoin(Paint.Join.ROUND);
tempPaint.setStrokeCap(Paint.Cap.ROUND);
return tempPaint;
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
// TODO Auto-generated method stub
super.onSizeChanged(w, h, oldw, oldh);
canvasBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
drawCanvas = new Canvas(canvasBitmap);
}
@Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
if (marker.size() > 0) {
for (int i = 0; i < paths.size(); i++) {
canvas.drawPath(paths.get(i), setUpPaint(pathscolor.get(i)));
}
for (int i = 0; i < points.size(); i++) {
canvas.drawPoint(points.get(i).x, points.get(i).y,
setUpPaint(pointcolor.get(i)));
}
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
// TODO Auto-generated method stub
float touchX = event.getX();
float touchY = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
touch_start(touchX, touchY);
invalidate();
break;
case MotionEvent.ACTION_MOVE:
touch_move(touchX, touchY);
invalidate();
break;
case MotionEvent.ACTION_UP:
touch_up();
invalidate();
break;
default:
return false;
}
invalidate();
return true;
}
private void touch_start(float x, float y) {
drawPoint = true;
drawPath.reset();
drawPath.moveTo(x, y);
drawCanvas.drawPath(drawPath, drawPaint);
mX = x;
mY = y;
}
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) {
drawPath.quadTo(mX, mY, (x + mX) / 2, (y + mY) / 2);
drawPoint = false;
drawCanvas.drawPath(drawPath,drawPaint);
mX = x;
mY = y;
}
}
private void touch_up() {
if (drawPoint == true) {
drawCanvas.drawPoint(mX, mY, drawPaint);
Point p = new Point();
p.set((int) mX, (int) mY);
points.add(p);
pointcolor.add(drawPaint.getColor());
marker.add(0);
} else {
drawPath.lineTo(mX, mY);
drawCanvas.drawPath(drawPath, drawPaint);
paths.add(drawPath);
drawPath = new Path();
drawPath.reset();
pathscolor.add(drawPaint.getColor());
marker.add(1);
}
}
public void clear() {
if (marker.size() > 0) {
paths.clear();
points.clear();
pathscolor.clear();
pointcolor.clear();
invalidate();
}
}
public void undo() {
if (marker.size() > 0) {
if (marker.get(marker.size() - 1) == 1) {
if (paths.size() > 0) {
paths.remove(paths.size() - 1);
pathscolor.remove(pathscolor.size() - 1);
marker.remove(marker.size() - 1);
invalidate();
}
} else {
if (points.size() > 0) {
points.remove(points.size() - 1);
pointcolor.remove(pointcolor.size() - 1);
marker.remove(marker.size() - 1);
invalidate();
}
}
}
}
}
【问题讨论】：
-
在 touch_move 方法中你不调用 drawCanvas.drawPath(..)
-
@GabrieleMariotti 我编辑了我的代码并在触摸移动中添加了 drawPath() 但不走运它仍然不显示路径颜色，直到我在绘制后抬起手指。
-
你称之为无效。所以你的 onDraw() 被调用。这里 marker==0 所以它不绘制。
-
@GabrieleMariotti 我试过但没有运气。你能相应地编辑我的代码吗？
标签： java android android-canvas android-custom-view