Android:在给定图像上自定义绘制(使用SurfaceView)
我试图加载一个图像到SurfaceView,并在此图像上画一些划痕 为此,我创建了一个自定义SurfaceView,MySurfaceView,它具有以下功能:Android:在给定图像上自定义绘制(使用SurfaceView),android,bitmap,android-canvas,surfaceview,Android,Bitmap,Android Canvas,Surfaceview,我试图加载一个图像到SurfaceView,并在此图像上画一些划痕 为此,我创建了一个自定义SurfaceView,MySurfaceView,它具有以下功能: public MySurfaceView(Context context, AttributeSet attrs) { super(context, attrs); mHolder = getHolder(); mHolder.addCallback(this); mPaint.setStyle(Pain
public MySurfaceView(Context context, AttributeSet attrs)
{
super(context, attrs);
mHolder = getHolder();
mHolder.addCallback(this);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeWidth(3);
mPaint.setColor(Color.WHITE);
setWillNotDraw(false);
}
public void setImageBitmap(Bitmap bitmap) {
mBitmap = bitmap;
}
@Override
protected void onDraw(Canvas canvas) {
canvas.drawBitmap(mBitmap, x, y, null);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
mPath = new Path();
mPath.moveTo(event.getX(), event.getY());
} else if (event.getAction() == MotionEvent.ACTION_MOVE) {
mPath.lineTo(event.getX(), event.getY());
} else if (event.getAction() == MotionEvent.ACTION_UP) {
mPath.lineTo(event.getX(), event.getY());
}
if (mPath != null) {
Canvas canvas = mHolder.lockCanvas();
canvas.drawPath(mPath, mPaint);
mHolder.unlockCanvasAndPost(canvas);
}
return true;
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
}
基本上,如果在构造函数中保持setWillNotDraw(false),SurfaceView将显示我设置的位图mBitmap。否则,如果我对此进行注释,它将允许我在黑色背景上绘制路径
有没有什么方法我可以同时做到这两个,把图像(mBitmap)放在背景中,并在这张图像上绘制路径?你们能提供一些代码吗。非常感谢 我明白了
它基本上也将绘制路径设置为onDraw(Canvas-Canvas)函数。确保绘制路径后SurfaceView调用onDraw。我们需要在触控事件中调用invalidate()
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawBitmap(mBitmapScaled, x, y, null);
if (mPath != null) {
canvas.drawPath(mPath, mPaint);
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
mPath = new Path();
mPath.moveTo(event.getX(), event.getY());
} else if (event.getAction() == MotionEvent.ACTION_MOVE) {
mPath.lineTo(event.getX(), event.getY());
} else if (event.getAction() == MotionEvent.ACTION_UP) {
mPath.lineTo(event.getX(), event.getY());
}
invalidate();
return true;
}
或者更好的是,您可以将mPath更改为ArrayList,以便在图像上放置更多路径。您的渲染代码位于两个不同的位置。在onDraw()中绘制所有图形,包括位图和路径。通过向视图发送无效事件来启动绘图。谢谢!如何在onDraw中绘制路径?我认为绘图路径必须由onTouchEvent()触发,对吗?