您正在绘制一条线,根据文档,drawLine 函数将:
使用指定的绘制绘制具有指定起点和终点 x,y 坐标的线段。
请注意,由于一条线始终是“框起来的”,因此在绘画中会忽略样式。
不会绘制退化线(长度为 0)。
canvas.drawLine(0, canvas.getHeight() / 2, canvas.getWidth(), canvas.getHeight() / 2, dashPaint)
要绘制虚线,建议使用Path原语
private Path mPath;
mPath = new Path();
mPath.moveTo(0, h / 2);
mPath.quadTo(w/2, h/2, w, h/2);
// h and w are height and width of the screen
Paint mPaint = new Paint();
mPaint.setARGB(255, 0, 0, 0);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setPathEffect(new DashPathEffect(new float[]{5, 10, 15, 20}, 0));
在 onDraw()
canvas.drawPath(mPath, mPaint);
快照
我有背景和虚线画在它上面。
例子
public class FingerPaintActivity extends Activity {
MyView mv;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mv = new MyView(this);
setContentView(mv);
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setColor(0xFFFF0000);
mPaint.setARGB(255, 0, 0, 0);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setPathEffect(new DashPathEffect(new float[]{10, 40,}, 0));
mPaint.setStrokeWidth(12);
}
private Paint mPaint;
public class MyView extends View {
private Bitmap mBitmap;
private Canvas mCanvas;
private Path mPath;
private Paint mBitmapPaint;
Context context;
public MyView(Context c) {
super(c);
context = c;
mPath = new Path();
mBitmapPaint = new Paint(Paint.DITHER_FLAG);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
mBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
mCanvas = new Canvas(mBitmap);
mPath.moveTo(0, h / 2);
mPath.quadTo(w / 2, h / 2, w, h / 2);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
canvas.drawPath(mPath, mPaint);
}
}
}
根据您的需要修改上述内容。