画图，然后触摸可以滑动

来源：互联网发布：python 数组加减编辑：程序博客网时间：2024/06/05 18:32

public class DrawView extends View {    public DrawView(Context context) {        super(context);    }    public DrawView(Context context, @Nullable AttributeSet attrs) {        super(context, attrs);    }    public DrawView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);    }    private int cx = 100;    private int cy = 100;    /**     * Canvas canvas画布.....paint画笔     * @param canvas     */    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        //中心点x坐标,y坐标,半径,画笔        Paint paint = new Paint();        paint.setColor(Color.RED);//设置颜色        paint.setStrokeWidth(2);//描边的宽度2个像素        //Paint.Style.FILL填充,,Paint.Style.STROKE描边 ,,Paint.Style.FILL_AND_STROKE填充并且描边        paint.setStyle(Paint.Style.FILL);        paint.setAntiAlias(true);//设置抗锯齿        canvas.drawCircle(cx,cy,100,paint);    }    @Override    public boolean onTouchEvent(MotionEvent event) {        switch (event.getAction()){            case MotionEvent.ACTION_DOWN:                cx = (int) event.getX();                cy = (int) event.getY();                break;            case MotionEvent.ACTION_MOVE:                cx = (int) event.getX();                cy = (int) event.getY();                break;            case MotionEvent.ACTION_UP:                cx = (int) event.getX();                cy = (int) event.getY();                break;        }        //重新绘制....自动去调用onDraw        postInvalidate();//.........可以使用在子线程        //invalidate();//...只能用在主线程        return true;    }}

在activity中引用即可

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