Question

我想控制来自MainActivity的Surface View上的绘图。（用户）项目的Github链接在帖子的末尾给出。

MainActivity在SurfaceView实例上调用draw(Drawing)方法。

我有以下代码，表面视图仅在我启用断点调试时绘制。

我已访问过这些链接，未找到解决方案：

Android SurfaceView empty

Drawing using the Surfaceview creates blank screen

Android drawing on surfaceview and canvas

我下载的教程：

Drawing Triangles, Rhombuses and Other Custom Shapes on an Android Canvas

Android Coding - Drawing on SurfaceView

我认为这是一个视图创建过程中的问题所以我添加了创建检查：

public void draw(Drawing drawing) {    

        this.drawing = drawing;    

        if (surfaceHolder.isCreating()) {

            surfaceHolder.addCallback(new SurfaceHolder.Callback() {
                @Override
                public void surfaceCreated(SurfaceHolder holder) {   

                    thread = new Thread(LushSurfaceView.this);
                    thread.start();    
                }    

            });


        } else {


            thread = new Thread(this);
            thread.start();   

        }    
    }

这是主题：

 @Override
    public void run() {
        if (drawing != null) {


            switch (drawing) {


                case RECT:
                    drawRectShape();
                    break;
            }


        }
    }

另外，我故意添加延迟等待表面视图初始化。

private void drawRectShape() {

        if (surfaceHolder.getSurface().isValid()) {


            Canvas canvas = surfaceHolder.lockCanvas();
            try {
                Thread.sleep(300);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

            if (canvas != null && !surfaceHolder.isCreating()) {
                Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
                paint.setStyle(Paint.Style.STROKE);
                paint.setStrokeWidth(30);


                Random random = new Random();

                int w = canvas.getWidth();
                int h = canvas.getHeight();
                int left = Math.round(w/2);
                int top = Math.round(h/2);
                int right = 200;
                int bottom =200;

                int r = random.nextInt(255);
                int g = random.nextInt(255);
                int b = random.nextInt(255);
                paint.setColor(0xff000000 + (r << 16) + (g << 8) + b);
                canvas.drawRect(new Rect(left, top, right, bottom), paint);

                surfaceHolder.unlockCanvasAndPost(canvas);
            }
        }

    }

代码在以下情况下有效：我启用了断点调试。
简单调试不会显示任何内容。
我多次重新创建这个场景。

我正在使用Nexus 6（OS 7.1.1）作为测试设备。（不是模仿者）。

项目来源github。

Surface View仅在断点调试中绘制

0 个答案: