Android编程两activity间切换问题

Question

LZ手头一个Android程序有两个activity，其中副activity主要就是画个图，且画图需要使用主activity中的一个数组的数据，我明明是先把有关数值填进了数组，完成了数组的处理之后才用intent开启的第二个activty，但实际上副activity使用的还是数组在未处理前的全零状态进行的与画图有关的运算，代码如下

主activity的声明

``` private LayoutInflater layoutInflater;
private View activity_main;

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    layoutInflater = LayoutInflater.from(this);
    activity_main = layoutInflater.inflate(R.layout.activity_main, null);       
    setContentView(activity_main);

副activity

```protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new MyView(this));
    }

    class MyView extends View
    {
        //effect 为路径效果（折线，曲线等）
        PathEffect effect= new PathEffect();
        private int[] colors;
        private Paint paint;
        private Path path;
        private int widthScr;
        private int heightScr;
        private MainActivity mainAc;
        public MyView(Context context){
            super(context);
            mainAc=new MainActivity();

            Display mDisplay = getWindowManager().getDefaultDisplay();
            widthScr = mDisplay.getWidth();
            heightScr= mDisplay.getHeight();
            paint = new Paint();
            paint.setStyle(Paint.Style.STROKE);

            paint.setStrokeWidth(8);
            waitMain();
            path=new Path();
            path.moveTo(xAxis, yAxis);  
            for (int j=0; j<10;j++){
                    path.lineTo( j*75 + xAxis , j*75 + yAxis);//自动生成坐标，并画出路径            
            }           
        }
            private void waitMain() {
            // TODO Auto-generated method stub
                if(mainAc.startPaint[0] == 1){
                    xAxis = widthScr/2;
                    yAxis = heightScr/2;
                }else{
                    xAxis = 0;
                    yAxis = 0;
                }

        }
            @SuppressLint("DrawAllocation")
            @Override
            protected void onDraw (Canvas canvas){          
                canvas.drawColor(Color.BLACK);//画布背景为黑色
                effect=new CornerPathEffect(10);//选择曲线效果
                paint.setPathEffect(effect);
                paint.setColor(Color.WHITE);
                canvas.drawPath(path, paint);

                invalidate();
            }   

        }

两activity之间切换，MyPaint就是副activity的名字

``` Intent intent = new Intent(this,MyPaint.class);
startActivity(intent);

LZ乃Android入门菜鸡，求问这bug是为啥？该怎么改？求大神指点

Answer 1

mainAc=new MainActivity();这算什么呀，建议去看看基础，android开发没java基础也不行。

Intent intent = new Intent(this,MyPaint.class);
startActivity(intent);
数组在切换的时候传递

 Bundle map = new Bundle();
map.putSerializable("alistdata", new int[]{15,2,12,2});
map.putSerializable("ad",new String[]{"5","6"});
intent.putExtra("sd", map);
　　对应的接收：
(int[])this.getIntent().getBundleExtra("sd").getSerializable("alistdata")
(String[])this.getIntent().getBundleExtra("sd").getSerializable("ad")