Android 关于GridView那些事

最近用了好多GridView,今天小编总结一下，关于GridView的那些注意的东西...

<ImageView
                        android:id="@+id/ItemImage"
                        android:layout_height="50dp"
                        android:layout_width="50dp"
                        android:scaleType="fitXY"
                        android:adjustViewBounds="true"
                        android:clickable="true"
                        android:layout_marginTop="@dimen/smaller_space"
                        android:layout_centerHorizontal="true">
                </ImageView>

public View.OnTouchListener onTouchListener = new View.OnTouchListener() {
        @Override
        public boolean onTouch(View view, MotionEvent event) {
            switch (event.getAction()) {
                case MotionEvent.ACTION_UP:
                    changeLight((ImageView) view, 0);
//                    listener.onCustomItemClk(listener.getPostion());
//                    view.getParent().requestDisallowInterceptTouchEvent(false);//通知父控件勿拦截本控件
                    // onclick
                    break;
                case MotionEvent.ACTION_DOWN:
                    changeLight((ImageView) view, -80);
                    break;
                case MotionEvent.ACTION_MOVE:
                    // changeLight(view, 0);
                    break;
                case MotionEvent.ACTION_CANCEL:
                    changeLight((ImageView) view, 0);
                    break;
                default:
                    changeLight((ImageView) view, 0);
                    break;
            }
            return false;
        }

    };

    /**
    *改变gridview图片的颜色值
    **/
    private void changeLight(ImageView imageview, int brightness) {
        ColorMatrix matrix = new ColorMatrix();
        matrix.set(new float[] { 1, 0, 0, 0, brightness, 0, 1, 0, 0,
                brightness, 0, 0, 1, 0, brightness, 0, 0, 0, 1, 0 });
        imageview.setColorFilter(new ColorMatrixColorFilter(matrix));

    }

public interface OnCustomItemClickListener{
    public int getPostion();
    public void onCustomItemClk(int i);
    }

   holder.itemImage.setOnTouchListener(onTouchListener);
        holder.itemImage.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                clickPos = i;
                listener.onCustomItemClk(clickPos);
            }
        });

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:state_pressed="true"><shape android:shape="rectangle">
        <stroke android:width="1.0px" android:color="@color/line" />

        <gradient android:angle="270.0" android:endColor="#ffe8ecef" android:startColor="#ffe8ecef" />
    </shape></item>
    <item android:state_focused="true"><shape android:shape="rectangle">
        <gradient android:angle="270.0" android:endColor="#ffe8ecef" android:startColor="#ffe8ecef" />

        <stroke android:width="1.0px" android:color="@color/line" />
    </shape></item>
    <item><shape android:shape="rectangle">
        <gradient android:angle="270.0" android:endColor="@color/gray" android:startColor="@color/gray" />

        <stroke android:width="0.5px" android:color="@color/line" />
    </shape></item>

</selector>

@Override
    protected void dispatchDraw(Canvas canvas)
    {
        super.dispatchDraw(canvas);

        int column = 1;
        try
        {
            //通过反射拿到列数
            Field field = GridView.class.getDeclaredField("mNumColumns");
            field.setAccessible(true);
            column = field.getInt(this);
        }
        catch (NoSuchFieldException e)
        {
            e.printStackTrace();
        }
        catch (IllegalAccessException e)
        {
            e.printStackTrace();
        }

        int childCount = getChildCount();
        Paint paint = new Paint();
        paint.setStyle(Paint.Style.STROKE);
        paint.setColor(getContext().getResources().getColor(R.color.line));
        for (int i = 0; i < childCount; i++)
        {
            View cellView = getChildAt(i);
            Log.e(">>>>>>>>>>>>>>>","i="+i+"||||||||||"+"top"+cellView.getTop()+"bottom"+cellView.getBottom()+"left"+cellView.getLeft()+"right"+cellView.getRight());

            if (cellView.getTop()!=0){
                //顶部线，坐标+1是为了画在cellView上
                canvas.drawLine(cellView.getLeft(), cellView.getTop() + 1, cellView.getRight(), cellView.getTop() + 1, paint);
            }

            //左边线
            canvas.drawLine(cellView.getLeft() + 1, cellView.getTop(), cellView.getLeft() + 1, cellView.getBottom(), paint);

            if ((i + 1) % column == 0)      //最右边一列单元格画上右边线
            {
                canvas.drawLine(cellView.getRight(), cellView.getTop() + 1, cellView.getRight(), cellView.getBottom() + 1, paint);
            }
            if ((i + column) >= childCount)  //最后column个单元格画上底边线
            {
                canvas.drawLine(cellView.getLeft(), cellView.getBottom() + 1, cellView.getRight(), cellView.getBottom() + 1, paint);
            }
            if (childCount % column != 0 && i == childCount - 1)   //如果最后一个单元格不在最右一列，单独为它画上右边线
            {
                canvas.drawLine(cellView.getRight() + 1, cellView.getTop() + 1, cellView.getRight() + 1, cellView.getBottom() + 1, paint);
                canvas.drawLine(cellView.getRight()+1, cellView.getBottom() + 1, cellView.getLeft(), cellView.getBottom() + 1, paint);
            }
        }
    }