动态计算Gridview的高度，宽度，将GridView居中实现代码

动态计算Gridview的高度，宽度，将GridView居中。

/**
 * 设置GridView居中
 * 当父目录是RelativeLayout  需要在GridView设置android:layout_centerHorizontal="true"
 * 当父目录是LinearLayout 需要在父目录设置  android:gravity="center_horizontal"
 * @param gridView
 */
public static void calGridViewSumWH(GridView gridView) {
 int numColumns;
 int horizontalSpacing;
 try {
  numColumns = getFieldValue("mRequestedNumColumns", gridView);
  if (numColumns < 1) return;
  horizontalSpacing = getFieldValue("mRequestedHorizontalSpacing", gridView);

  ListAdapter listAdapter = gridView.getAdapter();
  if (listAdapter == null) return;

  int totalHeight = 0;
  int totalWidth = 0;
  int len = listAdapter.getCount();
  for (int i = 0; i < len; i++) {
View listItem = listAdapter.getView(i, null, gridView);
listItem.measure(0, 0);
if (i < numColumns)
 totalWidth+= listItem.getMeasuredWidth();

if ((i + 1) % numColumns == 0 && (i + 1) != len) {
 if (Build.VERSION.SDK_INT > Build.VERSION_CODES.JELLY_BEAN) {
  totalHeight += listItem.getMeasuredHeight() + gridView.getVerticalSpacing();
 } else {
  totalHeight += listItem.getMeasuredHeight();
 }
}
if ((i + 1) == len) {
 totalHeight += listItem.getMeasuredHeight();
}
  }
  if (len < numColumns) {
gridView.setNumColumns(len);
  }
  if (Build.VERSION.SDK_INT > Build.VERSION_CODES.JELLY_BEAN) {
totalWidth = totalWidth + horizontalSpacing * (numColumns - 1);
  }

  ViewGroup.LayoutParams params = gridView.getLayoutParams();
  params.height = totalHeight;
  params.width = totalWidth;
  gridView.setLayoutParams(params);
 } catch (Exception e) {
  e.printStackTrace();
 }
}

/**
 * 动态获取属性值
 * @param attributeName
 * @param gridView
 * @return
 */
public static int getFieldValue(String attributeName, GridView gridView) {
 try {
  Field field = GridView.class.getDeclaredField(attributeName);
  field.setAccessible(true);
  return Integer.parseInt(field.get(gridView).toString());
 } catch (Exception e) {
  e.printStackTrace();
 }
 return 0;
}

然后xml在设置的时候，需要如下设置

因为上述代码测量得到的宽高会受到图片大小的影响，一旦图片大于父容器中设置的130dp，那样子测量得到的宽高也会变动，导致最后展示的效果会有所偏差。