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[操作系统]ScrollView中嵌套GridView,ListView只显示一行的解决办法


转载:http://blog.csdn.net/luohai859/article/details/39347583

关于为什么只显示一行,个人理解是:如果单独使用GridView和ListView,里面的内容是固定的,底层系统很容易计算出控件要占用的宽高,当外面嵌套一层ScrollView后,就能做上下或左右滑动,但能滑动多少系统不知道,这时就需要你给计算出一个滑动区域给ScrollView。而这个数值就是通过GridView和ListView中的内容总的宽高之和。有更精确的理解欢迎赐教。解决的办法有两种:

方法一:就是上面说的通过计算出来ListView或者GridView中的子列高度和 进行显示:
public void setListViewHeightBasedOnChildren(ListView listView) {    ListAdapter listAdapter = listView.getAdapter();     if (listAdapter == null) {      return;    }     int totalHeight = 0;    for (int i = 0; i < listAdapter.getCount(); i++) {      View listItem = listAdapter.getView(i, null, listView);      listItem.measure(0, 0);      totalHeight += listItem.getMeasuredHeight();    }     ViewGroup.LayoutParams params = listView.getLayoutParams();    params.height = totalHeight + (listView.getDividerHeight() * (listAdapter.getCount() - 1));    ((MarginLayoutParams)params).setMargins(15, 15, 15, 15);   listView.setLayoutParams(params);  }

方法二:重写GridView和ListView的onMeasure方法,直接给它一个足够大的高度:

重写ListView:

public class MyListView extends ListView {    public MyListView(Context context) {     // TODO Auto-generated method stub     super(context);   }    public MyListView(Context context, AttributeSet attrs) {     // TODO Auto-generated method stub     super(context, attrs);   }    public MyListView(Context context, AttributeSet attrs, int defStyle) {     // TODO Auto-generated method stub     super(context, attrs, defStyle);   }    @Override   protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {     // TODO Auto-generated method stub     int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2,         MeasureSpec.AT_MOST);     super.onMeasure(widthMeasureSpec, expandSpec);   } }

重写GridView:

public class MyGridView extends GridView{    public MyGridView(Context context, AttributeSet attrs) {        super(context, attrs);      }         public MyGridView(Context context) {        super(context);      }         public MyGridView(Context context, AttributeSet attrs, int defStyle) {        super(context, attrs, defStyle);      }         @Override      public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {           int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2,            MeasureSpec.AT_MOST);        super.onMeasure(widthMeasureSpec, expandSpec);      }  }