public class Utility {
public static void setListViewHeightBasedOnChildren(ListView listView) {
ListAdapter listAdapter = listView.getAdapter();
if (listAdapter == null) {
// pre-condition
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));
listView.setLayoutParams(params);
}
}
几乎完成了我的工作.但是当我尝试它时,我在listItem.measure(0,0)行得到一个NullPointer异常. listItem本身已初始化,但该方法仍会抛出异常.请告诉我如何解决这个问题.
这是我的代码:
public class ExpenseReportsActivity extends Activity {
private ListView lvReports;
private ExpenseReportListAdapter adapter;
private Button btnSend;
private Button btnCancel;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.expensereports);
lvReports = (ListView)findViewById(R.id.lv_reports);
lvReports.setBackgroundResource(R.drawable.shape_expense_report_list);
ColorDrawable cd = new ColorDrawable(0xFFffffff);
lvReports.setDivider(cd);
lvReports.setDividerHeight(1);
adapter = new ExpenseReportListAdapter(this);
lvReports.setAdapter(adapter);
int totalHeight = 0;
for (int i = 0; i < adapter.getCount(); i++) {
View listItem = adapter.getView(i, null, lvReports);
listItem.measure(0, 0);
totalHeight += listItem.getMeasuredHeight();
}
ViewGroup.LayoutParams params = lvReports.getLayoutParams();
params.height = totalHeight + (lvReports.getDividerHeight() * (adapter.getCount() - 1));
lvReports.setLayoutParams(params);
}
}
我正在处理的另一个解决方法是使用我的自定义视图的onWindowFocusChanged方法.它告诉视图的精确高度.问题是当我仍在我的Activiy的onCreate方法中时,事件不会被触发,也不会在我的Activity的onWindowFocusChanged方法中触发.我尝试了一个自定义事件,但它从未触发过(它放在我的自定义视图的onWindowFocusChanged方法中,并且监听器在我的Activity的onWindowFocusChanged方法中).
本文由 投稿者 创作,文章地址:https://blog.isoyu.com/archives/android-scrollviewzhongdelistviewqianzaidejiejuefang.html
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