我正在创建一个示例 android 应用程序，其中当应用程序处于横向模式时，ExpandableListView 显示在左侧。但是，当应用程序以纵向模式运行时，ExpandableListView 必须在单击 showpopup 按钮时显示为 PopupWindow。我们如何在 Android 的 PopupWindow 中添加 ExpandableListView？
我对 popupwindow 和 ExpandableListView 做了一些初步研究。这是我尝试过的代码（用于纵向模式）
public class LoginActivity extends Activity
{
private Button btnShowPopUp;
private PopupWindow mpopup;
ExpandableListAdapter adapter;
private ExpandListAdapter ExpAdapter;
private ArrayList<ExpandListGroup> ExpListItems;
private ExpandableListView ExpandList;
@Override
public void onCreate (Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
try
{
btnShowPopUp = (Button) findViewById(R.id.btnShowPopUp);
btnShowPopUp.setOnClickListener(new OnClickListener()
{
public void onClick (View arg0)
{
PopupwithExpndLst();
//PopupwithBtn();
}
});
}
catch (Exception ex)
{
Log.i("Test", "Error is " + ex.getMessage());
}
}
public void PopupwithExpndLst ()
{
try
{
View popUpView = getLayoutInflater().inflate(R.layout.explist, null); // inflating popup layout
mpopup = new PopupWindow(popUpView, LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT, true); // Creation of popup
mpopup.setAnimationStyle(android.R.style.Animation_Dialog);
mpopup.showAtLocation(popUpView, Gravity.BOTTOM, 0, 0); // Displaying popup
ExpandList = (ExpandableListView) findViewById(R.id.lstExpList);
adapter = new MyExpandableListAdapter(this);
ExpandList.setAdapter(adapter);
}
catch (Exception ex)
{
Log.i("Test", "Error is " + ex.getMessage());
}
}
public void PopupwithBtn ()
{
View popUpView = getLayoutInflater().inflate(R.layout.popup, null); // inflating popup layout
mpopup = new PopupWindow(popUpView, LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT, true); // Creation of popup
mpopup.setAnimationStyle(android.R.style.Animation_Dialog);
mpopup.showAtLocation(popUpView, Gravity.BOTTOM, 0, 0); // Displaying popup
ExpandList = (ExpandableListView) findViewById(R.id.lstExpList);
adapter = new MyExpandableListAdapter(this);
ExpandList.setAdapter(adapter);
Button btnOk = (Button) popUpView.findViewById(R.id.btnOk);
btnOk.setOnClickListener(new OnClickListener()
{
public void onClick (View v)
{
mpopup.dismiss(); // dismissing the popup
}
});
Button btnCancel = (Button) popUpView.findViewById(R.id.btnCancel);
btnCancel.setOnClickListener(new OnClickListener()
{
public void onClick (View v)
{
mpopup.dismiss(); // dismissing the popup
}
});
}
public ArrayList<ExpandListGroup> SetStandardGroups ()
{
ArrayList<ExpandListGroup> list = new ArrayList<ExpandListGroup>();
ArrayList<ExpandListChild> list2 = new ArrayList<ExpandListChild>();
ExpandListGroup gru1 = new ExpandListGroup();
gru1.setName("Comedy");
ExpandListChild ch1_1 = new ExpandListChild();
ch1_1.setName("A movie");
ch1_1.setTag(null);
list2.add(ch1_1);
ExpandListChild ch1_2 = new ExpandListChild();
ch1_2.setName("An other movie");
ch1_2.setTag(null);
list2.add(ch1_2);
ExpandListChild ch1_3 = new ExpandListChild();
ch1_3.setName("And an other movie");
ch1_3.setTag(null);
list2.add(ch1_3);
gru1.setItems(list2);
list2 = new ArrayList<ExpandListChild>();
ExpandListGroup gru2 = new ExpandListGroup();
gru2.setName("Action");
ExpandListChild ch2_1 = new ExpandListChild();
ch2_1.setName("A movie");
ch2_1.setTag(null);
list2.add(ch2_1);
ExpandListChild ch2_2 = new ExpandListChild();
ch2_2.setName("An other movie");
ch2_2.setTag(null);
list2.add(ch2_2);
ExpandListChild ch2_3 = new ExpandListChild();
ch2_3.setName("And an other movie");
ch2_3.setTag(null);
list2.add(ch2_3);
gru2.setItems(list2);
list.add(gru1);
list.add(gru2);
return list;
}
@Override
public boolean onCreateOptionsMenu (Menu menu)
{
getMenuInflater().inflate(R.menu.activity_login, menu);
return true;
}
}
我的 ActivityLogin.xml 是
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<Button
android:id="@+id/btnShowPopUp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="ShowPopUp" >
</Button>
</LinearLayout>
我的 explist.xml 是
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#90FFFFFF"
android:orientation="vertical" >
<TextView
android:id="@+id/txtEmpty"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:text="No items" />
<ExpandableListView
android:id="@+id/lstExpList"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:groupIndicator="@null" />
popup.xml 是
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#90FFFFFF"
android:orientation="vertical" >
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:text="PopUp Window"
android:textColor="#000000"
android:textStyle="bold" >
</TextView>
<Button
android:id="@+id/btnOk"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Ok" >
</Button>
<Button
android:id="@+id/btnCancel"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Cancel" >
</Button>
我的 ExpendableListAdapter.java 是
public class ExpandListAdapter extends BaseExpandableListAdapter
{
private Context context;
private ArrayList<ExpandListGroup> groups;
public ExpandListAdapter(Context context, ArrayList<ExpandListGroup> groups)
{
try
{
this.context = context;
this.groups = groups;
}
catch (Exception ex)
{
Log.i("Test", "Error is " + ex.getMessage());
}
}
public void addItem (ExpandListChild item, ExpandListGroup group)
{
if (!groups.contains(group))
{
groups.add(group);
}
int index = groups.indexOf(group);
ArrayList<ExpandListChild> ch = groups.get(index).getItems();
ch.add(item);
groups.get(index).setItems(ch);
}
public Object getChild (int groupPosition, int childPosition)
{
ArrayList<ExpandListChild> chList = groups.get(groupPosition).getItems();
return chList.get(childPosition);
}
public long getChildId (int groupPosition, int childPosition)
{
return childPosition;
}
public View getChildView (int groupPosition, int childPosition, boolean isLastChild, View view, ViewGroup parent)
{
ExpandListChild child = (ExpandListChild) getChild(groupPosition, childPosition);
if (view == null)
{
LayoutInflater inflater = (LayoutInflater) context.getSystemService(context.LAYOUT_INFLATER_SERVICE);
view = inflater.inflate(R.layout.expandlist_child_item, null);
}
TextView tv = (TextView) view.findViewById(R.id.tvChild);
tv.setText(child.getName().toString());
tv.setTag(child.getTag());
return view;
}
public int getChildrenCount (int groupPosition)
{
// TODO Auto-generated method stub
ArrayList<ExpandListChild> chList = groups.get(groupPosition).getItems();
return chList.size();
}
public Object getGroup (int groupPosition)
{
// TODO Auto-generated method stub
return groups.get(groupPosition);
}
public int getGroupCount ()
{
// TODO Auto-generated method stub
return groups.size();
}
public long getGroupId (int groupPosition)
{
// TODO Auto-generated method stub
return groupPosition;
}
public View getGroupView (int groupPosition, boolean isLastChild, View view, ViewGroup parent)
{
// TODO Auto-generated method stub
ExpandListGroup group = (ExpandListGroup) getGroup(groupPosition);
if (view == null)
{
LayoutInflater inf = (LayoutInflater) context.getSystemService(context.LAYOUT_INFLATER_SERVICE);
view = inf.inflate(R.layout.expamdlist_group_item, null);
}
TextView tv = (TextView) view.findViewById(R.id.tvGroup);
tv.setText(group.getName());
return view;
}
public boolean hasStableIds ()
{
// TODO Auto-generated method stub
return true;
}
public boolean isChildSelectable (int groupPosition, int childPosition)
{
// TODO Auto-generated method stub
return true;
}
}
在 LoginActivity 类中，如果我在 btnShowpopup 的 onclick 方法中使用 PopupwithBtn() 函数，则弹出窗口按预期工作，但是当我使用 PopupwithExpndLst() 时。
在 PopupwithExpndLst() 方法中，当我尝试为可消耗列表设置适配器时，它显示空指针异常。请帮我解决问题。
在此先感谢 Bimzee