我遇到了一个相当奇怪的问题。我的逻辑很简单,我的应用程序使用了一个NavigationDrawer
作为主要应用程序导航,由于可用选项的复杂性,我想使用一个ExpandableListViev
来嵌套一些导航项。
问题是什么?也很简单:项目列表在抽屉中加载,但它们不会展开显示其子项。
问题是:有什么原因它不会展开?我应该使用其他UI小部件吗?
一些注释:我在另一个活动中添加了相同的代码,但是我将ExpandableListViev
添加到了一个简单的LinearLayout
上,作为唯一的元素,并且它在那里运行良好。
我的活动布局:
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<FrameLayout
android:id="@+id/content_frame"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<ExpandableListView
android:id="@+id/left_drawer"
android:layout_width="240dp"
android:layout_height="match_parent"
android:layout_gravity="start"
android:background="@color/secondary_color_holo"/>
</android.support.v4.widget.DrawerLayout>
活动代码:
private DrawerLayout mDrawerLayout;
private ExpandableListView mDrawerList;
private ExpandableDrawerAdapter mDrawerAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerList = (ExpandableListView) findViewById(R.id.left_drawer);
// set up the drawer's list view with items and click listener
mDrawerAdapter = new ExpandableDrawerAdapter(this);
mDrawerList.setAdapter(mDrawerAdapter);
mDrawerList.setOnGroupClickListener(new DrawerGroupClickListener());
mDrawerList.setOnChildClickListener(new DrawerChildClickListener());
}
最后是一个非常简单的适配器:
public class ExpandableDrawerAdapter extends BaseExpandableListAdapter {
private static final int CAMPAIGNS = 0;
private static final int CONVERSIONS = 1;
private static final int MYACCOUNT = 2;
private LayoutInflater mInflater;
private String[] mainNavItems, campaignNavItems, myAccountNavItems;
public ExpandableDrawerAdapter (Activity context) {
this.mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
this.mainNavItems = context.getResources().getStringArray(R.array.main_nav_items);
this.campaignNavItems = context.getResources().getStringArray(R.array.campaigns_nav_items);
this.myAccountNavItems = context.getResources().getStringArray(R.array.my_account_nav_items);
}
public Object getChild(int groupPosition, int childPosition) {
switch (groupPosition) {
case CAMPAIGNS:
return campaignNavItems[childPosition];
case MYACCOUNT:
return myAccountNavItems[childPosition];
default:
return "";
}
}
public long getChildId(int groupPosition, int childPosition) {
return childPosition;
}
public View getChildView(final int groupPosition, final int childPosition,
boolean isLastChild, View convertView, ViewGroup parent) {
if (convertView == null) {
convertView = mInflater.inflate(R.layout.drawer_child_list_item, null);
}
TextView childText = (TextView) convertView.findViewById(R.id.drawer_child_list_item_text);
childText.setText((String) getChild(groupPosition, childPosition));
return convertView;
}
public int getChildrenCount(int groupPosition) {
switch (groupPosition) {
case CAMPAIGNS:
Constants.logMessage("Children for group position: " + groupPosition + " are: " + campaignNavItems.length);
return campaignNavItems.length;
case CONVERSIONS:
Constants.logMessage("Children for group position: " + groupPosition + " are: " + 0);
return 0;
case MYACCOUNT:
Constants.logMessage("Children for group position: " + groupPosition + " are: " + myAccountNavItems.length);
return myAccountNavItems.length;
default:
return 0;
}
}
public Object getGroup(int groupPosition) {
return mainNavItems[groupPosition];
}
public int getGroupCount() {
return mainNavItems.length;
}
public long getGroupId(int groupPosition) {
return groupPosition;
}
public View getGroupView(int groupPosition, boolean isExpanded,
View convertView, ViewGroup parent) {
if (convertView == null) {
convertView = mInflater.inflate(R.layout.drawer_list_item,
null);
}
TextView groupText = (TextView) convertView.findViewById(R.id.drawer_list_item_text);
groupText.setText((String) getGroup(groupPosition));
return convertView;
}
public boolean hasStableIds() {
return true;
}
public boolean isChildSelectable(int groupPosition, int childPosition) {
return true;
}
}
ExpandableListView
上设置了一个OnGroupClickListener
,希望您从该侦听器的onGroupClick()
回调中返回false
,否则您将使用true
作为返回值来阻止折叠/展开事件(意味着您已经处理了该事件,因此不需要其他操作)。 - user