[英]Android Listview in Baseadapter how can I save changes to the list
[英]How can I add child fragments to a fragment in Android using a BaseAdapter
此图说明了我的活动的复杂性。 有多层(在这种情况下为3层)片段需要动态加载。 重复的片段使用LinearListView加载,我在这里找到了一个视图库: https : //github.com/frankiesardo/LinearListView 。 这允许列表像ListView一样加载,但是避免了在ScrollView中使用ListView的问题。
这是一些示例代码:
line_item_list.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/line_item_list">
<TextView
android:layout_width="171dp"
android:layout_height="wrap_content"
android:text="LineItem List"
android:id="@+id/line_item_list_text" />
<com.linearlistview.LinearListView
android:id="@+id/line_item_wrapper"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:divider="#f00"
android:orientation="vertical"
android:showDividers="middle"
app:dividerThickness="16dp"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/tools"/>
</LinearLayout>
line_item.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/line_item">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="my line item."
android:id="@+id/line_item_text"
android:layout_gravity="center_horizontal" />
<!-- notes child items go here -->
</LinearLayout>
LineItemFragment.java使用适配器加载片段(此代码中的lineItem在上图中显示为单词“ Part”。)
public class LineItemFragment extends Fragment {
LineItemAdapter adapter;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
LinearListView lineItems = (LinearListView)container.findViewById(R.id.line_item_wrapper);
adapter = new LineItemAdapter(this.getContext(), getChildFragmentManager());
lineItems.setAdapter(adapter);
return null;
}
}
LineItemAdapter.java
public class LineItemAdapter extends BaseAdapter{
ArrayList<String> lineItems = new ArrayList<String>();
Context context;
FragmentManager fm;
public LineItemAdapter(Context context, FragmentManager fragmentManager) {
this.context = context;
lineItems.add("Item A");
lineItems.add("Item B");
lineItems.add("Item C");
this.fm = fragmentManager;
}
@Override
public int getCount() {
return lineItems.size();
}
@Override
public Object getItem(int position) {
return lineItems.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
convertView = ((LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE))
.inflate(R.layout.line_item, parent, false);
}
((TextView)convertView.findViewById(R.id.line_item_text)).setText(getItem(position).toString());
// *** The getView method could load the child fragments
return convertView;
}
}
在上一个文件(***)中,我目前认为getView方法应加载下一级子片段,但是我尝试过的所有方法均无效。 看来布局还没有膨胀,因此我无法为其添加子视图。
我的问题是,“如何从getView中添加子片段?” 也许我正在解决这个错误。
这是我尝试过的一个示例:
lineItemAdapter.java中的getView方法(***):
.
.
.
LinearLayout notes = (LinearLayout) ((LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE))
.inflate(R.layout.line_item, parent, false);
LinearLayout b = (LinearLayout)((LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE))
.inflate(R.layout.note_list, notes).getRootView();
NoteListFragment noteListFragment = new NoteListFragment();
fm.beginTransaction().add(b.getId(), noteListFragment).commit();
.
.
.
我有一个这样的例外。
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.myapplication, PID: 12207
java.lang.RuntimeException: Unable to start activity
ComponentInfo{com.example.myapplication/com.example.myapplication.DetailActivity}: java.lang.IllegalStateException: Fragment does not have a view
at
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
at
android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
.
.
.
提前致谢。
编辑
我是否需要向xml添加片段,即:
line_item.xml ...新节点:
<fragment android:name="com.example.noteListFragment"
android:id="@+id/note_list_fragment"
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="wrap_content" />
最后,我为此目的离开了碎片,并删除了通货膨胀代码。 取而代之的是,我使用xml中的include加载相同的布局结构,因此我不必构建比已有的更大的xml文件。
对于本应放在片段中的功能,我将其放置在presenter类中,然后使用来自ButterKnife的视图注入将presenter绑定到视图中的适当级别。
我仍在使用事件总线在@ mt0s等建议的层之间进行通信。
如果您想朝这个方向发展,以下代码可以帮助您:
使用include我可以将整个结构放在一起,将每个图层的布局保留在自己的xml文件中:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_workorder"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
>
<LinearLayout
android:id="@+id/workorder_detail_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<include layout="@layout/workorder_header"/> <!-- include other layouts -->
<include layout="@layout/workorder_service_items"/>
</LinearLayout>
</LinearLayout>
接下来,我创建了一个Presenter.class文件来设置适配器,使用ButterKnife绑定到视图的该部分:
public class WorkOrderPresenter implements PropertyChangeListener
{
private View detailView;
private WorkOrder workOrder; // the object to display
private List<WorkorderAsset> assetList;
// Set your bindings to the view, passing the id from the layout.
@Bind(R.id.workorderasset_list) View serviceItemDetail;
@Bind(R.id.workorderasset_list_content) LinearListView assets;
@Bind(R.id.number_of_service_items) TextView numberOfServiceItems;
@Bind(R.id.total_value) TextView totalView;
WorkOrderAssetAdapter workOrderAssetAdapter; // an adapter for a child list
// Constructor
public WorkOrderPresenter(View view, WorkOrder wo, final Activity activity)
{
workOrder = wo;
detailView = view;
ButterKnife.bind(this, detailView); //this is where the binding actually happens
workOrderAssetContent = Provider.GetItems // Load you items for the adapter.
// My system gives items back asynchronously:
workOrderAssetContent.getWorkOrderAssets(workOrder.getWorkOrderID(), new iProvideCallback<List<WorkorderAsset>>() {
@Override
public void onSuccess(iResponse<List<WorkorderAsset>> response) {
assetList = response.getResponse();
numberOfServiceItems.setText(String.valueOf(assetList.size()));
workOrderAssetAdapter = new WorkOrderAssetAdapter(activity, assetList); // construct the adapter with items.
assets.setAdapter(workOrderAssetAdapter);
}
@Override
public void onFailure(iResponse<List<WorkorderAsset>> response) {
Toast.makeText(activity.getApplicationContext(), R.string.ServiceItemsError, Toast.LENGTH_LONG);
}
});
}
}
这是显示项目的适配器:
public class WorkOrderAssetAdapter extends BaseAdapter
{
private Activity activity;
private List<WorkorderAsset> workorderAssetList;
private static LayoutInflater inflater = null;
// Constructor
public WorkOrderAssetAdapter(Activity a, List<WorkorderAsset> items)
{
workorderAssetList = items;
activity = a;
inflater = LayoutInflater.from(activity);
}
@Override
public int getCount() { return workorderAssetList.size(); }
@Override
public Object getItem(int position) { return workorderAssetList.get(position); }
@Override
public long getItemId(int position) { return position; }
// view holder for the item
public static class ViewHolder extends WorkOrderAssetViewHolder
{
@Bind(R.id.line_item_text) TextView line_item_text;
@Bind(R.id.line_item_list) LinearListView list;
// Adapter, Data Provider and Presenter for the next level.
public WorkOrderAssetLineItemAdapter adapter;
public WorkOrderAssetLineItemProvider provider;
public WorkOrderAssetLineItemPresenter presenter;
private Activity activity;
private WorkorderAsset workOrderAsset;
public VehicleViewHolder(WorkorderAsset asset, final View view, Activity activity_in)
{
ButterKnife.bind(this, view);
workOrderAsset = asset;
activity = activity_in;
workOrderAssetLineItemContent = new WorkOrderAssetLineItemContent(((RoadFS)activity.getApplication()).getServer(), ((RoadFS)activity.getApplication()).getApplicationContext());
workOrderAssetLineItemContent.getWorkOrderAssetLineItems(
workOrderAsset.getWorkOrderID(),
workOrderAsset.getWorkOrderAssetID(),
new iProvideCallback<List<WorkorderAssetLineItem>>() {
@Override
public void onSuccess(iResponse response) {
list.setAdapter(new WorkOrderAssetLineItemAdapter(activity,
(List<WorkorderAssetLineItem>) response.getResponse(),
view));
}
@Override
public void onFailure(iResponse response) {
}
});
}
@Override
public View getView(final int position, View view, ViewGroup parent)
{
WorkorderAsset workOrderAsset;
workOrderAsset = workorderAssetList.get(position);
ViewHolder holder;
if (view != null) {
holder = (ViewHolder) view.getTag();
} else {
view = inflater.inflate(R.layout.workorder_detail_workorderasset_vehicle, parent, false);
holder = new VehicleViewHolder(workOrderAsset, view, activity);
view.setTag(holder);
}
holder.item_text.setText(workOrderAsset.getVIN());
holder.workOrderAssetLineItemContent = new WorkOrderAssetLineItemContent(((RoadFS) activity.getApplication()).getServer(), activity);
holder.workOrderAssetLineItemAdapter = new WorkOrderAssetLineItemAdapter(activity, WorkOrderAssetLineItemContent.workorderAssetLineItemList, view);
return view;
}
}
这个例子有点不完整,我还没有一个示例项目,但是希望它能对某人有所帮助。 它不能按预期方式回答问题,但是经过两种方式的尝试,我认为这是一个更好的解决方案,因为它比处理片段的复杂性要简单。 片段仍将用于更改屏幕尺寸/方向,但片段将不用于复杂的布局。 感谢您的任何意见。
对适配器使用不同的类
public class TabCategory extends Fragment { private ListView listView; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // Inflate the layout for this fragment View tabCat=inflater.inflate(R.layout.tab_all, container, false); listView = (ListView) tabCat.findViewById(R.id.listView); //ADAPTER CategoryList adapter = new CategoryList(getContext()); listView.setAdapter(adapter); return tabCat; } }
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