Android 获取空的RecyclerView
这是我第一次与RecyclerView合作,我遇到了一个问题。我正试图从抽屉碎片上看出来。抽屉的菜单很好用,但我看不到那里的回收站。有人能帮我吗 这是我的片段的布局:Android 获取空的RecyclerView,android,android-fragments,android-recyclerview,navigation-drawer,Android,Android Fragments,Android Recyclerview,Navigation Drawer,这是我第一次与RecyclerView合作,我遇到了一个问题。我正试图从抽屉碎片上看出来。抽屉的菜单很好用,但我看不到那里的回收站。有人能帮我吗 这是我的片段的布局: <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#DADADA"
tools:context="com.example.entwicklung1.designtestapp.NavigationDrawerFragment"
android:orientation="horizontal">
<LinearLayout
android:id="@+id/linid"
android:layout_width="match_parent"
android:layout_height="120dp"
android:background="#0064a7"
android:paddingLeft="20dp">
<ImageView
android:layout_width="240dp"
android:layout_height="120dp"
android:elevation="20dp"
android:gravity="center_vertical"
android:src="@drawable/zanderlogo" />
</LinearLayout>
<android.support.v7.widget.RecyclerView
android:id="@+id/drawerList"
android:layout_width="match_parent"
android:layout_height="wrap_content"
></android.support.v7.widget.RecyclerView>
</LinearLayout>
代码如下:
public class NavigationDrawerFragment extends Fragment {
private RecyclerView recyclerView;
public static final String PREF_FILE_NAME = "testpref";
public static final String KEY_USER_LEARNED_DRAWNER = "user_learned_drawer";
private ActionBarDrawerToggle mDrawerToggle;
private DrawerLayout mDrawerLayout;
private MyAdapter adapter;
private boolean mUserLearnedDrawer;
private boolean mFromSavedInstanceState;
private View containerView;
public NavigationDrawerFragment() {
// Required empty public constructor
}
public List<Information> getData(){
List<Information> data = new ArrayList<>();
int[] icons={R.drawable.ic_number1,R.drawable.ic_number2,R.drawable.ic_number3,R.drawable.ic_number4,R.drawable.ic_number5};
String[] titles ={"News", "Produkte","Homepage","Kontakt","Anfahrt"};
for(int i=0;i<titles.length; i++){
Information current=new Information();
current.iconId=icons[i];
current.title=titles[i];
data.add(current);
}
return data;
}
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mUserLearnedDrawer = Boolean.valueOf(readFromPreferences(getActivity(), KEY_USER_LEARNED_DRAWNER, "false"));
mFromSavedInstanceState = savedInstanceState != null ? true : false;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View layout=inflater.inflate(R.layout.fragment_navigation_drawer, container, false);
recyclerView=(RecyclerView)layout.findViewById(R.id.drawerList);
adapter = new MyAdapter(getActivity(),getData());
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
recyclerView.setAdapter(adapter);
return layout;
}
public void setUp(int fragmentId, DrawerLayout drawerLayout, final Toolbar toolbar) {
containerView=getActivity().findViewById(fragmentId);
mDrawerLayout = drawerLayout;
mDrawerToggle = new ActionBarDrawerToggle(getActivity(),
drawerLayout, toolbar, R.string.drawer_open, R.string.drawer_close) {
@Override
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
if(!mUserLearnedDrawer){
mUserLearnedDrawer=true;
saveToPreferences(getActivity(),KEY_USER_LEARNED_DRAWNER,mUserLearnedDrawer+"");
}
getActivity().supportInvalidateOptionsMenu();
}
@Override
public void onDrawerClosed(View drawerView) {
super.onDrawerClosed(drawerView);
getActivity().supportInvalidateOptionsMenu();
}
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
mDrawerLayout.post(new Runnable() {
@Override
public void run() {
mDrawerToggle.syncState();
if(!mUserLearnedDrawer && !mFromSavedInstanceState){
mDrawerLayout.openDrawer(containerView);
}
}
});
}
public static void saveToPreferences(Context context, String preferenceName, String preferenceValue) {
SharedPreferences sharedPreferences = context.getSharedPreferences(PREF_FILE_NAME, Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString(preferenceName, preferenceValue);
editor.apply();
}
public static String readFromPreferences(Context context, String preferenceName, String defaultValue) {
SharedPreferences sharedPreferences = context.getSharedPreferences(PREF_FILE_NAME, Context.MODE_PRIVATE);
return sharedPreferences.getString(preferenceName, defaultValue);
}
}
公共类NavigationDrawerFragment扩展片段{
私人回收站;
公共静态最终字符串PREF_FILE_NAME=“testpref”;
公共静态最终字符串键\u USER\u LEARNED\u DRAWNER=“USER\u LEARNED\u drawer”;
私有操作bardrawertoggle mDrawerToggle;
私人抽屉布局mDrawerLayout;
专用MyAdapter适配器;
私有布尔mUserLearnedDrawer;
私有布尔值mFromSavedInstanceState;
私有视图容器视图;
公共导航抽屉碎片(){
//必需的空公共构造函数
}
公共列表getData(){
列表数据=新的ArrayList();
int[]icons={R.drawable.ic_number1,R.drawable.ic_number2,R.drawable.ic_number3,R.drawable.ic_number4,R.drawable.ic_number5};
字符串[]标题={“新闻”、“产品”、“主页”、“康塔克”、“安法特”};
对于(inti=0;i您不在适配器构造函数中设置数据。因此,您的数据为空
List<Information> data = Collections.emptyList();
public MyAdapter(Context context,List<Information> data) {
inflater=LayoutInflater.from(context);
this.data = data;
^^^^^^^^^^^^^^^^ add this statement
}
List data=Collections.emptyList();
公共MyAdapter(上下文、列表数据){
充气器=充气器。从(上下文);
这个数据=数据;
^^^^^^^^^^^^^^^^添加此语句
}
更新:
需要将顶部线性布局的方向更改为“垂直”请记住:
- 传递给适配器的列表不能为空
- 如果为空,请记住在适配器上调用#notifyDataSetChanged()
- 必须将LayoutManager设置为RecyclerView
谢谢。但这并不能解决问题。仍然是空白片段。尝试将recycler视图的布局高度设置为匹配父级。只是为了测试。您将顶部线性布局的方向设置为水平,将第一项宽度设置为匹配父级,所以,您的recycler视图不在布局中。您应该将顶部线性布局的方向设置为veRTICLI更新了我的答案。如果对你有帮助,请接受。
List<Information> data = Collections.emptyList();
public MyAdapter(Context context,List<Information> data) {
inflater=LayoutInflater.from(context);
this.data = data;
^^^^^^^^^^^^^^^^ add this statement
}