Java RecyclerView未在单击项目时将详细信息窗格替换为片段
每次我单击平板电脑上的“回收者视图”项目时，它都会打开一个活动，而不是用片段替换详细信息窗格 以下代码行是我用来检测是否存在详细信息窗格的代码：Java RecyclerView未在单击项目时将详细信息窗格替换为片段,java,android,listview,arraylist,master-detail,Java,Android,Listview,Arraylist,Master Detail,每次我单击平板电脑上的“回收者视图”项目时，它都会打开一个活动，而不是用片段替换详细信息窗格 以下代码行是我用来检测是否存在详细信息窗格的代码： mTwoPane = Objects.requireNonNull(getActivity()).findViewById(R.id.detail_container) != null; 关于正确放置这行代码的位置有什么想法吗 活动XML <?xml version="1.0" encoding="utf-8"?> <LinearL
mTwoPane = Objects.requireNonNull(getActivity()).findViewById(R.id.detail_container) != null;
<?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.widget.Toolbar
android:id="@+id/masterToolbar"
android:layout_width="match_parent"
android:layout_height="?actionBarSize"
>
<LinearLayout
android:id="@+id/singleline_text_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center_vertical"
android:orientation="vertical">
<TextView
android:id="@+id/md_toolbar_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
style="@android:style/TextAppearance.Material.Widget.ActionBar.Title"/>
</LinearLayout>
</android.widget.Toolbar>
<RelativeLayout
android:id="@+id/master_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</LinearLayout>
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.widget.Toolbar
android:id="@+id/masterToolbar"
android:layout_width="0dp"
android:layout_height="?actionBarSize"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toStartOf="@+id/detailBackgroundToolbar"
app:layout_constraintHorizontal_weight="2"
app:layout_constraintTop_toTopOf="parent">
<LinearLayout
android:id="@+id/singleline_text_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center_vertical"
android:orientation="vertical">
<TextView
android:id="@+id/md_toolbar_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
style="@android:style/TextAppearance.Material.Widget.ActionBar.Title"/>
</LinearLayout>
</android.widget.Toolbar>
<RelativeLayout
android:id="@+id/master_container"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintHorizontal_weight="2"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toStartOf="@+id/divider"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintTop_toBottomOf="@+id/masterToolbar" />
<View
android:id="@+id/divider"
android:layout_width="1dp"
android:layout_height="0dp"
android:background="?attr/dividerColor"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toEndOf="@+id/masterToolbar"
app:layout_constraintTop_toBottomOf="@+id/masterToolbar" />
<android.widget.Toolbar
android:id="@+id/detailBackgroundToolbar"
android:layout_width="0dp"
android:layout_height="?actionBarSize"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_weight="3"
app:layout_constraintStart_toEndOf="@+id/masterToolbar"
app:layout_constraintTop_toTopOf="parent" />
<android.support.v7.widget.CardView
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_margin="4dp"
app:cardCornerRadius="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="@+id/divider"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintWidth_percent="0.5">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<include layout="@layout/toolbar_dualline"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
<FrameLayout
android:id="@+id/detail_container"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
</android.support.v7.widget.CardView>
<View
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="@+id/divider"
app:layout_constraintTop_toBottomOf="@+id/detailBackgroundToolbar" />
</android.support.constraint.ConstraintLayout>
<?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.widget.Toolbar
android:id="@+id/masterToolbar"
android:layout_width="match_parent"
android:layout_height="?actionBarSize"
>
<LinearLayout
android:id="@+id/singleline_text_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center_vertical"
android:orientation="vertical">
<TextView
android:id="@+id/md_toolbar_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
style="@android:style/TextAppearance.Material.Widget.ActionBar.Title"/>
</LinearLayout>
</android.widget.Toolbar>
<RelativeLayout
android:id="@+id/master_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</LinearLayout>
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.widget.Toolbar
android:id="@+id/masterToolbar"
android:layout_width="0dp"
android:layout_height="?actionBarSize"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toStartOf="@+id/detailBackgroundToolbar"
app:layout_constraintHorizontal_weight="2"
app:layout_constraintTop_toTopOf="parent">
<LinearLayout
android:id="@+id/singleline_text_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center_vertical"
android:orientation="vertical">
<TextView
android:id="@+id/md_toolbar_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
style="@android:style/TextAppearance.Material.Widget.ActionBar.Title"/>
</LinearLayout>
</android.widget.Toolbar>
<RelativeLayout
android:id="@+id/master_container"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintHorizontal_weight="2"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toStartOf="@+id/divider"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintTop_toBottomOf="@+id/masterToolbar" />
<View
android:id="@+id/divider"
android:layout_width="1dp"
android:layout_height="0dp"
android:background="?attr/dividerColor"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toEndOf="@+id/masterToolbar"
app:layout_constraintTop_toBottomOf="@+id/masterToolbar" />
<android.widget.Toolbar
android:id="@+id/detailBackgroundToolbar"
android:layout_width="0dp"
android:layout_height="?actionBarSize"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_weight="3"
app:layout_constraintStart_toEndOf="@+id/masterToolbar"
app:layout_constraintTop_toTopOf="parent" />
<android.support.v7.widget.CardView
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_margin="4dp"
app:cardCornerRadius="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="@+id/divider"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintWidth_percent="0.5">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<include layout="@layout/toolbar_dualline"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
<FrameLayout
android:id="@+id/detail_container"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
</android.support.v7.widget.CardView>
<View
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="@+id/divider"
app:layout_constraintTop_toBottomOf="@+id/detailBackgroundToolbar" />
</android.support.constraint.ConstraintLayout>
public class MyFragment extends Fragment {
public MyFragment() {}
List<Product> wcList;
RecyclerView mRecyclerView;
/**
* Whether or not the activity is in two-pane mode, i.e. running on a tablet device.
*/
public boolean mTwoPane;
public static MyFragment newInstance() {
return new MyFragment();
}
@Override
public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.activity_main, container, false);
mTwoPane = Objects.requireNonNull(getActivity()).findViewById(R.id.detail_container) != null;
mRecyclerView = view.findViewById(R.id.recyclerView_list);
mRecyclerView.setHasFixedSize(true);
mRecyclerView.setLayoutManager(new LinearLayoutManager(this.getActivity()));
mRecyclerView.addItemDecoration(new DividerItemDecoration(Objects.requireNonNull(getContext()), LinearLayout.VERTICAL));
myList = new ArrayList<>();
String[] items = getResources().getStringArray(R.array.product_names);
String[] itemDescriptions = getResources().getStringArray(R.array.product_descriptions);
for (int n = 0; n < items.length; n++){
Product desserts = new Product();
desserts.setProductName(items[n]);
wdessertsc.setProductDescriptions(itemDescriptions[n]);
myList.add(desserts);
}
MyListAdapter listAdapter = new MyListAdapter(getActivity(), myList);
mRecyclerView.setAdapter(listAdapter);
return view;
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
mTwoPane = Objects.requireNonNull(getActivity()).findViewById(R.id.detail_container) != null;
super.onActivityCreated(savedInstanceState);
}
}
public class MyListAdapter extends RecyclerView.Adapter<MyListAdapter.MyViewHolder> {
public boolean mTwoPane;
private Context mCtx;
private List<Product> myList;
public MyListAdapter(Context mCtx, List<Product> myList) {
this.mCtx = mCtx;
this.myList = myList;
}
@NonNull
@Override
public MyListAdapter.MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(mCtx);
View view = inflater.inflate(R.layout.listitem_dualline, parent,false);
return new MyListAdapter.MyViewHolder(view);
}
@Override
public void onBindViewHolder(@NonNull final MyListAdapter.MyViewHolder holder, final int position) {
Log.d(TAG, "onBindViewHolder: called.");
final Product product = myList.get(holder.getAdapterPosition());
holder.textviewTitle.setText(product.getProductName());
holder.textviewSubtitle.setText(product.getPRoductDescription());
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mTwoPane) {
Fragment newFragment;
if (product.getStationName().equals(v.getResources().getString(R.string.product_1))) {
newFragment = new FragmentProduct1();
} else {
newFragment = new FragmentProdcut2();
}
MyActivity activity = (MyActivity) v.getContext();
FragmentTransaction transaction = activity.getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.detail_container, newFragment);
transaction.commit();
} else {
Intent intent;
if (product.getStationName().equals(v.getResources().getString(R.string.product_1))) {
intent = new Intent(v.getContext(), Product1Activity.class);
} else {
intent = new Intent(v.getContext(), Product2Activity.class);
}
mCtx.startActivity(intent);
}
}
});
}
@Override
public int getItemCount() {
return myList.size();
}
class MyViewHolder extends RecyclerView.ViewHolder {
RelativeLayout relativeLayout;
TextView textviewTitle, textviewSubtitle;
StationViewHolder(View itemView) {
super(itemView);
mTwoPane = itemView.findViewById(R.id.detail_container) != null;
relativeLayout = itemView.findViewById(R.id.listitem_relativelayout);
textviewTitle = itemView.findViewById(R.id.listitem_title);
textviewSubtitle = itemView.findViewById(R.id.listitem_subtitle);
}
}
}
公共类MyFragment扩展了片段{
公共MyFragment（）{}
列表列表；
回收视图mRecyclerView；
/**
*活动是否处于双窗格模式，即在平板电脑设备上运行。
*/
公共布尔值窗格；
公共静态MyFragment newInstance（）{
返回新的MyFragment（）；
}
@凌驾
创建视图时的公共视图（@NonNull LayoutInflater inflater、ViewGroup容器、Bundle savedInstanceState）{
视图=充气机。充气（R.layout.activity\u main，容器，错误）；
mTwoPane=Objects.requirennoull（getActivity（））.findViewById（R.id.detail\u容器）！=null；
mRecyclerView=view.findviewbyd（R.id.recyclerView\u列表）；
mRecyclerView.setHasFixedSize（true）；
mRecyclerView.setLayoutManager（新的LinearLayoutManager（this.getActivity（））；
addItemDecoration（新的DividerItemDecoration（Objects.requireNonNull（getContext（）），LinearLayout.VERTICAL））；
myList=新的ArrayList（）；
String[]items=getResources（）.getStringArray（R.array.product_name）；
String[]itemsdescriptions=getResources（）.getStringArray（R.array.product_descriptions）；
对于（int n=0；npublic class MyFragment extends Fragment {
public MyFragment() {}
List<Product> wcList;
RecyclerView mRecyclerView;
/**
* Whether or not the activity is in two-pane mode, i.e. running on a tablet device.
*/
public boolean mTwoPane;
public static MyFragment newInstance() {
return new MyFragment();
}
@Override
public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.activity_main, container, false);
mTwoPane = Objects.requireNonNull(getActivity()).findViewById(R.id.detail_container) != null;
mRecyclerView = view.findViewById(R.id.recyclerView_list);
mRecyclerView.setHasFixedSize(true);
mRecyclerView.setLayoutManager(new LinearLayoutManager(this.getActivity()));
mRecyclerView.addItemDecoration(new DividerItemDecoration(Objects.requireNonNull(getContext()), LinearLayout.VERTICAL));
myList = new ArrayList<>();
String[] items = getResources().getStringArray(R.array.product_names);
String[] itemDescriptions = getResources().getStringArray(R.array.product_descriptions);
for (int n = 0; n < items.length; n++){
Product desserts = new Product();
desserts.setProductName(items[n]);
wdessertsc.setProductDescriptions(itemDescriptions[n]);
myList.add(desserts);
}
MyListAdapter listAdapter = new MyListAdapter(getActivity(), myList);
mRecyclerView.setAdapter(listAdapter);
return view;
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
mTwoPane = Objects.requireNonNull(getActivity()).findViewById(R.id.detail_container) != null;
super.onActivityCreated(savedInstanceState);
}
}
public class MyListAdapter extends RecyclerView.Adapter<MyListAdapter.MyViewHolder> {
public boolean mTwoPane;
private Context mCtx;
private List<Product> myList;
public MyListAdapter(Context mCtx, List<Product> myList) {
this.mCtx = mCtx;
this.myList = myList;
}
@NonNull
@Override
public MyListAdapter.MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(mCtx);
View view = inflater.inflate(R.layout.listitem_dualline, parent,false);
return new MyListAdapter.MyViewHolder(view);
}
@Override
public void onBindViewHolder(@NonNull final MyListAdapter.MyViewHolder holder, final int position) {
Log.d(TAG, "onBindViewHolder: called.");
final Product product = myList.get(holder.getAdapterPosition());
holder.textviewTitle.setText(product.getProductName());
holder.textviewSubtitle.setText(product.getPRoductDescription());
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mTwoPane) {
Fragment newFragment;
if (product.getStationName().equals(v.getResources().getString(R.string.product_1))) {
newFragment = new FragmentProduct1();
} else {
newFragment = new FragmentProdcut2();
}
MyActivity activity = (MyActivity) v.getContext();
FragmentTransaction transaction = activity.getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.detail_container, newFragment);
transaction.commit();
} else {
Intent intent;
if (product.getStationName().equals(v.getResources().getString(R.string.product_1))) {
intent = new Intent(v.getContext(), Product1Activity.class);
} else {
intent = new Intent(v.getContext(), Product2Activity.class);
}
mCtx.startActivity(intent);
}
}
});
}
@Override
public int getItemCount() {
return myList.size();
}
class MyViewHolder extends RecyclerView.ViewHolder {
RelativeLayout relativeLayout;
TextView textviewTitle, textviewSubtitle;
StationViewHolder(View itemView) {
super(itemView);
mTwoPane = itemView.findViewById(R.id.detail_container) != null;
relativeLayout = itemView.findViewById(R.id.listitem_relativelayout);
textviewTitle = itemView.findViewById(R.id.listitem_title);
textviewSubtitle = itemView.findViewById(R.id.listitem_subtitle);
}
}
}
公共类MyListAdapter扩展了RecyclerView.Adapter{
公共布尔值窗格；
私有上下文mCtx；
私人名单；
公共MyListAdapter（上下文mCtx，列表myList）{
this.mCtx=mCtx；
this.myList=myList；
}
@非空
@凌驾
public MyListAdapter.MyViewHolder onCreateViewHolder（@NonNull ViewGroup父级，int-viewType）{
LayoutFlater充气机=LayoutFlater.from（mCtx）；
视图=充气机。充气（R.layout.listitem_双线，父项，false）；
返回新的MyListAdapter.MyViewHolder（视图）；
}
@凌驾
public void onBindViewHolder（@NonNull final MyListAdapter.MyViewHolder，final int position）{
Log.d（标记“onBindViewHolder:called”）；
最终产品Product=myList.get（holder.getAdapterPosition（））；
holder.textviewTitle.setText（product.getProductName（））；
holder.textviewSubtitle.setText（product.getPRoductDescription（））；
holder.itemView.setOnClickListener（新视图.OnClickListener（）{
@凌驾
公共void onClick（视图v）{
如果（mTwoPane）{
新片段；
if（product.getStationName（）.equals（v.getResources（）.getString（R.string.product_1）））{
newFragment=newfragmentproduct1（）；
}否则{
newFragment=newfragmentprodcut2（）；
}
MyActivity=（MyActivity）v.getContext（）；
FragmentTransaction=activity.getSupportFragmentManager（）.beginTransaction（）；
事务.替换（R.id.detail\u容器，newFragment）；
commit（）；
}否则{
意图；
if（product.getStationName（）.equals（v.getResources（）.getString（R.string.product_1）））{
intent=新的intent（v.getContext（），Product1Activity.class）；
}否则{
intent=newintent（v.getContext（），Product2Activity.class）；
}
mCtx.启动触觉（意图）；
}
}
});
}
@凌驾
public int getItemCount（）{
返回myList.size（）；
}
类MyViewHolder扩展了RecyclerView.ViewHolder{
相对的相对的；
TextView textviewTitle，textviewSubtitle；
StationViewHolder（查看项目视图）{
超级（项目视图）；
mTwoPane=itemView.findviewbyd（R.id.detail\u容器）！=null；
relativeLayout=itemView.findViewById（R.id.listitem\u relativeLayout）；
textviewTitle=itemView.findViewById（R.id.listitem\u title）；
textviewSubtitle=itemView.findViewById（R.id.listitem\u subtitle）；
}
}
}
mTwoPane=itemView.findViewById（R.id.detail\u container）！=无效将始终为false
为什么?
因为您的detail\u容器
不是视图持有者的项目容器的一部分，所以itemView
将始终