I have an activity which opens a fragment with view pager. when I change between the tabs I get this error: The specified child already has a parent. You must call removeView() on the child's parent first.
I think is the problem is from the header of the RecyclerView and I posted a new question about it here
the view pager code is:
private void mViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFragment(new a_Frag(), getString("A"));
adapter.addFragment(new b_Frag(), getString("B"));
adapter.addFragment(new c_Frag(), getString("C"));
viewPager.setAdapter(adapter);
}
the a_frag code as example:
public class a_Frag extends Fragment {
RecyclerView recyclerView;
public a_Frag() {
}
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.rv, container, false);
recyclerView = (RecyclerView) view.findViewById(R.id.rv);
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
recyclerView.setAdapter(new a_Adapter(getContext(), R.layout.group_header));
return recyclerView;
}
ExpandableRecyclerView code:
public class ExpandableRecyclerView extends RecyclerView {
public ExpandableRecyclerView(Context context) {
super(context, null);
initRecycler();
}
public ExpandableRecyclerView(Context context, AttributeSet attrs) {
super(context, attrs);
initRecycler();
}
public ExpandableRecyclerView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
initRecycler();
}
private void initRecycler() {
setClipToPadding(false);
setItemAnimator(new DefaultItemAnimator());
}
@Override
public Parcelable onSaveInstanceState() {
//begin boilerplate code that allows parent classes to save state
Parcelable superState = super.onSaveInstanceState();
SavedState ss = new SavedState(superState);
//end
if (getAdapter() != null)
ss.stateToSave = ((Adapter) this.getAdapter()).getExpandedGroups();
return ss;
}
@Override
public void onRestoreInstanceState(Parcelable state) {
//begin boilerplate code so parent classes can restore state
if (!(state instanceof SavedState)) // if state is not instance of out SaveState just restore in reg way
{
super.onRestoreInstanceState(state);
return;
}
// else if cast him to SavedState
SavedState ss = (SavedState) state;
super.onRestoreInstanceState(ss.getSuperState());
//end
if (getAdapter() != null)
((Adapter) getAdapter()).setExpandedGroups(ss.stateToSave);
}
@Override
public void setAdapter(RecyclerView.Adapter adapter) {
if (!(adapter instanceof Adapter))
throw new IllegalArgumentException("adapter has to be of type ExpandableRecyclerView.Adapter");
super.setAdapter(adapter);
}
public interface OnChildItemClickedListener {
void onChildItemClicked(int group, int position);
}
static class SavedState implements Parcelable {
public static final SavedState EMPTY_STATE = new SavedState() {
};
//required field that makes Parcelables from a Parcel
public static final Creator<SavedState> CREATOR =
new Creator<SavedState>() {
public SavedState createFromParcel(Parcel in) {
return new SavedState(in);
}
public SavedState[] newArray(int size) {
return new SavedState[size];
}
};
SparseBooleanArray stateToSave;
Parcelable superState;
SavedState() {
superState = null;
}
SavedState(Parcelable superState) {
this.superState = superState != EMPTY_STATE ? superState : null;
}
private SavedState(Parcel in) {
Parcelable superState = in.readParcelable(ExpandableRecyclerView.class.getClassLoader());
this.superState = superState != null ? superState : EMPTY_STATE;
this.stateToSave = in.readSparseBooleanArray();
}
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(@NonNull Parcel out, int flags) {
out.writeParcelable(superState, flags);
out.writeSparseBooleanArray(this.stateToSave);
}
public Parcelable getSuperState() {
return superState;
}
}
public static abstract class Adapter<CVH extends ViewHolder, GVH extends ViewHolder, C, G> extends RecyclerView.Adapter<ViewHolder> {
private static final int TYPE_HEADER = 0;
SparseBooleanArray expanded = new SparseBooleanArray();
private OnChildItemClickedListener onChildItemClickedListener;
public Adapter() {
}
boolean isExpanded(int group) {
return expanded.get(group);
}
SparseBooleanArray getExpandedGroups() {
return expanded;
}
public void setExpandedGroups(SparseBooleanArray expanded) {
this.expanded = expanded;
}
public void expand(int group) {
if (isExpanded(group))
return;
// this lines of code calculate number of shown item in recycler view. also group is counting .
int position = 0;
for (int i = 0; i < group; i++) {
position++;
if (isExpanded(i))
position += getChildItemCount(i);
}
position++; // this for percent group
notifyItemRangeInserted(position, getChildItemCount(group)); // notify recycler view for expanding
expanded.put(group, true); // save expanding in sparce array
}
public void collapse(int group) {
if (!isExpanded(group)) // if is not expanded . so nothing to collapse.
return;
int position = 0;
for (int i = 0; i < group; i++) {
position++;
if (isExpanded(i))
position += getChildItemCount(i); // item
}
position++;
notifyItemRangeRemoved(position, getChildItemCount(group));
expanded.put(group, false);
}
public abstract int getGroupItemCount();
public abstract int getChildItemCount(int group);
@Override
public int getItemCount() {
int count = 0;
for (int i = 0; i <= getGroupItemCount(); i++) {
count += isExpanded(i) ? getChildItemCount(i) + 1 : 1;
}
return count;
}
public abstract G getGroupItem(int position);
public abstract C getChildItem(int group, int position);
public Object getItem(int i) {
int group = 0;
while (group <= getGroupItemCount()) {
if (i > 0 && !isExpanded(group)) {
i--;
group++;
continue;
}
if (i > 0 && isExpanded(group)) {
i--;
if (i < getChildItemCount(group))
return getChildItem(group, i);
i -= getChildItemCount(group);
group++;
continue;
}
if (i == 0)
return getGroupItem(group);
}
throw new IndexOutOfBoundsException();
}
@Override
public void onBindViewHolder(ViewHolder holder, int i) {
int group = 0;
while (group <= getGroupItemCount()) {
if (i > 0 && !isExpanded(group)) {
i--;
group++;
continue;
}
if (i > 0 && isExpanded(group)) {
i--;
if (i < getChildItemCount(group)) {
onBindChildViewHolder((CVH) holder, group, i);
return;
}
i -= getChildItemCount(group);
group++;
continue;
}
if (i == 0) {
onBindGroupViewHolder((GVH) holder, group);
return;
}
}
throw new IndexOutOfBoundsException();
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
return viewType == TYPE_HEADER ? onCreateGroupViewHolder(parent) : onCreateChildViewHolder(parent, viewType);
}
protected abstract GVH onCreateGroupViewHolder(ViewGroup parent);
protected abstract CVH onCreateChildViewHolder(ViewGroup parent, int viewType);
public abstract int getChildItemViewType(int group, int position);
@Override
public int getItemViewType(int i) {
int group = 0;
while (group <= getGroupItemCount()) {
if (i > 0 && !isExpanded(group)) {
i--;
group++;
continue;
}
if (i > 0 && isExpanded(group)) {
i--;
if (i < getChildItemCount(group))
return getChildItemViewType(group, i);
i -= getChildItemCount(group);
group++;
continue;
}
if (i == 0)
return TYPE_HEADER;
}
throw new IndexOutOfBoundsException();
}
public void setOnChildItemClickedListener(OnChildItemClickedListener onItemClickedListener) {
this.onChildItemClickedListener = onItemClickedListener;
}
public void onBindChildViewHolder(CVH holder, final int group, final int position) {
holder.itemView.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
if (Adapter.this.onChildItemClickedListener != null) {
Adapter.this.onChildItemClickedListener.onChildItemClicked(group, position);
}
}
});
}
public void onBindGroupViewHolder(final GVH holder, final int group) {
if (holder instanceof GroupViewHolder)
((GroupViewHolder) holder).setExpanded(isExpanded(group));
holder.itemView.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if (isExpanded(group)) {
collapse(group);
if (holder instanceof GroupViewHolder)
((GroupViewHolder) holder).collapse();
} else {
expand(group);
if (holder instanceof GroupViewHolder)
((GroupViewHolder) holder).expand();
}
}
});
}
}
public static abstract class GroupViewHolder extends ViewHolder {
public GroupViewHolder(View itemView) {
super(itemView);
}
public abstract void expand();
public abstract void collapse();
public abstract boolean isExpanded();
public abstract void setExpanded(boolean expanded);
}
public static class SimpleGroupViewHolder extends GroupViewHolder {
ImageView expandedIndicator;
TextView text;
private boolean expanded;
public SimpleGroupViewHolder(Context context) {
super(View.inflate(context, R.layout.group_header, null));
itemView.setLayoutParams(new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT));
expandedIndicator = (ImageView) itemView.findViewById(R.id.carbon_groupExpandedIndicator);
text = (TextView) itemView.findViewById(R.id.carbon_groupText);
}
public SimpleGroupViewHolder(Context context, int layout) {
super(View.inflate(context, layout, null));
itemView.setLayoutParams(new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT));
expandedIndicator = (ImageView) itemView.findViewById(R.id.carbon_groupExpandedIndicator);
text = (TextView) itemView.findViewById(R.id.carbon_groupText);
}
public void expand() {
ValueAnimator animator = ValueAnimator.ofFloat(0, 1);
animator.setInterpolator(new DecelerateInterpolator());
animator.setDuration(200);
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
ViewHelper.setRotation(expandedIndicator, 180 * (float) (animation.getAnimatedValue()));
expandedIndicator.postInvalidate();
}
});
animator.start();
expanded = true;
}
public void collapse() {
ValueAnimator animator = ValueAnimator.ofFloat(1, 0);
animator.setInterpolator(new DecelerateInterpolator());
animator.setDuration(200);
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
ViewHelper.setRotation(expandedIndicator, 180 * (float) (animation.getAnimatedValue()));
expandedIndicator.postInvalidate();
}
});
animator.start();
expanded = false;
}
@Override
public boolean isExpanded() {
return expanded;
}
public void setExpanded(boolean expanded) {
ViewHelper.setRotation(expandedIndicator, expanded ? 180 : 0);
this.expanded = expanded;
}
public String getText() {
return text.getText().toString();
}
public void setText(String t) {
text.setText(t);
}
}
}
the adapters are the same except for the data so I will put one example:
Adapter code example:
public class Adapter extends ExpandableRecyclerView.Adapter<Adapter.ChildViewHolder, Adapter.GroupViewHolder, String, String> {
private DatabaseHelper db;
private ArrayList List;
private int layout;
public Adapter(Context c, int resource) {
layout = resource;
db = new DatabaseHelper(c);
List = db.getRecords();//returns list
}
@Override
public int getGroupItemCount() {
return List.size() - 1;
}
@Override
public int getChildItemCount(int i) {
return 1;
}
@Override
public String getGroupItem(int i) {
return null;
}
@Override
public String getChildItem(int group, int child) {
return null;
}
@Override
protected GroupViewHolder onCreateGroupViewHolder(ViewGroup parent) {
return new GroupViewHolder(parent.getContext(), layout);
}
@Override
protected ChildViewHolder onCreateChildViewHolder(ViewGroup parent, int viewType) {
View rootView = LayoutInflater.from(parent.getContext()).inflate(R.layout.group_item, parent, false);
return new ChildViewHolder(rootView);
}
@Override
public void onBindGroupViewHolder(GroupViewHolder holder, int group) {
super.onBindGroupViewHolder(holder, group);
holder.setText1("A");
holder.setText2("B");
}
@Override
public void onBindChildViewHolder(ChildViewHolder holder, int group, int position) {
super.onBindChildViewHolder(holder, group, position);
holder.t1.setText("t1");
holder.t2.setText("t2");
holder.t3.setText("t3");
holder.t4.setText("t4");
}
@Override
public int getChildItemViewType(int i, int i1) {
return 1;
}
static class GroupViewHolder extends ExpandableRecyclerView.GroupViewHolder {
ImageView expandedIndicator;
TextView text1;
TextView text2;
private boolean expanded;
GroupViewHolder(Context context, int layout) {
super(View.inflate(context, layout, null));
itemView.setLayoutParams(new RecyclerView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT));
expandedIndicator = (ImageView) itemView.findViewById(R.id.groupExpandedIndicator);
text1 = (TextView) itemView.findViewById(R.id.text1);
text2 = (TextView) itemView.findViewById(R.id.text2);
}
public void expand() {
ValueAnimator animator = ValueAnimator.ofFloat(0, 1);
animator.setInterpolator(new DecelerateInterpolator());
animator.setDuration(200);
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
ViewHelper.setRotation(expandedIndicator, 180 * (float) (animation.getAnimatedValue()));
expandedIndicator.postInvalidate();
}
});
animator.start();
expanded = true;
}
public void collapse() {
ValueAnimator animator = ValueAnimator.ofFloat(1, 0);
animator.setInterpolator(new DecelerateInterpolator());
animator.setDuration(200);
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
ViewHelper.setRotation(expandedIndicator, 180 * (float) (animation.getAnimatedValue()));
expandedIndicator.postInvalidate();
}
});
animator.start();
expanded = false;
}
@Override
public boolean isExpanded() {
return expanded;
}
public void setExpanded(boolean expanded) {
ViewHelper.setRotation(expandedIndicator, expanded ? 180 : 0);
this.expanded = expanded;
}
void setText1(String t) {
text1.setText(t);
}
void setText2(String t) {
text2.setText(t);
}
}
class ChildViewHolder extends RecyclerView.ViewHolder {
private TextView t1;
private TextView t2;
private TextView t3;
private TextView t4;
ChildViewHolder(View itemView) {
super(itemView);
t1 = (TextView) itemView.findViewById(R.id.tv1);
t2 = (TextView) itemView.findViewById(R.id.tv2);
t3 = (TextView) itemView.findViewById(R.id.tv3);
t4 = (TextView) itemView.findViewById(R.id.tv4);
}
}
}
group_header.xml:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clickable="true">
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:id="@+id/Card1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginLeft="7dp"
android:layout_marginRight="7dp"
android:layout_marginTop="10dp"
card_view:cardCornerRadius="10dp"
card_view:cardElevation="5dp">
<LinearLayout 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="wrap_content"
android:gravity="right"
android:orientation="horizontal">
<TextView
android:id="@+id/text1"
style="@style/MyLargeTextAppearance"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:gravity="center"
android:padding="16dp"
android:textColor="@color/highlight"
android:textStyle="bold" />
</LinearLayout>
</android.support.v7.widget.CardView>
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/Card1"
android:layout_gravity="center"
android:layout_marginLeft="7dp"
android:layout_marginRight="7dp"
android:layout_marginTop="1dp"
card_view:cardCornerRadius="10dp"
card_view:cardElevation="5dp">
<LinearLayout 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="wrap_content"
android:gravity="right"
android:orientation="horizontal">
<TextView
android:id="@+id/text2"
style="@style/MyLargeTextAppearance"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:gravity="center"
android:padding="16dp"
android:textColor="@color/highlight"
android:textStyle="bold" />
<ImageView
android:id="@+id/groupExpandedIndicator"
android:layout_width="24dp"
android:layout_height="24dp"
android:layout_gravity="center_vertical"
android:layout_marginEnd="16dp"
android:layout_marginRight="16dp"
app:srcCompat="@drawable/ic_expand_more" />
</LinearLayout>
</android.support.v7.widget.CardView>
</RelativeLayout>
group_item.xml:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:id="@+id/card"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginLeft="7dp"
android:layout_marginRight="7dp"
android:layout_marginTop="10dp"
card_view:cardCornerRadius="10dp"
card_view:cardElevation="5dp">
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@color/materialGray"
android:orientation="vertical"
android:padding="@dimen/activity_horizontal_margin">
<TextView
android:id="@+id/t1"
style="@style/MyLargeTextAppearance"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:text="TextView" />
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="@color/separatorViewBackground" />
<TextView
android:id="@+id/t2"
style="@style/MyLargeTextAppearance"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:text="TextView" />
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="@color/separatorViewBackground" />
<TextView
android:id="@+id/t3"
style="@style/MyLargeTextAppearance"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:text="TextView"/>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="@color/separatorViewBackground" />
<TextView
android:id="@+id/t4"
style="@style/MyLargeTextAppearance"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:text="TextView" />
</LinearLayout>
</android.support.v7.widget.CardView>
