Error using RecyclerView: the specified child already has a parent

Question

I am trying to create a listView with a new RecyvlerView adapter. I followed the exact guide provided on the Android developer resources. But this gives me a strange error: The indicated child already has a parent. You must first call removeView () on the parent parent. I have the latest SDK. I also define dependencies in gradle.

MyActivity (Primary Activity):

public class MyActivity extends Activity { private RecyclerView mRecyclerView; private RecyclerView.Adapter mAdapter; private RecyclerView.LayoutManager mLayoutManager; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_my); mRecyclerView = (RecyclerView) findViewById(R.id.my_recycler_view); // use this setting to improve performance if you know that changes // in content do not change the layout size of the RecyclerView mRecyclerView.setHasFixedSize(true); // use a linear layout manager mRecyclerView.setLayoutManager(new LinearLayoutManager(this)); mRecyclerView.setItemAnimator(new DefaultItemAnimator()); // specify an adapter (see also next example) mAdapter = new MyAdapter(new String[]{"Zain", "Nadeem"}); mRecyclerView.setAdapter(mAdapter); } } 

Myadapter:

 public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> { private String[] mDataset; // Provide a reference to the views for each data item // Complex data items may need more than one view per item, and // you provide access to all the views for a data item in a view holder // Provide a suitable constructor (depends on the kind of dataset) public MyAdapter(String[] myDataset) { mDataset = myDataset; } // Create new views (invoked by the layout manager) @Override public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { // create a new view LayoutInflater inflater = LayoutInflater.from(parent.getContext()); View v = inflater.inflate(R.layout.my_text_view, parent, true); ViewHolder vh = new ViewHolder( v ); return vh; } // Replace the contents of a view (invoked by the layout manager) @Override public void onBindViewHolder(ViewHolder holder, int position) { // - get element from your dataset at this position // - replace the contents of the view with that element holder.mTextView.setText(mDataset[position]); } // Return the size of your dataset (invoked by the layout manager) @Override public int getItemCount() { return mDataset.length; } public static class ViewHolder extends RecyclerView.ViewHolder { // each data item is just a string in this case public TextView mTextView; public ViewHolder(View v) { super(v); mTextView = (TextView) v.findViewById(R.id.item_title); } } } 

my_text_view.xml (layout for list items):

 <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="80dp" > <!-- title --> <TextView android:id="@+id/item_title" android:layout_width="fill_parent" android:layout_height="wrap_content" android:textColor="@android:color/darker_gray" android:layout_marginLeft="8dp" android:layout_marginRight="8dp" android:layout_marginTop="8dp" android:textSize="22dp" /> </RelativeLayout> 

activity_my.xml (main action):

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" xmlns:card_view="http://schemas.android.com/apk/res-auto" android:layout_height="fill_parent" android:layout_width="fill_parent" android:background="@android:color/holo_orange_light" > <!-- A CardView that contains a TextView --> <android.support.v7.widget.RecyclerView android:id="@+id/my_recycler_view" android:scrollbars="vertical" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MyActivity"/> </LinearLayout> 

And here is the output of logcat:

 10-28 01:20:30.287 22729-22729/osman.zaingz.com.lollipop E/AndroidRuntime﹕ FATAL EXCEPTION: main Process: osman.zaingz.com.lollipop, PID: 22729 java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child parent first. at android.view.ViewGroup.addViewInner(ViewGroup.java:3562) at android.view.ViewGroup.addView(ViewGroup.java:3415) at android.view.ViewGroup.addView(ViewGroup.java:3360) at android.support.v7.widget.RecyclerView$4.addView(RecyclerView.java:322) at android.support.v7.widget.ChildHelper.addView(ChildHelper.java:79) at android.support.v7.widget.RecyclerView$LayoutManager.addViewInt(RecyclerView.java:4845) at android.support.v7.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:4803) at android.support.v7.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:4791) at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1316) at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1265) at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:522) at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:1918) at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:2155) at android.view.View.layout(View.java:14817) at android.view.ViewGroup.layout(ViewGroup.java:4631) at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671) at android.widget.LinearLayout.layoutHorizontal(LinearLayout.java:1660) at android.widget.LinearLayout.onLayout(LinearLayout.java:1436) at android.view.View.layout(View.java:14817) at android.view.ViewGroup.layout(ViewGroup.java:4631) at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453) at android.widget.FrameLayout.onLayout(FrameLayout.java:388) at android.view.View.layout(View.java:14817) at android.view.ViewGroup.layout(ViewGroup.java:4631) at com.android.internal.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:374) at android.view.View.layout(View.java:14817) at android.view.ViewGroup.layout(ViewGroup.java:4631) at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453) at android.widget.FrameLayout.onLayout(FrameLayout.java:388) at android.view.View.layout(View.java:14817) at android.view.ViewGroup.layout(ViewGroup.java:4631) at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:1983) at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1740) at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:996) at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5600) at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761) at android.view.Choreographer.doCallbacks(Choreographer.java:574) at android.view.Choreographer.doFrame(Choreographer.java:544) at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747) at android.os.Handler.handleCallback(Handler.java:733) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:136) at android.app.ActivityThread.main(ActivityThread.java:5001) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601) 

Please help me fix this problem. Thank:)

Answer 1

when inflating, you should not attach the view to its parent element. You wrote:

 View v = inflater.inflate(R.layout.my_text_view, parent, true); 

which should be:

 View v = inflater.inflate(R.layout.my_text_view, parent, false); 

Answer 2

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="80dp"> <TextView android:id="@+id/item_title" android:layout_width="fill_parent" android:layout_height="wrap_content" android:textColor="@android:color/darker_gray" android:layout_marginLeft="8dp" android:layout_marginRight="8dp" android:layout_marginTop="8dp" android:textSize="22dp" /> </RelativeLayout> 

RelativeLayout is the parent of your TextView with item_title . Then, when RecyclerView tries to add a TextView that has a parent element, it throws an exception.

Try this code:

 public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { // create a new view Log.d(TAG, "onCreateViewHolder"); RelativeLayout v = (RelativeLayout)LayoutInflater.from(parent.getContext()) .inflate(R.layout.list_item, parent, false); // set the view size, margins, paddings and layout parameters View view = v.findViewById(R.id.text1); v.removeView(view); ViewHolder vh = new ViewHolder(view); return vh; }