`addOnScrollListener(OnScrollListener)`
 means you can add more than one listener to a RecyclerView.


`removeOnScrollListener(OnScrollListener)`
means you can remove one of the listeners that attached to a specific RecyclerView. **If `the arg` was set null**, it equals to `clearOnScrollListeners()` method.

And, `clearOnScrollListeners()` let you remove all the listener from a RecyclerView.

I am making ios app on XCODE 6.3 by Swift.
And my app will have the choose language function like the image below

![enter image description here][1]


  [1]: http://i.stack.imgur.com/iO1M5.png

I already have storyboard for my local language. 
But i can&#39;t find out how to change the localization programmatically off the app by the button.

Anyone know how to do it

How can I change locale programmatically with Swift

I have the following code in my bash script. Now I wanna use it in POSIX sh. How can I convert it?
 

    DIR=&quot;$( cd &quot;$( dirname &quot;${BASH_SOURCE[0]}&quot; )&quot; &gt; /dev/null &amp;&amp; pwd )&quot;

How to get script directory in POSIX sh?

`setOnScrollListener` is deprecated. Reading the docs [from here][1] it tells to Use `addOnScrollListener(OnScrollListener)` and `removeOnScrollListener(OnScrollListener)`. 

What is the proper way to `add and remove OnScrollListener`? 

Do i need to use `removeOnScrollListner` in `onPause` and set it up again using `addOnScrollListener` in `onResume`??

  [1]: https://developer.android.com/reference/android/support/v7/widget/RecyclerView.html#setOnScrollListener(android.support.v7.widget.RecyclerView.OnScrollListener)

Android setOnScrollListener on RecyclerView deprecated

<code>setOnScrollListener</code> is deprecated. Reading the docs <a href="https://developer.android.com/reference/android/support/v7/widget/RecyclerView.html#setOnScrollListener(android.support.v7.widget.RecyclerView.OnScrollListener)" target="_blank" rel="noopener noreferrer">from here</a> it tells to Use <code>addOnScrollListener(OnScrollListener)</code> and <code>removeOnScrollListener(OnScrollListener)</code>.
What is the proper way to <code>add and remove OnScrollListener</code>?
Do i need to use <code>removeOnScrollListner</code> in <code>onPause</code> and set it up again using <code>addOnScrollListener</code> in <code>onResume</code>??

I am trying to remove all the elements from my `RecyclerView` in my `onRestart` method so the items don&#39;t get loaded twice:

    @Override
    protected void onRestart() {
        super.onRestart();

        // first clear the recycler view so items are not populated twice
        for (int i = 0; i &lt; recyclerAdapter.getSize(); i++) {
            recyclerAdapter.delete(i);
        }

        // then reload the data
        PostCall doPostCall = new PostCall(); // my AsyncTask... 
        doPostCall.execute();
    }

But for some reason the `delete` method I created in the `adapter` is not functioning properly:

in RecyclerAdapter.java: 

    public void delete(int position){
        myList.remove(position);
        notifyItemRemoved(position);
    }

    public int getSize(){
        return myList.size();
    }

I think every other item in my list gets deleted instead of the entire list.

With a `listview` it was so easy and I simply called `adapter.clear()`.

Can someone please help me fix up the code?

I think I should be using `notifyItemRangeRemoved(...,...);` but I am not sure how. TIA

Remove all items from RecyclerView

I want to keep all the transformation, stoke and animations identical and was thinking if we can pass resource ID or asset name in Glide to load it locally?

Using Glide for Android, how do I load images from asset and resources?

I have a Recycler View with the Images loaded from the Internal Storage.
I want to Highlight the selected item when clicked.
I tried a lot of thing but it was not working.
Actually what I need is when I click any item in Recycler View that Item must go in My ArrayList and it should also get highlighted and again when I click or say unselect it must again become normal.
Here is my Code:
          
    public class Images extends Fragment {
		private List&lt;ImageHolder&gt; imageList;
		Cursor imageCursor;

		RecyclerView recyclerView;
		MyImageAdapter adapter;
		ActionButton clickButton;
		List&lt;String&gt; listofImages;
		List&lt;Integer&gt; pos;
		int columnIndex;
		StringBuilder stringBuilder;
		@Override
		public View onCreateView(LayoutInflater inflater, ViewGroup container,   Bundle savedInstanceState) {
			View rootlayout = inflater.inflate(R.layout.image, container, false);
			listofImages=new ArrayList&lt;String&gt;();
			pos=new ArrayList&lt;Integer&gt;();
			stringBuilder=new StringBuilder();
			ContentResolver imageResolver = getActivity().getContentResolver();
			Uri imageUri = android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
			String projection[]={MediaStore.Images.Thumbnails._ID,MediaStore.Images.Media.TITLE};
			imageCursor = getActivity().managedQuery(imageUri, projection, null, null, null);

			clickButton= (ActionButton) rootlayout.findViewById(R.id.action_button);
		   
			recyclerView = (RecyclerView) rootlayout.findViewById(R.id.recycler_view_image);
			adapter = new MyImageAdapter(getActivity(), getImageList());

			recyclerView.setAdapter(adapter);
			recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));

			recyclerView.addOnItemTouchListener(new RecyclerTouchListener(getActivity(),recyclerView,new RecyclerTouchListener.ClickListener() {
				@Override
				public void onClick(View view, int position) {
				   TextView tv= (TextView) view.findViewById(R.id.list_text_all);
						int flag=0;

						String[] projection = {MediaStore.Images.Media.DATA};
						imageCursor = getActivity().managedQuery(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
								projection, 
								null,       
								null,
								null);
						columnIndex = imageCursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
						imageCursor.moveToPosition(position);
						// Get image filename
						String imagePath = imageCursor.getString(columnIndex);
						if (listofImages.contains(imagePath)){
							Log.d(&quot;Contains Test&quot;,&quot;Yes&quot;);
							listofImages.remove(imagePath);
							pos.remove(position);
						} else {
							listofImages.add(imagePath);
							pos.add(position);
							Log.d(&quot;Contains Test&quot;,&quot;No&quot;);
						}

					String s=listofImages.size()+&quot; &quot;+imagePath;
					Log.d(&quot;Inserted&quot;,s);
				}

				@Override
				public void onLongClick(View view, int position) {}
			}));

			clickButton.setOnClickListener(new View.OnClickListener() {
				@Override
				public void onClick(View v) {
					for (int i=0;i&lt;listofImages.size();i++){
						stringBuilder.append(listofImages.get(i)+&quot;\n&quot;);
					}
					Toast.makeText(getActivity(),stringBuilder,Toast.LENGTH_LONG).show();
			   	}
			});

			return rootlayout;
		}

		public List&lt;ImageHolder&gt; getImageList() {
			imageList=new ArrayList&lt;ImageHolder&gt;();

			if(imageCursor!=null &amp;&amp; imageCursor.moveToFirst()){

			   int titleColumn = imageCursor.getColumnIndex
						(android.provider.MediaStore.Images.Media.TITLE);
				int idColumn = imageCursor.getColumnIndex
						(android.provider.MediaStore.Images.Media._ID);

				do {
					ImageHolder img=new ImageHolder();
					img.id=imageCursor.getLong(idColumn);
					img.title=imageCursor.getString(titleColumn);

					img.iconid= imageCursor.getInt(idColumn);


					imageList.add(img);
				}
				while (imageCursor.moveToNext());
			}
		   
			return  imageList;
		}
    }


This is my Adapter Class:

    public class MyImageAdapter extends RecyclerView.Adapter&lt;MyImageAdapter.MyViewHolder&gt; {
		Context context;
		private LayoutInflater inflater;
		List&lt;ImageHolder&gt; data= Collections.emptyList();
		private ClickListener clickListener;
		int width,height;

		public MyImageAdapter(Context context, List&lt;ImageHolder&gt; data1) {
			inflater = LayoutInflater.from(context);
			this.data=data1;
			this.context=context;
		}

		@Override
		public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
			View view = inflater.inflate(R.layout.all_row, parent, false);
			MyViewHolder holder=new MyViewHolder(view);
			return holder;
		}

		@Override
		public void onBindViewHolder(MyViewHolder holder, int position) {
			try{
				ImageHolder current=data.get(position);
				holder.title.setText(current.title);
			   
				Log.d(&quot;Imageid:&quot;+current.iconid,&quot;&quot;);
				Uri IMAGE_URI = Uri.withAppendedPath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, &quot;&quot; + current.iconid);

				Bitmap bitmap = Bitmap.createScaledBitmap(decodeUri(IMAGE_URI), 200, 200, true);
				holder.img.setImageBitmap(bitmap);
			}
			catch(Exception e){}
		}
		public void deleteRecyclerData(int position){
			data.remove(position);
			notifyItemRemoved(position);
		}


		private Bitmap decodeUri(Uri selectedImage) throws FileNotFoundException {
			BitmapFactory.Options o = new BitmapFactory.Options();
			o.inJustDecodeBounds = true;
			BitmapFactory.decodeStream(
				   context.getContentResolver().openInputStream(selectedImage), null, o);

			final int REQUIRED_SIZE = 100;

			int width_tmp = o.outWidth, height_tmp = o.outHeight;
			int scale = 1;
			while (true) {
				if (width_tmp / 2 &lt; REQUIRED_SIZE || height_tmp / 2 &lt; REQUIRED_SIZE) {
					break;
				}
				width_tmp /= 2;
				height_tmp /= 2;
				scale *= 2;
			}

			BitmapFactory.Options o2 = new BitmapFactory.Options();
			o2.inSampleSize = scale;
			return BitmapFactory.decodeStream(
					context.getContentResolver().openInputStream(selectedImage), null, o2);
		}
		@Override
		public int getItemCount() {
			return data.size();
		}

		public class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
			TextView title;
		  // TextView artist;
			ImageView img;
			CheckBox checkBox;

			public MyViewHolder(View itemView) {
				super(itemView);
				title= (TextView) itemView.findViewById(R.id.list_text_all);
				img= (ImageView) itemView.findViewById(R.id.list_image_all);
				img.setOnClickListener(this);
			}

			@Override
			public void onClick(View v) {}
		}
		public interface ClickListener{
			public void itemClicked(View view, int position);
		}
	}

how to highlight the selected Item of Recycler View?

I installed (Android studio 1.2 + SDK pack) for the first time, I created a test project with demo tab activity. I have not written a single line of code, everything has been generated by Android Studio

In fragment_main.xml the following problem occurs.

![enter image description here][1]


  [1]: http://i.stack.imgur.com/WQMWU.png

    java.lang.ClassNotFoundException: android.support.v4.view.ViewPropertyAnimatorListener
    	at org.jetbrains.android.uipreview.ModuleClassLoader.load(ModuleClassLoader.java:127)
    	at com.android.tools.idea.rendering.RenderClassLoader.findClass(RenderClassLoader.java:53)
    	at org.jetbrains.android.uipreview.ModuleClassLoader.findClass(ModuleClassLoader.java:84)
    	at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
    	at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
    	at java.lang.Class.getDeclaredConstructors0(Native Method)
    	at java.lang.Class.privateGetDeclaredConstructors(Class.java:2585)
    	at java.lang.Class.getConstructor0(Class.java:2885)
    	at java.lang.Class.getConstructor(Class.java:1723)
    	at org.jetbrains.android.uipreview.ViewLoader.createNewInstance(ViewLoader.java:348)
    	at org.jetbrains.android.uipreview.ViewLoader.loadView(ViewLoader.java:105)
    	at com.android.tools.idea.rendering.LayoutlibCallback.loadView(LayoutlibCallback.java:177)
    	at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:214)
    	at android.view.BridgeInflater.createViewFromTag(BridgeInflater.java:142)
    	at android.view.LayoutInflater.inflate(LayoutInflater.java:482)
    	at android.view.LayoutInflater.inflate(LayoutInflater.java:414)
    	at com.android.layoutlib.bridge.bars.BridgeActionBar.&lt;init&gt;(BridgeActionBar.java:84)
    	at com.android.layoutlib.bridge.bars.AppCompatActionBar.&lt;init&gt;(AppCompatActionBar.java:56)
    	at com.android.layoutlib.bridge.impl.RenderSessionImpl.createActionBar(RenderSessionImpl.java:1691)
    	at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:362)
    	at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:321)
    	at com.android.ide.common.rendering.LayoutLibrary.createSession(LayoutLibrary.java:350)
    	at com.android.tools.idea.rendering.RenderTask$2.compute(RenderTask.java:497)
    	at com.android.tools.idea.rendering.RenderTask$2.compute(RenderTask.java:485)
    	at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:894)
    	at com.android.tools.idea.rendering.RenderTask.createRenderSession(RenderTask.java:485)
    	at com.android.tools.idea.rendering.RenderTask.render(RenderTask.java:590)
    	at com.intellij.android.designer.designSurface.AndroidDesignerEditorPanel$6.run(AndroidDesignerEditorPanel.java:480)
    	at com.intellij.util.ui.update.MergingUpdateQueue.execute(MergingUpdateQueue.java:320)
    	at com.intellij.util.ui.update.MergingUpdateQueue.execute(MergingUpdateQueue.java:310)
    	at com.intellij.util.ui.update.MergingUpdateQueue$2.run(MergingUpdateQueue.java:254)
    	at com.intellij.util.ui.update.MergingUpdateQueue.flush(MergingUpdateQueue.java:269)
    	at com.intellij.util.ui.update.MergingUpdateQueue.flush(MergingUpdateQueue.java:227)
    	at com.intellij.util.ui.update.MergingUpdateQueue.run(MergingUpdateQueue.java:217)
    	at com.intellij.util.concurrency.QueueProcessor.runSafely(QueueProcessor.java:238)
    	at com.intellij.util.Alarm$Request$1.run(Alarm.java:351)
    	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
    	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    	at java.lang.Thread.run(Thread.java:745)

xml:    

    &lt;RelativeLayout xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
        xmlns:tools=&quot;http://schemas.android.com/tools&quot; android:layout_width=&quot;match_parent&quot;
        android:layout_height=&quot;match_parent&quot; android:paddingLeft=&quot;@dimen/activity_horizontal_margin&quot;
        android:paddingRight=&quot;@dimen/activity_horizontal_margin&quot;
        android:paddingTop=&quot;@dimen/activity_vertical_margin&quot;
        android:paddingBottom=&quot;@dimen/activity_vertical_margin&quot;
        tools:context=&quot;.MainActivity$PlaceholderFragment&quot;&gt;
    
        &lt;TextView android:id=&quot;@+id/section_label&quot; android:layout_width=&quot;wrap_content&quot;
            android:layout_height=&quot;wrap_content&quot; /&gt;
    
    &lt;/RelativeLayout&gt;


Activity(No code errors here but I am surprised to see calls of deprecated functions in a demo code):   
    
    import java.util.Locale;
    
    import android.support.v7.app.ActionBarActivity;
    import android.support.v7.app.ActionBar;
    import android.support.v4.app.Fragment;
    import android.support.v4.app.FragmentManager;
    import android.support.v4.app.FragmentTransaction;
    import android.support.v4.app.FragmentPagerAdapter;
    import android.os.Bundle;
    import android.support.v4.view.ViewPager;
    import android.view.Gravity;
    import android.view.LayoutInflater;
    import android.view.Menu;
    import android.view.MenuItem;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.TextView;
    
    
    public class MainActivity extends ActionBarActivity implements ActionBar.TabListener {
    
        /**
         * The {@link android.support.v4.view.PagerAdapter} that will provide
         * fragments for each of the sections. We use a
         * {@link FragmentPagerAdapter} derivative, which will keep every
         * loaded fragment in memory. If this becomes too memory intensive, it
         * may be best to switch to a
         * {@link android.support.v4.app.FragmentStatePagerAdapter}.
         */
        SectionsPagerAdapter mSectionsPagerAdapter;
    
        /**
         * The {@link ViewPager} that will host the section contents.
         */
        ViewPager mViewPager;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            // Set up the action bar.
            final ActionBar actionBar = getSupportActionBar();
            actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
    
            // Create the adapter that will return a fragment for each of the three
            // primary sections of the activity.
            mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
    
            // Set up the ViewPager with the sections adapter.
            mViewPager = (ViewPager) findViewById(R.id.pager);
            mViewPager.setAdapter(mSectionsPagerAdapter);
    
            // When swiping between different sections, select the corresponding
            // tab. We can also use ActionBar.Tab#select() to do this if we have
            // a reference to the Tab.
            mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
                @Override
                public void onPageSelected(int position) {
                    actionBar.setSelectedNavigationItem(position);
                }
            });
    
            // For each of the sections in the app, add a tab to the action bar.
            for (int i = 0; i &lt; mSectionsPagerAdapter.getCount(); i++) {
                // Create a tab with text corresponding to the page title defined by
                // the adapter. Also specify this Activity object, which implements
                // the TabListener interface, as the callback (listener) for when
                // this tab is selected.
                actionBar.addTab(
                        actionBar.newTab()
                                .setText(mSectionsPagerAdapter.getPageTitle(i))
                                .setTabListener(this));
            }
        }
    
    
        @Override
        public boolean onCreateOptionsMenu(Menu menu) {
            // Inflate the menu; this adds items to the action bar if it is present.
            getMenuInflater().inflate(R.menu.menu_main, menu);
            return true;
        }
    
        @Override
        public boolean onOptionsItemSelected(MenuItem item) {
            // Handle action bar item clicks here. The action bar will
            // automatically handle clicks on the Home/Up button, so long
            // as you specify a parent activity in AndroidManifest.xml.
            int id = item.getItemId();
    
            //noinspection SimplifiableIfStatement
            if (id == R.id.action_settings) {
                return true;
            }
    
            return super.onOptionsItemSelected(item);
        }
    
        @Override
        public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
            // When the given tab is selected, switch to the corresponding page in
            // the ViewPager.
            mViewPager.setCurrentItem(tab.getPosition());
        }
    
        @Override
        public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
        }
    
        @Override
        public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
        }
    
        /**
         * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
         * one of the sections/tabs/pages.
         */
        public class SectionsPagerAdapter extends FragmentPagerAdapter {
    
            public SectionsPagerAdapter(FragmentManager fm) {
                super(fm);
            }
    
            @Override
            public Fragment getItem(int position) {
                // getItem is called to instantiate the fragment for the given page.
                // Return a PlaceholderFragment (defined as a static inner class below).
                return PlaceholderFragment.newInstance(position + 1);
            }
    
            @Override
            public int getCount() {
                // Show 3 total pages.
                return 3;
            }
    
            @Override
            public CharSequence getPageTitle(int position) {
                Locale l = Locale.getDefault();
                switch (position) {
                    case 0:
                        return getString(R.string.title_section1).toUpperCase(l);
                    case 1:
                        return getString(R.string.title_section2).toUpperCase(l);
                    case 2:
                        return getString(R.string.title_section3).toUpperCase(l);
                }
                return null;
            }
        }
    
        /**
         * A placeholder fragment containing a simple view.
         */
        public static class PlaceholderFragment extends Fragment {
            /**
             * The fragment argument representing the section number for this
             * fragment.
             */
            private static final String ARG_SECTION_NUMBER = &quot;section_number&quot;;
    
            /**
             * Returns a new instance of this fragment for the given section
             * number.
             */
            public static PlaceholderFragment newInstance(int sectionNumber) {
                PlaceholderFragment fragment = new PlaceholderFragment();
                Bundle args = new Bundle();
                args.putInt(ARG_SECTION_NUMBER, sectionNumber);
                fragment.setArguments(args);
                return fragment;
            }
    
            public PlaceholderFragment() {
            }
    
            @Override
            public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                     Bundle savedInstanceState) {
                View rootView = inflater.inflate(R.layout.fragment_main, container, false);
                return rootView;
            }
        }
    
    }


android.support.v7.internal.widget.ActionBarOverlayLayout could not be instantiated

I have an Android app that uses Dagger 2 for dependency injection. I am also using the latest gradle build tools that allow a build variant for unit testing and one for instrumentation tests. I am using `java.util.Random` in my app, and I want to mock this for testing. The classes I&#39;m testing don&#39;t use any Android stuff, so they&#39;re just regular java classes.

In my main code I define a `Component` in a class that extends the `Application` class, but in the unit tests I&#39;m not using an `Application`. I tried defining a test `Module` and `Component`, but Dagger won&#39;t generate the `Component`. I have also tried using the `Component` that I defined in my application and swapping the `Module` when I build it, but the application&#39;s `Component` doesn&#39;t have `inject` methods for my test classes. How can I provide a mock implementation of `Random` for testing?

Here&#39;s some sample code:

Application:

    public class PipeGameApplication extends Application {
    
        private PipeGame pipeGame;
    
        @Singleton
        @Component(modules = PipeGameModule.class)
        public interface PipeGame {
            void inject(BoardFragment boardFragment);
            void inject(ConveyorFragment conveyorFragment);
        }
    
        @Override
        public void onCreate() {
            super.onCreate();
            pipeGame = DaggerPipeGameApplication_PipeGame.create();
        }
    
        public PipeGame component() {
            return pipeGame;
        }
    }

Module:

    @Module
    public class PipeGameModule {
    
        @Provides
        @Singleton
        Random provideRandom() {
            return new Random();
        }
    }

Base class for tests:


    public class BaseModelTest {
    
        PipeGameTest pipeGameTest;
    
        @Singleton
        @Component(modules = PipeGameTestModule.class)
        public interface PipeGameTest {
            void inject(BoardModelTest boardModelTest);
            void inject(ConveyorModelTest conveyorModelTest);
        }
    
        @Before
        public void setUp() {
            pipeGameTest = DaggerBaseModelTest_PipeGameTest.create(); // Doesn&#39;t work
        }
    
        public PipeGameTest component() {
            return pipeGameTest;
        }
    }

or:

    public class BaseModelTest {
    
        PipeGameApplication.PipeGame pipeGameTest;
    
        // This works if I make the test module extend
        // the prod module, but it can&#39;t inject my test classes
        @Before
        public void setUp() {
            pipeGameTest = DaggerPipeGameApplication_PipeGame.builder().pipeGameModule(new PipeGameModuleTest()).build();
        }
    
        public PipeGameApplication.PipeGame component() {
            return pipeGameTest;
        }
    }

Test Module:

    @Module
    public class PipeGameTestModule {
    
        @Provides
        @Singleton
        Random provideRandom() {
            return mock(Random.class);
        }
    }

Android Unit Tests with Dagger 2

I need to center elements in each row so they will be like in this mockup.
I&#39;ve been searching if there is any layout that works that way without look.
items are centered in their rows.

![mockup][1]


This is how it looks now in my code.![enter image description here][2]


  [1]: http://i.stack.imgur.com/w11fv.png]
  [2]: http://i.stack.imgur.com/GuTGy.jpg

How to center items of a recyclerview?

When I have to use a classic adapter with a [ListView](https://developer.android.com/guide/topics/ui/layout/listview.html), I update my data in the ListView like this:

    myAdapter.swapArray(data);
    
    public swapArray(List&lt;Data&gt; data) {
      clear();
      addAll(data);
      notifyDataSetChanged();
    }

I would like to know what is the best practice for a [RecyclerView](https://developer.android.com/training/material/lists-cards.html). Because in a **RecyclerView** adapter you can&#39;t do a `clear` and `addAll` as in **ListView**.

So I tried just with a `notifyDataSetChanged`, but it didn&#39;t work. 
Then I tried with a swapAdapter on my view:

    List&lt;Data&gt; data = newData;
    
    MyRecyclerAdapter adapter = new MyRecyclerAdapter(data);
    
    // swapAdapter on my recyclerView (instead of a .setAdapter like with a classic listView).
    recyclerViewList.swapAdapter(adapter, false);

But with this last solution, I still have to create a new instance of my adapter and I feel like it&#39;s not the best solution. I should be able just to change my data without a new `MyRecyclerAdapter`.

Best way to update data with a RecyclerView adapter

Our QA has detected a bug: when rotating the Android device (Droid Turbo), the following **RecyclerView-related crash** happened:

&gt;  java.lang.IndexOutOfBoundsException:
&gt;     Inconsistency detected. Invalid item position 2(offset:2).state:3

To me, it looks like an internal error inside RecyclerView, as I can&#39;t think of any way of this being caused directly by our code...

Has anyone encountered this problem?

What would be the solution?

A brutal workaround could be perhaps to catch the exception when it happens and re-create the RecyclverView instance from scratch, to avoid getting left with a corrupted state.

But, if possible, I would like to understand the problem better (and perhaps fix it at its source), instead of masking it.

The bug is not easy to reproduce, but it is fatal when it happens.

The full stack-trace:

    W/dalvikvm( 7546): threadid=1: thread exiting with uncaught exception (group=0x41987d40)
    	E/AndroidRuntime( 7546): FATAL EXCEPTION: main
    	E/AndroidRuntime( 7546): Process: com.oblong.mezzedroid, PID: 7546
    	E/AndroidRuntime( 7546): java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid item position 2(offset:2).state:3
    	E/AndroidRuntime( 7546): 	at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:3382)
    	E/AndroidRuntime( 7546): 	at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:3340)
    	E/AndroidRuntime( 7546): 	at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:1810)
    	E/AndroidRuntime( 7546): 	at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1306)
    	E/AndroidRuntime( 7546): 	at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1269)
    	E/AndroidRuntime( 7546): 	at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:523)
    	E/AndroidRuntime( 7546): 	at org.liboid.recycler_view.RecyclerViewContainer$LiLinearLayoutManager.onLayoutChildren(RecyclerViewContainer.java:179)
    	E/AndroidRuntime( 7546): 	at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:1942)
    	E/AndroidRuntime( 7546): 	at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:2237)
    	E/AndroidRuntime( 7546): 	at org.liboid.recycler_view.LiRecyclerView.onLayout(LiRecyclerView.java:30)
    	E/AndroidRuntime( 7546): 	at android.view.View.layout(View.java:14946)
    	E/AndroidRuntime( 7546): 	at android.view.ViewGroup.layout(ViewGroup.java:4651)
    	E/AndroidRuntime( 7546): 	at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
    	E/AndroidRuntime( 7546): 	at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
    	E/AndroidRuntime( 7546): 	at android.view.View.layout(View.java:14946)
    	E/AndroidRuntime( 7546): 	at android.view.ViewGroup.layout(ViewGroup.java:4651)
    	E/AndroidRuntime( 7546): 	at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
    	E/AndroidRuntime( 7546): 	at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
    	E/AndroidRuntime( 7546): 	at android.view.View.layout(View.java:14946)
    	E/AndroidRuntime( 7546): 	at android.view.ViewGroup.layout(ViewGroup.java:4651)
    	E/AndroidRuntime( 7546): 	at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671)
    	E/AndroidRuntime( 7546): 	at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525)
    	E/AndroidRuntime( 7546): 	at android.widget.LinearLayout.onLayout(LinearLayout.java:1434)
    	E/AndroidRuntime( 7546): 	at com.oblong.mezzedroid.workspace.content.bins.BinsContainerLayout.onLayout(BinsContainerLayout.java:22)
    	E/AndroidRuntime( 7546): 	at android.view.View.layout(View.java:14946)
    	E/AndroidRuntime( 7546): 	at android.view.ViewGroup.layout(ViewGroup.java:4651)
    	E/AndroidRuntime( 7546): 	at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671)
    	E/AndroidRuntime( 7546): 	at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525)
    	E/AndroidRuntime( 7546): 	at android.widget.LinearLayout.onLayout(LinearLayout.java:1434)
    	E/AndroidRuntime( 7546): 	at android.view.View.layout(View.java:14946)
    	E/AndroidRuntime( 7546): 	at android.view.ViewGroup.layout(ViewGroup.java:4651)
    	E/AndroidRuntime( 7546): 	at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
    	E/AndroidRuntime( 7546): 	at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
    	E/AndroidRuntime( 7546): 	at android.view.View.layout(View.java:14946)
    	E/AndroidRuntime( 7546): 	at android.view.ViewGroup.layout(ViewGroup.java:4651)
    	E/AndroidRuntime( 7546): 	at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
    	E/AndroidRuntime( 7546): 	at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
    	E/AndroidRuntime( 7546): 	at android.view.View.layout(View.java:14946)
    	E/AndroidRuntime( 7546): 	at android.view.ViewGroup.layout(ViewGroup.java:4651)
    	E/AndroidRuntime( 7546): 	at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671)
    	E/AndroidRuntime( 7546): 	at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525)
    	E/AndroidRuntime( 7546): 	at android.widget.LinearLayout.onLayout(LinearLayout.java:1434)
    	E/AndroidRuntime( 7546): 	at android.view.View.layout(View.java:14946)
    	E/AndroidRuntime( 7546): 	at android.view.ViewGroup.layout(ViewGroup.java:4651)
    	E/AndroidRuntime( 7546): 	at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
    	E/AndroidRuntime( 7546): 	at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
    	E/AndroidRuntime( 7546): 	at android.view.View.layout(View.java:14946)
    	E/AndroidRuntime( 7546): 	at android.view.ViewGroup.layout(ViewGroup.java:4651)
    	E/AndroidRuntime( 7546): 	at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671)
    	E/AndroidRuntime( 7546): 	at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525)
    	E/AndroidRuntime( 7546): 	at android.widget.LinearLayout.onLayout(LinearLayout.java:1434)
    	E/AndroidRuntime( 7546): 	at android.view.View.layout(View.java:14946)
    	E/AndroidRuntime( 7546): 	at android.view.ViewGroup.layout(ViewGroup.java:4651)
    	E/AndroidRuntime( 7546): 	at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
    	E/AndroidRuntime( 7546): 	at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
    	E/AndroidRuntime( 7546): 	at android.view.View.layout(View.java:14946)
    	E/AndroidRuntime( 7546): 	at android.view.ViewGroup.layout(ViewGroup.java:4651)
    	E/AndroidRuntime( 7546): 	at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2132)
    	E/AndroidRuntime( 7546): 	at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1872)
    	E/AndroidRuntime( 7546): 	at andro

Content Type	Original Author	Original Content on Stackoverflow
Question	Kushal Sharma	View Question on Stackoverflow
Solution 1 - Android	MewX	View Answer on Stackoverflow

Android setOnScrollListener on RecyclerView deprecated

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