So my code simply makes a list of CardViews using RecyclerView. Upon running my code i kept getting a weird error claiming there was an error in my xml. After tinkering for a while i found out that in my layout file if i change <RecyclerView> to <android.support.v7.widget.RecyclerView> everything would work just fine. Why is this happening?
My activity.
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.Menu;
import android.view.MenuItem;
import java.util.ArrayList;
public class CardListActivity extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_card_list);
RecyclerView recyclerView = (RecyclerView)findViewById(R.id.cardList);
recyclerView.setHasFixedSize(true);
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
recyclerView.setLayoutManager(linearLayoutManager);
ArrayList<String> list = new ArrayList<>();
for(int i = 0; i < 20; i++) {list.add("Item " + i);}
CardListAdapter cardListAdapter = new CardListAdapter(list);
recyclerView.setAdapter(cardListAdapter);
}
}
My Adapter
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.util.List;
public class CardListAdapter extends RecyclerView.Adapter<CardListAdapter.CardListViewHolder> {
private List<String> list;
public CardListAdapter(List<String> list) {
this.list = list;
}
@Override
public CardListViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.card_layout,viewGroup,false);
return new CardListViewHolder(v);
}
@Override
public void onBindViewHolder(CardListViewHolder cardListViewHolder, int i) {
String s = list.get(i);
cardListViewHolder.title.setText(s);
}
@Override
public int getItemCount() {
return list.size();
}
public static class CardListViewHolder extends RecyclerView.ViewHolder {
TextView title;
public CardListViewHolder(View itemView) {
super(itemView);
title = (TextView)itemView.findViewById(R.id.title);
}
}
}
My layout file, note, changing <RecyclerView> to <android.support.v7.widget.RecyclerView> fixes the error.
<RelativeLayout 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:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".CardListActivity">
<RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/cardList">
</RecyclerView>
When i run with <RecyclerView> i get this error, .
`Process: com.liquidink.lollipopmaterialui, PID: 7317
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.liquidink.lollipopmaterialui/com.liquidink.lollipopmaterialui.CardListActivity}: android.view.InflateException: Binary XML file line #8: Error inflating class RecyclerView
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: android.view.InflateException: Binary XML file line #8: Error inflating class RecyclerView
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:757)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:806)
at android.view.LayoutInflater.inflate(LayoutInflater.java:504)
at android.view.LayoutInflater.inflate(LayoutInflater.java:414)
at android.view.LayoutInflater.inflate(LayoutInflater.java:365)
at android.support.v7.app.ActionBarActivityDelegateBase.setContentView(ActionBarActivityDelegateBase.java:228)
at android.support.v7.app.ActionBarActivity.setContentView(ActionBarActivity.java:102)
at com.liquidink.lollipopmaterialui.CardListActivity.onCreate(CardListActivity.java:18)
at android.app.Activity.performCreate(Activity.java:5933)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: java.lang.ClassNotFoundException: Didn't find class "android.view.RecyclerView" on path: DexPathList[[zip file "/data/app/com.liquidink.lollipopmaterialui-2/base.apk"],nativeLibraryDirectories=[/vendor/lib, /system/lib]]
at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
at android.view.LayoutInflater.createView(LayoutInflater.java:571)
at android.view.LayoutInflater.onCreateView(LayoutInflater.java:665)
at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:65)
at android.view.LayoutInflater.onCreateView(LayoutInflater.java:682)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:741)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:806)
at android.view.LayoutInflater.inflate(LayoutInflater.java:504)
at android.view.LayoutInflater.inflate(LayoutInflater.java:414)
at android.view.LayoutInflater.inflate(LayoutInflater.java:365)
at android.support.v7.app.ActionBarActivityDelegateBase.setContentView(ActionBarActivityDelegateBase.java:228)
at android.support.v7.app.ActionBarActivity.setContentView(ActionBarActivity.java:102)
at com.liquidink.lollipopmaterialui.CardListActivity.onCreate(CardListActivity.java:18)
at android.app.Activity.performCreate(Activity.java:5933)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Suppressed: java.lang.ClassNotFoundException: android.view.RecyclerView
at java.lang.Class.classForName(Native Method)
at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
... 26 more
Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack available
`
RecyclerView is not included in base Android framework, only widgets in base Android framework (like ListView, GridView etc) can be specified in layout without full namespace. RecyclerView is part of recyclerview-v7 support library.