我使用navigation bar创建了包含一些内容的recyclerview，我添加了fragments这些内容，但fragments没有打开。
该应用为crashing尝试向recyclerview调用虚拟方法。
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.GestureDetector;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;
import com.sun.suni.design.fragments.AboutUS;
import com.sun.suni.design.fragments.Overview;
import com.sun.suni.design.fragments.Products;
import com.sun.suni.design.fragments.ReachUs;
import java.util.ArrayList;
import java.util.List;
/**
* A simple {@link Fragment} subclass.
*/
public class NavigationDrawerFragment extends Fragment {
private RecyclerView recyclerView;
private ActionBarDrawerToggle sDrawerToggle;
private DrawerLayout sDrawerLayout;
private SunAdapter adapter;
private View containerView;
public static final String PREF_FILE_NAME = "navtest";
public static final String KEY_USER_LEARNED_DRAWER = "user_learned_drawer";
private boolean sUserLearnedDrawer;
private boolean sFromSavedInstanceState;
public NavigationDrawerFragment() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
sUserLearnedDrawer = Boolean.valueOf(readFromPreferences(getActivity(),KEY_USER_LEARNED_DRAWER,"false"));
if (savedInstanceState != null) {
sFromSavedInstanceState = true;
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View layout = inflater.inflate(R.layout.fragment_navigation_drawer, container, false);
recyclerView = (RecyclerView) layout.findViewById(R.id.drawer_list);
adapter = new SunAdapter(getActivity(),getData());
recyclerView.setAdapter(adapter);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
recyclerView.addOnItemTouchListener(new RecyclerTouchListener(getActivity(), recyclerView, new ClickListener() {
@Override
public void onClick(View view, int posititon) {
Fragment fragment = null;
switch (posititon) {
case 0:
fragment = new Products();
break;
case 1:
fragment = new AboutUS();
break;
case 2:
fragment = new Overview();
break;
case 3:
fragment = new ReachUs();
break;
default:
break;
}
if (fragment != null) {
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.drawer_list, fragment).commit();
// update selected item and title, then close the drawer
} else {
// error in creating fragment
Log.e("MainActivity", "Error in creating fragment");
}
}
@Override
public void onLongClick(View view, int position) {
Toast.makeText(getActivity(),"onLongClick"+position,Toast.LENGTH_SHORT).show();
}
}));
return layout;
}
public static List<Info> getData(){
List<Info> data = new ArrayList<>();
int[] icons = {R.drawable.products,R.drawable.aboutus,R.drawable.blog,R.drawable.reachus};
String[] titles = {"PRODUCTS", "ABOUT US ", "BLOG", "REACH US"};
for (int i=0;i<titles.length && i<icons.length;i++){
Info current = new Info();
current.iconId = icons[i];
current.title = titles[i];
data.add(current);
}
return data;
}
public void setUp(int fragmentId,DrawerLayout drawerLayout, final Toolbar toolbar) {
containerView = getActivity().findViewById(fragmentId);
sDrawerLayout = drawerLayout;
sDrawerToggle = new ActionBarDrawerToggle(getActivity(), drawerLayout, toolbar, R.string.drawer_open,R.string.drawer_close){
@Override
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
if (!sUserLearnedDrawer){
sUserLearnedDrawer = true;
saveToPreferences(getActivity(), KEY_USER_LEARNED_DRAWER, sUserLearnedDrawer+"");
}
getActivity().invalidateOptionsMenu();
}
@Override
public void onDrawerClosed(View drawerView) {
super.onDrawerClosed(drawerView);
getActivity().invalidateOptionsMenu();
}
@Override
public void onDrawerSlide(View drawerView, float slideOffset) {
if (slideOffset < 0.5){
toolbar.setAlpha(1-slideOffset);
}
}
};
if (!sUserLearnedDrawer && !sFromSavedInstanceState){
sDrawerLayout.openDrawer(containerView);
}
sDrawerLayout.setDrawerListener(sDrawerToggle);
sDrawerLayout.post(new Runnable() {
@Override
public void run() {
sDrawerToggle.syncState();
}
});
}
public static void saveToPreferences(Context conrext, String preferenceName, String preferenceValue){
SharedPreferences sP = conrext.getSharedPreferences(PREF_FILE_NAME, conrext.MODE_PRIVATE);
SharedPreferences.Editor editor = sP.edit();
editor.putString(preferenceName, preferenceValue);
editor.apply();
}
public static String readFromPreferences(Context context, String preferenceName, String defaultValue){
SharedPreferences sP = context.getSharedPreferences(PREF_FILE_NAME, context.MODE_PRIVATE);
return sP.getString(preferenceName,defaultValue);
}
class RecyclerTouchListener implements RecyclerView.OnItemTouchListener {
private GestureDetector gestureDetector;
private ClickListener clickListener;
public RecyclerTouchListener(Context context, final RecyclerView recyclerView, final ClickListener clickListener){
this.clickListener = clickListener;
gestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener(){
@Override
public boolean onSingleTapUp(MotionEvent e) {
return true;
}
@Override
public void onLongPress(MotionEvent e) {
View child = recyclerView.findChildViewUnder(e.getX(), e.getY());
if (child != null && clickListener != null){
clickListener.onLongClick(child, recyclerView.getChildPosition(child));
}
}
});
}
@Override
public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
View child = rv.findChildViewUnder(e.getX(), e.getY());
if (child != null && clickListener != null && gestureDetector.onTouchEvent(e)){
clickListener.onClick(child, rv.getChildPosition(child));
}
return false;
}
@Override
public void onTouchEvent(RecyclerView rv, MotionEvent e) {
}
@Override
public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
}
}
public interface ClickListener {
public void onClick(View view, int posititon);
public void onLongClick(View view, int position);
}
}
logcat的：
FATAL EXCEPTION: main
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: Process: com.sun.suni.design, PID: 5400
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.support.v7.widget.RecyclerView$ViewHolder.shouldIgnore()' on a null object reference
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.support.v7.widget.RecyclerView.findMinMaxChildLayoutPositions(RecyclerView.java:2978)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:2824)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:3071)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.View.layout(View.java:15596)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.ViewGroup.layout(ViewGroup.java:4966)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1076)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.View.layout(View.java:15596)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.ViewGroup.layout(ViewGroup.java:4966)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.support.v4.widget.DrawerLayout.onLayout(DrawerLayout.java:1067)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.View.layout(View.java:15596)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.ViewGroup.layout(ViewGroup.java:4966)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.widget.FrameLayout.layoutChildren(FrameLayout.java:573)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.widget.FrameLayout.onLayout(FrameLayout.java:508)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.View.layout(View.java:15596)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.ViewGroup.layout(ViewGroup.java:4966)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.widget.LinearLayout.onLayout(LinearLayout.java:1466)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.View.layout(View.java:15596)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.ViewGroup.layout(ViewGroup.java:4966)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.widget.FrameLayout.layoutChildren(FrameLayout.java:573)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.widget.FrameLayout.onLayout(FrameLayout.java:508)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.View.layout(View.java:15596)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.ViewGroup.layout(ViewGroup.java:4966)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.widget.LinearLayout.onLayout(LinearLayout.java:1466)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.View.layout(View.java:15596)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.ViewGroup.layout(ViewGroup.java:4966)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.widget.FrameLayout.layoutChildren(FrameLayout.java:573)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.widget.FrameLayout.onLayout(FrameLayout.java:508)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.View.layout(View.java:15596)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.ViewGroup.layout(ViewGroup.java:4966)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2072)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1829)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1054)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5779)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.Choreographer.doCallbacks(Choreographer.java:580)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.Choreographer.doFrame(Choreographer.java:550)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.os.Handler.handleCallback(Handler.java:739)
12-08 12:50:20.750 5400-5400/com.sun.suni.design E/AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:95)
SunAdapter：
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.Collections;
import java.util.List;
/**
* Created by CloudicaLabs on 12/1/2015.
*/
public class SunAdapter extends RecyclerView.Adapter<SunAdapter.MyViewHolder> {
private LayoutInflater inflater;
List<Info> data = Collections.emptyList();
public SunAdapter(Context context, List<Info> data) {
inflater = LayoutInflater.from(context);
this.data = data;
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = inflater.inflate(R.layout.custom_row, parent, false);
MyViewHolder holder = new MyViewHolder(view);
return holder;
}
@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
Info current = data.get(position);
holder.title.setText(current.title);
holder.icon.setImageResource(current.iconId);
}
@Override
public int getItemCount() {
return data.size();
}
class MyViewHolder extends RecyclerView.ViewHolder {
TextView title;
ImageView icon;
public MyViewHolder(View itemView) {
super(itemView);
title = (TextView) itemView.findViewById(R.id.listText);
icon = (ImageView) itemView.findViewById(R.id.listIcon);
}
}
}
答案 0 :(得分：0)
问题出在这里
fragmentManager.beginTransaction().replace(R.id.drawer_list, fragment).commit();
您正在替换Recyclerview内的片段。因此，在第一个参数中，您需要提供FrameLayout的资源ID。