我如何在模式列表或網格中顯示我的列表

我需要您的幫助，我需要在模式列表或網格中顯示我的列表，這就是爲什麼我使用recyclerview，但這不起作用，並給我以下與「 recyclerView.setLayoutManager（新LinearLayoutManager（本））;！我如何在模式列表或網格中顯示我的列表

然而，當我使用的ListView之前工作的罰款

你能幫助我請，謝謝

這個我activity_videos

<?xml version="1.0" encoding="utf-8"?> 
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:fitsSystemWindows="true" 
    android:id="@+id/parentLayout" 
    tools:context=".UI.Videos"> 

    <android.support.design.widget.AppBarLayout 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:theme="@style/AppTheme.AppBarOverlay" 
     > 

     <android.support.v7.widget.Toolbar 
      android:id="@+id/toolbar" 
      android:layout_width="match_parent" 
      android:layout_height="?attr/actionBarSize" 
      android:background="#FFFFFF" 
      app:popupTheme="@style/AppTheme.PopupOverlay" > 
      <TextView 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:textAppearance="?android:attr/textAppearanceLarge" 
       android:text="Videos" 
       android:textColor="#303F9F" 
       android:layout_gravity="center" 
       android:id="@+id/Videos" /> 

     </android.support.v7.widget.Toolbar> 
    </android.support.design.widget.AppBarLayout> 

    <android.support.v4.widget.DrawerLayout 
     xmlns:android="http://schemas.android.com/apk/res/android" 
     xmlns:app="http://schemas.android.com/apk/res-auto" 
     xmlns:tools="http://schemas.android.com/tools" 
     android:id="@+id/drawer_layout" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:fitsSystemWindows="true" 
     tools:openDrawer="start"> 

     <include 
      layout="@layout/content_videos" 
      android:layout_width="match_parent" 
      android:layout_height="match_parent"/> 

     <android.support.design.widget.NavigationView 
      android:id="@+id/nav_view" 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:layout_gravity="start" 
      android:fitsSystemWindows="true" 
      app:headerLayout="@layout/nav_header_main" 
      app:menu="@menu/activity_main_drawer"/> 

    </android.support.v4.widget.DrawerLayout> 

</android.support.design.widget.CoordinatorLayout>

我的內容視頻：

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:paddingBottom="@dimen/activity_vertical_margin" 
    android:paddingLeft="@dimen/activity_horizontal_margin" 
    android:paddingRight="@dimen/activity_horizontal_margin" 
    android:paddingTop="@dimen/activity_vertical_margin" 
    app:layout_behavior="@string/appbar_scrolling_view_behavior" 
    tools:context=".UI.Videos" 
    tools:showIn="@layout/activity_videos"> 

     <Space 
     android:layout_width="20px" 
     android:layout_height="20px" 
     android:id="@+id/space" /> 

    <android.support.v4.widget.SwipeRefreshLayout 
     android:id="@+id/activity_main_swipe_refresh_layout" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:layout_below="@+id/space" 
     android:layout_alignParentLeft="true" 
     android:layout_alignParentStart="true" 
     android:layout_marginTop="56dp"> 


     <android.support.v7.widget.RecyclerView 
      android:id="@+id/recyclerView" 
      android:scrollbars="vertical" 
      android:layout_width="match_parent" 
      android:layout_height="match_parent"/> 


    </android.support.v4.widget.SwipeRefreshLayout> 
</RelativeLayout>

我對自定義列表adabtor：

public class CustomListViewAdapterV extends RecyclerView.Adapter<CustomListViewAdapterV.ViewHolder> { 

    List<Video> videoList; 
    Context context; 

    // Constructors 
    public CustomListViewAdapterV(Context context, ArrayList<Video> objects) { 

     this.context = context; 
     videoList = objects; 
    } 

    @Override 
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { 

     View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_videos, parent, false); 
     return new ViewHolder(v); 
    } 
    @Override 
    public void onBindViewHolder(ViewHolder holder, int position) { 
     Video item = videoList.get(position); 
     holder.textViewTitle.setText(item.getTitle()); 
     // holder.textViewCreated_time.setText(item.getCreated_time()); 
     // holder.textViewId.setText(item.getId()); 
     Picasso.with(context).load(item.getThumbnail_medium_url()).placeholder(R.mipmap.ic_launcher).error(R.mipmap.ic_launcher).into(holder.imageView); 

     holder.rootView.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 

      } 
     }); 
    } 
    @Override 
    public int getItemCount() { 
     return videoList.size(); 
    } 

    public static class ViewHolder extends RecyclerView.ViewHolder { 
     RelativeLayout rootView; 
     ImageView imageView; 
     TextView textViewTitle; 
     // public final TextView textViewCreated_time; 
    // public final TextView textViewId; 
     private ViewHolder(View rootView) { 
      super(rootView); 
      this.imageView = imageView; 
      this.textViewTitle = textViewTitle; 
     // this.textViewCreated_time = textViewCreated_time; 
     // this.textViewId = textViewId; 
     } 



     public static void create(RelativeLayout rootView) { 
      ImageView imageView = (ImageView) rootView.findViewById(R.id.imageView); 
      TextView textViewTitle = (TextView) rootView.findViewById(R.id.textViewTitle); 
     //  TextView textViewCreated_time = (TextView) rootView.findViewById(R.id.textViewCreated_time); 
     //  TextView textViewId = (TextView) rootView.findViewById(R.id.textViewId); 
     } 
    } 
}

，這是我mainactivity：

public class Videos extends MainActivity { 

    private View parentView; 
    private ArrayList<Video> videoList; 
    private CustomListViewAdapterV adapter; 
    SwipeRefreshLayout mSwipeRefreshLayout; 
    RecyclerView recyclerView; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     recyclerView = (RecyclerView) findViewById(R.id.recyclerView); 
     recyclerView.setLayoutManager(new LinearLayoutManager(this)); 
     adapter = new CustomListViewAdapterV(Videos.this, videoList); 

     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_videos); 
     mSwipeRefreshLayout = (SwipeRefreshLayout) findViewById(R.id.activity_main_swipe_refresh_layout); 
     Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 

     setSupportActionBar(toolbar); 
     videoList = new ArrayList<>(); 
     parentView = findViewById(R.id.parentLayout); 
     DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout); 
     ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close); 
     drawer.setDrawerListener(toggle); 
     toggle.syncState(); 
     NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view); 
     navigationView.setNavigationItemSelectedListener(this); 


     mSwipeRefreshLayout.setColorSchemeResources(R.color.blue, R.color.green, R.color.blue); 
     mSwipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() { 
        @Override 
        public void onRefresh() { 
         doYourUpdate(); 
        } 
       } 
     ); 
      ItemClickSupport.addTo(recyclerView).setOnItemClickListener(new ItemClickSupport.OnItemClickListener() { 
      @Override 
      public void onItemClicked(RecyclerView recyclerView, int position, View v) { 
        Intent intent = new Intent(getApplicationContext(), Daylimotion.class); 
        startActivity(intent); 
      } 
     }); 
       if (InternetConnection.isNetworkAvailable(getApplicationContext())) { 

        //Creating an object of our api interface 
        ApiInterface api = ApiClientV.getApiInterface(); 
        /** 
        * Calling JSON 
        */ 
        Call<VideoList> call = api.getJsn(); 
        /** 
        * Enqueue Callback will be call when get response... 
        */ 
        call.enqueue(new Callback<VideoList>() { 
         @Override 
         public void onResponse(Call<VideoList> call, Response<VideoList> response) { 
          //Dismiss Dialog 
          if(response.isSuccessful()) { 
           /** 
           * Got Successfully 
           */ 

           videoList = response.body().getList(); 
           // adapter.notifiyDataSetChanged(); 

           /** 
           * Binding that List to Adapter 
           */ 
           //This is to show data for first time when we run the app. 
           adapter = new CustomListViewAdapterV(Videos.this, videoList); 
           recyclerView.setAdapter(adapter); 

          } else { 
           Snackbar.make(parentView, R.string.string_some_thing_wrong, Snackbar.LENGTH_LONG).show(); 
          } 
         } 

         @Override 
         public void onFailure(Call<VideoList> call, Throwable t) { 
         } 
        }); 
       } else { 
        Snackbar.make(parentView, R.string.string_internet_connection_not_available, Snackbar.LENGTH_LONG).show(); 
       } 
      } 

    private void doYourUpdate() { 

      mSwipeRefreshLayout.setRefreshing(false); // Disables the refresh icon 
     } 


    @Override 
    public void onBackPressed() { 
     DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout); 
     if (drawer.isDrawerOpen(GravityCompat.START)) { 
      drawer.closeDrawer(GravityCompat.START); 
     } else { 
      super.onBackPressed(); 
     } 
    } 
    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.show, menu); 
     return true; 
    } 
    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     int layoutId = R.layout.list_item; 

     int spanCount = 2; 
     switch (item.getItemId()) { 
      case R.id.linearVertical: // Vertical scrollable using LinearLayoutManager. 
       recyclerView.setLayoutManager(new LinearLayoutManager(this)); 
       break; 

      case R.id.staggeredGridviewVertical: // Vertical scrollable using StaggeredGridLayoutManager. 
       recyclerView.setLayoutManager(new StaggeredGridLayoutManager(spanCount, StaggeredGridLayoutManager.VERTICAL)); 
       break; 

     } 

       return super.onOptionsItemSelected(item); 

    }

有錯誤是：

FATAL EXCEPTION: main 
                       Process: com.example.sajdour.fcg_sajdour, PID: 23620 
                       java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.sajdour.fcg_sajdour/com.example.sajdour.fcg_sajdour.UI.Videos}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.RecyclerView.setLayoutManager(android.support.v7.widget.RecyclerView$LayoutManager)' on a null object reference 
                        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3254) 
                        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3350) 
                        at android.app.ActivityThread.access$1100(ActivityThread.java:222) 
                        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1795) 
                        at android.os.Handler.dispatchMessage(Handler.java:102) 
                        at android.os.Looper.loop(Looper.java:158) 
                        at android.app.ActivityThread.main(ActivityThread.java:7229) 
                        at java.lang.reflect.Method.invoke(Native Method) 
                        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230) 
                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120) 
                        Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.RecyclerView.setLayoutManager(android.support.v7.widget.RecyclerView$LayoutManager)' on a null object reference 
                        at com.example.sajdour.fcg_sajdour.UI.Videos.onCreate(Videos.java:46) 
                        at android.app.Activity.performCreate(Activity.java:6876)

來源

2016-10-20 user3451238

的可能的複製[什麼是空指針異常，怎麼解決呢？（http://stackoverflow.com/questions/218384/what -is-a-nullpointerexception-and-how-do-i-fix-it） –

您的recyclerView爲空。在調用super.onCreate（）和setContentView（）之後初始化recyclerview – kcg

呦你應該創建網格佈局管理器：

recyclerView.setLayoutManager(new GridLayoutManager(this, 2));

關於錯誤。您的回收者視圖在onCreate（）中爲null。您應該在setContentView（）和recyclerView方法調用之前調用findViewById（R.id.myRecycler）。在你的情況下：

@Override 
protected void onCreate(Bundle savedInstanceState) { 

    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_videos); 

    recyclerView = (RecyclerView) findViewById(R.id.recyclerView); 

    recyclerView.setLayoutManager(new LinearLayoutManager(this)); 
    adapter = new CustomListViewAdapterV(Videos.this, videoList); 
    ... 
}

來源

2016-10-20 12:44:50

你的實際問題是，你正試圖做的東西在這兩個之前。這兩個應該來任何東西之前，以避免錯誤你有

super.onCreate(savedInstanceState); 
setContentView(R.layout.activity_videos);

所以，像這樣：

//A bunch of code 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
    //PAY ATTENTION HERE 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_videos); 

    recyclerView = (RecyclerView) findViewById(R.id.recyclerView); 
    recyclerView.setLayoutManager(new LinearLayoutManager(this)); 
    adapter = new CustomListViewAdapterV(Videos.this, videoList); 
    mSwipeRefreshLayout = (SwipeRefreshLayout) findViewById(R.id.activity_main_swipe_refresh_layout); 
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 

    //even more code

來源

2016-10-20 12:46:30

您recyclerView爲空。在調用super.onCreate（）& setContentView（）後初始化recyclerview。更改前5線在你的影片活動的onCreate方法

super.onCreate(savedInstanceState); 
setContentView(R.layout.activity_videos); 

recyclerView = (RecyclerView) findViewById(R.id.recyclerView); 
recyclerView.setLayoutManager(new LinearLayoutManager(this)); 
adapter = new CustomListViewAdapterV(Videos.this, videoList);

來源

2016-10-20 12:47:53 kcg

我如何在模式列表或網格中顯示我的列表

回答

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