卡片视图不可见

我想添加卡片视图与回收站视图。但它没有显示任何内容，只是一个空白的视图。卡片视图不可见

我在这里看到了这方面的问题，它有回答为回收者视图和卡视图添加依赖关系。这是在我的gradle中。另一种是用getItemCount这样的：

@Override 
    public int getItemCount() { 
     return mImage.length; 
    }

这也是我认为是对的我已经使用则为list.size（）; 我不明白发生了什么事。我想从数据库中检索数据，可能会出错。任何人都可以请帮忙。

TableListAdapter

public class TableListAdapter extends RecyclerView.Adapter<TableListAdapter.TableViewHolder> { 

    TimeTableHelper db; 

    private List<TimeTable> List; 

    public TableListAdapter(List<TimeTable> List) { 
      this.List = List; 
    } 

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

    @Override 
    public void onBindViewHolder(TableViewHolder contactViewHolder, int i) { 

     TimeTable table = db.getTables(i); 
     TimeTable ci = List.get(i); 
     contactViewHolder.tableTitle.setText(table.getTitle()); 
    } 

    @Override 
    public TableViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) { 
     View itemView = LayoutInflater. 
        from(viewGroup.getContext()). 
        inflate(R.layout.table_card, viewGroup, false); 

     return new TableViewHolder(itemView); 
    } 

    public static class TableViewHolder extends RecyclerView.ViewHolder { 

     protected TextView tableTitle; 
     protected CardView cv; 
     protected Switch aSwitch; 


     public TableViewHolder(View v) { 
      super(v); 
      tableTitle = (TextView) v.findViewById(R.id.tableTitle); 
      cv = (CardView) v.findViewById(R.id.card_view); 
      aSwitch = (Switch) v.findViewById(R.id.switch2); 
     } 
    } 
}

TimeTableList活动

public class TimeTableList extends AppCompatActivity { 

    private RecyclerView recyclerView; 
    public ArrayList<TimeTable> items; 
    public TableListAdapter adapter; 


    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_time_table_list); 
     Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
     toolbar.setTitle("Time Table"); 
     toolbar.setTitleTextColor(Color.parseColor("#FFFFFF")); 

     toolbar.setNavigationIcon(R.drawable.ic_arrow_back_white_24dp); 
     setSupportActionBar(toolbar); 
     toolbar.setNavigationOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       onBackPressed(); 
      } 
     }); 

     recyclerView = (RecyclerView)findViewById(R.id.RecyclerView); 
     LinearLayoutManager llm = new LinearLayoutManager(this); 

     items=new ArrayList<>(); 
     recyclerView.setLayoutManager(llm); 

     recyclerView.setHasFixedSize(true); 

     initRecyclerAdapter(); 

     ImageButton fab = (ImageButton) findViewById(R.id.imgbtn_fab); 
     fab.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 
       Intent i = new Intent(getApplicationContext(),NewTimeTable.class); 
       startActivity(i); 
      } 
     }); 
    } 

    private void initRecyclerAdapter() { 
     adapter = new TableListAdapter(items); 
     recyclerView.setAdapter(adapter); 
    } 
}

列表XML布局：

<?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:fitsSystemWindows="true" 
    tools:context="com.example.siddhi.timetablelayout.activities.TimeTableList"> 

    <android.support.design.widget.AppBarLayout android:layout_height="wrap_content" 
     android:layout_width="match_parent" android:theme="@style/AppTheme.AppBarOverlay" 
     android:id="@+id/view5"> 

     <android.support.v7.widget.Toolbar android:id="@+id/toolbar" 
      android:layout_width="match_parent" android:layout_height="?attr/actionBarSize" 
      android:background="?attr/colorPrimary" app:popupTheme="@style/AppTheme.PopupOverlay" 
      app:titleTextAppearance="@style/Toolbar.TitleText"/> 

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

    <android.support.v7.widget.RecyclerView 
     android:layout_height="match_parent" 
     android:layout_width="match_parent" 
     android:id="@+id/RecyclerView" 
     android:background="@android:color/white" 
     android:layout_below="@+id/view5" /> 
    <LinearLayout 
     android:orientation="horizontal" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignParentBottom="true" 
     android:layout_alignParentEnd="true" 
     android:layout_alignParentRight="true" 
     android:layout_gravity="bottom|end"> 

     <include layout="@layout/myfab"/> 
    </LinearLayout> 
</RelativeLayout>

table_card XML：

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:card_view="http://schemas.android.com/apk/res-auto" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:weightSum="1" 
    android:orientation="vertical" 
    android:measureWithLargestChild="false"> 
    <!-- A CardView that contains a TextView --> 

    <android.support.v7.widget.CardView 
     xmlns:card_view="http://schemas.android.com/apk/res-auto" 
     android:id="@+id/card_view" 
     android:layout_width="match_parent" 
     android:layout_height="60dp" 
     card_view:cardCornerRadius="4dp" 
     android:layout_marginLeft="10dp" 
     android:layout_marginRight="10dp" 
     android:layout_marginTop="10dp"> 

     <RelativeLayout 
      android:layout_width="match_parent" 
      android:layout_height="match_parent" 
      android:background="@android:color/white"> 

      <TextView 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:layout_centerVertical="true" 
       android:layout_marginLeft="20dp" 
       android:textAppearance="@android:style/TextAppearance.Medium" 
       android:id="@+id/tableTitle" /> 

      <Switch 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:id="@+id/switch2" 
       android:layout_centerVertical="true" 
       android:layout_alignParentRight="true" 
       android:layout_alignParentEnd="true" 
       android:layout_marginRight="20dp" /> 


     </RelativeLayout> 

     </android.support.v7.widget.CardView> 

</LinearLayout>

摇篮：

apply plugin: 'com.android.application' 

android { 
    compileSdkVersion 23 
    buildToolsVersion '23.0.1' 

    defaultConfig { 
     applicationId "com.example.siddhi.timetablelayout" 
     minSdkVersion 16 
     targetSdkVersion 23 
     versionCode 1 
     versionName "1.0" 
    } 
    buildTypes { 
     release { 
      minifyEnabled false 
      proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' 
     } 
    } 
} 

dependencies { 
    compile fileTree(include: ['*.jar'], dir: 'libs') 
    compile 'com.android.support:design:23.1.1' 
    compile 'com.android.support:appcompat-v7:23.1.1' 
    compile 'com.android.support:cardview-v7:23.1.1' 
    compile 'com.android.support:recyclerview-v7:23.1.1' 
    compile 'com.google.android.gms:play-services:8.3.0' 
    compile 'com.google.android.gms:play-services-wearable:8.3.0' 
    compile 'com.google.android.gms:play-services-maps:7.5.0' 
    compile 'com.google.android.support:wearable:1.3.0' 
}

TimeTableHelper：

public class TimeTableHelper extends SQLiteOpenHelper{ 


    private static final String TABLE_TIME_TABLE = "timetables"; 
    private static final String KEY_TABLE_TITLE = "tabletitle"; 
    private static final String KEY_STATUS = "status"; 
    private static final String KEY_TABLE_ID = "tableid"; 
    private static final String KEY_TABLE_COLOR = "tablecolor"; 

    public TimeTableHelper(Context context) { 
     super(context, Constants.DATABASE_NAME, null, Constants.DATABASE_VERSION); 

    } 


    @Override 
    public void onCreate(SQLiteDatabase db) { 
    } 
    @Override 
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 

     db.execSQL("DROP TABLE IF EXISTS " + TABLE_TIME_TABLE); 

     // createTable(db); 
     // onCreate(db); 
    } 
    public void addTimeTable(TimeTable table) { 
     SQLiteDatabase db = this.getWritableDatabase(); 

     ContentValues values = new ContentValues(); 

     values.put(KEY_TABLE_TITLE, table.getTitle()); 
     values.put(KEY_STATUS, table.getStatus()); 
     values.put(KEY_TABLE_COLOR, table.getTableColor()); 

     db.insert(TABLE_TIME_TABLE, null, values); 

     db.close(); 
    } 

    public TimeTable getTables(int id) { 

     SQLiteDatabase db = this.getReadableDatabase(); 

     Cursor cursor = db.query(TABLE_TIME_TABLE, new String[] { KEY_TABLE_ID, 
         KEY_TABLE_TITLE, KEY_TABLE_COLOR ,KEY_STATUS}, KEY_TABLE_ID + "=?", 
       new String[] { String.valueOf(id) }, null, null, null, null); 

     cursor.moveToFirst(); 

     TimeTable table = new TimeTable(Integer.parseInt(cursor.getString(0)), 
       cursor.getString(1), Integer.parseInt(cursor.getString(2)),Integer.parseInt(cursor.getString(3))); 

     return table; 

    } 

    public List<TimeTable> getAllTables() { 
     List<TimeTable> conList = new ArrayList<TimeTable>(); 

     String selectQuery = "SELECT * FROM " + TABLE_TIME_TABLE; 

     SQLiteDatabase db = this.getWritableDatabase(); 
     Cursor cursor = db.rawQuery(selectQuery, null); 

     if (cursor.moveToFirst()) { 
      do { 

       TimeTable table = new TimeTable(); 

       table.setId(Integer.parseInt(cursor.getString(0))); 
       table.setTitle(cursor.getString(1)); 
       table.setStatus(cursor.getInt(2)); 
       table.setTableColor(Integer.parseInt(cursor.getString(3))); 

       conList.add(table); 
      } while (cursor.moveToNext()); 
     } 

     return conList; 
    } 
}

创建表：

String CREATE_TIME_TABLE = "CREATE TABLE " + TABLE_TIME_TABLE + "(" 
      + KEY_TABLE_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," 
      + KEY_TABLE_TITLE + " TEXT," 
      + KEY_STATUS + " TEXT," 
      + KEY_TABLE_COLOR + " TEXT" + ")"; 

    db.execSQL(CREATE_TIME_TABLE);

谢谢。

来源

2016-03-02 Sid

'私人列表清单;'只是从我身边有轻微强迫症的问题，但请不要使用Pascal大小写命名变量名，唯一的类名应该有名字以大写字母 – Bhargav

开头在'onCreateViewHolder（）'中，您正在为'R.layout.table_card'充气，但您已在此发布'card.xml'代码，您是否也可以在此处发布'table_card.xml'文件的代码 – Bhargav

只有table_card。对不起，我会编辑名称。@ Bhargav – Sid

你没有添加的内容调用它，因为我可以在你的代码中看到的，这就是为什么它显示空白因为当时的清单大小为ZERO。

您刚刚初始化您的列表并设置适配器。在初始化适配器之前，在列表中添加一些数据。

您的代码

recyclerView = (RecyclerView)findViewById(R.id.RecyclerView); 
     LinearLayoutManager llm = new LinearLayoutManager(this); 

     items=new ArrayList<>(); // **Add data to list after initialization** 
     recyclerView.setLayoutManager(llm); 

     recyclerView.setHasFixedSize(true); 

     initRecyclerAdapter(); 

     ImageButton fab = (ImageButton) findViewById(R.id.imgbtn_fab); 
     fab.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 
       Intent i = new Intent(getApplicationContext(),NewTimeTable.class); 
       startActivity(i); 
      } 
     });

来源

2016-03-02 06:01:35

我改变了这个timeTableHelper = new TimeTableHelper（this）; items = new ArrayList （timeTableHelper.getAllTables（））; ,,,,工作...比你.. @ Anuj Sharma – Sid

干杯！快乐编码:) –

从我所看到的，要传递一个空列表进入TimeTableList（活动）的TableListAdapter。由于在创建适配器期间列表大小为0，因此不会为RecyclerView创建任何cardView。

要么你应该添加一些数据点到列表中创建实例的TableListAdapter

前TableListAdapter有一个公共无效updateRecyclerAdapter（名单itemList中），你可以调用后创建适配器的实例。该方法可以可能类似于下面的代码

public void updateAdapaterList(List<TimeTable> newTimeTableList) { 
    //Replace the current list with new list 
    this.List = newTimeTableList; 
    //notify the adapter that the data set has changed 
    notifyDataSetChanged(); 
}

ALSO

确保你重写getItemCount()方法在RecyclerAdapter如下。

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

而且我会强烈建议使用合适的驼峰规则而编码。:)

来源

2016-03-02 05:49:12

我试过使用updateRecyclerAdapter，但没有工作.. @ Vaibhav Singhal – Sid

你重写了getItemCount（）方法来返回timeTableList的大小吗？ –

是的，我已经做了.. @Override public int getItemCount（）{ return tableList.size（）; } – Sid

从你的代码我所看到的就是你忘了的数据点添加到items变量

只要改变你的活动代码到这一点，在这里我也做了改变，通过添加给出@VaibhavSinghal功能更新您的回收观点适配器，然后通过传递你的列表中，您从TimeTableHelper.getAllTables（获取列表）

public class TimeTableList extends AppCompatActivity { 

    private RecyclerView recyclerView; 
    public ArrayList<TimeTable> items; 
    public TableListAdapter adapter; 


    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_time_table_list); 
     Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
     toolbar.setTitle("Time Table"); 
     toolbar.setTitleTextColor(Color.parseColor("#FFFFFF")); 

     toolbar.setNavigationIcon(R.drawable.ic_arrow_back_white_24dp); 
     setSupportActionBar(toolbar); 
     toolbar.setNavigationOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       onBackPressed(); 
      } 
     }); 

     recyclerView = (RecyclerView)findViewById(R.id.RecyclerView); 
     LinearLayoutManager llm = new LinearLayoutManager(this); 

     items=new ArrayList<>(); 
     recyclerView.setLayoutManager(llm); 

     recyclerView.setHasFixedSize(true); 

     initRecyclerAdapter(); 
     // Get reference to your time tableHelper 
     TimeTableHelper timeTableHelper = new TimeTableHelper(this); 
     // Update your adapter with elements returned by getAllTables() function 
     updateAdapterList(timeTableHelper.getAllTables()); 

     ImageButton fab = (ImageButton) findViewById(R.id.imgbtn_fab); 
     fab.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 
       Intent i = new Intent(getApplicationContext(),NewTimeTable.class); 
       startActivity(i); 
      } 
     }); 
    } 

    private void initRecyclerAdapter() { 
     adapter = new TableListAdapter(items); 
     recyclerView.setAdapter(adapter); 
    } 

    public void updateAdapaterList(List<TimeTable> newTimeTableList) { 
     //Replace the current list with new list 
     this.List = newTimeTableList; 
     //notify the adapter that the data set has changed 
     notifyDataSetChanged(); 
    } 


}

来源

2016-03-02 05:56:43 Bhargav

谢谢你..总结所有的答案和工作.. :-) @Bhargav – Sid

卡片视图不可见

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