Question

我使用ListView完美地工作，但决定更新我的代码以使用RecyclerView。

我看到没有默认实现，对类似问题的回答很老。

使用某种光标是最好的方法，还是有更好的选择？

这些是我的代码片段，用于处理具有硬编码值的RecyclerView：

MainActivity

    recyclerView = (RecyclerView)findViewById(R.id.recycler_view);
    mLayoutmanager = new LinearLayoutManager(this);
    recyclerView.setLayoutManager(mLayoutmanager);

    mAdapter = new recyclerViewDataAdapter();
    recyclerView.setAdapter(mAdapter);

recyclerViewDataAdapter

public class recyclerViewDataAdapter extends RecyclerView.Adapter {

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

        //lets populate our recyler view with the item created;
        //get the view from the layout inflator
        //  third parameter is set to false to prevent viewgroup to attach to root
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycler_item,parent,false);

        // as this method need to return the viewHolder type
        // need to convert our view to the view holder
        RecyclerView.ViewHolder viewHolder = new RecyclerView.ViewHolder(view) {
            @Override
            public String toString() {
                return super.toString();
            }
        };
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {

    }

    @Override
    public int getItemCount() {
        return 3000;
    }
}

activity_main

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

recycler_item

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="10dp"
    android:orientation="vertical">

    <TextView
        android:id="@+id/textView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Hii "
        android:textSize="30sp" />
</LinearLayout>

这是我的DatabaseAdapter，它与ListView完美配合：

public class DatabaseHelper extends SQLiteAssetHelper {

    private static final int DATABASE_VERSION = 1;

    private static final String DATABASE_NAME = "database9.db";
    private static final String BOOKS = "books";
    private static final String AUTHORS = "authors";

    public DatabaseHelper (Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        // setForcedUpgrade();
    }

    // Getting all books
    public ArrayList<Author> getAllAuthors() {

        ArrayList<Author> authorList = new ArrayList<>();

        // Select all query
        String selectQuery = "SELECT id, name FROM " + AUTHORS + " ORDER BY name_alphabetic";

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

        // looping through all rows and adding to list
        if (cursor.moveToFirst()) {
            do {
                // create new author object
                Author author = new Author();
                // set ID and name of author object
                author.setID(Integer.parseInt(cursor.getString(0)));
                author.setName(cursor.getString(1));
                // pass author object to authorList array
                authorList.add(author);
            } while (cursor.moveToNext());
        }

        // return author list
        return authorList;
    }
}

Answer 1

你可以尝试

在您的活动中

ArrayList<Author> authors = dbHandler. getAllAuthors();
recyclerView.setHasFixedSize(true);

// ListView
recyclerView.setLayoutManager(new LinearLayoutManager(youractivity.this));


// create an Object for Adapter
CardViewDataAdapter1  mAdapter = new CardViewDataAdapter1(authors);

// set the adapter object to the Recyclerview
recyclerView.setAdapter(mAdapter);

您的适配器看起来像

 class CardViewDataAdapter1 extends RecyclerView.Adapter<CardViewDataAdapter1.ViewHolder> {
   private ArrayList<Author> dataSet;


public CardViewDataAdapter1(ArrayList<Author> os_versions) {

    dataSet = os_versions;
}


@Override
public CardViewDataAdapter1.ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
  // create a new view
    View itemLayoutView = LayoutInflater.from(viewGroup.getContext()).inflate(
            R.layout.recycler_item, null);

    itemLayoutView.setLayoutParams(new RecyclerView.LayoutParams(RecyclerView.LayoutParams.MATCH_PARENT, RecyclerView.LayoutParams.WRAP_CONTENT));

    // create ViewHolder

    CardViewDataAdapter1.ViewHolder viewHolder = new CardViewDataAdapter1.ViewHolder(itemLayoutView);

    return viewHolder;
}

@Override
public void onBindViewHolder(CardViewDataAdapter1.ViewHolder viewHolder, int i) {

    Author fp = dataSet.get(i);

    viewHolder.tv_name.setText(fp.getName());




    viewHolder.menu = fp;
}

@Override
public int getItemCount() {

    return dataSet.size();
}

public void updateList(List<Author> temp) {
    dataSet = (ArrayList<Author>) temp;
    notifyDataSetChanged();
}

// inner class to hold a reference to each item of RecyclerView
public  class ViewHolder extends RecyclerView.ViewHolder {

    public TextView tv_name;


    public Author menu;
    public ViewHolder(View itemLayoutView) {
        super(itemLayoutView);

        tv_name = (TextView) itemLayoutView  .findViewById(R.id.tv_name);


       }

   }
 }

您的recycler_item.xml

<?xml version="1.0" encoding="utf-8"?>
   <android.support.v7.widget.CardView 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"
  card_view:cardCornerRadius="5dp"
 card_view:cardBackgroundColor="#FFFFFF"
    card_view:cardUseCompatPadding="true"
   >
<LinearLayout
  android:layout_width="match_parent"
   android:layout_height="wrap_content"
   android:orientation="vertical">
    <TextView
        android:id="@+id/tv_name"
        android:layout_width="match_parent"
         android:layout_height="wrap_content"
        android:text="Enamul"/>

 </LinearLayout>

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

在RecyclerView中显示数据

1 个答案: