Question

我正在尝试在MainActivity上显示我的recyclerView，但似乎无法做到。这是我的代码:(编译没有错误）

private RecyclerView recyclerView;
private MyAdapter adapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


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

    adapter = new MyAdapter(this, getData());

    recyclerView.setAdapter(adapter);


    // Add Code to display recyclerView on Main...
}

// This is not my actual data, just testing it out
public static List<Block> getData() {
    List<Block> data = new ArrayList<>();
    String[] ids = {"310", "313", "320"};
    String[] names = {"name of three ten", "name of three thirteen", "name of three twenty"};
    for (int i=0; i<ids.length; i++) {
        data.add(new Block(ids[i], names[i]));
    }
    return data;
}

myActivity Class：

private final LayoutInflater inflater;

// Data: (information)
List<Block> data = new ArrayList<>();

public MyAdapter(Context context, List<Block> data) {
    inflater = LayoutInflater.from(context);
    this.data = data;
}

@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = inflater.inflate(R.layout.block, parent, false);
    MyViewHolder holder = new MyViewHolder(view);
    return holder;
}

@Override
public void onBindViewHolder(RecyclerView.ViewHolder h, int position) {
    MyViewHolder holder = new MyViewHolder(h.itemView);
    Block current = data.get(position);
    holder.id.setText(current.getId());
    holder.name.setText(current.getName());

}

@Override
public int getItemCount() {
    return 0;
}

class MyViewHolder extends RecyclerView.ViewHolder {
    TextView id;
    TextView name;
    Button button;

    // Constructor
    public MyViewHolder(View itemView) {
        super(itemView);
        id = (TextView) itemView.findViewById(R.id.the_course_id);
        name = (TextView) itemView.findViewById(R.id.course_name);
        button = (Button) itemView.findViewById(R.id.click);

    }
}

}

我现在要做的就是当我运行模拟器时，我会看到recyclerView的内容。但是，我一直坚持这一点，因为似乎没有任何效果。请注意，我是Android的初学者，请原谅我，如果这非常简单。

Answer 1

您应该在getItemCount中返回列表中的项目数，如下所示：

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

Answer 2

将onBindViewHolder更改为：

@Override
public void onBindViewHolder(RecyclerView.ViewHolder h, int position) {
    Block current = data.get(position);
    h.id.setText(current.getId());
    h.name.setText(current.getName());

}

还将@SelçukCihan解决方案添加到此

修改

此外，如果您想使用MyViewHolder，则必须更改以下内容：

首先改变班级签名：

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder>

并且还更改onBindViewHolder的签名：

public void onBindViewHolder(MyViewHolder h, int position)

最后更改MyViewHolder类的签名：

static class MyViewHolder extends RecyclerView.ViewHolder

Answer 3

好的，您需要更改以下内容：更新 -

recyclerView.setLayoutManager(new LinearLayoutManager(this));

to

recyclerView.setLayoutManager(new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false));

并在适配器类中更改：

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

就是这样。快乐的编码：）

在MainActivity上显示recyclerView

3 个答案: