Question

这是我第一次实施RecyclerView。

我正在尝试从数据库中检索数据，然后实例化一个名为服务的类，该类将用于动态创建CardView以作为项目显示在RecyclerView中。 RecyclerView是Fragment类的一部分。

Fragment类：

package com.alsowaygh.getitdone.view.services;

import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.widget.CardView;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

import com.alsowaygh.getitdone.R;
import com.alsowaygh.getitdone.controller.service.QueryServices;
import com.alsowaygh.getitdone.controller.service.Service;

import java.util.ArrayList;

public class ServicesListFragment extends Fragment {
    private RecyclerView mRecyclerView;
    private RecyclerView.Adapter mAdapter;
    private CardView mServiceCardView;
    private RecyclerView.LayoutManager mLayoutManager;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View rootView = inflater.inflate(R.layout.services_list_fragment, container, false);

        mRecyclerView = rootView.findViewById(R.id.services_recycler_view);
        mServiceCardView = rootView.findViewById(R.id.service_card_view);
        mLayoutManager = new LinearLayoutManager(rootView.getContext());
        mRecyclerView.setLayoutManager(mLayoutManager);

        //retreive argument from CategoriesListFragment (selected)
        String selectedCategory = getArguments().getString("category");

        //Query services for selected category
        QueryServices queryServices = new QueryServices();
        ArrayList<Service> services = queryServices.getServicesForCategory(selectedCategory);


        mAdapter = new ServiceListAdapter(services);
        mRecyclerView.setAdapter(mAdapter);

        return rootView;
    }

}

片段布局包括Recycler View：

<LinearLayout android:id="@+id/categories_list_fragment"
    android:name="com.alsowaygh.getitdone.view.services.ServicesListFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_marginBottom="8dp"
    android:layout_marginTop="8dp"
    xmlns:android="http://schemas.android.com/apk/res/android">

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

</LinearLayout>

适配器类这是我卡住的地方，代码不完整：

package com.alsowaygh.getitdone.view.services;

import android.support.annotation.NonNull;
import android.support.v7.widget.CardView;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.alsowaygh.getitdone.R;
import com.alsowaygh.getitdone.controller.service.Service;

import java.util.ArrayList;

public class ServiceListAdapter extends RecyclerView.Adapter {


    private ArrayList<Service> mServices;

    public static class ViewHolder extends RecyclerView.ViewHolder{

        public ViewHolder(View itemView) {
            super(itemView);
        }
    }

    public ServiceListAdapter(ArrayList<Service> services){
        mServices = services;
    }

    @NonNull
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        // create a new view
        CardView v = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.list_item_service, parent, false);
    }

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

    }

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

布局，包括必须添加到RecyclerView的CardView

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto"
        android:id="@+id/service_card_view"
        android:layout_width="match_parent"
        android:layout_height="140dp"
        android:layout_gravity="center"
        card_view:cardBackgroundColor="@color/defaultActivityBackground"
        card_view:cardCornerRadius="10dp"
        card_view:contentPadding="5dp">

        <TextView
            android:id="@+id/title"
            style="@style/item_list_service_title_text_style"
            android:layout_width="221dp"
            android:layout_height="40dp"
            android:layout_gravity="top"
            android:layout_marginLeft="10dp"
            android:gravity="center_vertical"
            android:text="Service Title" />

        <TextView
            android:id="@+id/providerName"
            style="@style/item_list_service_detail_text_style"
            android:layout_width="221dp"
            android:layout_height="40dp"
            android:layout_gravity="center_vertical"
            android:layout_marginLeft="10dp"
            android:gravity="center_vertical"
            android:text="Provider Name" />

        <TextView
            android:id="@+id/price"
            style="@style/item_list_service_detail_text_style"
            android:layout_width="221dp"
            android:layout_height="38dp"
            android:layout_gravity="bottom"
            android:layout_marginLeft="10dp"
            android:gravity="center_vertical"
            android:text="Price" />

        <ImageView
            android:id="@+id/imageView"
            android:layout_width="141dp"
            android:layout_height="140dp"
            android:layout_gravity="right"
            android:tint="@color/colorAccent"
            android:background="@android:color/white"
            app:srcCompat="@drawable/service_image_placeholder" />
    </android.support.v7.widget.CardView>
</LinearLayout>

我不知道如何将各种东西放在一起，以便在RecyclerView中动态嵌入CardView

非常感谢您的帮助..

Answer 1

让我先开始帮助您onCreateViewHolder()和onBindViewHolder()

@NonNull
@Override
public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    // create a new view
    View v = LayoutInflater.from(parent.getContext())
            .inflate(R.layout.list_item_service, parent, false);
    return new MyViewHolder(v);
    }

另外，

@Override
public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
    MyViewHolder holder1 = (MyViewHolder) holder;
    holder1.titleTextView.setText("...");
    //Set the rest of UI elements the same way
    }

现在，将MyViewHolder这样的ViewHolder类替换为

public static class MyViewHolder extends RecyclerView.ViewHolder{

    TextView titleTextView;
    //Create the other UI elements here for use in onBindViewHolder()

    public ViewHolder(View itemView) {
        super(itemView);

        titleTextView = itemView.findViewById(R.id.text_view_title);
        //Initialise other UI elements here
    }
}

随时问你是否被困在任何地方。

如何在RecyclerView中动态添加CardView？

1 个答案: