Retrofit解析网页Json数据简单实例

Retrofit封装了从Web API下载数据，解析成一个普通的java对象（POJO），这里我们一个菜谱的API做简单演示，供大家一起学习思考。API文档网站http://www.tngou.net/doc/cook的菜谱API接口：http://www.tngou.net/api/cook/list

添加依赖

compile 'com.squareup.retrofit2:retrofit:2.1.0'    compile 'com.github.bumptech.glide:glide:3.7.0'    compile 'com.squareup.retrofit2:converter-gson:2.1.0'    compile 'com.android.support:recyclerview-v7:23.4.0'

网络请求接口

然后每一次使用都需要定义一个接口，用于下载网络数据，注意其中的{category}是为了之后更好的扩展性，我们定义一个未知的子目录，通过参数中指定可以访问固定的子目录

public interface Service {   @GET("/api/{category}/list")//网址下面的子目录   category表示分类，因为子目录只有一点不一样    Call<Tngou> getList(@Path("category") String path,                        @Query("id") int id,@Query("page") int page,@Query("row")int row);}

布局

1、自定义显示在Recycle日View的item

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="horizontal"    android:layout_width="match_parent"    android:layout_height="wrap_content">    <ImageView        android:layout_width="60dp"        android:layout_height="60dp"        android:src="@mipmap/ic_launcher"        android:id="@+id/iv_item"        />    <LinearLayout        android:orientation="vertical"        android:layout_gravity="center_vertical"        android:layout_width="0dp"        android:layout_weight="1"        android:layout_height="wrap_content">        <TextView        android:id="@+id/tv_title"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="title"        android:textAppearance="@android:style/TextAppearance.Large"        />        <TextView            android:id="@+id/tv_info"            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:text="title"            android:maxLines="2"            android:ellipsize="end"            />    </LinearLayout></LinearLayout>

2、主布局

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    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"    tools:context="jiang.rxjavaandvolloy.MainActivity">   <android.support.v7.widget.RecyclerView       android:id="@+id/rv_mian"       android:layout_width="match_parent"       android:layout_height="match_parent"       android:scrollbars="vertical"/></RelativeLayout>

实体Bean

public class Tngou {//加上注解    @SerializedName("status")    private boolean status;    @SerializedName("total")    private int total;    @SerializedName("tngou")    private List<Cook> list;    public boolean isStatus() {        return status;    }    public void setStatus(boolean status) {        this.status = status;    }    public int getTotal() {        return total;    }    public void setTotal(int total) {        this.total = total;    }    public List<Cook> getList() {        return list;    }    public void setList(List<Cook> list) {        this.list = list;    }}

public class Cook {    @SerializedName("id")    private int id;    @SerializedName("name")    private String name;//名称    @SerializedName("food")    private String food;//食物    @SerializedName("img")    private String img;//图片    @SerializedName("images")    private String images;//图片,    @SerializedName("description")    private String description;//描述    @SerializedName("keywords")    private String keywords;//关键字    @SerializedName("message")    private String message;//资讯内容    @SerializedName("count")    private int count;//访问次数    @SerializedName("fcount")    private int fcount;//收藏数    @SerializedName("rcount")    private int rcount;//评论读数    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getFood() {        return food;    }    public void setFood(String food) {        this.food = food;    }    public String getImg() {        return img;    }    public void setImg(String img) {        this.img = img;    }    public String getImages() {        return images;    }    public void setImages(String images) {        this.images = images;    }    public String getDescription() {        return description;    }    public void setDescription(String description) {        this.description = description;    }    public String getKeywords() {        return keywords;    }    public void setKeywords(String keywords) {        this.keywords = keywords;    }    public String getMessage() {        return message;    }    public void setMessage(String message) {        this.message = message;    }    public int getCount() {        return count;    }    public void setCount(int count) {        this.count = count;    }    public int getFcount() {        return fcount;    }    public void setFcount(int fcount) {        this.fcount = fcount;    }    public int getRcount() {        return rcount;    }    public void setRcount(int rcount) {        this.rcount = rcount;    }}

RecyclerView适配器

public class MyRvAdapter extends RecyclerView.Adapter<MyRvAdapter.MyViewHolder> {    private Context context;    private List<Cook> list;    public MyRvAdapter(Context context, List<Cook> list) {        this.context = context;        this.list = list;    }    @Override    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        return new MyViewHolder(LayoutInflater.from(parent.getContext())        .inflate(R.layout.item_content,parent,false));    }    @Override    public void onBindViewHolder(MyViewHolder holder, int position) {        Cook cook=list.get(position);        holder.tvTitle.setText(cook.getName());        holder.tvInfo.setText(cook.getDescription());        Glide.with(context)                .load("http://tnfs.tngou.net/img"+cook.getImg())                .into(holder.ivImg);    }    @Override    public int getItemCount() {        if(list!=null)        {            return list.size();        }        return 0;    }    class MyViewHolder extends RecyclerView.ViewHolder{        ImageView ivImg;        TextView tvTitle;        TextView tvInfo;         public MyViewHolder(View itemView) {             super(itemView);             ivImg= (ImageView) itemView.findViewById(R.id.iv_item);             tvTitle= (TextView) itemView.findViewById(R.id.tv_title);             tvInfo= (TextView) itemView.findViewById(R.id.tv_info);         }     }}

MainActivity

public class MainActivity extends AppCompatActivity implements Callback<Tngou> {    private RecyclerView rv;    private MyRvAdapter myRvAdapter;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        Retrofit retrofit=new Retrofit.Builder().baseUrl("http://www.tngou.net")                .addConverterFactory(GsonConverterFactory.create()).build();        Service service=retrofit.create(Service.class);        Call<Tngou> call=service.getList("cook",11,11,120);        call.enqueue(this);        rv= (RecyclerView) findViewById(R.id.rv_mian);        LinearLayoutManager lr=new LinearLayoutManager(this);        lr.setOrientation(OrientationHelper.VERTICAL);        rv.setLayoutManager(lr);        rv.setItemAnimator(new DefaultItemAnimator());    }    @Override    public void onResponse(Call<Tngou> call, Response<Tngou> response) {        List<Cook>  list=response.body().getList();        myRvAdapter=new MyRvAdapter(this,list);        rv.setAdapter(myRvAdapter);        LinearLayoutManager layoutManager = (LinearLayoutManager) rv.getLayoutManager();        //屏幕中最后一个可见子项的position//        int lastVisibleItemPosition = layoutManager.findLastVisibleItemPosition();//        //当前屏幕所看到的子项个数//        int visibleItemCount = layoutManager.getChildCount();//        //当前RecyclerView的所有子项个数//        int totalItemCount = layoutManager.getItemCount();//        int state = rv.getScrollState();//        if(visibleItemCount > 0 && lastVisibleItemPosition == totalItemCount - 1 && state == rv.SCROLL_STATE_IDLE){//            myRvAdapter.notifyDataSetChanged();//        }    }    @Override    public void onFailure(Call<Tngou> call, Throwable t) {    }}