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"
/>
<Tex
1052a
tView
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) {

}
}