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) { } }