安卓 牛刀初试

前言

因工作需要，学了点安卓知识。现在已经能写点简单页面，解析数据并展示，但是老是忘记，卡壳。特整理一下并记录要点。

正题

一、所需框架

1.okHttp  网络请求
2.Gson   字符串转Json
3.GsonFormat  Json转Bean
4.Glide 加载图片

二、特殊配置
由于我这里用到的是http请求 需要特殊配置

manifest 文件添加配置

   //允许网络访问
  <uses-permission android:name="android.permission.INTERNET"></uses-permission>  
 // http请求需额外设置网络安全配置
 <application
        android:networkSecurityConfig="@xml/net_work_config"                  
        .../>
//新建net_work_config文件 配置明文访问权限
<network-security-config>
    <base-config cleartextTrafficPermitted="true" />
</network-security-config>

三、进入正题

• Activity 核心代码

public class HomeActivity extends AppCompatActivity {
    private OkHttpClient okHttpClient;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home);
        initData();
    }

    /*初始化数据*/
    private void initData() {
        okHttpClient = new OkHttpClient();
        //1.创建请求
        Request request = new Request.Builder().url("http://v.juhe.cn/toutiao/index?key=160f6a145f32d7c5410a2437923e01ea").build();
        Call call = okHttpClient.newCall(request);
        //2.异步发送请求
        call.enqueue(new Callback() {
            @Override
            public void onFailure(@NonNull Call call, @NonNull IOException e) {
                Log.i("test",e.getMessage());
            }

            //2.1  数据处理      
            @Override
            public void onResponse(@NonNull Call call, @NonNull Response response) throws IOException {
                //2.2 Json反序列化
                Gson gson = new Gson();
                NewsBean newsBean = gson.fromJson(response.body().string(),NewsBean.class);
                //2.3 刷新UI
                HomeActivity.this.runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        RecyclerView rv = findViewById(R.id.rv);
                        rv.setLayoutManager(new LinearLayoutManager(HomeActivity.this));
                        rv.setAdapter(new MyHomeAdapter(newsBean.getResult().getData(),HomeActivity.this));
                    }
                });
            }
        });
    }
}

• Adapter 核心代码

public class MyHomeAdapter extends RecyclerView.Adapter<MyHomeAdapter.MyViewHolder> {

    private List<NewsBean.ResultBean.DataBean> dataBeans;
    private Context context;
    //构造函数
    public MyHomeAdapter(List<NewsBean.ResultBean.DataBean> dataBeans, Context context) {
        this.dataBeans = dataBeans;
        this.context = context;
    }

    //将home_recycler绑定给MyViewHolder
    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = View.inflate(context,R.layout.home_recycler,null);
        return new MyViewHolder(view);
    }

    //填充展示数据
    @Override
    public void onBindViewHolder(@NonNull MyViewHolder holder, @SuppressLint("RecyclerView") int position) {
        NewsBean.ResultBean.DataBean dataBean = dataBeans.get(position);
        holder.tv_title.setText(dataBean.getTitle());
        holder.tv_desc.setText(dataBean.getAuthor_name() + "        " +dataBean.getDate());
        Glide.with(context).load(dataBean.getThumbnail_pic_s()).into(holder.iv);
        
        //监听点击事件
        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(context,"点击了"+position+"行",Toast.LENGTH_LONG).show();
            }
        });
    }
    
    @Override
    public int getItemCount() {
        return dataBeans.size();
    }

    //MyViewHolder 处理   将MyViewHolder持有控件 和home_recycler内部控件一一关联
    protected class MyViewHolder extends RecyclerView.ViewHolder{

        private ImageView iv;
        private TextView tv_title;
        private TextView tv_desc;

        public MyViewHolder(@NonNull View itemView) {
            super(itemView);
            this.iv =  itemView.findViewById(R.id.iv);
            this.tv_title =  itemView.findViewById(R.id.tv_title);
            this.tv_desc =  itemView.findViewById(R.id.tv_desc);
        }
    }
}

• Bean 的处理

通过GsonFormat  生成 Bean代码

四、成品展示

1.gif