Android网络开发之Volley--Volley自定义Request

1、自定义一个解析Json的Request，这里使用JackSon框架来解析Json。你也可以自定义一个解析XML的Request，或者使用FastSon来解析Json。

2、我们首先来看一下StringRequest的源码。继承自Request<T>，主要是重写parseNetworkResponse()和deliverResponse()方法。

public class StringRequest extends Request<String> {
    private final Listener<String> mListener;

    /**
     * Creates a new request with the given method.
     *
     * @param method the request {@link Method} to use
     * @param url URL to fetch the string at
     * @param listener Listener to receive the String response
     * @param errorListener Error listener, or null to ignore errors
     */
    public StringRequest(int method, String url, Listener<String> listener,
            ErrorListener errorListener) {
        super(method, url, errorListener);
        mListener = listener;
    }

    /**
     * Creates a new GET request.
     *
     * @param url URL to fetch the string at
     * @param listener Listener to receive the String response
     * @param errorListener Error listener, or null to ignore errors
     */
    public StringRequest(String url, Listener<String> listener, ErrorListener errorListener) {
        this(Method.GET, url, listener, errorListener);
    }

    @Override
    protected void deliverResponse(String response) {
        mListener.onResponse(response);
    }

    @Override
    protected Response<String> parseNetworkResponse(NetworkResponse response) {
        String parsed;
        try {
            parsed = new String(response.data, HttpHeaderParser.parseCharset(response.headers));
        } catch (UnsupportedEncodingException e) {
            parsed = new String(response.data);
        }
        return Response.success(parsed, HttpHeaderParser.parseCacheHeaders(response));
    }
}

3、首先定义实体类

public class Weather {
    private WeatherInfo weatherinfo;

    public WeatherInfo getWeatherinfo() {
        return weatherinfo;
    }

    @JsonProperty("weatherinfo")
    public void setWeatherinfo(WeatherInfo weatherinfo) {
        this.weatherinfo = weatherinfo;
    }

}

public class WeatherInfo {
    private String city;
    private String cityid;
    private String temp;
    private String WD;
    private String WS;
    private String SD;
    private String WSE;
    private String time;
    private String isRadar;
    private String Radar;
    private String njd;
    private String qy;

    public String getCity() {
        return city;
    }

    @JsonProperty("city")
    public void setCity(String city) {
        this.city = city;
    }

    public String getCityid() {
        return cityid;
    }

    @JsonProperty("cityid")
    public void setCityid(String cityid) {
        this.cityid = cityid;
    }

    public String getTemp() {
        return temp;
    }

    @JsonProperty("temp")
    public void setTemp(String temp) {
        this.temp = temp;
    }

    public String getWD() {
        return WD;
    }

    @JsonProperty("WD")
    public void setWD(String wD) {
        WD = wD;
    }

    public String getWS() {
        return WS;
    }

    @JsonProperty("WS")
    public void setWS(String wS) {
        WS = wS;
    }

    public String getSD() {
        return SD;
    }

    @JsonProperty("SD")
    public void setSD(String sD) {
        SD = sD;
    }

    public String getWSE() {
        return WSE;
    }

    @JsonProperty("WSE")
    public void setWSE(String wSE) {
        WSE = wSE;
    }

    public String getTime() {
        return time;
    }

    @JsonProperty("time")
    public void setTime(String time) {
        this.time = time;
    }

    public String getIsRadar() {
        return isRadar;
    }

    @JsonProperty("isRadar")
    public void setIsRadar(String isRadar) {
        this.isRadar = isRadar;
    }

    public String getRadar() {
        return Radar;
    }

    @JsonProperty("Radar")
    public void setRadar(String radar) {
        Radar = radar;
    }

    public String getNjd() {
        return njd;
    }

    @JsonProperty("njd")
    public void setNjd(String njd) {
        this.njd = njd;
    }

    public String getQy() {
        return qy;
    }

    @JsonProperty("qy")
    public void setQy(String qy) {
        this.qy = qy;
    }

}

4、实现JacksonRequest

public class JacksonRequest<T> extends Request<T>{
    private final Listener<T> mListener;

    private Class<T> mClass;

    private static ObjectMapper objectMapper = new ObjectMapper();

    public JacksonRequest(int method, String url, Class<T> clazz, Listener<T> listener, ErrorListener errorListener) {
        super(method, url, errorListener);
        // TODO Auto-generated constructor stub
        mListener = listener;
        mClass = clazz;
    }

    public JacksonRequest(String url, Class<T> clazz, Listener<T> listener, ErrorListener errorListener){
        this(Method.GET, url, clazz, listener, errorListener);
    }

    @Override
    protected Response<T> parseNetworkResponse(NetworkResponse response) {
        // TODO Auto-generated method stub
        try {
            String jsonString = new String(response.data, HttpHeaderParser.parseCharset(response.headers));
            return Response.success(objectMapper.readValue(jsonString, mClass), HttpHeaderParser.parseCacheHeaders(response));
        } catch (UnsupportedEncodingException e) {
            // TODO Auto-generated catch block
            return Response.error(new ParseError(e));
        } catch (JsonParseException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (JsonMappingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return null;
    }

    @Override
    protected void deliverResponse(T response) {
        // TODO Auto-generated method stub
        mListener.onResponse(response);
    }

}

5、Jackson的使用，和StringRequest的使用是一样的。

public class JacksonActivity extends Activity {
    private RequestQueue requestQueue;

    private TextView mTvShow;

    private String result = "";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_jackson);

        initView();
    }

    public void initView(){
        mTvShow = (TextView) findViewById(R.id.tv_jackson);

        requestQueue = Volley.newRequestQueue(getBaseContext());
        requestQueue.add(jacksonRequest);
        requestQueue.start();
    }

    private JacksonRequest<Weather> jacksonRequest = new JacksonRequest<Weather>("http://www.weather.com.cn/data/sk/101010100.html",
            Weather.class,
            new Response.Listener<Weather>() {

                @Override
                public void onResponse(Weather response) {
                    // TODO Auto-generated method stub
                    WeatherInfo info = response.getWeatherinfo();
                    result += info.getCity() + "\n" + info.getTemp() + "\n" +info.getTime();
                    mTvShow.setText(result);
                }
            }, new Response.ErrorListener(){

                @Override
                public void onErrorResponse(VolleyError error) {
                    // TODO Auto-generated method stub
                    mTvShow.setText(error.toString());
                }

            });
}

6、不要忘记加入网络访问权限

<uses-permission android:name="android.permission.INTERNET"/>

7、参考博文：

http://blog.csdn.net/guolin_blog/article/details/17482095/