OkHttp 库 - 简单帖子上的 NetworkOnMainThreadException

Question

我想在 Android 中使用OkHttp 库进行网络连接。 我从他们网站上写的简单帖子示例开始：

public static final MediaType JSON = MediaType.parse("application/json; charset=utf-8");

OkHttpClient client = new OkHttpClient();

String post(String url, String json) throws IOException {
  RequestBody body = RequestBody.create(JSON, json);
  Request request = new Request.Builder()
      .url(url)
      .post(body)
      .build();
  Response response = client.newCall(request).execute();
  return response.body().string();
}

有了这个电话：

String response = post("http://www.roundsapp.com/post", json);

此调用以 NetworkOnMainThreadException 结束。
我可以用 AsyncTask 包装调用， 但据我从示例中了解到，OkHttp 库应该有已经处理好了.. 我做错了吗？

Answer 1

你应该使用 OkHttp 的异步方法。

public static final MediaType JSON = MediaType.parse("application/json; charset=utf-8");

OkHttpClient client = new OkHttpClient();

Call post(String url, String json, Callback callback) {
  RequestBody body = RequestBody.create(JSON, json);
  Request request = new Request.Builder()
      .url(url)
      .post(body)
      .build();
  Call call = client.newCall(request);
  call.enqueue(callback);
  return call;
}

然后您的响应将在回调（OkHttp 2.x）中处理：

post("http://www.roundsapp.com/post", json, new Callback() {
  @Override
  public void onFailure(Request request, Throwable throwable) {
     // Something went wrong
  }

  @Override public void onResponse(Response response) throws IOException {
    if (response.isSuccessful()) {
       String responseStr = response.body().string();
       // Do what you want to do with the response.
    } else {
       // Request not successful
    }
  }
});

或 OkHttp 3.x/4.x：

post("http://www.roundsapp.com/post", "", new Callback() {
        @Override
        public void onFailure(Call call, IOException e) {
            // Something went wrong
        }

        @Override
        public void onResponse(Call call, Response response) throws IOException {
            if (response.isSuccessful()) {
                String responseStr = response.body().string();
                // Do what you want to do with the response.
            } else {
                // Request not successful
            }
        }
    });

查看他们的食谱以获取更多示例：http://square.github.io/okhttp/recipes/

Answer 2

根据 OkHttp 文档： 它支持同步阻塞调用和带有回调的异步调用。 您的示例在主线程和 Android 上，因为如果您尝试在主线程上进行网络调用，3.0 版会引发该异常

更好的选择是将它与改造和 Gson 一起使用： http://square.github.io/retrofit/ https://code.google.com/p/google-gson/

以下是示例： http://engineering.meetme.com/2014/03/best-practices-for-consuming-apis-on-android/ http://heriman.net/?p=5

Answer 3

如果你按照这些步骤来实现OKHTTP，那么你肯定会通过应用两行代码在多个屏幕上调用多个API

UpdateListener updateListener = new UpdateListener(HitAPIActivity.this, baseHTTPRequest);
updateListener.getJsonData();

第 1 步：

baseHTTPRequest = new BaseHTTPRequest();
    //    baseHTTPRequest.setURL("https://api.geonames.org/citiesJSON?north=44.1&south=-9.9&east=-22.4&west=55.2&lang=de&username=demohttps://api.geonames.org/citiesJSON?north=44.1&south=-9.9&east=-22.4&west=55.2&lang=de&username=demo");
baseHTTPRequest.setURL("http://jsonparsing.parseapp.com/jsonData/moviesDemoItem.txt");
        baseHTTPRequest.setRequestCode(reqType);
        baseHTTPRequest.setCachedRequired(true);

        UpdateListener updateListener = new UpdateListener(HitAPIActivity.this, baseHTTPRequest);
        updateListener.executeRequest();

第 2 步：创建请求类

/** * 由 Deepak Sharma 于 2016 年 4 月 7 日创建。 * 这是一个具有基本参数的 HTTP 请求类。 * 如果要添加更多参数，请创建该类的子类 * 并与您的子类一起添加。不要修改这个类。 */

 public class BaseHTTPRequest<T> {

    private Context context;
    private String URL;
    private int requestCode;
    private List<T> listParameters;
    private String header;
    private boolean isCachedRequired;

    public Context getContext() {
        return context;
    }
    public void setContext(Context context) {
        this.context = context;
    }
    public void setURL(String URL) {
        this.URL = URL;
    }
    public String getURL() {
        return URL;
    }

    public int getRequestCode() {
        return requestCode;
    }

    public void setRequestCode(int requestCode) {
        this.requestCode = requestCode;
    }

    public List<T> getListParameters() {
        return listParameters;
    }

    public void setListParameters(List<T> listParameters) {
        this.listParameters = listParameters;
    }

    public String getHeader() {
        return header;
    }

    public void setHeader(String header) {
        this.header = header;
    }

    public boolean isCachedRequired() {
        return isCachedRequired;
    }
    public void setCachedRequired(boolean cachedRequired) {
        isCachedRequired = cachedRequired;
    }
}

第四步：创建监听类

导入android.util.Log； 导入 com.google.gson.Gson； 导入 java.io.IOException； 导入 dxswifi_direct.com.wifidirectcommunication.base.model.request.BaseHTTPRequest； 导入okhttp3.Call； 导入okhttp3.MediaType； 导入okhttp3.OkHttpClient； 导入okhttp3.Callback； 导入okhttp3.Request； 导入okhttp3.RequestBody； 导入okhttp3.Response;

/** * 由 Deepak Sharma 于 2016 年 4 月 7 日创建。 * @电子邮件：dpsharma.sharma1@gmail.com * 这是一个简单的 java 类，它将帮助您进行 HTTP 请求/响应，它将 * 对您的通信活动做出响应。 */

public class UpdateListener {

    private OnUpdateViewListener onUpdateViewListener;

    OkHttpClient okHttpClient = new OkHttpClient();
    BaseHTTPRequest mRequestModel;
    private String mURL = null;
    private Request mRequest = null;

    public interface OnUpdateViewListener {
        void updateView(String responseString, boolean isSuccess,int reqType);
    }

    public UpdateListener(OnUpdateViewListener onUpdateView, final BaseHTTPRequest requestModel) {
        this.mRequestModel = requestModel;
        this.onUpdateViewListener = onUpdateView;

        if (requestModel.isCachedRequired())
        {
            /*File httpCacheDirectory = new File(requestModel.getContext().getCacheDir(), "responses");
            Cache cache = null;
            cache = new Cache(httpCacheDirectory, 10 * 1024 * 1024);
            if (cache != null) {
                okHttpClient.setCache(cache);
            }*/
        }

        /*mURL = null;
        if (requestModel.getListParameters()!=null && requestModel.getListParameters().size()>0)
        {
            HttpUrl.Builder urlBuilder = HttpUrl.parse(requestModel.getURL()).newBuilder();
            List<RequestParameter> requestParameters = requestModel.getListParameters();
            for (int i=0; i<requestParameters.size();i++)
            {
                urlBuilder.addQueryParameter(requestParameters.get(i).getKey(),requestParameters.get(i).getValue());
            }
            mURL = urlBuilder.build().toString();
        }
        else
        {
            mURL = requestModel.getURL();
        }*/

            mURL = requestModel.getURL();
        if (mRequestModel.getListParameters()!=null && mRequestModel.getListParameters().size()>1)
        {
            MediaType JSON = MediaType.parse("application/json; charset=utf-8");
            mRequest = new Request.Builder()
                    .url(mURL)
                    .post(RequestBody.create(JSON, new Gson().toJson(BaseHTTPRequest.class)))
                    .build();
        }
        else
        {
            mRequest = new Request.Builder()
                    .url(mURL)
                    .build();
        }

    }

    public void executeRequest()
    {
        Call call = okHttpClient.newCall(mRequest);
        call.enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                e.printStackTrace();
                onUpdateViewListener.updateView(NetworkException.getErrorMessage(e), false, mRequestModel.getRequestCode());
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                if (!response.isSuccessful()) {
                    // You can also throw your own custom exception
                    throw new IOException("Unexpected code " + response);
                } else {
                    Log.i("Response:",response.toString());
                    Log.i("Response body:",response.body().toString());
                    Log.i("Response message:",response.message());
                    onUpdateViewListener.updateView(response.body().string(),true, mRequestModel.getRequestCode());
                }
                // do something wih the result
            }
        });
    }
}

第 5 步：从您请求的活动中，实现监听器

public class HitAPIActivity extends AppCompatActivity implements View.OnClickListener, UpdateListener.OnUpdateViewListener{

@Override
    public void updateView(final String responseString, boolean isSuccess, int reqType) {

if (isSuccess)
        {

if (!responseString.contains("failure")
                    && !responseString.contains("Error")) {
                // Handle request on the basis of Request Type.
                switch (reqType) {
                    case ApiConstants.GET_CONTACTS:

break;

default:
break;

}

}
}

}