使用okhttp发送http post的Android应用程序崩溃

Question

btnLogin.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        {
            StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
                    .permitAll().build();
            StrictMode.setThreadPolicy(policy);
            //Intent mainMenu = new Intent(LoginActivity.this, MainMenu.class);
            //LoginActivity.this.startActivity(mainMenu);

            LoginImpl li = new LoginImpl();
            int userID = li.login(txtUsername.getText().toString(), txtPassword.getText().toString());

            new AlertDialog.Builder(LoginActivity.this)
                    .setTitle("TEST")
                    .setMessage("USER ID = " + userID)
                    .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int which) {

                        }
                    })
                    .setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int which) {

                        }
                    })
                    .setIcon(android.R.drawable.ic_dialog_alert)
                    .show();
        }

    }
});

package diplomski.thop.thopmobileclient.controller.requests;
import java.io.IOException;
import com.google.gson.Gson;
import diplomski.thop.thopmobileclient.controller.implementation.Urls;
import diplomski.thop.thopmobileclient.model.User;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;

public class LoginRequest {

    OkHttpClient client;

    public LoginRequest() {
        client = new OkHttpClient();
    }

    public int sendLoginRequest(String username, String password) {
        User user = new User(username, password);
        String requestJson = new Gson().toJson(user);
        RequestBody body = RequestBody.create(Urls.JSON, requestJson);
        Request request = new Request.Builder().url(Urls.LOGIN_URL).post(body).build();
        try (Response response = client.newCall(request).execute()) {
            String returnResponse = response.body().string();
            if (returnResponse.equalsIgnoreCase("Fail")) {
                return -1;
            } else {
                return Integer.parseInt(returnResponse);
            }
        } catch (IOException e) {
            e.printStackTrace();
            return -1;
        }
    }

}

public static final String START_URL = "http://10.0.2.2:8080/ThopWebService/rest/";
public static final String LOGIN_URL = START_URL + "user/login";

apply plugin: 'com.android.application'

android {
    compileSdkVersion 24
    buildToolsVersion "24.0.2"

    defaultConfig {
        applicationId "diplomski.thop.thopmobileclient"
        minSdkVersion 19
        targetSdkVersion 24
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:24.2.0'
    compile 'com.android.volley:volley:1.0.0'
    compile group: 'com.google.code.gson', name: 'gson', version: '2.6.2'
    compile 'com.squareup.okhttp3:okhttp:3.4.1'
}

Answer 1

   jackOptions {
     enabled true
   }