java - Android Java Http 请求发布

Question

我创建了一个最简单的应用程序，一个默认应用程序，我想尝试从 php 页面发布和检索某些内容 MyActivty.Java 看起来像:

package com.dolganiuc.victor.myapplication;

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.util.Log;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;

public class MainActivity extends ActionBarActivity {

    private static final String TAG = "victorMessage";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Log.i(TAG, "onCreate");
        postData();


    }

    public void postData() {

        // Create a new HttpClient and Post Header
        HttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new HttpPost("http://93.117.158.187/");

        try {
            // Add your data
            List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
            nameValuePairs.add(new BasicNameValuePair("id", "12345"));
            nameValuePairs.add(new BasicNameValuePair("stringdata", "AndDev is Cool!"));
            httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));

            // Execute HTTP Post Request
            HttpResponse response = httpclient.execute(httppost);

            Log.i(TAG, response.toString());
        } catch (ClientProtocolException e) {
            // TODO Auto-generated catch block
        } catch (IOException e) {
            // TODO Auto-generated catch block
        }

    }

}

当 Android Studio 调试一切正常时，我在 2 个设备 Android 4.4.2 KitKat 和 Android 5.0 Lollipop 上运行这些应用程序，并且在这两个设备上应用程序正在关闭检索错误不幸的是我的应用程序已关闭。

问题是什么？

系统错误

06-11 13:18:02.042    1142-1161/? W/System.err﹕ java.lang.NullPointerException: Attempt to invoke interface method 'int java.util.List.size()' on a null object reference
06-11 13:18:02.042    1142-1161/? W/System.err﹕ at com.android.internal.telephony.PhoneBase.privatizeCellInfoList(PhoneBase.java:1252)
06-11 13:18:02.042    1142-1161/? W/System.err﹕ at com.android.internal.telephony.PhoneBase.getAllCellInfo(PhoneBase.java:1240)
06-11 13:18:02.042    1142-1161/? W/System.err﹕ at com.android.internal.telephony.PhoneProxy.getAllCellInfo(PhoneProxy.java:337)
06-11 13:18:02.042    1142-1161/? W/System.err﹕ at com.android.phone.PhoneInterfaceManager.getAllCellInfo(PhoneInterfaceManager.java:1486)
06-11 13:18:02.042    1142-1161/? W/System.err﹕ at com.android.internal.telephony.ITelephony$Stub.onTransact(ITelephony.java:691)
06-11 13:18:02.042    1142-1161/? W/System.err﹕ at android.os.Binder.execTransact(Binder.java:446)

Answer 1

第一个 问题可能是您没有添加 INTERNET在您的 AndroidManifest.xml 中获得许可.要解决此问题，只需添加此行 <uses-permission android:name="android.permission.INTERNET" />在你的 list 中。

其他 问题是您试图在主线程上执行发布请求。它导致NetworkOnMainThreadException .你应该使用 AsyncTask或 Handler执行网络请求，像这样:

public class MainActivity extends ActionBarActivity {

    private static final String TAG = "victorMessage";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Log.i(TAG, "onCreate");
        new HttpPostTask().execute();
    }

    private class HttpPostTask extends AsyncTask<Void, Void, String> {

        @Override
        protected String doInBackground(Void... params) {
            HttpClient httpclient = new DefaultHttpClient();
            HttpPost httppost = new HttpPost("http://93.117.158.187/");

            try {
                // Add your data
                List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
                nameValuePairs.add(new BasicNameValuePair("id", "12345"));
                nameValuePairs.add(new BasicNameValuePair("stringdata", "AndDev is Cool!"));
                httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));

                // Execute HTTP Post Request
                HttpResponse response = httpclient.execute(httppost);

                Log.i(TAG, response.toString());
                return response.toString();
            } catch (ClientProtocolException e) {
                // TODO Auto-generated catch block
            } catch (IOException e) {
                // TODO Auto-generated catch block
            }

            return null;
        }

        @Override
        protected void onPostExecute(String response) {
            super.onPostExecute(response);

            //do something with you response, connected with UI thread.
        }
    }
}