java连接安卓和php mySQL

3 月，2 周 Questions & Answers 2513

我是安卓编程的新手。我正在尝试创建一个应用程序，将与互联网上的数据库进行通信。作为帮助，我正在使用来自安卓hive的项目。首先，我想创建一个应用程序，将一些数据发送到本地主机上的数据库。我正在使用WAMP

在运行我的应用程序并插入要存储在db上的数据后，我遇到了一系列异常，我的应用程序崩溃。例如：

E/Buffer Error（545）：转换结果java时出错。lang.NullPointerException
E/JSON解析器（545）：解析数据组织时出错。json。JSONException:在的字符0处结束输入
E/AndroidRuntime（545）：致命异常：异步任务#1
E/AndroidRuntime（545）：java。lang.RuntimeException:执行doInBackground（）时出错

还有很多其他的例外

我的php脚本（或任何你想叫它们的）工作正常，但我想问题出在JSONParser或其他安卓活动中。。。我一直在寻找解决方案，但我找不到，或者我无法理解它。另外，我从安卓hive下载了代码，但在我的计算机上无法运行。与我的项目类似的问题

创建订单（产品或其他产品）的活动：

package com.example.heywaiter;

import java.util.ArrayList;
import java.util.List;

import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONException;
import org.json.JSONObject;

import 安卓.app.Activity;
import 安卓.app.ProgressDialog;
import 安卓.content.Intent;
import 安卓.os.AsyncTask;
import 安卓.os.Bundle;
import 安卓.util.Log;
import 安卓.view.View;
import 安卓.widget.Button;
import 安卓.widget.EditText;

public class NewProductActivity extends Activity{

    private ProgressDialog pDialog;

JSONParser jsonParser = new JSONParser();
EditText inputTablle;
EditText inputOrder;
EditText inputQuantity;
Button btnOrder;

private static String url_create_product = "http://127.0.0.1/安卓_connect/create_product.php";
private static final String TAG_SUCCESS = "success";

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.new_product);

    inputTablle = (EditText) findViewById(R.id.inputTablle);
    inputOrder = (EditText) findViewById(R.id.inputOrder);
    inputQuantity = (EditText) findViewById(R.id.inputQuantity);
    btnOrder = (Button) findViewById(R.id.btnOrder);

    btnOrder.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            new CreateNewProduct().execute();
        }
    });
}

内部类：

class CreateNewProduct extends AsyncTask<String, String, String>{



    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(NewProductActivity.this);
        pDialog.setMessage("Sending order...");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(true);
        pDialog.show();
    }

    @Override
    protected String doInBackground(String... args) {
        String tablle = inputTablle.getText().toString();
        String drink = inputOrder.getText().toString();
        String quantity = inputQuantity.getText().toString();

        List<NameValuePair> params = new ArrayList<NameValuePair>();
        params.add(new BasicNameValuePair("tablle", tablle));
        params.add(new BasicNameValuePair("drink", drink));
        params.add(new BasicNameValuePair("quantity", quantity));

        JSONObject json = jsonParser.makeHttpRequest(url_create_product, "POST", params);

        Log.d("Create Response", json.toString());

        try{

            int success = json.getInt(TAG_SUCCESS);

            if(success ==1){
                Intent i = new Intent(getApplicationContext(), MainActivity.class);
                startActivity(i);

                finish();
            }else{

            }
        }catch(JSONException e){
            e.printStackTrace();
        }
        return null;
    }

    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);
        pDialog.dismiss();
    }

}

}

JSONParser

package com.example.heywaiter;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.List;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;

import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;

import 安卓.util.Log;

public class JSONParser {


static InputStream is = null;
static JSONObject jObj = null;
static String json = "";

// constructor
public JSONParser() {

}

// function get json from url
// by making HTTP POST or GET mehtod
public JSONObject makeHttpRequest(String url, String method,
        List<NameValuePair> params) {

    // Making HTTP request
    try {

        // check for request method
        if(method == "POST"){
            // request method is POST
            // defaultHttpClient
            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpPost httpPost = new HttpPost(url);
            httpPost.setEntity(new UrlEncodedFormEntity(params));

            HttpResponse httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();

        }else if(method == "GET"){
            // request method is GET
            DefaultHttpClient httpClient = new DefaultHttpClient();
            String paramString = URLEncodedUtils.format(params, "utf-8");
            url += "?" + paramString;
            HttpGet httpGet = new HttpGet(url);

            HttpResponse httpResponse = httpClient.execute(httpGet);
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();
        }          


        } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

    try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                is, "iso-8859-1"), 8);
        StringBuilder sb = new StringBuilder();
        String line = null;
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        }
        is.close();
        json = sb.toString();
    } catch (Exception e) {
        Log.e("Buffer Error", "Error converting result " + e.toString());
    }

    // try parse the string to a JSON object
    try {
        jObj = new JSONObject(json);
    } catch (JSONException e) {
        Log.e("JSON Parser", "Error parsing data " + e.toString());
    }

    // return JSON String
    return jObj;

 }
}

如果您需要我的安卓Manifest：

    <?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:安卓="http://schemas.安卓.com/apk/res/安卓"
    package="com.example.heywaiter"
    安卓:versionCode="1"
    安卓:versionName="1.0" >

    <uses-sdk
        安卓:minSdkVersion="8"
        安卓:targetSdkVersion="14" />

    <application
        安卓:allowBackup="true"
        安卓:icon="@drawable/ic_launcher"
        安卓:label="@string/app_name"
        安卓:theme="@style/AppTheme" >
        <activity
            安卓:name="com.example.heywaiter.Splash"
            安卓:label="@string/app_name" >
            <intent-filter>
                <action 安卓:name="安卓.intent.action.MAIN" />

                <category 安卓:name="安卓.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            安卓:name="com.example.heywaiter.MainActivity"
            安卓:label="@string/app_name" >
            <intent-filter>
                <action 安卓:name="com.example.heywaiter.MainActivity" />

                <category 安卓:name="安卓.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
        <activity 
            安卓:name=".NewProductActivity"
            安卓:label="New Product">
        </activity>
        <activity
            安卓:name=".AllProductsActivity"
            安卓:label="All Products" >
        </activity>
    </application>
    <!--  Internet Permissions -->
    <uses-permission 安卓:name="安卓.permission.INTERNET" />
    <uses-permission 安卓:name="安卓.permission.ACCESS_WIFI_STATE" />
</manifest>

提前感谢！：）

共 (2) 个答案

# 1 楼答案

将其用于保存到数据库

nameValuePairs2 = new  ArrayList<NameValuePair>();
nameValuePairs2.add(new BasicNameValuePair("username",username));
nameValuePairs2.add(new BasicNameValuePair("password",password));
try{
  HttpClient httpclient = new DefaultHttpClient();
  HttpPost httppost = new HttpPost(mainurl+"registration.php");
  httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
  HttpResponse response = httpclient.execute(httppost);
  String the_string_response = convertResponseToString(response);
  //    Toast.makeText(getApplicationContext(), "Response " + the_string_response, Toast.LENGTH_LONG).show();
 }catch(Exception e){
//  Toast.makeText(getApplicationContext(), "ERROR " + e.getMessage(), Toast.LENGTH_LONG).show();
//   System.out.println("Error in http connection "+e.toString());
}

# 2 楼答案
我花了一段时间才发现问题出在哪里，我简直不敢相信问题出在哪里

连接到本地主机而不是：
```
private static String url_create_product = "http://127.0.0.1/android_connect/create_product.php";
```
在NewProductActivity中。java类应使用以下代码：
```
private static String url_all_products = "https://10.0.2.2/android_connect/create_product.php";
```
由于某些原因，您不能使用127.0.0.1，但使用10.0.2.2一切都会很好

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java连接安卓和php mySQL

共 (2) 个答案

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# 2 楼答案