将值发送到 json php webservice android答案

【问题标题】：Send value to json php webservice android将值发送到 json php webservice android
【发布时间】：2015-09-12 07:09:13
【问题描述】：

我正在尝试使用 json 和 PHP 网络服务将 edittext 值插入到 mysql 表中。我找到了执行此操作的代码；当 web 服务工作时，它应该传递“成功”消息。但是当点击提交按钮时它会强制关闭。这是代码：

    protected void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_main);
mhost=(EditText) findViewById(R.id.field_host);
        mdb=(EditText) findViewById(R.id.field_db);
        muser=(EditText) findViewById(R.id.field_user);
        mpassword=(EditText) findViewById(R.id.field_password);

        mConnection=(Button) findViewById(R.id.insert);
        mConnection.setOnClickListener(new OnClickListener() {

                    @Override
                    public void onClick(View v) {
                        // TODO Auto-generated method stub
                        new Connect().execute();

                    }
                });
        } 
    class Connect extends AsyncTask<String, String, String>{

            @Override
            protected String doInBackground(String... args) {
                // TODO Auto-generated method stub
                String HOST=mhost.getText().toString();
                String USER=muser.getText().toString();
                String DB=mdb.getText().toString();
                String PASSWORD=mpassword.getText().toString();

                List<NameValuePair> params=new ArrayList<NameValuePair>();
                params.add(new BasicNameValuePair("nfc_tag", HOST));
                params.add(new BasicNameValuePair("meter_reading", USER));
                params.add(new BasicNameValuePair("reading_datetime", DB));
                params.add(new BasicNameValuePair("image_name", PASSWORD));


                JSONObject json=jp.makeHttpRequest(connection_url, "POST", params);

                try {

                    int success=json.getInt(Tag_success);
                    if(success==1){

                        Toast.makeText(getApplicationContext(), "Connected :-)", Toast.LENGTH_LONG);
                    }else{

                        Toast.makeText(getApplicationContext(), "Not Connected :(", Toast.LENGTH_LONG);
                    }

                } catch (JSONException e) {
                    // TODO: handle exception
                    e.printStackTrace();
                }
                return null;
            }

        }

JsonParser 类

public class JsonParser {

    static InputStream IS=null;
    static JSONObject JB=null;
    static String json="";

    public JsonParser(){


    }
    public JSONObject makeHttpRequest(String url,String method,List<NameValuePair> params){
        try {

            if(method=="POST"){

                DefaultHttpClient httpClient=new DefaultHttpClient();
                HttpPost httpPost=new HttpPost(url);
                httpPost.setEntity(new UrlEncodedFormEntity(params));

            }else if(method=="GET"){
                 DefaultHttpClient httpClient=new DefaultHttpClient();
                 String paramaString =URLEncodedUtils.format(params, "utf-8");
                 url +="?"+paramaString;
                 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) {
            // TODO: handle exception
        }catch (IOException e) {
            // TODO: handle exception
            e.printStackTrace();
        }

        try {

            BufferedReader reader=new BufferedReader(new InputStreamReader(IS,"iso-8859"),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) {
            // TODO: handle exception
            Log.e("Buffer Error","Connection Error"+e.toString());
        }
        try {
            JB=new JSONObject(json);
        } catch (JSONException e) {
            // TODO: handle exception
            Log.e("JSON Parser", e.toString());
        }

        return JB;
    }

PHP 脚本

<?php
$host=$_POST['nfc_tag'];
$user=$_POST['meter_reading'];
$db=$_POST['reading_datetime'];
$password=$_POST['image_name'];

$response=array();
$connect=mysql_connect($host,$user,$password);

if(mysql_select_db($db,$connect)){

$response['success']=1;
}else{
$response['success']=2;
}
echo json_encode($response);
?>

【问题讨论】：

请发布异常堆栈跟踪。
@kiturk3 LogCat : "09-14 12:02:46.454: E/Buffer Error(6380): Connection Errorjava.lang.NullPointerException: lock == null ", "09-14 12:02 :46.454: E/JSON Parser(6380): org.json.JSONException: 字符 0 处的输入结束 ", "09-14 12:02:46.474: E/AndroidRuntime(6380): java.lang.RuntimeException: An执行 doInBackground() 时发生错误"

标签： android json web-services

【解决方案1】：

你初始化你的 EditText 了吗？认为这是因为您尚未初始化 EditText“mhost”和“muser”并直接读取值。例如。 mhost=(EditText)findViewById(R.id.mhost);

【讨论】：

是的，我已经初始化了所有的编辑文本和按钮。请检查我的更新

【解决方案2】：

初始化mConnection。它看起来像一个 Button，所以在调用它的 setOnClickListener 方法之前这样做

mConnection = (Button) findViewById(R.id.**YouButtonId**);
mhost = (EditText) findViewById(R.id.**YouEditTextId**); //if its a edittext
mConnection.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {
                    // TODO Auto-generated method stub
                    new Connect().execute();

                }
            });

【讨论】：