使用 6.0 API (Android) 从服务器发送和接收数据

Question

我真的很困惑，我正在尝试开发一个允许我从服务器发送和接收数据的简单函数。

操作如下：

在 activity 中，我对服务器上的 PHP 文件执行 HTTP POST，"PHP file" 获取我发送的数据（通常是字符串），并使用通过 http 发送的参数执行查询。

示例：

我的android应用程序发送了一个带有这个值"PIPPO"的字符串，在PHP文件中有一个查询，例如：

$value = PIPPO /* 从 android app 接收到的数据*/ Select * 来自字符 where(characters.name=".$value.")

p.s。所有数据使用 JSON 格式

问题是：我一直使用一个函数（工作正常）但现在所有方法都已弃用，我找不到最新 API.

方法的替代方法

这是我的代码：

public class ReadServer extends Activity {
 String result;
 public String readserver(String id_data, String data){
 try{
  HttpClient httpclient = new DefaultHttpClient();
  HttpPost httpPost = new HttpPost("myurl/queryMobile.php");
  StringBuilder builder = new StringBuilder();
  String json = "";
  //Build jsonObject
  JSONObject jsonObject = new JSONObject();
  jsonObject.accumulate(id_data, data);
  //Convert JSONObject to JSON to String
  json = jsonObject.toString();

  //Set json to StringEntity
  StringEntity se = new StringEntity(json);
  //Set httpPost Entity
  httpPost.setEntity(se);
  //Set some headers to inform server about the type of the content
  httpPost.setHeader("Accept", "application/json");
  httpPost.setHeader("Content-type", "application/json");

  //Execute POST request to the given URL
  HttpResponse httpResponse = httpclient.execute(httpPost);
  //Receive response as inputStream
  StatusLine statusLine = httpResponse.getStatusLine();
  int statusCode = statusLine.getStatusCode();
  //Convert input stream to string
  AlertDialog.Builder alertDialog;

  switch(statusCode){
  case 200:
  HttpEntity entity = httpResponse.getEntity();
  InputStream content = entity.getContent();
  BufferedReader reader = new BufferedReader(new InputStreamReader(content));
  String line="";
  try{
  while ((line = reader.readLine()) != null) {
  builder.append(line);
  result = builder.toString();
  }
  }catch(Exception e){
  alertDialog = new AlertDialog.Builder(this);
  alertDialog.setTitle("400 Bad Request");
  alertDialog.setMessage("Non è stato possibile soddisfare la tua richiesta, riprova più tardi.");
  alertDialog.show();
  }
  break;

Answer 1

试试这个代码。 :)

    public class MainActivity extends AppCompatActivity {

     @Override
     protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      new Test().execute();
     }


     //AsyncTask 
     class Test extends AsyncTask < String, Void, String > {

      @Override
      protected String doInBackground(String...params) {
       InputStream in = null;
       String queryResult = "";
       URL url = new URL("http://www.android.com/");
       HttpURLConnection urlConnection = (HttpURLConnection)          url.openConnection();

      //add parameters
      urlConnection.setReadTimeout(10000);
      urlConnection.setConnectTimeout(15000);
      urlConnection.setRequestMethod("POST");
      urlConnection.setDoInput(true);
      urlConnection.setDoOutput(true);

     List<NameValuePair> params = new ArrayList<NameValuePair>();
     params.add(new BasicNameValuePair("firstParam", paramValue1));
     params.add(new BasicNameValuePair("secondParam", paramValue2));
     params.add(new BasicNameValuePair("thirdParam", paramValue3));
       try {
    //write OutputStream
    OutputStream os = urlConnection.getOutputStream();
    BufferedWriter writer = new BufferedWriter(
            new OutputStreamWriter(os, "UTF-8"));
    writer.write(getQuery(params));
    writer.flush();
    writer.close();
    os.close();


        InputStream in = new     BufferedInputStream(urlConnection.getInputStream());
        queryResult = readStream( in );
       } finally {
        urlConnection.disconnect();
       }
       return queryResult;

      }
      private String readStream(InputStream iStream) throws IOException {

       //Buffered reader allows us to read line by line
       try (BufferedReader bReader =
        new BufferedReader(new InputStreamReader(iStream))) {
        StringBuilder builder = new StringBuilder();
        String line;
        while ((line = bReader.readLine()) != null) { //Read till end
         builder.append(line);
        }
        return builder.toString();
       }
      }
    private String getQuery(List<NameValuePair> params) throws   UnsupportedEncodingException
    {
        StringBuilder result = new StringBuilder();
        boolean first = true;

        for (NameValuePair pair : params)
        {
            if (first)
                first = false;
            else
                result.append("&");

            result.append(URLEncoder.encode(pair.getName(), "UTF-8"));
            result.append("=");
            result.append(URLEncoder.encode(pair.getValue(), "UTF-8"));
        }

        return result.toString();
    }
      protected void onPostExecute(String data) {
       // do further things 
       Toast toast = Toast.makeText(getApplicationContext(), data,
        Toast.LENGTH_SHORT);
       toast.show();

      }

     }

    }

Answer 2

也许是时候开始使用截击了。这是一个很棒的图书馆，专为解决您的问题而设计。

对截击一无所知。别担心。 Here 是一个完美的视频，可以告诉您 volley 的功能。它包含了将它包含在你的项目中的所有步骤（虽然无非就是提一下gradle依赖）

我还提到了如何在代码中使用它的示例。

public class MainActivity extends Activity {
    private TextView txtDisplay;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         txtDisplay = (TextView) findViewById(R.id.txtDisplay);

         RequestQueue queue = Volley.newRequestQueue(this);
         String url = "myurl/queryMobile.php";

         JSONObject params = new JSONObject();
         params.put("name", "Dexter");

         JsonObjectRequest jsObjRequest = 
                 new JsonObjectRequest(Request.Method.POST,
                          url,
                          param,
                          new Response.Listener<JSONObject>() {
                              @Override
                              public void onResponse(JSONObject response) {
                              // TODO Auto-generated method stub
                              txtDisplay.setText("Response => "+response.toString());
                              findViewById(R.id.progressBar1).setVisibility(View.GONE);
}}, 
                         new Response.ErrorListener() {
                              @Override
                              public void onErrorResponse(VolleyError error) {
                              // TODO Auto-generated method stub
                              }
                         });
  queue.add(jsObjRequest);
  }
}

原始代码（和教程）可用here。

相信我，总有一天你会不得不开始凌空抽射，为什么不是今天呢！

使用 6.0 API (Android) 从服务器发送和接收数据

Send and receive data from server using 6.0 API (Android)

php

android

json

http-post

deprecated