我怎样才能获取在Android应用程序从Web服务器上的数据？ [英] How can I fetch data from a web server in an android application?
问题描述
我想找回在Android应用程序从Web服务器上的数据，并且不知道从哪里开始。我应该使用Web服务？
I want to retrieve data from a web server in an android application, and don't know where to begin. Should I use web services?
推荐答案
我会推荐这些教程：
连接机器人与PHP和MySQL ，< A HREF =http://www.vogella.com/articles/AndroidJSON/article.html#json_android> JSON在Android的和的 PHP与库MySQLi
我用这些教程，并设法得到你正在尝试做的工作没有太大的困难是什么。
I used these tutorials and managed to get what you are trying to do working without too much difficulty.
他们之间descibe怎么办你attemping什么在每个阶段，android的应用程序，数据库和Web服务器端，并有包括什么，你就可以做的处理和使用所接收的信息的额外信息的每一步
Between them they descibe each step in how to do what you are attemping at each stage, the android application, the database and the web server side and has extra information included for what you can then do to process and use the received information
我唯一要补充的是，连接用的android PHP和MySQL教程使用mysql_在PHP中是pcated德$ P $。最好使用库MySQLi这就是为什么我列入第三连接。
The only thing I would add is that the Connect android with PHP and MySql tutorial makes use of mysql_ in php which is deprecated. Much better to use MySqli which is why I included the third link.
您想要做什么的基本轮廓是这样的：
The basic outline of what you want to do is this:
1）在Android应用程序中使用的一类像这样提出请求到服务器PHP脚本：
1) in the android app make a request to a server php script using a class like this:
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 android.util.Log;
public class JSONParser {
// Response from the HTTP Request
static InputStream httpResponseStream = null;
// JSON Response String to create JSON Object
static String jsonString = "";
// Method to issue HTTP request, parse JSON result and return JSON Object
public JSONObject makeHttpRequest(String url, String method,
List<NameValuePair> params) {
try {
// get a Http client
DefaultHttpClient httpClient = new DefaultHttpClient();
// If required HTTP method is POST
if (method == "POST") {
// Create a Http POST object
HttpPost httpPost = new HttpPost(url);
// Encode the passed parameters into the Http request
httpPost.setEntity(new UrlEncodedFormEntity(params));
// Execute the request and fetch Http response
HttpResponse httpResponse = httpClient.execute(httpPost);
// Extract the result from the response
HttpEntity httpEntity = httpResponse.getEntity();
// Open the result as an input stream for parsing
httpResponseStream = httpEntity.getContent();
}
// Else if it is GET
else if (method == "GET") {
// Format the parameters correctly for HTTP transmission
String paramString = URLEncodedUtils.format(params, "utf-8");
// Add parameters to url in GET format
url += "?" + paramString;
// Execute the request
HttpGet httpGet = new HttpGet(url);
// Execute the request and fetch Http response
HttpResponse httpResponse = httpClient.execute(httpGet);
// Extract the result from the response
HttpEntity httpEntity = httpResponse.getEntity();
// Open the result as an input stream for parsing
httpResponseStream = httpEntity.getContent();
}
// Catch Possible Exceptions
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
// Create buffered reader for the httpResponceStream
BufferedReader httpResponseReader = new BufferedReader(
new InputStreamReader(httpResponseStream, "iso-8859-1"), 8);
// String to hold current line from httpResponseReader
String line = null;
// Clear jsonString
jsonString = "";
// While there is still more response to read
while ((line = httpResponseReader.readLine()) != null) {
// Add line to jsonString
jsonString += (line + "\n");
}
// Close Response Stream
httpResponseStream.close();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
try {
// Create jsonObject from the jsonString and return it
return new JSONObject(jsonString);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
// Return null if in error
return null;
}
}
}
它处理通信，打开一个连接，并接收一个JSON字符串，它然后处理成JSON对象。
Which handles communication, opens a connection and receives a json string which it then processes into a JSON object.
2）在PHP服务器上，打开你的SQL数据库的mysqli的连接，运行mysqli->查询（），并完成类似，结果如下：
2) in the php server, open an mysqli connection to your SQL database, run an mysqli->query() and do something like the following with the result:
if (mysqli_num_rows($result) > 0) {
// looping through all results
$response["apps"] = array();
while ($row = mysqli_fetch_array($result)) {
$apps = array();
$apps["name"] = $row["name"];
$apps["package"] = $row["package"];
$apps["version"] = $row["version"];
$apps["dateversion"] = $row["dateversion"];
$apps["sdkver"] = $row["sdkver"];
$apps["pathroot"] = $row["pathroot"];
$apps["rootname"] = $row["rootname"];
$apps["apkmd5"] = $row["apkmd5"];
$apps["extraapkmd5"] = $row["extraapkmd5"];
$apps["instructionsmd5"] = $row["instructionsmd5"];
$apps["assetsmd5"] = $row["assetsmd5"];
$apps["root"] = $row["root"];
$apps["current"] = $row["current"];
// push single product into final response array
array_push($response["apps"], $apps);
}
// success
$response["success"] = 1;
// echoing JSON response
echo json_encode($response);
这遍历数据库的响应和连接codeS成被送回了Android应用程序，然后可以处理它一个JSON字符串。
This iterates through the database response and encodes it into a JSON string which is sent back to the android app which can then process it.
如何创建这样的事情是联系在一起的教程都解释
How to create something like this is all explained in the tutorials linked
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