Android 3.3 API 18
你好,
我正在使用android开发我的第一个应用程序。该应用程序将必须连接到在线数据库以存储用户数据。
我正在寻找包含MySQL数据库的云存储。但是,我的App可以直接连接到该MySQL数据库并从中推入和拉出数据吗?还是我需要做其他事情?
非常感谢您的任何建议,
是的,你可以这么做。
您需要的材料:
1. 首先在清单文件中设置Internet权限
<uses-permission android:name="android.permission.INTERNET" />
2.创建 一个类以从服务器发出HTTPRequest(我正在使用json parisng获取值)
例如:
public class JSONfunctions { public static JSONObject getJSONfromURL(String url) { InputStream is = null; String result = ""; JSONObject jArray = null; // Download JSON data from URL try { HttpClient httpclient = new DefaultHttpClient(); HttpPost httppost = new HttpPost(url); HttpResponse response = httpclient.execute(httppost); HttpEntity entity = response.getEntity(); is = entity.getContent(); } catch (Exception e) { Log.e("log_tag", "Error in http connection " + e.toString()); } // Convert response to string 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(); result = sb.toString(); } catch (Exception e) { Log.e("log_tag", "Error converting result " + e.toString()); } try { jArray = new JSONObject(result); } catch (JSONException e) { Log.e("log_tag", "Error parsing data " + e.toString()); } return jArray; } }
3. 在MainActivity“创建类的对象”中JsonFunctions,将url作为参数从您要获取数据的位置传递
MainActivity
JsonFunctions
JSONObject jsonobject;
jsonobject = JSONfunctions.getJSONfromURL("http://YOUR_DATABASE_URL");
4. 然后,最后读取jsontags并将值存储在arraylist中,如果需要,稍后在listview中显示它
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由于上述答案我写了很长回来,现在HttpClient,HttpPost,HttpEntity已在阿比23.删除您可以使用下面的的build.gradle(应用级)的代码仍继续使用org.apache.http的项目。
HttpClient
HttpPost
HttpEntity
org.apache.http
android { useLibrary 'org.apache.http.legacy' signingConfigs {} buildTypes {} }
或者您可以使用HttpURLConnection如下所示从服务器获取响应
HttpURLConnection
public String getJSON(String url, int timeout) { HttpURLConnection c = null; try { URL u = new URL(url); c = (HttpURLConnection) u.openConnection(); c.setRequestMethod("GET"); c.setRequestProperty("Content-length", "0"); c.setUseCaches(false); c.setAllowUserInteraction(false); c.setConnectTimeout(timeout); c.setReadTimeout(timeout); c.connect(); int status = c.getResponseCode(); switch (status) { case 200: case 201: BufferedReader br = new BufferedReader(new InputStreamReader(c.getInputStream())); StringBuilder sb = new StringBuilder(); String line; while ((line = br.readLine()) != null) { sb.append(line+"\n"); } br.close(); return sb.toString(); } } catch (MalformedURLException ex) { Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, ex); } catch (IOException ex) { Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, ex); } finally { if (c != null) { try { c.disconnect(); } catch (Exception ex) { Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, ex); } } } return null;
}
或您可以使用第三方库(如Volley)Retrofit来调用webservice api并获取响应,然后使用FasterXML- jackson,解析google-gson。
Volley
Retrofit
FasterXML- jackson
google-gson