数据推送到Android应用 [英] Push data to android app
问题描述
我正在开发一个通过Web服务PHP连接到MySQL数据库的Android应用程序。现在,我可以从MySQL数据库中读取数据并将其添加到我的Android SQLite数据库就好了。
I am developing an android app that is connected to a Mysql database through a php webservice. Right now I can read the data from the Mysql database and add them to my android sqlite database just fine.
现在我需要从数据库到应用推到数据的任何更新。寻找到这个有很多之后,建议最好的解决方案是GCM但是由于该项目的一些限制,我不能使用它。任何人都可以提出任何替代方案牢记我在所有这一切都相当新。
Now I need to push any updates to the data from the database to the app. After looking into this a lot the best solution that is suggested is GCM however due to some restrictions in the project I am not allowed to use it. Can anyone suggest any alternatives keeping in mind that I am fairly new at all of this.
感谢。
推荐答案
AsyncTask的是由Android提供了一个抽象类,这有助于我们正确地使用UI线程。这个类允许我们执行长/后台操作并显示在UI线程上它的结果,而无需操纵线程。
AsyncTask is an abstract class provided by Android which helps us to use the UI thread properly. This class allows us to perform long/background operations and show its result on the UI thread without having to manipulate threads.
您可以使用AsyncTask的打电话给你的web服务:
You can use AsyncTask to call your webservices:
private class LongOperation extends AsyncTask<String, Void, String> {
@Override
protected String doInBackground(String... params) {
try {
//call your webservice to perform MySQL database opration
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
.permitAll().build();
StrictMode.setThreadPolicy(policy);
HttpClient httpclient = new DefaultHttpClient();
HttpGet httpget = new Http Get("http://yourserver.com/webservices/service.php?id="
+ URLEncoder.encode("record_id") +"¶m1="
+ URLEncoder.encode("param1 value") + "¶m2="+ URLEncoder.encode("param2 value"));
HttpResponse response = httpclient.execute(httpget);
final String str=EntityUtils.toString(response.getEntity());
myjson = new JSONObject(str);
//perform JSON parsing to get webservice result.
if (myjson.has("success") == true) {
//Updation is succesful
} else {
//failed to perform updation
}
} catch (InterruptedException e) {
e.printStackTrace();
}
return "Executed";
}
@Override
protected void onPostExecute(String result) {
// This will be executed after completion of webservice call. and `String result` will have returned value from doInBackground()
// might want to change "executed" for the returned string passed
// into onPostExecute() but that is upto you
}
@Override
protected void onPreExecute() {}
@Override
protected void onProgressUpdate(Void... values) {}
}
现在,通过创建 LongOperation
类的对象进行Web服务调用,
now, perform webservice call by creating object of LongOperation
class,
LongOperation webCall = new LongOperation();
webCall.execute();
在PHP中,你应该写如下:
in PHP you should wrote as follows:
<?php
//DB Connection code:
$dbhost = "server";
$dbuser = "user_name";
$dbpassword = "pass";
$database = "your_db";
// connect to the database
$db = mysql_connect($dbhost, $dbuser, $dbpassword) or die("Connection Error: ".mysql_error());
mysql_select_db($database, $db) or die("Error conecting to db.");
header("Content-type: text/json");
if (!isset($_GET['id']) || $_GET['id'] == "" ||!isset($_GET['param1']) || $_GET['param1'] == "" || !isset($_GET['param2']) || $_GET['param2'] == "" ){
echo json_encode(array('error' => 'Required arguments missing.'));
exit;
}
$id = mysql_real_escape_string($_GET['id']); //escape string to prevent SQL injection attack.
$param1 = mysql_real_escape_string($_GET['param1']);
$param2 = mysql_real_escape_string($_GET['param2']);
$sql = "update your_table set param1='$param1',param2='$param2' where id=$id";
mysql_query($sql);
if (mysql_affected_rows()==1) {
echo json_encode(array('success' => "updated"));
}else{
echo json_encode(array('error' => "not updated"));
}
?>
您可以使用POST方法将参数传递给web服务,使之更加安全。 :)
You can use POST method to pass parameters to webservice to make it more secure. :)
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