如何用android（PHP）连接到MySQL数据库？

Question

I have tried almost all the code that have been encountered about this issue.

I leave sample code below.

//select.php
         <?php
$host='127.0.0.1';
$uname='root';
$pwd='';
$db="android";
$id=$_REQUEST['id'];
$con = mysql_connect($host,$uname,$pwd) or die("connection failed");
$sqlString = "select * from sample where id='$id'  ";
$rs = mysql_query($sqlString);  
if($rs){
while($objRs = mysql_fetch_assoc($rs)){
$output[] = $objRs; }
echo json_encode($output); }
mysql_close($con);
?>

//Main Activity

        @Override
        public void onClick(View v) {

        id=e_id.getText().toString();
        select();
        }
        });
        }

        public void select()    {
        ArrayList<NameValuePair> nameValuePairs = new 
        ArrayList<NameValuePair>();
        nameValuePairs.add(new BasicNameValuePair("id",id));

        try
        {
        HttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new HttpPost("http://10.0.2.2/select.php");
        httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
        HttpResponse response = httpclient.execute(httppost);
        HttpEntity entity = response.getEntity();
        is = entity.getContent();
        Log.e("pass 1", "connection success ");
        }
        catch(Exception e)
        {
        Log.e("Fail 1", e.toString());
        Toast.makeText(getApplicationContext(), "Invalid IP Address",
        Toast.LENGTH_LONG).show();
        }

        try
        {
        BufferedReader reader = new BufferedReader
        (new InputStreamReader(is,"iso-8859-1"),8);
        StringBuilder sb = new StringBuilder();
        while ((line = reader.readLine()) != null)
        {
        sb.append(line + "
");
        }
        is.close();
        result = sb.toString();
        Log.e("pass 2", "connection success ");
        }
        catch(Exception e)
        {
        Log.e("Fail 2", e.toString());
        }

        try
        {
        JSONObject json_data = new JSONObject(result);
        name=(json_data.getString("name"));
        Toast.makeText(getBaseContext(), "Name : "+name,
        Toast.LENGTH_SHORT).show();
        }
        catch(Exception e)
        {
        Log.e("Fail 3", e.toString());
        }        }}

I wrote this to.

 <uses-permission android:name="android.permission.INTERNET"/>  

//logcat

   E/Fail 1: android.os.NetworkOnMainThreadException
 E/Fail 2: java.lang.NullPointerException: lock == null
 E/Fail 3: java.lang.NullPointerException

When I try to run the application I get the INVALID IP ADDRESS error. I need some suggestions. What should I try to connect to MySQL database with android (PHP)?

Answer 1

Exception clearly showing that you are calling network operation on main thread that's why it is not working . Use async task for network operation and then it will work. From api level 11 android restricted network operations on main thread and if do this it will throw an error network on main thread exception. And you are getting the same exception.