Android：org.JSONException“無法將字符串轉換為JSONObject”

Question

您好，我是Android的新手，尤其是JSon。 我正在嘗試將我的android應用程序與連接到WAMP的php文件連接起來。 但是我得到“字符串不能轉換為JSONObject。這是我的php代碼：

if(isset($_POST['check'])){

$name = $_POST['txtuser'];
$pass = $_POST['txtpass'];

$sql = "Select * from tbluser where username = '".$name."' and password = '".$pass."'";
$query = mysql_query($sql, $conn);
$result = mysql_fetch_array($query);
$flag['code'] = 0;

if(mysql_num_rows($query) > 0){

$flag['code'] = 1;
echo '<script type="text/javascript">alert("Hello");</script>';
json_encode($flag);

}

這是我的Android代碼：

public void select()
{
ArrayList<NameValuePair> userpass = new ArrayList<NameValuePair>();

String x = txtname.getText().toString();
String y = txtpass.getText().toString();

userpass.add(new BasicNameValuePair("user", x));
userpass.add(new BasicNameValuePair("pass",y));

try
{
    HttpClient httpclient = new DefaultHttpClient();
    HttpPost httppost = new HttpPost("http://192.168.254.100/adphptest/index.php");
    httppost.setEntity(new UrlEncodedFormEntity(userpass));
    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 + "\n");
    }
    is.close();
    json = sb.toString();
Log.e("pass 2", "connection success ");
}
catch(Exception e)
{
    Log.e("Fail 2", e.toString());
}     

try
{
    JSONObject json_data = new JSONObject(json);


    code=(json_data.getInt("code"));

    if(code==1)
    {
    Toast.makeText(getBaseContext(), "User verified!",
    Toast.LENGTH_SHORT).show();
    }
    else
    {
    Toast.makeText(getBaseContext(), "Invalid!",
    Toast.LENGTH_LONG).show();
    }
}
catch(Exception e)
{
    Log.e("Fail 3", e.toString());
}
}

Answer 1

轉到c：\\ wamp \\ alias \\ phpmyadmin.conf並更改它

<Directory "c:/wamp/apps/phpmyadmin3.4.5/">
Options Indexes FollowSymLinks MultiViews
AllowOverride all
    Order Deny,Allow
Deny from all
Allow from 127.0.0.1
</Directory>

至

<Directory "c:/wamp/apps/phpmyadmin3.4.5/">
Options Indexes FollowSymLinks MultiViews
AllowOverride all
    Order Deny,Allow
    Allow from all
</Directory>

Answer 2

除非我錯過了一些明顯的問題，否則問題是在輸出json對象之前，您的php文件將在此行中回顯非json字符串

echo '<script type="text/javascript">alert("Hello");</script>';

這是您的Android json解析代碼看到的第一件事，因此失敗了。