我的代码很好，不会返回任何错误，但检索到的值与前一个字段相同。。例如，如果我将表3设置为"HELLO"，那么表4也是"HELLO"，这有点错误，我想要单独的值。。这是我的密码。。。
我的登录活动：
public class SigninActivity extends AsyncTask<String,Void,String>{
private TextView statusField,roleField, sampleField;
private Context context;
private int byGetOrPost = 0;
//flag 0 means get and 1 means post.(By default it is get.)
public SigninActivity(Context context,TextView statusField,TextView roleField,TextView sampleField,int flag) {
this.context = context;
this.statusField = statusField;
this.roleField = roleField;
this.sampleField = sampleField;
byGetOrPost = flag;
}
protected void onPreExecute(){
}
@Override
protected String doInBackground(String... arg0) {
if(byGetOrPost == 0){ //means by Get Method
try{
String username = (String)arg0[0];
String password = (String)arg0[1];
String link = "http://XXX.XXX.X.X/XXX/ins.php?username="
+username+"&password="+password;
URL url = new URL(link);
HttpClient client = new DefaultHttpClient();
HttpGet request = new HttpGet();
request.setURI(new URI(link));
HttpResponse response = client.execute(request);
BufferedReader in = new BufferedReader
(new InputStreamReader(response.getEntity().getContent()));
StringBuffer sb = new StringBuffer("");
String line="";
while ((line = in.readLine()) != null) {
sb.append(line);
break;
}
in.close();
return sb.toString();
}catch(Exception e){
return new String("Exception: " + e.getMessage());
}
}
else{
try{
String username = (String)arg0[0];
String password = (String)arg0[1];
String link="http://XXX.XXX.X.X/XXX/sel.php";
String data = URLEncoder.encode("username", "UTF-8")
+ "=" + URLEncoder.encode(username, "UTF-8");
data += "&" + URLEncoder.encode("password", "UTF-8")
+ "=" + URLEncoder.encode(password, "UTF-8");
URL url = new URL(link);
URLConnection conn = url.openConnection();
conn.setDoOutput(true);
OutputStreamWriter wr = new OutputStreamWriter
(conn.getOutputStream());
wr.write( data );
wr.flush();
BufferedReader reader = new BufferedReader
(new InputStreamReader(conn.getInputStream()));
StringBuilder sb = new StringBuilder();
String line = null;
// Read Server Response
while((line = reader.readLine()) != null)
{
sb.append(line);
break;
}
return sb.toString();
}catch(Exception e){
return new String("Exception: " + e.getMessage());
}
}
}
@Override
protected void onPostExecute(String result){
this.statusField.setText("Login Successful");
this.roleField.setText(result);
this.sampleField.setText(result);
}
}
我的select.php文件（sel.php）：
<?php
$con=mysqli_connect("localhost","root","","db_name");
if (mysqli_connect_errno($con))
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$username = $_POST['username'];
$password = $_POST['password'];
$result = mysqli_query($con,"SELECT role,sample FROM table1 WHERE
username='$username' and password='$password'");
$row = mysqli_fetch_array($result);
$data = $row[0];
if($data){
echo $data;
}
mysqli_close($con);
?>
这就是您的问题所在：
@Override
protected void onPostExecute(String result){
this.statusField.setText("Login Successful");
this.roleField.setText(result);
this.sampleField.setText(result);
}
如果希望sampleField和roleField的值不同，则应设置不同的值。
更新
我知道你的另一个问题在哪里了。在未更新的PHP源代码中，你从数据库表中选择了role和sample，但你只输出role，因为$data等于$row[0]。如果您也想要sample，那么还需要检索$row[1]。
或者，您也可以使用$row["role"]和$row["sample"]来获取从数据库表返回的值。
<?php
$con=mysqli_connect("localhost","root","","db_name");
if (mysqli_connect_errno($con))
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$username = $_POST['username'];
$password = $_POST['password'];
$result = mysqli_query($con,"SELECT role,sample FROM table1 WHERE
username='$username' and password='$password'");
$row = mysqli_fetch_array($result);
if($row){
// returns a json object in the form
// {"role":"<role-from-database>","sample":"<sample-from-database>"}
$output = array("role" => $row["role"] ,"sample" => $row["sample"]);
echo json_encode($output);
}
mysqli_close($con);
?>
使用更新的PHP源代码，您应该在SigninActivity中处理JSON对象。
更新2
@Override
protected void onPostExecute(String result){
String role = "", sample = "";
// read the json object with JsonReader
JsonReader reader = new JsonReader(new StringReader(result));
reader.beginObject();
while (reader.hasNext()) {
String name = reader.nextName();
if (name.equals("role")) {
role = reader.nextString();
} else if (name.equals("sample")) {
sample = reader.nextString();
} else {
reader.skipValue();
}
}
reader.endObject();
// set the text here
}
如果这有帮助，请告诉我。