如何从服务器获取单个数据到 android volley 中的 textview？

Question

我是 android 新手，我正在处理登录和密码活动，如果您忘记了密码，那么在输入正确的电子邮件后，服务器会将密码发送到应该设置为 settext 的 textview。我制作了 php 文件但是我无法在 android 中进行编码 ..我希望通过 volley 获取数据。 这是我的 php 文件：

<?php 

include ('config.php');

$sql = "SELECT * FROM UserInfo WHERE email='".$email."'";



$r = mysqli_query($con,$sql);

$result = array();

while($row = mysqli_fetch_array($r)){
    array_push($result,array(
        'password'=>$row['password'],

    ));
}

echo json_encode(array('result'=>$result));

mysqli_close($con);

?>

这是我的忘记密码活动：

     public class ForgotPasswordActivity extends AppCompatActivity {

    private String fremail;
    private ProgressDialog pDialog;
    protected EditText femail;
    protected Button mSubmitButton;
    TextView pas;

    private static String url_create_book = "http://cloud.....com/broccoli/fpassword.php";




     @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_forgot_password);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);



          pas=(TextView)findViewById(R.id.pas) ;
          femail=(EditText)findViewById(R.id.feml);

          Button submit= (Button) findViewById(R.id.sbtn);
          submit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {


                pDialog = new ProgressDialog(ForgotPasswordActivity.this);
                pDialog.setMessage("Please wait..");
                pDialog.setIndeterminate(false);
                pDialog.setCancelable(true);
                pDialog.show();
                fremail = femail.getText().toString();



                // new CreateNewProduct().execute();
                StringRequest stringRequest = new StringRequest(Request.Method.POST, url_create_book,
                        new Response.Listener<String>() {
                            @Override
                            public void onResponse(String response) {
                                pDialog.dismiss();

                                try {
                                    JSONObject object     = new JSONObject(response);
                                    JSONArray jsonArray   = object.getJSONArray("result");
                                    JSONObject jsonObject = jsonArray.getJSONObject(0);

// fetch password from JSON
                                    String password         = jsonObject.getString("password");
// use password in textviewfemail.setText(password, TextView.BufferType.EDITABLE);
                                    pas.setText(password, TextView.BufferType.EDITABLE);



                                }
                                catch (JSONException e) {
                                    Toast.makeText(ForgotPasswordActivity.this, e.toString(), Toast.LENGTH_LONG).show();
                                }


                            }

                        },

                        new Response.ErrorListener() {
                            @Override
                            public void onErrorResponse(VolleyError error) {
                                pDialog.dismiss();
                                Toast.makeText(ForgotPasswordActivity.this, error.toString(), Toast.LENGTH_LONG).show();
                            }
                        }) {
                    @Override
                    protected Map<String, String> getParams() {
                        Map<String, String> params = new HashMap<String, String>();
                        params.put("email", fremail);


                        return params;
                    }
                };
                RequestQueue requestQueue = Volley.newRequestQueue(ForgotPasswordActivity.this);
                requestQueue.add(stringRequest);

            }

        });
    }








    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case android.R.id.home:
                onBackPressed();
                return true;
            default:
                return super.onOptionsItemSelected(item);
        }
    }

}

这是我的 xml：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center_horizontal"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.zeba.broccoli.Login">

    <!-- Login progress -->
    <LinearLayout
        android:gravity="center_horizontal"
        android:orientation="vertical"
        android:id="@+id/login_form"
        android:layout_width="match_parent"
        android:layout_height="match_parent">


        <ImageView android:src="@drawable/logobr"
            android:layout_width="wrap_content"
            android:layout_height="72dp"
            android:layout_marginTop="40dp"
            android:layout_gravity="center_horizontal" />





        <LinearLayout
            android:id="@+id/email_login_form"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:orientation="vertical">





            <android.support.design.widget.TextInputLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content">






                <AutoCompleteTextView
                    android:id="@+id/feml"
                    android:layout_width="match_parent"

                    android:hint="email"
                    android:inputType="textEmailAddress"
                    android:maxLines="1"
                    android:singleLine="true"
                    android:background="@drawable/rounded_edittext"

                    android:layout_height="40dp"
                    android:paddingLeft="5dp"

                    android:layout_marginBottom="20dip"/>

            </android.support.design.widget.TextInputLayout>


          </LinearLayout>



            <Button
                android:id="@+id/sbtn"
                style="?android:textAppearanceSmall"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="16dp"
                android:text="Submit"
                android:background="@drawable/mybutton"

                android:textColor="#fff"
                android:textStyle="bold"
                android:elevation="0dp" />

            <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:orientation="horizontal"
                android:weightSum="1" >
                <TextView
                    android:id="@+id/fpss"
                    android:layout_width="fill_parent"
                    android:layout_height="wrap_content"
                    android:layout_weight="0.5"
                    android:gravity="center"
                    android:layout_marginTop="16dp"
                    android:text="Your Password is:" />
                <TextView
                    android:id="@+id/pas"
                    android:layout_width="fill_parent"
                    android:layout_height="wrap_content"
                    android:layout_weight="0.5"
                    android:gravity="center"
                    android:layout_marginTop="16dp"


                    />

我在 logcat 中没有收到任何错误，但是当我在设备上运行它时会显示

jsonException....Index 0 out of 0 range[0...0]

Answer 1

您的PHP 代码正在发送JSON 格式的密码，首先解码您的代码中的JSON 并获取密码：

new Response.Listener<String>() {
@Override
public void onResponse(String response) {
pDialog.dismiss();

try {
JSONObject object     = new JSONObject(response);
JSONArray jsonArray   = object.getJSONArray("result");
JSONObject jsonObject = jsonArray.getJSONObject(0);

// fetch password from JSON
// UPDATED HERE
String password         = jsonObject.getString("password");

femail.setText(password, TextView.BufferType.EDITABLE);

} 
catch (JSONException e) {
Toast.makeText(getContext(), e.toString(), Toast.LENGTH_LONG).show();
}  

},

PHP

<?php 

include ('config.php');

// updated here, value is mapped 
$email = $_POST['email'];

$sql = "SELECT * FROM UserInfo WHERE email='".$email."'";



$r = mysqli_query($con,$sql);

//checking if email is valid or not
if(mysqli_fetch_array($r) == NULL){
echo "Invalid email";
}
else{
$result = array();

while($row = mysqli_fetch_array($r)){
    array_push($result,array(
        'password'=>$row['password'],

    ));
}
echo json_encode(array('result'=>$result));
}
mysqli_close($con);

?>

Answer 2

使用 JsonObjectRequest 代替 StringRequest

    JsonObjectRequest request = new JsonObjectRequest(Request.Method.POST, url, json, new Response.Listener<JSONObject>() {
                            @Override
                            public void onResponse(JSONObjectresponse) {
                          // you code here
 }
}
, new Response.ErrorListener() {
                            @Override
                            public void onErrorResponse(VolleyError error) {

                            }
                        }) {
                    @Override
                    public Map<String, String> getHeaders() throws AuthFailureError {
                        Map<String, String> headers = new HashMap<String, String>();
                    // add your header here
                        return headers;
                    }
                };