[英]How to display/request JSON Object using Android Volley?
我在Android Studio中遇到有關如何請求JSON對象的問題。
我的Logcat只能在String onResponse上打印String,而不能在JSONObject值上打印。 我在AccessActivity.java中的try {}行中遇到問題
我的代碼說明如下。
我有從mysql數據庫中獲取的這些JSON對象輸出。
{
"access":"PA001",
"password":"123",
"fullname":"ARCADE",
"branch":"HQ",
"section":"MPR"
}
在我的PHP代碼中,這就是我獲取數據並將其編碼為JSON對象的方式。
access.php
<?php
$conn = mysqli_connect("","","","");
if(
isset($_POST['access']) &&
isset($_POST['password'])
){
$access = $_POST['access'];
$password = $_POST['password'];
$sql = "SELECT * FROM table WHERE access = '$access' AND password = '$password' ";
$result = mysqli_query($conn, $sql);
if($result && mysqli_num_rows($result) > 0){
while($row = mysqli_fetch_array($result)){
$accessdb = $row['access'];
$passworddb = $row['password'];
$fullnamedb = $row['fullname'];
$branchdb = $row['branch'];
$sectiondb = $row['section'];
echo "success_access";
$response = array('access' => $accessdb, 'password' => $passworddb, 'fullname' => $fullnamedb, 'branch' => $branchdb, 'section' => $sectiondb);
echo json_encode($response);
}
mysqli_free_result($result);
} else {
echo "access_failed";
}
}
?>
但是我的問題出現在Android Studio中,
這是我的代碼。
AccessActivity.java
public class AccessActivity extends AppCompatActivity{
final String TAG = this.getClass().getName();
EditText etAccess, etPassword;
Button bLogin;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
etAccess = (EditText)findViewById(R.id.etAccess);
etPassword = (EditText)findViewById(R.id.etPassword);
bLogin = (Button)findViewById(R.id.bLogin);
bLogin.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String url = "http://localhost/access.php";
StringRequest stringRequest = new StringRequest(Request.Method.POST, url, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
Log.e(TAG, "Response is = " + response);
if(response.equals("success_access")){
try {
JSONObject jsonObject = new JSONObject(response);
Log.e(TAG, "JSON Object is = " + jsonObject);
final String accessdb = jsonObject.getString("access");
final String passworddb = jsonObject.getString("password");
final String fullnamedb = jsonObject.getString("fullname");
final String branchdb = jsonObject.getString("branch");
final String sectiondb = jsonObject.getString("branch");
Intent intent = new Intent(AccessActivity.this, NextActivity.class);
intent.putExtra("access", accessdb);
intent.putExtra("password", passworddb);
intent.putExtra("fullname", fullnamedb);
intent.putExtra("branch", branchdb);
intent.putExtra("section", sectiondb);
AccessActivity.this.startActivity(intent);
} catch (JSONException e) {
e.printStackTrace();
}
} else{
Toast.makeText(getApplicationContext(), "Access Error", Toast.LENGTH_SHORT).show();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getApplicationContext(), "Volley Error", Toast.LENGTH_SHORT).show();
}
}){
@Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String, String> params = new HashMap<>();
params.put("access", etAccess.getText().toString());
params.put("password", etPassword.getText().toString());
return params;
}
};
MySingleton.getInstance(getApplicationContext()).addToRequestQueue(stringRequest);
}
});
}
}
更新:
我的logcat顯示此
08-22 10:22:22.059 19801-19908/com.apps.test D/NetworkSecurityConfig: No Network Security Config specified, using platform default
08-22 10:22:22.064 19801-19801/com.apps.test E/my.com.apps.test.Activity: Response is = success_access{"access":"PA001","password":"123","fullname":"ARCADE","branch":"HQ","section":"HQ"}
08-22 10:22:22.112 19801-19825/com.apps.test D/EGL_emulation: eglMakeCurrent: 0xb3305060: ver 2 0 (tinfo 0xb3303200)
08-22 10:22:22.128 19801-19825/com.apps.test D/EGL_emulation: eglMakeCurrent: 0xb3305060: ver 2 0 (tinfo 0xb3303200)
08-22 10:22:22.134 19801-19825/com.apps.test D/EGL_emulation: eglMakeCurrent: 0xb3305060: ver 2 0 (tinfo 0xb3303200)
08-22 10:22:22.140 19801-19825/com.apps.test D/EGL_emulation: eglMakeCurrent: 0xb3305060: ver 2 0 (tinfo 0xb3303200)
08-22 10:22:23.697 19801-19825/com.apps.test D/EGL_emulation: eglMakeCurrent: 0xb3305060: ver 2 0 (tinfo 0xb3303200)
08-22 10:22:25.751 19801-19825/com.apps.test D/EGL_emulation: eglMakeCurrent: 0xb3305060: ver 2 0 (tinfo 0xb3303200)
08-22 10:22:25.780 19801-19825/com.apps.test D/EGL_emulation: eglMakeCurrent: 0xb3305060: ver 2 0 (tinfo 0xb3303200)
感謝有人可以幫助我解決此問題。 謝謝。
嘗試這個。
在AccessActivity中
Intent intent = new Intent(AccessActivity.this, NextActivity.class);
intent.putExtra("access", accessdb);
intent.putExtra("password", passworddb);
intent.putExtra("fullname", fullnamedb);
intent.putExtra("branch", branchdb);
intent.putExtra("section", sectiondb);
AccessActivity.this.startActivity(intent);
更改
LoginActivity.this.startActivity(intent);
至
AccessActivity.this.startActivity(intent);
在NextActivity中
Intent intent = getIntent();
String access = intent.getStringExtra("access");
String password = intent.getStringExtra("password");
String fullname = intent.getStringExtra("fullname");
String branch = intent.getStringExtra("branch");
String section = intent.getStringExtra("section");
已編輯
更改
if(response.equals("success_access")){
}
至
if(response.contains("success_access")){
}
並根據您的代碼。 您需要確保當前的Activity是com.apps.test.AccessActivity
或com.apps.test.AccessActivity
。
已編輯
改成
if (response.contains("success_access")) {
String res = response.substring(response.indexOf("{"));
try {
JSONObject jsonObject = new JSONObject(res);
final String accessdb = jsonObject.getString("access");
final String passworddb = jsonObject.getString("password");
final String fullnamedb = jsonObject.getString("fullname");
final String branchdb = jsonObject.getString("branch");
final String sectiondb = jsonObject.getString("branch");
Log.e("Tag", accessdb);
} catch (JSONException e) {
e.printStackTrace();
}
}
您正在請求一個JsonObject嗎? 您似乎對StringRequest有所了解,因此請保持簡單。 將您的StringRequest
更改為JsonObjectRequest
。
問題:
正如您在logcat中看到的那樣,從服務器獲得的響應是success_access{"access":"PA001","password":"123","fullname":"ARCADE","branch":"HQ","section":"HQ"}
首先,這不是有效的JSON
。 同樣,這就是response
變量的值。 現在,您的response.equals("success_access")
將永遠不會返回true,因此代碼控件將永遠不會進入if
塊。
解決方案:
理想情況下,不應有諸如success_access
類的多余字符串,否則您的響應應該是一個始終包含一個指定字段的JSON
對象(例如, result
字段)。 為了顯示成功,您的JSON如下所示:
{
result : "success_access",
/* other parameters down here */
}
並且在失敗的情況下:
{
result : "access_failed"
}
然后,您的代碼應將respose
字符串轉換為JSON
(您的服務器代碼應確保其始終返回有效的JSON),以檢查result
字段的值並繼續進行操作。
快速解決 :
將您的代碼更改為:
....
Log.e(TAG, "Response is = " + response);
String result = response.replace("{.*}","");
String jsonString = response.replace(result, "");
if(result.equals("success_access")){
try {
JSONObject jsonObject = new JSONObject(jsonString);
....
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