我想使用我的应用程序创建登录注册系统，但无法正常工作。这里的代码我认为我有错误。
PHP登录脚本：
<?php
//load and connect to MySQL database stuff
require("config.inc.php");
if (!empty($_POST)) {
//gets user's info based off of a username.
$query = "
SELECT
id,
username,
password
FROM users
WHERE
username = :username
";
$query_params = array(
':username' => $_POST['username']
);
try {
$stmt = $db->prepare($query);
$result = $stmt->execute($query_params);
}
catch (PDOException $ex) {
// For testing, you could use a die and message.
//die("Failed to run query: " . $ex->getMessage());
//or just use this use this one to product JSON data:
$response["success"] = 0;
$response["message"] = "Database Error1. Please Try Again!";
die(json_encode($response));
}
//This will be the variable to determine whether or not the user's information is correct.
//we initialize it as false.
$validated_info = false;
//fetching all the rows from the query
$row = $stmt->fetch();
if ($row) {
//if we encrypted the password, we would unencrypt it here, but in our case we just
//compare the two passwords
if ($_POST['password'] === $row['password']) {
$login_ok = true;
}
}
// If the user logged in successfully, then we send them to the private members-only page
// Otherwise, we display a login failed message and show the login form again
if ($login_ok) {
$response["success"] = 1;
$response["message"] = "Login successful!";
die(json_encode($response));
} else {
$response["success"] = 0;
$response["message"] = "Invalid Credentials!";
die(json_encode($response));
}
} else {
$response["message"] = "Enter username and password!";
die(json_encode($response));
}
?>
<h1>Login</h1>
<form action="login.php" method="post">
Username:<br />
<input type="text" name="username" placeholder="username" />
<br /><br />
Password:<br />
<input type="password" name="password" placeholder="password" value="" />
<br /><br />
<input type="submit" value="Login" />
</form>
<a href="register.php">Register</a>
<?php
?>
LoginActivity：
public class LoginActivity extends ActionBarActivity {
Button btnLogin;
Button btnLinkToRegister;
EditText inputEmail;
EditText inputPassword;
TextView loginErrorMsg;
private ProgressDialog pDialog;
JSONParser jsonParser = new JSONParser();
// JSON Response node names
private static String KEY_SUCCESS = "success";
private static String KEY_ERROR = "error";
private static String KEY_ERROR_MSG = "error_msg";
private static String KEY_UID = "uid";
private static String KEY_NAME = "name";
private static String KEY_EMAIL = "email";
private static String KEY_CREATED_AT = "created_at";
private static final String TAG_MESSAGE = "message";
// Testing on emulator
private static String LOGIN_URL = "http://10.0.2.2/webservice/login.php";
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
getSupportActionBar().hide();
setContentView(R.layout.login);
// Importing all assets like buttons, text fields
inputEmail = (EditText) findViewById(R.id.loginEmail);
inputPassword = (EditText) findViewById(R.id.loginPassword);
btnLogin = (Button) findViewById(R.id.btnLogin);
btnLinkToRegister = (Button) findViewById(R.id.btnLinkToRegisterScreen);
loginErrorMsg = (TextView) findViewById(R.id.login_error);
// Login button Click Event
btnLogin.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
new LoginProcess().execute();
}
});
// Link to Register Screen
btnLinkToRegister.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
Intent i = new Intent(getApplicationContext(),
RegisterActivity.class);
startActivity(i);
finish();
}
});
}
private class LoginProcess extends AsyncTask<String, String, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(LoginActivity.this);
pDialog.setMessage("Attempting login...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
@Override
protected String doInBackground(String... args) {
// Check for success tag
int success;
String username = inputEmail.getText().toString();
String password = inputPassword.getText().toString();
try {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("username", username));
params.add(new BasicNameValuePair("password", password));
Log.d("request!", "starting");
// getting product details by making HTTP request
JSONObject json = jsonParser.makeHttpRequest(LOGIN_URL, "POST",
params);
// check your log for json response
Log.d("Login attempt", json.toString());
// json success tag
success = json.getInt(KEY_SUCCESS);
if (success == 1) {
Log.d("Login Successful!", json.toString());
Intent i = new Intent(LoginActivity.this,
MainActivity.class);
finish();
startActivity(i);
return json.getString(TAG_MESSAGE);
} else {
Log.d("Login Failure!", json.getString(TAG_MESSAGE));
return json.getString(TAG_MESSAGE);
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog once product deleted
pDialog.dismiss();
if (file_url != null) {
Toast.makeText(LoginActivity.this, file_url, Toast.LENGTH_LONG).show();
}
}
}
}
JSONParser类：
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
public JSONObject getJSONFromUrl(String url, List<NameValuePair> params) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(params));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "n");
}
is.close();
json = sb.toString();
Log.e("JSON", json);
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
Log.d("JSON Parser", json);
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
public JSONObject makeHttpRequest(String url, String method,
List<NameValuePair> params) {
// Making HTTP request
try {
// check for request method
if(method == "POST"){
// request method is POST
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(params));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}else if(method == "GET"){
// request method is GET
DefaultHttpClient httpClient = new DefaultHttpClient();
String paramString = URLEncodedUtils.format(params, "utf-8");
url += "?" + paramString;
HttpGet httpGet = new HttpGet(url);
HttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
当我想使用正确的用户名和密码登录时，它正在工作，但如果我输入正确的用户名和密码错误，我就会收到错误消息。但是如果我删除了query_params：
$result = $stmt->execute($query_params);
我没有任何错误，但我无法登录
logcat：
08-31 10:40:39.885: E/Trace(1239): error opening trace file: No such file or directory (2)
08-31 10:40:40.785: D/dalvikvm(1239): GC_FOR_ALLOC freed 118K, 2% free 10936K/11143K, paused 55ms, total 57ms
08-31 10:40:40.845: I/dalvikvm-heap(1239): Grow heap (frag case) to 13.346MB for 2764816-byte allocation
08-31 10:40:40.954: D/dalvikvm(1239): GC_CONCURRENT freed 1K, 2% free 13635K/13895K, paused 24ms+6ms, total 108ms
08-31 10:40:41.334: D/libEGL(1239): loaded /system/lib/egl/libEGL_emulation.so
08-31 10:40:41.345: D/(1239): HostConnection::get() New Host Connection established 0x2a126450, tid 1239
08-31 10:40:41.357: D/libEGL(1239): loaded /system/lib/egl/libGLESv1_CM_emulation.so
08-31 10:40:41.376: D/libEGL(1239): loaded /system/lib/egl/libGLESv2_emulation.so
08-31 10:40:41.455: W/EGL_emulation(1239): eglSurfaceAttrib not implemented
08-31 10:40:41.465: D/OpenGLRenderer(1239): Enabling debug mode 0
08-31 10:40:45.545: D/request!(1239): starting
08-31 10:40:45.645: W/EGL_emulation(1239): eglSurfaceAttrib not implemented
08-31 10:40:48.205: E/JSON Parser(1239): Error parsing data org.json.JSONException: Value <br of type java.lang.String cannot be converted to JSONObject
08-31 10:40:48.355: W/dalvikvm(1239): threadid=11: thread exiting with uncaught exception (group=0x40a13300)
08-31 10:40:48.754: E/AndroidRuntime(1239): FATAL EXCEPTION: AsyncTask #1
08-31 10:40:48.754: E/AndroidRuntime(1239): java.lang.RuntimeException: An error occured while executing doInBackground()
08-31 10:40:48.754: E/AndroidRuntime(1239): at android.os.AsyncTask$3.done(AsyncTask.java:299)
08-31 10:40:48.754: E/AndroidRuntime(1239): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
08-31 10:40:48.754: E/AndroidRuntime(1239): at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
08-31 10:40:48.754: E/AndroidRuntime(1239): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
08-31 10:40:48.754: E/AndroidRuntime(1239): at java.util.concurrent.FutureTask.run(FutureTask.java:137)
08-31 10:40:48.754: E/AndroidRuntime(1239): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
08-31 10:40:48.754: E/AndroidRuntime(1239): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
08-31 10:40:48.754: E/AndroidRuntime(1239): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
08-31 10:40:48.754: E/AndroidRuntime(1239): at java.lang.Thread.run(Thread.java:856)
08-31 10:40:48.754: E/AndroidRuntime(1239): Caused by: java.lang.NullPointerException
08-31 10:40:48.754: E/AndroidRuntime(1239): at com.example.diycenter.LoginActivity$LoginProcess.doInBackground(LoginActivity.java:118)
08-31 10:40:48.754: E/AndroidRuntime(1239): at com.example.diycenter.LoginActivity$LoginProcess.doInBackground(LoginActivity.java:1)
08-31 10:40:48.754: E/AndroidRuntime(1239): at android.os.AsyncTask$2.call(AsyncTask.java:287)
08-31 10:40:48.754: E/AndroidRuntime(1239): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
08-31 10:40:48.754: E/AndroidRuntime(1239): ... 5 more
08-31 10:40:51.844: E/WindowManager(1239): Activity com.example.diycenter.LoginActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@4148a190 that was originally added here
08-31 10:40:51.844: E/WindowManager(1239): android.view.WindowLeaked: Activity com.example.diycenter.LoginActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@4148a190 that was originally added here
08-31 10:40:51.844: E/WindowManager(1239): at android.view.ViewRootImpl.<init>(ViewRootImpl.java:374)
08-31 10:40:51.844: E/WindowManager(1239): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:292)
08-31 10:40:51.844: E/WindowManager(1239): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:224)
08-31 10:40:51.844: E/WindowManager(1239): at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:149)
08-31 10:40:51.844: E/WindowManager(1239): at android.view.Window$LocalWindowManager.addView(Window.java:547)
08-31 10:40:51.844: E/WindowManager(1239): at android.app.Dialog.show(Dialog.java:277)
08-31 10:40:51.844: E/WindowManager(1239): at com.example.diycenter.LoginActivity$LoginProcess.onPreExecute(LoginActivity.java:96)
08-31 10:40:51.844: E/WindowManager(1239): at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:586)
08-31 10:40:51.844: E/WindowManager(1239): at android.os.AsyncTask.execute(AsyncTask.java:534)
08-31 10:40:51.844: E/WindowManager(1239): at com.example.diycenter.LoginActivity$1.onClick(LoginActivity.java:69)
08-31 10:40:51.844: E/WindowManager(1239): at android.view.View.performClick(View.java:4084)
08-31 10:40:51.844: E/WindowManager(1239): at android.view.View$PerformClick.run(View.java:16966)
08-31 10:40:51.844: E/WindowManager(1239): at android.os.Handler.handleCallback(Handler.java:615)
08-31 10:40:51.844: E/WindowManager(1239): at android.os.Handler.dispatchMessage(Handler.java:92)
08-31 10:40:51.844: E/WindowManager(1239): at android.os.Looper.loop(Looper.java:137)
08-31 10:40:51.844: E/WindowManager(1239): at android.app.ActivityThread.main(ActivityThread.java:4745)
08-31 10:40:51.844: E/WindowManager(1239): at java.lang.reflect.Method.invokeNative(Native Method)
08-31 10:40:51.844: E/WindowManager(1239): at java.lang.reflect.Method.invoke(Method.java:511)
08-31 10:40:51.844: E/WindowManager(1239): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
08-31 10:40:51.844: E/WindowManager(1239): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
08-31 10:40:51.844: E/WindowManager(1239): at dalvik.system.NativeStart.main(Native Method)
答案 0 :(得分：-1)
OP在编辑中写道：
更新：我找到了我添加的解决方案：
在我创建JSONObject之前在JSONParser类中的Log.e("jsonlol", json);然后我在logcat中检查消息是什么，它就像那样：
08-31 12:31:16.854: E/jsonlol(786): <br /> 08-31 12:31:16.854: E/jsonlol(786): <b>Notice</b>: Undefined variable: login_ok in <b>C:\xampp\htdocs\webservice\login.php</b> on line <b>54</b><br /> 08-31 12:31:16.854: E/jsonlol(786): {"success":0,"message":"Invalid Credentials!"} 08-31 12:31:17.012: E/JSON Parser(786): Error parsing data org.json.JSONException: Value <br of type java.lang.String cannot be converted to JSONObject所以我去了第54行的php文件login.php并且有一个变量名称问题我只是改变了
$validated_info = false;通过
$login_ok = false;如果您按照mybringback教程进行操作，那么脚本就会出错。