Im trying to set up an android login page using PHP and MySQL. I came across this Google 'Volley.jar' Library and i am trying to implement it but my LoginActivity has errors when getting the details and using the AppController to make a request. I have attached the LoginACtivity and AppController code. Login Activity
我试图使用PHP和MySQL建立一个Android登录页面。我遇到了这个Google'Volley.jar'库,我正在尝试实现它,但是我的LoginActivity在获取详细信息并使用AppController发出请求时出错。我已经附加了LoginACtivity和AppController代码。登录活动
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
inputUsername = (EditText) findViewById(R.id.username);
inputPassword = (EditText) findViewById(R.id.password);
btnLogin = (Button) findViewById(R.id.btnLogin);
// Progress dialog
pDialog = new ProgressDialog(this);
pDialog.setCancelable(false);
// Session manager
session = new SessionManager(getApplicationContext());
// Check if user is already logged in or not
if (session.isLoggedIn()) {
// User is already logged in. Take him to main activity
Intent intent = new Intent(LoginActivity.this, MainActivity.class);
startActivity(intent);
finish();
}
// Login button Click Event
btnLogin.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
String username = inputUsername.getText().toString();
String password = inputPassword.getText().toString();
// Check for empty data in the form
if (username.trim().length() > 0 && password.trim().length() > 0) {
// login user
checkLogin(username, password);
} else {
// Prompt user to enter credentials
Toast.makeText(getApplicationContext(),
"Please enter the credentials!", Toast.LENGTH_LONG)
.show();
}
}
});
}
private void checkLogin(final String username, final String password) {
// Tag used to cancel the request
String tag_string_req = "req_login";
pDialog.setMessage("Logging in ...");
showDialog();
StringRequest strReq = new StringRequest(Method.POST,
AppConfig.URL_REGISTER, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
Log.d(TAG, "Login Response: " + response.toString());
hideDialog();
try {
JSONObject jObj = new JSONObject(response);
boolean error = jObj.getBoolean("error");
// Check for error node in json
if (!error) {
// user successfully logged in
// Create login session
session.setLogin(true);
// Launch main activity
Intent intent = new Intent(LoginActivity.this,
MainActivity.class);
startActivity(intent);
finish();
} else {
// Error in login. Get the error message
String errorMsg = jObj.getString("error_msg");
Toast.makeText(getApplicationContext(),
errorMsg, Toast.LENGTH_LONG).show();
}
} catch (JSONException e) {
// JSON error
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.e(TAG, "Login Error: " + error.getMessage());
Toast.makeText(getApplicationContext(),
error.getMessage(), Toast.LENGTH_LONG).show();
hideDialog();
}
}) {
@Override
protected Map<String, String> getParams() {
// Posting parameters to login url
Map<String, String> params = new HashMap<String, String>();
params.put("tag", "login");
params.put("username", username);
params.put("password", password);
return params;
}
};
// Adding request to request queue
AppController.getInstance().addToRequestQueue(strReq, tag_string_req);
}
private void showDialog() {
if (!pDialog.isShowing())
pDialog.show();
}
private void hideDialog() {
if (pDialog.isShowing())
pDialog.dismiss();
}
AppController
private RequestQueue mRequestQueue;
private static AppController mInstance;
@Override
public void onCreate() {
super.onCreate();
mInstance = this;
}
public static synchronized AppController getInstance() {
return mInstance;
}
public RequestQueue getRequestQueue() {
if (mRequestQueue == null) {
mRequestQueue = Volley.newRequestQueue(getApplicationContext());
}
return mRequestQueue;
}
public <T> void addToRequestQueue(Request<T> req, String tag) {
req.setTag(TextUtils.isEmpty(tag) ? TAG : tag);
getRequestQueue().add(req);
}
public <T> void addToRequestQueue(Request<T> req) {
req.setTag(TAG);
getRequestQueue().add(req);
}
public void cancelPendingRequests(Object tag) {
if (mRequestQueue != null) {
mRequestQueue.cancelAll(tag);
}
}
And here is my logcat: 04-03 04:16:40.190: E/AndroidRuntime(1099): FATAL EXCEPTION: main 04-03 04:16:40.190: E/AndroidRuntime(1099): Process: com.example.zcasm_learningplatform, PID: 1099 04-03 04:16:40.190: E/AndroidRuntime(1099): java.lang.NullPointerException 04-03 04:16:40.190: E/AndroidRuntime(1099): at com.example.zcasm_learningplatform.LoginActivity.checkLogin(LoginActivity.java:154) 04-03 04:16:40.190: E/AndroidRuntime(1099): at com.example.zcasm_learningplatform.LoginActivity.access$2(LoginActivity.java:87) 04-03 04:16:40.190: E/AndroidRuntime(1099): at com.example.zcasm_learningplatform.LoginActivity$1.onClick(LoginActivity.java:76) 04-03 04:16:40.190: E/AndroidRuntime(1099): at android.view.View.performClick(View.java:4424) 04-03 04:16:40.190: E/AndroidRuntime(1099): at android.view.View$PerformClick.run(View.java:18383) 04-03 04:16:40.190: E/AndroidRuntime(1099): at android.os.Handler.handleCallback(Handler.java:733) 04-03 04:16:40.190: E/AndroidRuntime(1099): at android.os.Handler.dispatchMessage(Handler.java:95) 04-03 04:16:40.190: E/AndroidRuntime(1099): at android.os.Looper.loop(Looper.java:137) 04-03 04:16:40.190: E/AndroidRuntime(1099): at android.app.ActivityThread.main(ActivityThread.java:4998) 04-03 04:16:40.190: E/AndroidRuntime(1099): at java.lang.reflect.Method.invokeNative(Native Method) 04-03 04:16:40.190: E/AndroidRuntime(1099): at java.lang.reflect.Method.invoke(Method.java:515) 04-03 04:16:40.190: E/AndroidRuntime(1099): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777) 04-03 04:16:40.190: E/AndroidRuntime(1099): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593) 04-03 04:16:40.190: E/AndroidRuntime(1099): at dalvik.system.NativeStart.main(Native Method)
这是我的logcat:04-03 04:16:40.190:E / AndroidRuntime(1099):致命异常:主04-03 04:16:40.190:E / AndroidRuntime(1099):进程:com.example.zcasm_learningplatform, PID:1099 04-03 04:16:40.190:E / AndroidRuntime(1099):java.lang.NullPointerException 04-03 04:16:40.190:E / AndroidRuntime(1099):at com.example.zcasm_learningplatform.LoginActivity.checkLogin (LoginActivity.java:154)04-03 04:16:40.190:E / AndroidRuntime(1099):at com.example.zcasm_learningplatform.LoginActivity.access $ 2(LoginActivity.java:87)04-03 04:16:40.190: E / AndroidRuntime(1099):at com.example.zcasm_learningplatform.LoginActivity $ 1.onClick(LoginActivity.java:76)04-03 04:16:40.190:E / AndroidRuntime(1099):at android.view.View.performClick( View.java:4424)04-03 04:16:40.190:E / AndroidRuntime(1099):at android.view.View $ PerformClick.run(View.java:18383)04-03 04:16:40.190:E / AndroidRuntime(1099):在android.os.Handler.handleCallback(Handler.java:733)04-03 04:16:40.190:E / AndroidRuntime(1099):at android.os .Handler.dispatchMessage(Handler.java:95)04-03 04:16:40.190:E / AndroidRuntime(1099):at android.os.Looper.loop(Looper.java:137)04-03 04:16:40.190 :E / AndroidRuntime(1099):在android.app.ActivityThread.main(ActivityThread.java:4998)04-03 04:16:40.190:E / AndroidRuntime(1099):at java.lang.reflect.Method.invokeNative( Native Method)04-03 04:16:40.190:E / AndroidRuntime(1099):at java.lang.reflect.Method.invoke(Method.java:515)04-03 04:16:40.190:E / AndroidRuntime(1099) ):at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:777)04-03 04:16:40.190:E / AndroidRuntime(1099):at com.android.internal.os.ZygoteInit。 main(ZygoteInit.java:593)04-03 04:16:40.190:E / AndroidRuntime(1099):at dalvik.system.NativeStart.main(Native Method)
1 个解决方案
#1
0
Same error occured in my case also, i fixed the error by adding AppControler class to manifest. but there may be other objects which are causing this error. I cant see Line 154.
在我的情况下也发生了同样的错误,我通过将AppControler类添加到清单来修复错误。但可能有其他对象导致此错误。我看不到154号线。
In AndroidManifest.xml
<application
android:name="xxx.xxx.xxx.xxx.AppController"
....
>
here xxx refers your package name and ... refers your existing code
这里xxx是指你的包名,而...是指你现有的代码
#1
0
Same error occured in my case also, i fixed the error by adding AppControler class to manifest. but there may be other objects which are causing this error. I cant see Line 154.
在我的情况下也发生了同样的错误,我通过将AppControler类添加到清单来修复错误。但可能有其他对象导致此错误。我看不到154号线。
In AndroidManifest.xml
<application
android:name="xxx.xxx.xxx.xxx.AppController"
....
>
here xxx refers your package name and ... refers your existing code
这里xxx是指你的包名,而...是指你现有的代码