lutherdonkey
New Member
I am trying to create a login page which checks a SQLite database for the users details, and if they are present, they are advanced to the main page of the application. I keep getting the java.lang.NullPointerException and do not know what I am doing wrong. Please can you advise on where the issues are in the code?Login.java:\[code\] package com.B00512756.angertwo; public class Login extends Activity implements OnClickListener{ public static final String DATABASE_NAME = "login_database.db"; public static final String USER_INFO_TABLE = "user_information"; public static final String COLUMN_ID = "UserID"; public static final String COLUMN_RATING = "UserName"; public static final String COLUMN_NAME = "Password"; public SQLiteDatabase regDB; public EditText txtUserName; public EditText txtPassword; public static Button btnLogin; public static Button btnCancel; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.loginpage); txtUserName=(EditText)this.findViewById(R.id.txtUname); txtPassword=(EditText)this.findViewById(R.id.txtPwd); //btnLogin=(Button)this.findViewById(R.id.btnLogin); Button Login = (Button) findViewById(R.id.btnLogin); Button Register = (Button) findViewById(R.id.btnregister); Button Cancel = (Button) findViewById(R.id.btnCancel); Register.setOnClickListener(new View.OnClickListener() { public void onClick(View view) { Intent myIntent = new Intent(view.getContext(), Registration.class); startActivityForResult(myIntent, 0); finish(); } }); Cancel.setOnClickListener(new View.OnClickListener() { public void onClick(View view) { android.os.Process.killProcess(android.os.Process.myPid()); } }); Login.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub //String[] columns = new String[]{COLUMN_ID, COLUMN_RATING, COLUMN_NAME }; Cursor c = regDB.query(USER_INFO_TABLE, new String[] { COLUMN_ID, COLUMN_RATING, COLUMN_NAME}, null, null, null, null, null); String result = ""; int iRow = c.getColumnIndex(COLUMN_ID); int iRating = c.getColumnIndex(COLUMN_RATING); int iName = c.getColumnIndex(COLUMN_NAME); c.moveToLast(); for (int i = c.getCount() - 1; i >= 0; i--) { // Get the data result = result + c.getString(iRow) + " " + c.getString(iRating) + " " + c.getString(iName) + "\n" ; if("select * from USER_INFO_TABLE where UserName =" + "\""+ txtUserName + "\""+" and Password="+ "\""+ txtPassword != null); { Intent j = new Intent(); j.setClassName("com.B00512756.angertwo", "com.B00512756.angertwo.AngerprototypetwoActivity"); startActivity(j);} // Move the cursor c.moveToPrevious(); //return result; } c.close(); } }); } private SQLiteDatabase getWritableDatabase() { // TODO Auto-generated method stub return null; } @Override public void onClick(View arg0) { // TODO Auto-generated method stub }}\[/code\]Loginpage.xml:\[code\] <?xml version="1.0" encoding="UTF-8"?> <TableLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:stretchColumns="1"> <TableRow> <TextView android:text="User Name: " android:id="@+id/TextView01" android:layout_width="wrap_content" android:layout_height="wrap_content"> </TextView> <EditText android:text="" android:id="@+id/txtUname" android:layout_width="fill_parent" android:layout_height="wrap_content"> </EditText> </TableRow> <TableRow> <TextView android:text="Password: " android:id="@+id/TextView02" android:layout_width="wrap_content" android:layout_height="wrap_content"> </TextView> <EditText android:text="" android:id="@+id/txtPwd" android:layout_width="fill_parent" android:layout_height="wrap_content" android
assword="true"> </EditText> </TableRow> <TableRow> <Button android:text="Login" android:id="@+id/btnLogin" android:layout_width="fill_parent" android:layout_height="wrap_content"> </Button> <Button android:text="Register" android:id="@+id/btnregister" android:layout_width="fill_parent" android:layout_height="wrap_content"> </Button> <Button android:text="Cancel" android:id="@+id/btnCancel" android:layout_width="fill_parent" android:layout_height="wrap_content"> </Button> </TableRow> </TableLayout>\[/code\]AndroidManifest:\[code\]<?xml version="1.0" encoding="utf-8"?><manifest package="com.B00512756.angertwo" android:versionCode="1" android:versionName="1.0" xmlns:android="http://schemas.android.com/apk/res/android"> <uses-sdk android:minSdkVersion="8" /> <application android:name=".AppState" android:icon="@drawable/icon" android:label="@string/app_name"> <activity android:name=".Login" android:label="@string/main_title"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <activity android:name=".Login" android:label="@string/begin_label" android:theme="@android:style/Theme"></activity> <activity android:name=".Question1" android:label="@string/question_one" android:theme="@android:style/Theme"></activity> <activity android:name=".Question2" android:label="@string/question_two" android:theme="@android:style/Theme"></activity> <activity android:name=".Question3" android:label="@string/question_three" android:theme="@android:style/Theme"></activity> <activity android:name=".Question4" android:label="@string/question_four" android:theme="@android:style/Theme"></activity> <activity android:name=".Question5" android:label="@string/question_five" android:theme="@android:style/Theme"></activity> <!-- <activity android:name=".AngerprototypetwoActivity" android:label="@string/main_title" android:theme="@android:style/Theme"></activity> --> <activity android:name=".nextQ1" android:id="@+id/next_Q1_button" android:theme="@android:style/Theme"></activity> <activity android:name=".Strategies" android:label="@string/strategies_label" android:theme="@android:style/Theme"></activity> <activity android:name=".Contact" android:label="@string/begin_label" android:theme="@android:style/Theme"></activity> <activity android:name=".Strat_What_Is_Anger" android:label="@string/strategies_label_what_is_anger" android:theme="@android:style/Theme"></activity> <activity android:name=".Strat_Use_Distraction" android:label="@string/strategies_label_distraction" android:theme="@android:style/Theme"></activity> <activity android:name=".Registration" android:label="@string/registration" android:theme="@android:style/Theme"></activity> </application></manifest>\[/code\]Logcat:\[code\] 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): FATAL EXCEPTION: main 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): java.lang.NullPointerException 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at com.B00512756.angertwo.Login$3.onClick(Login.java:76) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at android.view.View.performClick(View.java:2408) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at android.view.View$PerformClick.run(View.java:8816) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at android.os.Handler.handleCallback(Handler.java:587) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at android.os.Handler.dispatchMessage(Handler.java:92) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at android.os.Looper.loop(Looper.java:123) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at android.app.ActivityThread.main(ActivityThread.java:4627) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at java.lang.reflect.Method.invokeNative(Native Method) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at java.lang.reflect.Method.invoke(Method.java:521) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at dalvik.system.NativeStart.main(Native Method) 05-19 17:08:17.121: WARN/ActivityManager(58): Force finishing activity com.B00512756.angertwo/.Login 05-19 17:08:17.641: WARN/ActivityManager(58): Activity pause timeout for HistoryRecord{4505c768 com.B00512756.angertwo/.Login} 05-19 17:08:19.731: INFO/Process(27481): Sending signal. PID: 27481 SIG: 9 05-19 17:08:19.751: INFO/WindowManager(58): WIN DEATH: Window{4507d5b0 com.B00512756.angertwo/com.B00512756.angertwo.Login paused=false} 05-19 17:08:19.751: INFO/ActivityManager(58): Process com.B00512756.angertwo (pid 27481) has died. 05-19 17:08:19.921: WARN/InputManagerService(58): Got RemoteException sending setActive(false) notification to pid 27481 uid 10045 05-19 17:08:20.341: DEBUG/dalvikvm(117): GC_EXTERNAL_ALLOC freed 484 objects / 27832 bytes in 383ms 05-19 17:08:24.590: DEBUG/dalvikvm(197): GC_EXPLICIT freed 100 objects / 4336 bytes in 127ms 05-19 17:08:28.610: WARN/ActivityManager(58): Activity destroy timeout for HistoryRecord{4505c768 com.B00512756.angertwo/.Login} 05-19 17:08:29.650: DEBUG/dalvikvm(264): GC_EXPLICIT freed 58 objects / 2800 bytes in 140ms 05-19 17:08:33.513: DEBUG/SntpClient(58): request time failed: java.net.SocketException: Address family not supported by protocol\[/code\]Additional info:\[code\]Login.setOnClickListener(new View.OnClickListener() { @SuppressWarnings("null") @Override public void onClick(View v) { // TODO Auto-generated method stub String name = txtUserName.getText().toString(); String pwd = txtPassword.getText().toString(); SQLiteDatabase regDB = null; //String[] columns = new String[]{COLUMN_ID, COLUMN_RATING, COLUMN_NAME }; Cursor c = regDB.query(USER_INFO_TABLE, new String[] { COLUMN_ID, COLUMN_RATING, COLUMN_NAME}, null, null, null, null, null); if(null!=c){ c.moveToFirst(); System.out.println("Cursor Size"+c.getCount()); } String result = ""; int iRow = c.getColumnIndex(COLUMN_ID); int iRating = c.getColumnIndex(COLUMN_RATING); int iName = c.getColumnIndex(COLUMN_NAME); c.moveToLast(); for (int i = c.getCount() - 1; i >= 0; i--) { // Get the data result = result + c.getString(iRow) + " " + c.getString(iRating) + " " + c.getString(iName) + "\n" ; if("select * from USER_INFO_TABLE where UserName =" + "\""+ name + "\""+" and Password="+ "\""+ pwd != null ); { Intent j = new Intent(); j.setClassName("com.B00512756.angertwo", "com.B00512756.angertwo.AngerprototypetwoActivity"); startActivity(j);} // Move the cursor c.moveToPrevious(); //return result; } c.close(); } });\[/code\]Null error is thrown at this line:\[code\]Cursor c = regDB.query(USER_INFO_TABLE, new String[] { COLUMN_ID, COLUMN_RATING, COLUMN_NAME}, null, null, null, null, null);\[/code\]You help is much appreciated 
assword="true"> </EditText> </TableRow> <TableRow> <Button android:text="Login" android:id="@+id/btnLogin" android:layout_width="fill_parent" android:layout_height="wrap_content"> </Button> <Button android:text="Register" android:id="@+id/btnregister" android:layout_width="fill_parent" android:layout_height="wrap_content"> </Button> <Button android:text="Cancel" android:id="@+id/btnCancel" android:layout_width="fill_parent" android:layout_height="wrap_content"> </Button> </TableRow> </TableLayout>\[/code\]AndroidManifest:\[code\]<?xml version="1.0" encoding="utf-8"?><manifest package="com.B00512756.angertwo" android:versionCode="1" android:versionName="1.0" xmlns:android="http://schemas.android.com/apk/res/android"> <uses-sdk android:minSdkVersion="8" /> <application android:name=".AppState" android:icon="@drawable/icon" android:label="@string/app_name"> <activity android:name=".Login" android:label="@string/main_title"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <activity android:name=".Login" android:label="@string/begin_label" android:theme="@android:style/Theme"></activity> <activity android:name=".Question1" android:label="@string/question_one" android:theme="@android:style/Theme"></activity> <activity android:name=".Question2" android:label="@string/question_two" android:theme="@android:style/Theme"></activity> <activity android:name=".Question3" android:label="@string/question_three" android:theme="@android:style/Theme"></activity> <activity android:name=".Question4" android:label="@string/question_four" android:theme="@android:style/Theme"></activity> <activity android:name=".Question5" android:label="@string/question_five" android:theme="@android:style/Theme"></activity> <!-- <activity android:name=".AngerprototypetwoActivity" android:label="@string/main_title" android:theme="@android:style/Theme"></activity> --> <activity android:name=".nextQ1" android:id="@+id/next_Q1_button" android:theme="@android:style/Theme"></activity> <activity android:name=".Strategies" android:label="@string/strategies_label" android:theme="@android:style/Theme"></activity> <activity android:name=".Contact" android:label="@string/begin_label" android:theme="@android:style/Theme"></activity> <activity android:name=".Strat_What_Is_Anger" android:label="@string/strategies_label_what_is_anger" android:theme="@android:style/Theme"></activity> <activity android:name=".Strat_Use_Distraction" android:label="@string/strategies_label_distraction" android:theme="@android:style/Theme"></activity> <activity android:name=".Registration" android:label="@string/registration" android:theme="@android:style/Theme"></activity> </application></manifest>\[/code\]Logcat:\[code\] 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): FATAL EXCEPTION: main 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): java.lang.NullPointerException 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at com.B00512756.angertwo.Login$3.onClick(Login.java:76) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at android.view.View.performClick(View.java:2408) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at android.view.View$PerformClick.run(View.java:8816) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at android.os.Handler.handleCallback(Handler.java:587) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at android.os.Handler.dispatchMessage(Handler.java:92) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at android.os.Looper.loop(Looper.java:123) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at android.app.ActivityThread.main(ActivityThread.java:4627) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at java.lang.reflect.Method.invokeNative(Native Method) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at java.lang.reflect.Method.invoke(Method.java:521) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 05-19 17:08:17.111: ERROR/AndroidRuntime(27481): at dalvik.system.NativeStart.main(Native Method) 05-19 17:08:17.121: WARN/ActivityManager(58): Force finishing activity com.B00512756.angertwo/.Login 05-19 17:08:17.641: WARN/ActivityManager(58): Activity pause timeout for HistoryRecord{4505c768 com.B00512756.angertwo/.Login} 05-19 17:08:19.731: INFO/Process(27481): Sending signal. PID: 27481 SIG: 9 05-19 17:08:19.751: INFO/WindowManager(58): WIN DEATH: Window{4507d5b0 com.B00512756.angertwo/com.B00512756.angertwo.Login paused=false} 05-19 17:08:19.751: INFO/ActivityManager(58): Process com.B00512756.angertwo (pid 27481) has died. 05-19 17:08:19.921: WARN/InputManagerService(58): Got RemoteException sending setActive(false) notification to pid 27481 uid 10045 05-19 17:08:20.341: DEBUG/dalvikvm(117): GC_EXTERNAL_ALLOC freed 484 objects / 27832 bytes in 383ms 05-19 17:08:24.590: DEBUG/dalvikvm(197): GC_EXPLICIT freed 100 objects / 4336 bytes in 127ms 05-19 17:08:28.610: WARN/ActivityManager(58): Activity destroy timeout for HistoryRecord{4505c768 com.B00512756.angertwo/.Login} 05-19 17:08:29.650: DEBUG/dalvikvm(264): GC_EXPLICIT freed 58 objects / 2800 bytes in 140ms 05-19 17:08:33.513: DEBUG/SntpClient(58): request time failed: java.net.SocketException: Address family not supported by protocol\[/code\]Additional info:\[code\]Login.setOnClickListener(new View.OnClickListener() { @SuppressWarnings("null") @Override public void onClick(View v) { // TODO Auto-generated method stub String name = txtUserName.getText().toString(); String pwd = txtPassword.getText().toString(); SQLiteDatabase regDB = null; //String[] columns = new String[]{COLUMN_ID, COLUMN_RATING, COLUMN_NAME }; Cursor c = regDB.query(USER_INFO_TABLE, new String[] { COLUMN_ID, COLUMN_RATING, COLUMN_NAME}, null, null, null, null, null); if(null!=c){ c.moveToFirst(); System.out.println("Cursor Size"+c.getCount()); } String result = ""; int iRow = c.getColumnIndex(COLUMN_ID); int iRating = c.getColumnIndex(COLUMN_RATING); int iName = c.getColumnIndex(COLUMN_NAME); c.moveToLast(); for (int i = c.getCount() - 1; i >= 0; i--) { // Get the data result = result + c.getString(iRow) + " " + c.getString(iRating) + " " + c.getString(iName) + "\n" ; if("select * from USER_INFO_TABLE where UserName =" + "\""+ name + "\""+" and Password="+ "\""+ pwd != null ); { Intent j = new Intent(); j.setClassName("com.B00512756.angertwo", "com.B00512756.angertwo.AngerprototypetwoActivity"); startActivity(j);} // Move the cursor c.moveToPrevious(); //return result; } c.close(); } });\[/code\]Null error is thrown at this line:\[code\]Cursor c = regDB.query(USER_INFO_TABLE, new String[] { COLUMN_ID, COLUMN_RATING, COLUMN_NAME}, null, null, null, null, null);\[/code\]You help is much appreciated