I am implementing a basic CRUD function in an android application. I am creating a CREATE method through my registration and READ on my login. I'm not receiving errors on my registration but when I login my app crashes and generates a null pointer exception on my cursor.
I call the method searchRecord on button click of login:
mLogin.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if(!mUsername.getText().toString().isEmpty() && !mPassword.getText().toString().isEmpty()) {
DBase db = new DBase(MainActivity.this);
if(db.searchRecord(mUsername.getText().toString(), mPassword.getText().toString())){
Toast.makeText(MainActivity.this, "Welcome, "+mUsername.getText().toString()+"!", Toast.LENGTH_LONG).show();
Intent intent = new Intent(MainActivity.this,TimeSetter.class);
startActivity(intent);
}
else {
Intent intent = new Intent(MainActivity.this,SignupActivity.class);
startActivity(intent);
}
}
}
});
Here is the searchRecord method in my DBase class:
public Boolean searchRecord(String username, String password) throws SQLException{
Boolean isUser = false;
String selectQuery = "SELECT * FROM "+DB_TABLE+" WHERE "+K_NAME+" = "+username+ " AND "+K_PASSWORD+" = "+password;
Cursor c = null;
c = dBase.rawQuery(selectQuery, null);
if(c.moveToFirst()){
isUser = false;
}
else {
isUser = false;
}
return isUser;
}
I actually based that on a get record function from a separate project that I found since I'm not really familiar with SQLite:
public String[] getRecord(int rid) throws SQLException{
String selectQuery = "SELECT * FROM "+DB_TABLE+" WHERE "+K_RID+" = "+rid;
Cursor c = null;
c = dBase.rawQuery(selectQuery, null);
String[] data = new String[2];
if(c.moveToFirst()){
int indexName = c.getColumnIndex(K_NAME);
int indexCourse = c.getColumnIndex(K_EMAIL);
int indexPassword = c.getColumnIndex(K_PASSWORD);
data[0] = c.getString(indexName);
data[1] = c.getString(indexCourse);
data[2] = c.getString(indexPassword);
}
return data;
}
And lastly, here is my database declaration:
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL(
"CREATE TABLE " + DB_TABLE + " (" +
K_RID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
K_NAME + " TEXT NOT NULL, " +
K_EMAIL + " TEXT NOT NULL, " +
K_PASSWORD + " TEXT NOT NULL);"
);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXIST " + DB_TABLE);
onCreate(db);
}
Here is my logs about the error:
02-25 22:33:22.261 21810-21810/com.exceptions.finalproject E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.exceptions.finalproject, PID: 21810
java.lang.NullPointerException: Attempt to invoke virtual method 'android.database.Cursor android.database.sqlite.SQLiteDatabase.rawQuery(java.lang.String, java.lang.String[])' on a null object reference
at com.exceptions.finalproject.DBase.searchRecord(DBase.java:84)
at com.exceptions.finalproject.MainActivity$1$1.onClick(MainActivity.java:38)
at android.view.View.performClick(View.java:4848)
at android.view.View$PerformClick.run(View.java:20262)
at android.os.Handler.handleCallback(Handler.java:815)
at android.os.Handler.dispatchMessage(Handler.java:104)
at android.os.Looper.loop(Looper.java:194)
at android.app.ActivityThread.main(ActivityThread.java:5637)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:960)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
It points to this line: c = dBase.rawQuery(selectQuery, null);
Thanks!
