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POandroid null pointer exception on savebutton click
 

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  1. POandroid null pointer exception on savebutton click
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    <p>I am encountering a <code>Null Pointer Exception</code> on the click on a button. Following is the error log and code. Kindly help. Thanks in advance. </p> <p><strong>LOGCAT:</strong> </p> <pre><code>03-15 11:56:06.611: E/AndroidRuntime(856): FATAL EXCEPTION: main 03-15 11:56:06.611: E/AndroidRuntime(856): java.lang.NullPointerException 03-15 11:56:06.611: E/AndroidRuntime(856): at com.android.database.Database_Manipulation.insertTitle(Database_Manipulation.java:58) 03-15 11:56:06.611: E/AndroidRuntime(856): at com.android.database.Task3Activity$1.onClick(Task3Activity.java:49) 03-15 11:56:06.611: E/AndroidRuntime(856): at android.view.View.performClick(View.java:3511) 03-15 11:56:06.611: E/AndroidRuntime(856): at android.view.View$PerformClick.run(View.java:14105) 03-15 11:56:06.611: E/AndroidRuntime(856): at android.os.Handler.handleCallback(Handler.java:605) 03-15 11:56:06.611: E/AndroidRuntime(856): at android.os.Handler.dispatchMessage(Handler.java:92) 03-15 11:56:06.611: E/AndroidRuntime(856): at android.os.Looper.loop(Looper.java:137) 03-15 11:56:06.611: E/AndroidRuntime(856): at android.app.ActivityThread.main(ActivityThread.java:4424) 03-15 11:56:06.611: E/AndroidRuntime(856): at java.lang.reflect.Method.invokeNative(Native Method) 03-15 11:56:06.611: E/AndroidRuntime(856): at java.lang.reflect.Method.invoke(Method.java:511) 03-15 11:56:06.611: E/AndroidRuntime(856): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 03-15 11:56:06.611: E/AndroidRuntime(856): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 03-15 11:56:06.611: E/AndroidRuntime(856): at dalvik.system.NativeStart.main(Native Method) 03-15 11:56:08.102: I/Process(856): Sending signal. PID: 856 SIG: 9 </code></pre> <p><strong>CODE:</strong></p> <pre><code>public class Database_Manipulation extends Activity { public static final String KEY_ROWID="id"; public static final String KEY_ISBN="isbn"; public static final String KEY_TITLE="title"; public static final String KEY_PUBLISHER="publisher"; private static final String TAG="DBAdapter"; private static final String DATABASE_NAME="books"; private static final String DATABASE_TABLE="titles"; private static final int DATABASE_VERSION=1; private static final String DATABASE_CREATE="create table titles(id integer primary key autoincrement,"+"isbn text not null,title text not null,"+"publisher text not null);"; private final Context context; private DatabaseHelper DBhelper; private SQLiteDatabase db; public Database_Manipulation(Context ctx) { this.context=ctx; DBhelper=new DatabaseHelper(context); } public Database_Manipulation open() throws SQLException { db=DBhelper.getWritableDatabase(); return this; } public void close() { DBhelper.close(); } public long insertTitle(String isbn,String title,String publisher) { ContentValues initialvalues=new ContentValues(); initialvalues.put(KEY_ISBN,isbn); initialvalues.put(KEY_TITLE, title); initialvalues.put(KEY_PUBLISHER, publisher); return db.insert(DATABASE_TABLE, null, initialvalues); } private static class DatabaseHelper extends SQLiteOpenHelper { public DatabaseHelper(Context context) { // TODO Auto-generated constructor stub super(context, DATABASE_NAME, null, DATABASE_VERSION); } @Override public void onCreate(SQLiteDatabase db) { // TODO Auto-generated method stub db.execSQL(DATABASE_CREATE); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { // TODO Auto-generated method stub Log.w(TAG,"UPGRADING"+oldVersion+"to"+newVersion+"which will destroy every old data"); db.execSQL("DROP TABLE IF EXISTS titles"); onCreate(db); } } } //calling the insert title method from the class below at the click event...Everything runs fine but when i click on save button it shows the above given log stack....HERE iS THE CLASS public class Task3Activity extends Activity { /** Called when the activity is first created. */ Context ctx; private String name_get=null,address_get=null,contact_no_get=null; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); //getting the name final EditText name=(EditText)findViewById(R.id.editText1); //getting the address final EditText address=(EditText)findViewById(R.id.editText2); //getting the contact no final EditText contactno=(EditText)findViewById(R.id.editText3); name_get=name.getText().toString(); address_get=address.getText().toString(); contact_no_get=contactno.getText().toString(); Toast.makeText(getApplicationContext(),name_get+address_get+contact_no_get,Toast.LENGTH_LONG).show(); //buttons final Button save=(Button)findViewById(R.id.button1); final Button update=(Button)findViewById(R.id.button2); final Button delete=(Button)findViewById(R.id.button3); //SAVE BUTTON save.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { long ret=0; Database_Manipulation dm=new Database_Manipulation(ctx); if(dm!=null) {ret=dm.insertTitle(name_get,address_get,contact_no_get); Toast.makeText(getApplicationContext(),"recieved somthing",Toast.LENGTH_SHORT).show(); } else Toast.makeText(getApplicationContext(), "empty context",Toast.LENGTH_SHORT).show(); } }); //UPDATE BUTTON update.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Toast.makeText(getApplicationContext(), address_get,Toast.LENGTH_SHORT).show(); } }); //DELETE BUTTON delete.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Toast.makeText(getApplicationContext(), contact_no_get,Toast.LENGTH_SHORT).show(); } }); }} </code></pre>
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    1. COCheck line number 58 in **Database_Manipulation.java**
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    2. CODouble click on the lines `03-15 11:56:06.611: E/AndroidRuntime(856): at com.android.database.Database_Manipulation.insertTitle(Database_Manipulation.java:58)` and `03-15 11:56:06.611: E/AndroidRuntime(856): at com.android.database.Task3Activity$1.onClick(Task3Activity.java:49) ` and see where they lead you in the code. Post those lines here.
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