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POGetting Null Pointer Exception while saving a checkbox value into database
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  1. POGetting Null Pointer Exception while saving a checkbox value into database
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    copied!<p>i want to add checkbox value into database,but it is showing error in the logcat,i had stored my value in variable "ta" and i have toasted it,then it is working,and when i am inserting that value into database it is showing error </p> <pre><code>package com.example.hhh; import android.os.Build; import android.os.Bundle; import android.annotation.SuppressLint; import android.annotation.TargetApi; import android.app.ActionBar; import android.app.ActionBar.Tab; import android.app.ActionBar.TabListener; import android.app.Activity; import android.view.Menu; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.CheckBox; import android.widget.Toast; public class MainActivity extends Activity implements OnClickListener { CheckBox ct1,ct2,ct3,ct4; protected DatabaseAdapter helper; String ta; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); helper=new DatabaseAdapter(this); helper.open(); ct1=(CheckBox)findViewById(R.id.checkBox1); ct2=(CheckBox)findViewById(R.id.checkBox2); ct3=(CheckBox)findViewById(R.id.checkBox3); ct4=(CheckBox)findViewById(R.id.checkBox4); ct1.setOnClickListener(this); ct2.setOnClickListener(this); ct3.setOnClickListener(this); ct4.setOnClickListener(this); } @Override public void onClick(View v) { // TODO Auto-generated method stub CheckBox ct=(CheckBox)v; if(ct.isChecked()) { ta=ct.getText().toString(); helper.Add(ta); Toast.makeText(MainActivity.this, ""+ta, Toast.LENGTH_SHORT).show(); helper.close(); } } } </code></pre> <p>abd database class is package com.example.hhh;</p> <pre><code>import android.content.ContentValues; import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteDatabase.CursorFactory; import android.database.sqlite.SQLiteOpenHelper; import android.util.Log; public class DatabaseAdapter { SQLiteDatabase db; DatabaseHelper helper; public static final String DATABASE="Hotel"; public static final int VERSION=2; public static final String query="create table hhh(id integer primary key,room text not null)"; private Context ctx; public DatabaseAdapter(Context ctx) { super(); this.ctx=ctx; } public class DatabaseHelper extends SQLiteOpenHelper { public DatabaseHelper(Context context ) { super(context, DATABASE, null, VERSION); // TODO Auto-generated constructor stub } @Override public void onCreate(SQLiteDatabase db) { // TODO Auto-generated method stub db.execSQL(query); } @Override public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) { // TODO Auto-generated method stub } } public DatabaseAdapter open() { helper=new DatabaseHelper(ctx); db=helper.getWritableDatabase(); return this; // TODO Auto-generated method stub } public void close() { // TODO Auto-generated method stub helper.close(); } public long Add(String ta) { ContentValues vals=new ContentValues(); vals.put("room", ta); long a=db.insert("Hotel", null, vals); return a; } } </code></pre> <p>and i sloved it by intializing "db" in open() method.</p>
 

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