title: NumberFormatException invalid int ""
body: <p>I am trying to take the input values from <code>EditText</code> and I want to save it to sqlite Database. I dont know how to use the logcat [also please explain how can I read the errors from the LogCat].</p>
  
  <p><strong>MainActivity.java:</strong></p>
  
  <pre><code>package com.example.database;
  
  import android.support.v7.app.ActionBarActivity;
  import android.text.Editable;
  import android.app.Activity;
  import android.content.Context;
  import android.database.sqlite.SQLiteDatabase;
  import android.database.sqlite.SQLiteDatabase.CursorFactory;
  import android.database.sqlite.SQLiteOpenHelper;
  import android.os.Bundle;
  import android.view.Menu;
  import android.view.MenuItem;
  import android.view.View;
  import android.widget.Button;
  import android.widget.EditText;
  import android.widget.Toast;
  
  
  public class MainActivity extends Activity{
  
      EditText first,last,age,classc;
      Button add,view;
  
      String FirstName;
      String LastName,Class;
      Integer Age;
  
      sqLit myDB;
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
          myDB = new sqLit(this);
          Link();
          xmlToVar();
          add.setOnClickListener(new View.OnClickListener() {
  
              @Override
              public void onClick(View v) {
                  // TODO Auto-generated method stub
                  Integer flag=myDB.insertValue(FirstName, LastName, Class, Age);
                  if (flag==1)
                  {
                      Context context=getApplicationContext();
                      Toast toast = Toast.makeText(context, "Record Added" , Toast.LENGTH_LONG);
                      toast.show();
                  }
                  else
                  {
                      Context context=getApplicationContext();
                      Toast toast = Toast.makeText(context, "Error Occured" , Toast.LENGTH_LONG);
                      toast.show();
                  }
              }
          });
      }
  
      public void Link()
      {
          first=(EditText) findViewById(R.id.editFirst);
          last=(EditText) findViewById(R.id.editLast);
          classc=(EditText) findViewById(R.id.editClass);
          age=(EditText) findViewById(R.id.editAge);
          add=(Button) findViewById(R.id.Add);
          view=(Button) findViewById(R.id.ViewAll);
      }
  
      public void xmlToVar()
      {
          FirstName = first.getText().toString();
          LastName = last.getText().toString();
          Class = classc.getText().toString();
          Age = Integer.parseInt(age.getText().toString());
      }
  
  
  }
  </code></pre>
  
  <p><strong>sqLit.java:</strong></p>
  
  <pre><code>package com.example.database;
  
  import org.w3c.dom.Text;
  
  import android.content.ContentValues;
  import android.content.Context;
  import android.database.sqlite.SQLiteDatabase;
  import android.database.sqlite.SQLiteOpenHelper;
  import android.database.sqlite.SQLiteDatabase.CursorFactory;
  
  public class sqLit extends SQLiteOpenHelper
  {
  
      public static final String DB_NAME="student12.db";
      public static final String TABLE_NAME="class1";
  
      public static final String COL_1="ROLL NO";
      public static final String COL_2="First Name";
      public static final String COL_3="Last Name";
      public static final String COL_4="Class";
      public static final String COL_5="Age";
  
  
  
  
      public sqLit(Context context) {
          super(context, DB_NAME, null, 1);
          // TODO Auto-generated constructor stub
      }
  
      @Override
      public void onCreate(SQLiteDatabase db) {
          // TODO Auto-generated method stub
          db.execSQL("Create table " + TABLE_NAME + "(" + COL_1 + "INTEGER AUTOINCREMENT PRIMARY KEY," + COL_2 + "TEXT," + COL_3 + "TEXT," + COL_4 + "TEXT," + COL_5 + "INTEGER)");
      }
  
      @Override
      public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
          // TODO Auto-generated method stub
          db.execSQL("Drop Table If Exist" + TABLE_NAME );
          onCreate(db);
      }
  
      public Integer insertValue(String FirstName, String LastName, String Class, Integer Age)
      {
  
          SQLiteDatabase db = this.getWritableDatabase();
          ContentValues contentV = new ContentValues();
          contentV.put(COL_2, FirstName);
          contentV.put(COL_3, LastName);
          contentV.put(COL_4, Class);
          contentV.put(COL_5, Age);
          long isInserted = db.insert(TABLE_NAME, null, contentV);
          if (isInserted == -1){
              return 0;
          }
          else
          {
              return 1;
          }
          }
  
  
  
  
  }
  </code></pre>
  
  <p>Also, please explain how to use LogCat as I don't understand how to read it. </p>
  
  <p><strong>LOGCAT:</strong></p>
  
  <pre><code>06-11 18:44:39.650: E/Trace(29536): error opening trace file: No such file or directory (2)
  06-11 18:44:39.660: D/AndroidRuntime(29536): Shutting down VM
  06-11 18:44:39.660: W/dalvikvm(29536): threadid=1: thread exiting with uncaught exception (group=0xb3f2b288)
  06-11 18:44:39.660: E/AndroidRuntime(29536): FATAL EXCEPTION: main
  06-11 18:44:39.660: E/AndroidRuntime(29536): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.database/com.example.database.MainActivity}: java.lang.NumberFormatException: Invalid int: ""
  06-11 18:44:39.660: E/AndroidRuntime(29536):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
  06-11 18:44:39.660: E/AndroidRuntime(29536):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
  06-11 18:44:39.660: E/AndroidRuntime(29536):    at android.app.ActivityThread.access$600(ActivityThread.java:130)
  06-11 18:44:39.660: E/AndroidRuntime(29536):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
  06-11 18:44:39.660: E/AndroidRuntime(29536):    at android.os.Handler.dispatchMessage(Handler.java:99)
  06-11 18:44:39.660: E/AndroidRuntime(29536):    at android.os.Looper.loop(Looper.java:137)
  06-11 18:44:39.660: E/AndroidRuntime(29536):    at android.app.ActivityThread.main(ActivityThread.java:4745)
  06-11 18:44:39.660: E/AndroidRuntime(29536):    at java.lang.reflect.Method.invokeNative(Native Method)
  06-11 18:44:39.660: E/AndroidRuntime(29536):    at java.lang.reflect.Method.invoke(Method.java:511)
  06-11 18:44:39.660: E/AndroidRuntime(29536):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
  06-11 18:44:39.660: E/AndroidRuntime(29536):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
  06-11 18:44:39.660: E/AndroidRuntime(29536):    at dalvik.system.NativeStart.main(Native Method)
  06-11 18:44:39.660: E/AndroidRuntime(29536): Caused by: java.lang.NumberFormatException: Invalid int: ""
  06-11 18:44:39.660: E/AndroidRuntime(29536):    at java.lang.Integer.invalidInt(Integer.java:138)
  06-11 18:44:39.660: E/AndroidRuntime(29536):    at java.lang.Integer.parseInt(Integer.java:359)
  06-11 18:44:39.660: E/AndroidRuntime(29536):    at java.lang.Integer.parseInt(Integer.java:332)
  06-11 18:44:39.660: E/AndroidRuntime(29536):    at com.example.database.MainActivity.xmlToVar(MainActivity.java:72)
  06-11 18:44:39.660: E/AndroidRuntime(29536):    at com.example.database.MainActivity.onCreate(MainActivity.java:34)
  06-11 18:44:39.660: E/AndroidRuntime(29536):    at android.app.Activity.performCreate(Activity.java:5008)
  06-11 18:44:39.660: E/AndroidRuntime(29536):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
  06-11 18:44:39.660: E/AndroidRuntime(29536):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
  06-11 18:44:39.660: E/AndroidRuntime(29536):    ... 11 more
  06-11 18:46:03.652: D/dalvikvm(30256): Not late-enabling CheckJNI (already on)
  06-11 18:46:03.682: E/Trace(30256): error opening trace file: No such file or directory (2)
  06-11 18:46:03.712: D/AndroidRuntime(30256): Shutting down VM
  06-11 18:46:03.712: W/dalvikvm(30256): threadid=1: thread exiting with uncaught exception (group=0xb3f2b288)
  06-11 18:46:03.712: E/AndroidRuntime(30256): FATAL EXCEPTION: main
  06-11 18:46:03.712: E/AndroidRuntime(30256): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.database/com.example.database.MainActivity}: java.lang.NumberFormatException: Invalid int: ""
  06-11 18:46:03.712: E/AndroidRuntime(30256):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
  06-11 18:46:03.712: E/AndroidRuntime(30256):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
  06-11 18:46:03.712: E/AndroidRuntime(30256):    at android.app.ActivityThread.access$600(ActivityThread.java:130)
  06-11 18:46:03.712: E/AndroidRuntime(30256):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
  06-11 18:46:03.712: E/AndroidRuntime(30256):    at android.os.Handler.dispatchMessage(Handler.java:99)
  06-11 18:46:03.712: E/AndroidRuntime(30256):    at android.os.Looper.loop(Looper.java:137)
  06-11 18:46:03.712: E/AndroidRuntime(30256):    at android.app.ActivityThread.main(ActivityThread.java:4745)
  06-11 18:46:03.712: E/AndroidRuntime(30256):    at java.lang.reflect.Method.invokeNative(Native Method)
  06-11 18:46:03.712: E/AndroidRuntime(30256):    at java.lang.reflect.Method.invoke(Method.java:511)
  06-11 18:46:03.712: E/AndroidRuntime(30256):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
  06-11 18:46:03.712: E/AndroidRuntime(30256):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
  06-11 18:46:03.712: E/AndroidRuntime(30256):    at dalvik.system.NativeStart.main(Native Method)
  06-11 18:46:03.712: E/AndroidRuntime(30256): Caused by: java.lang.NumberFormatException: Invalid int: ""
  06-11 18:46:03.712: E/AndroidRuntime(30256):    at java.lang.Integer.invalidInt(Integer.java:138)
  06-11 18:46:03.712: E/AndroidRuntime(30256):    at java.lang.Integer.parseInt(Integer.java:359)
  06-11 18:46:03.712: E/AndroidRuntime(30256):    at java.lang.Integer.parseInt(Integer.java:332)
  06-11 18:46:03.712: E/AndroidRuntime(30256):    at com.example.database.MainActivity.xmlToVar(MainActivity.java:73)
  06-11 18:46:03.712: E/AndroidRuntime(30256):    at com.example.database.MainActivity.onCreate(MainActivity.java:35)
  06-11 18:46:03.712: E/AndroidRuntime(30256):    at android.app.Activity.performCreate(Activity.java:5008)
  06-11 18:46:03.712: E/AndroidRuntime(30256):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
  06-11 18:46:03.712: E/AndroidRuntime(30256):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
  06-11 18:46:03.712: E/AndroidRuntime(30256):    ... 11 more
  06-11 18:53:33.378: E/Trace(2383): error opening trace file: No such file or directory (2)
  06-11 18:53:33.408: D/AndroidRuntime(2383): Shutting down VM
  06-11 18:53:33.408: W/dalvikvm(2383): threadid=1: thread exiting with uncaught exception (group=0xb3f2b288)
  06-11 18:53:33.408: E/AndroidRuntime(2383): FATAL EXCEPTION: main
  06-11 18:53:33.408: E/AndroidRuntime(2383): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.database/com.example.database.MainActivity}: java.lang.NumberFormatException: Invalid int: ""
  06-11 18:53:33.408: E/AndroidRuntime(2383):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
  06-11 18:53:33.408: E/AndroidRuntime(2383):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
  06-11 18:53:33.408: E/AndroidRuntime(2383):     at android.app.ActivityThread.access$600(ActivityThread.java:130)
  06-11 18:53:33.408: E/AndroidRuntime(2383):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
  06-11 18:53:33.408: E/AndroidRuntime(2383):     at android.os.Handler.dispatchMessage(Handler.java:99)
  06-11 18:53:33.408: E/AndroidRuntime(2383):     at android.os.Looper.loop(Looper.java:137)
  06-11 18:53:33.408: E/AndroidRuntime(2383):     at android.app.ActivityThread.main(ActivityThread.java:4745)
  06-11 18:53:33.408: E/AndroidRuntime(2383):     at java.lang.reflect.Method.invokeNative(Native Method)
  06-11 18:53:33.408: E/AndroidRuntime(2383):     at java.lang.reflect.Method.invoke(Method.java:511)
  06-11 18:53:33.408: E/AndroidRuntime(2383):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
  06-11 18:53:33.408: E/AndroidRuntime(2383):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
  06-11 18:53:33.408: E/AndroidRuntime(2383):     at dalvik.system.NativeStart.main(Native Method)
  06-11 18:53:33.408: E/AndroidRuntime(2383): Caused by: java.lang.NumberFormatException: Invalid int: ""
  06-11 18:53:33.408: E/AndroidRuntime(2383):     at java.lang.Integer.invalidInt(Integer.java:138)
  06-11 18:53:33.408: E/AndroidRuntime(2383):     at java.lang.Integer.parseInt(Integer.java:359)
  06-11 18:53:33.408: E/AndroidRuntime(2383):     at java.lang.Integer.parseInt(Integer.java:332)
  06-11 18:53:33.408: E/AndroidRuntime(2383):     at com.example.database.MainActivity.xmlToVar(MainActivity.java:73)
  06-11 18:53:33.408: E/AndroidRuntime(2383):     at com.example.database.MainActivity.onCreate(MainActivity.java:35)
  06-11 18:53:33.408: E/AndroidRuntime(2383):     at android.app.Activity.performCreate(Activity.java:5008)
  06-11 18:53:33.408: E/AndroidRuntime(2383):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
  06-11 18:53:33.408: E/AndroidRuntime(2383):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
  06-11 18:53:33.408: E/AndroidRuntime(2383):     ... 11 more
  </code></pre>