Android check box

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.*;

public class MainActivity extends Activity {

CheckBox c1,c2,c3;

Button b1;

            @Override

            protected void onCreate(Bundle savedInstanceState) {

                        super.onCreate(savedInstanceState);

                        setContentView(R.layout.activity_main);

                        c1=(CheckBox) findViewById(R.id.checkBox1);

                        c2=(CheckBox) findViewById(R.id.checkBox2);

                        c3=(CheckBox) findViewById(R.id.checkBox3);

                        b1=(Button) findViewById(R.id.button1);

                        b1.setOnClickListener(L1);

            }

public OnClickListener L1=new OnClickListener()

    {

    public void onClick(View v)    {

            String h1="",h2="",h3="",h4;

            if(v==b1) {

                  if(c1.isChecked()==true)

                         h1=c1.getText().toString();

                  if(c2.isChecked()==true)

                         h2=c2.getText().toString();

                  if(c3.isChecked()==true)

                         h3=c3.getText().toString();

                    h4=h1 +" "+h2 +" "+h3;

                   Toast.makeText(getBaseContext(),h4,Toast.LENGTH_LONG).show();

            }

    }

    }; }