Android : adding a button on android listview

i have get the data from local DB and display it in a listView and i had a custom row with button

main.xml will contain listview only

custom-row.xml

    `<?xml version="1.0" encoding="utf-8"?>
     <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/RelativeLayout1"
style="@color/background_gradient_start"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:alpha="0.6"
android:background="@color/background_gradient_start"
android:orientation="vertical" >

<LinearLayout
    android:id="@+id/linearLayout1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" >

    <RelativeLayout
        android:layout_width="177dp"
        android:layout_height="75dp"
        android:layout_weight="5" >

        <TextView
            android:id="@+id/textViewFlightNo"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignBaseline="@+id/textViewCodes"
            android:layout_alignBottom="@+id/textViewCodes"
            android:layout_alignParentLeft="true" />

        <TextView
            android:id="@+id/textViewCodes"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="true"
            android:layout_centerVertical="true"
            android:layout_marginRight="18dp"
            android:background="@color/transparent"
            android:text="Large Text"
            android:textAppearance="?android:attr/textAppearanceSmall"
            android:textColor="#000000"
            android:textSize="16dp" />

    </RelativeLayout>

    <RelativeLayout
        android:layout_width="142dp"
        android:layout_height="match_parent"
        android:layout_weight="5">

        <Button
            android:id="@+id/btn_share"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerHorizontal="true"
            android:layout_centerVertical="true"
            android:alpha="1"
            android:background="#3b3974"
            android:focusable="false"
            android:focusableInTouchMode="false"
            android:minWidth="90dp"
            android:text="Share"
            android:textColor="#f1ecef" />

    </RelativeLayout>

</LinearLayout>

`

activity

so under on Create

    `String [] fromFiledName =new String[]{db.KEY_CODE};

            int[] toViewIDs=new int[]{R.id.textViewCodes};

            SimpleCursorAdapter myCurAdapter=new SimpleCursorAdapter(
                    this, //context
                    R.layout.listview_row_codes,
                    cursor,
                    fromFiledName,
                    toViewIDs
                    );


            // set addapter to list view
            ListView mylistPRN=(ListView) findViewById(R.id.codeslist);
            mylistPRN.setAdapter(myCurAdapter);

            mylistPRN.setAdapter(myCurAdapter);

            mylistPRN.setOnItemClickListener(new OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> parent, View view, int position,
                        long id) {
                    //Intent intent2 = new Intent(this, PromoCodeActivity2.class);
                    Intent sendIntent = new Intent();
                   //intent.putExtra(PromoCodeActivity.requestString, httpRequestString);
                    //getItemAtPosition(position);
                    Cursor c = (Cursor) parent.getAdapter().getItem(position);

                    Intent share = new Intent(Intent.ACTION_SEND);
                    share.setType("text/plain");
                    share.putExtra(Intent.EXTRA_TEXT, "share code "+c.getString(c.getColumnIndex("code")));
                    startActivity(Intent.createChooser(share, "Share Text"));
                    //startActivity(intentD);


                }
            }); `

the code is working and when i click on the list view item it open for sharing but i need it to open when the button is clicked as currently i tried to link the button but i couldn't any help