How to remove the picture illustration in Android gallery _android

Copy Code code as follows:

/* Long press the picture in gallery to delete the picture.
Gallery.setonitemlongclicklistener (New Onitemlongclicklistener () {

@Override
public boolean Onitemlongclick (adapterview<?> arg0, View arg1,
Final int arg2, long arg3) {
TODO auto-generated Method Stub
New Alertdialog.builder (Sdcardactivity.this)
. SetIcon (Android. R.drawable.ic_dialog_alert)
. Settitle ("Warm Tip")
. Setmessage ("Do you really want to delete this picture?")
. Setpositivebutton (OK), new Dialoginterface.onclicklistener () {

@Override
public void OnClick (Dialoginterface dialog, int which) {
TODO auto-generated Method Stub
File File=new file (Constants.path+imagenames[arg2]);
if (file.exists ()) {
File.delete ();
}
}
})
. Setnegativebutton ("Cancel", null)
. Show ();
return true;
}

});
}