我如何找出电话为何执行Toast？

Question

@Override
public void onClick(View v){
switch(v.getId()) {
  ...
    case R.id.folder:
        Intent openFolder=new Intent(this,Folder.class);
        Toast.makeText(this, "Please wait...", Toast.LENGTH_SHORT).show();
        startActivity(openFolder);
        break;
    ...
 }
}

folder is the id of a textview. When the textview is clicked, Folder activity should be opened. But it takes 9 secs for the activity to open, so I decided to put a toast to let the user know the app is opening the activity. But somehow, this Toast isn't popping up why?

Can I use the debugger to find out why?