[Solved] How to show a dropdown type of menu on tap of button? [closed]

by 


 *<Button
            android:textAllCaps="false"
            android:id="@+id/topic_spinner"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:gravity="left|center_vertical"
            android:background="@android:drawable/btn_dropdown"
            android:singleLine="true"
            android:text="Choose a topic"
            android:textSize="20dp"
            >
        </Button>                                                           Button topic_spinner;                                  topic_spinner.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            final String[] items = new String[]{"Topic1", "Topic2", "Topic3"};
            ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_spinner_dropdown_item, items);
            new AlertDialog.Builder(getActivity()).setTitle("The Topic").setAdapter(adapter, new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    topic_spinner.setText(items[which]);
                    dialog.dismiss();

                }
            }).create().show();
        }
    });*

solved How to show a dropdown type of menu on tap of button? [closed]