Update app.py

app.py

@@ -5,6 +5,8 @@ if os.path.exists("./output/") == False:
     os.mkdir("./output/")
     
 archived = shutil.make_archive("./output.zip", 'zip', "./output/")
-if st.download_button(label="Download output "+str(len(os.listdir("./output/"))), data=archived, file_name='output.zip', mime='application/x-zip'):
-    st.write("download")
-st.write(os.listdir("./"))
+output_num = len(os.listdir("./output/"))
+if output_num > 0:
+    st.download_button(label="Download "+str(output_num)+" file", data=archived, file_name='output.zip', mime='application/x-zip'):
+
+print(os.listdir("./"))