Writing an Android GUI using Python

• Download examples (external link)

Introduction

The examples in this article will create menu, scroll view and popup window. For menu widget, programmer should override Android functions of activity, which are “onCreateOptionsMenu”, “onPrepareOptionsMenu”, “onOptionsItemSelected”. Using Python, the same functions should be defined and assigned to activity object. Popup window is often used to show information or perform some interactions with customer. Python permits define functions in another function, which is convenient to define widgets in popup window.

Scroll View

Creating scroll view is more directly and simple.

Create Scroll View Object

MyScroll = Service.ScrollViewClass._New(MyLayout);
MyScroll.setLinearLayoutParams(Service.FILL_PARENT,Service.WRAP_CONTENT);

Create Root Layout in the Scroll View

MyScrollLayout = Service.LinearLayoutClass._New(MyScroll);
MyScrollLayout.setOrientation("VERTICAL");
MyScrollLayout.setFrameLayoutParams(Service.FILL_PARENT,Service.WRAP_CONTENT);

Create a Button, When Clicked, We Create A New Button in Scroll View

MyButtonIndex = 1;
//#set onClick event listener
def MyButton_onClick(self,Ev) :
global MyButtonIndex;
//#Create a new button in scroll view
b = Service.ButtonClass._New(MyScrollLayout);
//#Set text content and color
    b.setText("Button" + str(MyButtonIndex));
    b.setTextColor(0xFFFF0000);   
    b.setLinearLayoutParams(Service.FILL_PARENT,Service.WRAP_CONTENT);
    MyButtonIndex = MyButtonIndex + 1;
return;
//#assign event listener to object
MyButton.onClick = MyButton_onClick;

Menu

For menu, we should override functions of the Activity object which are onCreateOptionsMenu, onPrepareOptionsMenu, and onOptionsItemSelected. The activity object is obtained using code “StarActivity = Service.ActivityClass.getCurrent();”.

Override Function “onCreateOptionsMenu”

In this function, we create some menu items:

def StarActivity_onCreateOptionsMenu(self,menu) :
    menu.add1(0, 1, 1, "open");
    menu.add1(0, 2, 2, "edit");
    menu.add1(0, 3, 3, "update");
    menu.add1(0, 4, 4, "clode");
    return True;
StarActivity.onCreateOptionsMenu = StarActivity_onCreateOptionsMenu;

Override Function “onPrepareOptionsMenu”

The function simply returns true to enable menu to show:

def StarActivity_onPrepareOptionsMenu(self,menu) :
    return True;
StarActivity.onPrepareOptionsMenu = StarActivity_onPrepareOptionsMenu;

Override Function “onOptionsItemSelected”

def StarActivity_onOptionsItemSelected(self,menuitem) :    
    id = menuitem.getItemId();
    if( id == 1 ) :
        self.setTitle("Open Text!");
    if( id == 2 ) :
        self.setTitle("Edit Text!");
    if( id == 3 ) :
        self.setTitle("Update Text!");
    if( id == 4 ) :
        self.setTitle("Close Text!");
    return True; 
StarActivity.onOptionsItemSelected = StarActivity_onOptionsItemSelected;

Popup Window

Popup window is often used to show information or perform some interactions with customer.

Create a Button, When Clicked, We Create a Popup Window

OpenPopWindowButton = Service.ButtonClass._New(ButtonLayout);
OpenPopWindowButton.setText("Open popup window");
OpenPopWindowButton.setLinearLayoutParams(Service.WRAP_CONTENT,Service.WRAP_CONTENT);  
def OpenPopWindowButton_onClick(self, Ev):
   …
    return;
OpenPopWindowButton.onClick = OpenPopWindowButton_onClick

In onClick Event Function, A Popup Window is Created

Because Python permits to define function in another function, we can create popup window and create functions for it.

def OpenPopWindowButton_onClick(self, Ev):
    //#create popup window
    MyPopupWindow = Service.PopupWindowClass._New()
    //#set onDismiss event listener
    def MyPopupWindow_onDismiss(self, Ev):
        Service.ToastClass._New().makeText("PopupWindow is dismiss",0).show();
        return;
    MyPopupWindow.onDismiss = MyPopupWindow_onDismiss;
    
    //#create root layout for popup window
    PopupLayout = Service.LinearLayoutClass._New();
    PopupLayout.setBackgroundColor(0xFF0000FF) #--blue
    //#create a button
    MyButton = Service.ButtonClass._New(PopupLayout);
    def MyButton_onClick(self, Ev) :
        //#when is clicked, we show information and close the popup window
        Service.ToastClass._New().makeText("Button is click",0).show();
        MyPopupWindow.dismiss();
        return;
    MyButton.onClick = MyButton_onClick;
    MyButton.setText("CloseWindow");
    MyButton.setLinearLayoutParams(Service.WRAP_CONTENT,Service.WRAP_CONTENT); 
    //#assign layout to popup window.
   MyPopupWindow.setContentView(PopupLayout);
    MyPopupWindow.setWidth(200);
    MyPopupWindow.setHeight(200);
    MyPopupWindow.setFocusable(True);      
    MyPopupWindow.showAtLocation(self,17,0,0);
    //#prevent garbage collected by python.
    MyPopupWindow._LockGC();
    return;