Activity and Intents

[wil...@planobe.com.br]

Hi guys!

Sorry for bother you with a simple question, but, I'm trying to learn how to start another activity with Ruboto. I followed a thousand tutorials like: https://github.com/ruboto/ruboto/wiki/Using-Activities-and-Intents, but I really couldn't understand some things. My goal is simple, I just want to catch a message from EditText(pressing a Button) and show in a TextView.

Can you make a simple tutorial step by step? It will help a lot!
Thanks!

[Scott Moyer]

Hi William,

While you could open an Activity to get a piece of information, it is really more appropriate to us an AlertDialog for that. Here's an example where we do that to get a line number (to jump to) in the demo-ruboto-irb script in Ruboto IRB:

et = edit_text(:hint => "Line number", :input_type => android.text.InputType::TYPE_CLASS_NUMBER)
     
goto = proc do
    @edit_script.requestFocus
    line = et.text.to_s.to_i - 1
    max_line = @edit_script.getLineCount
    line = max_line if line > max_line
    line = 1 if line < 1
     @edit_script.setSelection @edit_script.getLayout.getLineStart(line)
end

dialog = AlertDialog::Builder.new(@ruboto_java_instance).setTitle("Go to").setView(et).setPositiveButton("Go", goto).create
dialog.window.soft_input_mode = android.view.WindowManager::LayoutParams::SOFT_INPUT_STATE_ALWAYS_VISIBLE
dialog.show

The et (EditText) is the view for getting the information. You'll need to require 'ruboto/widget' and ruboto_import_widgets :EditText.

The goto proc will be called when the user presses the "Go" button.

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[Gerard Fowley]

William,

Did you have a look at the test code linked to in that wiki article ?

https://github.com/ruboto/ruboto/blob/master/test/activity/navigation_activity.rb

I only say that because that's what made Activities and Intents with jruby click for me.

Also, It seems that an AlertDialog may be more appropriate than an Activity for your goal of accepting a single input from the user.

-gf-

Gerard Fowley
CISSP
Information Security Consultant
Principal @ Iqeo LLC
gerard...@iqeo.net
508-769-9617
http://iqeo.net

--

[wil...@planobe.com.br]

Hey Scott!

Thanks for your help! But all of the code will look like this?

require 'ruboto/widget'
ruboto_import_widgets :EditText

class Walk_mobile_androidActivity
  def onCreate(bundle)

    set_contetnt_view = inear_layout :orientation => :vertical do

      et = edit_text(:hint => "Line number", :input_type => android.text.InputType::TYPE_CLASS_NUMBER)

      goto = proc do
        @edit_script.requestFocus
        line = et.text.to_s.to_i - 1
        max_line = @edit_script.getLineCount
        line = max_line if line > max_line
        line = 1 if line < 1
        @edit_script.setSelection @edit_script.getLayout.getLineStart(line)
      end

      dialog = AlertDialog::Builder.new(@ruboto_java_instance).setTitle("Go to").setView(et).setPositiveButton("Go", goto).create
      dialog.window.soft_input_mode = android.view.WindowManager::LayoutParams::SOFT_INPUT_STATE_ALWAYS_VISIBLE
      dialog.show

    end
  end
end

This code works on the Ruboto-core? Because is crashing in my emulator. One more thing, Can I do that in the same way that is explained on android documentation? http://developer.android.com/training/basics/firstapp/starting-activity.html#

oh, I forgot to say, I'm new on Ruboto development :D

[Scott]

No, the dialog should not be inside the Activity's content. Here's a shot at what you're trying to do:

require 'ruboto/activity'
require 'ruboto/widget'

ruboto_import_widgets :EditText, :LinearLayout, :TextView, :Button

class Walk_mobile_androidActivity
  def onCreate(bundle)
    self.contetnt_view = linear_layout(:orientation => :vertical) do

      button :text => "Get Info", :on_click_listener => (proc{show_dialog})

      @my_text = text_view

    end

  end

  def show_dialog

      et = edit_text(:hint => "Enter Your Info")

      get_info = proc do
        @my_text.text = et.text
      end

      dialog = AlertDialog::Builder.new(@ruboto_java_instance).setTitle("Your Info").setView(et).setPositiveButton("Go", get_info).create

      dialog.window.soft_input_mode = android.view.WindowManager::LayoutParams::SOFT_INPUT_STATE_ALWAYS_VISIBLE
      dialog.show

  end

end

[a a]

No, the dialog should not be inside the Activity's content.

Why the dialog can't be inside of MyActivity?
I think this is the reason why I get a NullPointerException at:

AlertDialog::Builder.new(@ruboto_java_instance)
...

Can someone clarify In which scope does @ruboto_java_instance exist ?
It has to exist inside of of MyActivity because how could you otherwise do this ->

search = EditText.new(@ruboto_java_instance)

...inside of MyActivity's onCreate method ?

Since it seems to be available inside of onCreate method, 
I also tried - from there - to copy @ruboto_java_instance into a 
$global_var.

$rji_glob = @ruboto_java_instance

And then again I tried to pass it to "AlertDialog::Builder.new($rji_glob)" (inside of Activity)
but still I see a NullPointerException...

Does this make sense?
Also why not allow to use @ruboto_java_instance from inside the Activity when in java the same construct is working? (Check here: http://www.chupamobile.com/tutorial-android/android-beginner-tutorial-part-43-alertdialog-custom-layout-312)

The reason I am giving attention to this details is because when I am using Ruboto and learning Android API's I found myself many times looking for java examples and then trying to translate them into some nice Ruby code.. But as I see a profound diversity in the code structure, I feel really discouraged because then this difference puts me in a position where I have to learn the tedious bits of the two different environments, which completely wastes the original purpose of doing things in simpler and nicer way.

I hope that in the near future Ruboto will fix all discrepancies with Android Java programming.
Since I am here, are there any other big differences that I should be aware of?
Thanks for helping.

[a a]

... Here's a shot at what you're trying to do:

I've also tried copying this example exactly as it is and I'm still getting the null pointer exception... what....?

[a a]

Wow, I spent nearly a day on this. Not trying the most evident solution because it was told to be wrong........
With "self" it works... damnit..

[Scott]

Let me say that there are a few errors with my code above. I think I was just trying to give an example of the structure. I wasn't actually testing the code. Here are the errors:

1) I Didn't call super in onCreate

2) I misspelled content in self.content_view

3) I didn't import AlertDialog or give its full name

This code works:

require 'ruboto/activity'
require 'ruboto/widget'

ruboto_import_widgets :EditText, :LinearLayout, :TextView, :Button

class Walk_mobile_androidActivity
  def onCreate(bundle)

    super
    self.content_view = linear_layout(:orientation => :vertical) do

      button :text => "Get Info", :on_click_listener => (proc{show_dialog})

      @my_text = text_view

    end

  end

  def show_dialog

      et = edit_text(:hint => "Enter Your Info")

      get_info = proc do
        @my_text.text = et.text
      end

      dialog = android.app.AlertDialog::Builder.new(@ruboto_java_instance).setTitle("Your Info").setView(et).setPositiveButton("Go", get_info).create

      dialog.window.soft_input_mode = android.view.WindowManager::LayoutParams::SOFT_INPUT_STATE_ALWAYS_VISIBLE
      dialog.show

  end

end

[Scott]

Yes, it is confusing. I have a tendency to use Ruboto IRB to debug. I don't think I fully understood (until today) that places in Ruboto IRB that require @ruboto_java_instance just use self in regular ruboto code (ruboto gen app). I think Uwe understands this subtle difference best. Uwe, help!

[Scott]

Ok, for the code above in a ruboto gen app:

1) Create the app

    ruboto gen app --package org.ruboto.example.my_test

2) Change the code in src/my_test_activity.rb

    require 'ruboto/activity'

    require 'ruboto/widget'

    

    ruboto_import_widgets :EditText, :LinearLayout, :TextView, :Button

    

    class MyTestActivity

      def onCreate(bundle)

        super

        self.content_view = linear_layout(:orientation => :vertical) do

          button :text => "Get Info", :on_click_listener => (proc{show_dialog})

          @my_text = text_view

        end

      end

    

      def show_dialog

          et = edit_text(:hint => "Enter Your Info")

    

          get_info = proc do

            @my_text.text = et.text

          end

    

          dialog = android.app.AlertDialog::Builder.new(self).setTitle("Your Info").setView(et).setPositiveButton("Go", get_info).create

[donV]

Hi a a and Scott!

I'm a bit late to the show (been working on the 1.2.0 release), but did this work out for you?