CHP2_Interactive App

Goals

• make activity and layout like bros
• let your app do something to  response  the user

Project One _ Adviser

• GUI components for layout

• spinner
• button
• textfield
• strings.xml
• activity
• java class

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Steps

1. build the project => basic layout and activity
2. refresh layout => put on all the GUI components you'd like to have
3. connect layout to the activity => appearance and the brain
4. java class => the logic of the  code  

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• Design Editor
• Palette
• GUI components toolbox
• Widgets
• Text Editor
• <TextView
• ID

Both Design and Text Editor were extends by Android View Class

• android : id
• android :text
• android : layout_width
• android : layout_height

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• Spinner => dropdown menu
• spinner add values => res (noncode assets) ; eg , graph , string
• strings.xml
• single string
• string array
• make spinner reference to string -array
• GUI elements => eg . button. textfield . spinner has similar properties , coz they are same "View class"
• write dead into text property or using strings.xml  handle static text 
• make you easily transfer to different languages. 
• uniform one place for modify your text
• app/src/main/res/values/strings.xml

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Quick Recap

• All of the GUI components are Android View class's subclass.
• <string-array name ="array">  =>strings.xml
• <item>string1</item>
• ...
• </string-array>
• "@array/array_name" => Layout
• android : onClick = "clickMethod" => Layout
• public void clickMethod(View view) { }  =>Activity
• R.java ,for reference
• findViewById() get view reference
• setText()
• getSelectedItem()
• File -> New ... -> Java Class