Android app 101

First Application

• different views
• layout
• event handler
• data binding
  • help app no need to initialize the variable each time, which can save time.
  • findViewById() find view will create or recreate when it is called.
  • It is a global technology for the whole app, like a reference.
  • how to use it
    • enable data binding in your build.gradle file

      android {
        buildFeatures {
          dataBinding true
        }
      }

    • sync your application
    • move the namespace declaration into layout tag and just keep view properties
    • declare a binding variable for binding the specific layout which you have defined a layout tag. Then using the following code to set data to data binding

      binding = DataBindingUtil.setContentView(this, R.layout.activity_main)

    • replace the findViewById to binding.idView
  • bind string value from a data class
    source code