{"id":737,"date":"2021-07-23T04:24:31","date_gmt":"2021-07-23T04:24:31","guid":{"rendered":"http:\/\/meatpie\/?p=737"},"modified":"2021-08-09T04:56:41","modified_gmt":"2021-08-09T04:56:41","slug":"weather-app-data-binding","status":"publish","type":"post","link":"https:\/\/snersbots.co.uk\/index.php\/weather-app-data-binding\/","title":{"rendered":"Age Calculator App – View Binding"},"content":{"rendered":"\n

Doing the Google Kotlin training courses on Udacity – here <\/a>– they’re free, why wouldn’t you. If you use View Binding, you can link the view to the code at compile time – potentially improving the performance.<\/p>\n\n\n\n\n\n\n\n

OK so the course is a few years old, and I’m getting some warnings – still a good course. Just cross reference for the latest details in the Kotlin language reference here: Using Kapt<\/a><\/p>\n\n\n\n

Oh that is out of date as well – going down a rabbit hole – try here: Stack Overflow<\/a><\/p>\n\n\n\n

Gradle:app<\/h2>\n\n\n\n

Which then takes me to here: Android Gradle Plugin<\/a><\/p>\n\n\n\n

The first thing you need to do is update your app Gradle – the one that goes build.gradle(:app). You need to add the Kotlin Kapt plugin as follows:<\/p>\n\n\n\n

plugins {\n    id 'com.android.application'\n    id 'kotlin-android'\n    id \"org.jetbrains.kotlin.kapt\" \n}<\/code><\/pre>\n\n\n\n
Or depending how your project is set up, you can alternatively do the following (same file)<\/p>\n\n\n\n
apply plugin: 'kotlin-android'\napply plugin: 'kotlin-kapt'<\/code><\/pre>\n\n\n\n
Enable data binding in the app gradle, at the top level.<\/p>\n\n\n\n
android.buildFeatures.dataBinding true<\/pre>\n\n\n\n
Layout<\/h2>\n\n\n\n
Add a new top level closure to each layout resource. Move the namespace info into this tag.<\/p>\n\n\n\n
<?<\/em>xml version=\"1.0\" encoding=\"utf-8\"?>\n<\/em><layout xmlns:android=\"http:\/\/schemas.android.com\/apk\/res\/android\"\n        xmlns:app=\"http:\/\/schemas.android.com\/apk\/res-auto\"\n        xmlns:tools=\"http:\/\/schemas.android.com\/tools\">\n\n    <androidx.constraintlayout.widget.ConstraintLayout ...<\/pre>\n\n\n\n
In the code<\/h2>\n\n\n\n
Make a binding variable. The type AgeCalcBinding is derived from the name of the layout file. In this case the layout file is called age_calc.xml.<\/p>\n\n\n\n
\/**\n * @property binding The binding class is autogenerated from the name of the layout it refers to\n *\/\n<\/em>private lateinit var binding: AgeCalcBinding<\/em><\/code>\n<\/pre>\n\n\n\n
Instantiate it at the earliest opportunity:<\/p>\n\n\n\n
super.onCreate(savedInstanceState)\nbinding = DataBindingUtil.setContentView(this, R.layout.age_calc<\/em>)<\/pre>\n\n\n\n
Then you can remove all the findViewById variables, and instead access the fields directly with the binding. prefex.<\/p>\n\n\n\n
binding.calculateButton.setOnClickListener {\n    <\/strong>calculateAge()\n}<\/strong>\n\nbinding.ageCalculated.setText(getString(R.string.fabulous<\/em>))\n\n<\/pre>\n\n\n\n
And here’s how to do an adapter for an AutoCompleteTextView the binding way.<\/p>\n\n\n\n
val monthNames = resources<\/em>.getStringArray(R.array.months<\/em>)
val adapter: ArrayAdapter<String> =
    ArrayAdapter<String>(this, android.R.layout.simple_list_item_1<\/em>, monthNames)

binding.editMonth.threshold <\/em>= 1
binding.editMonth.setAdapter(adapter)<\/pre>\n\n\n\n
Notes<\/h2>\n\n\n\n
It turns out to be very easy. Just be aware that you cannot just say binding.field.text = value for EditText. The reason is that EditText is an editable string type which you cannot assign. You have to use setText(value).<\/p>\n","protected":false},"excerpt":{"rendered":"
Doing the Google Kotlin training courses on Udacity – here – they’re free, why wouldn’t you. If you use View Binding, you can link the view to the code at compile time – potentially improving the performance.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,8],"tags":[48,49,35,52],"class_list":["post-737","post","type-post","status-publish","format-standard","hentry","category-android","category-software","tag-age-calculator","tag-android","tag-kotlin","tag-kotlin-view-binding"],"_links":{"self":[{"href":"https:\/\/snersbots.co.uk\/index.php\/wp-json\/wp\/v2\/posts\/737","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/snersbots.co.uk\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/snersbots.co.uk\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/snersbots.co.uk\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/snersbots.co.uk\/index.php\/wp-json\/wp\/v2\/comments?post=737"}],"version-history":[{"count":20,"href":"https:\/\/snersbots.co.uk\/index.php\/wp-json\/wp\/v2\/posts\/737\/revisions"}],"predecessor-version":[{"id":782,"href":"https:\/\/snersbots.co.uk\/index.php\/wp-json\/wp\/v2\/posts\/737\/revisions\/782"}],"wp:attachment":[{"href":"https:\/\/snersbots.co.uk\/index.php\/wp-json\/wp\/v2\/media?parent=737"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/snersbots.co.uk\/index.php\/wp-json\/wp\/v2\/categories?post=737"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/snersbots.co.uk\/index.php\/wp-json\/wp\/v2\/tags?post=737"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}