Lightweight helper library for Android Kotlin development
- Shared Preferences delegates
- Bundle args delegates
- Resources delegates
- View<->Data Binding
Step 1. Add the JitPack repository to your build file
allprojects {
repositories {
...
maven { url 'https://jitpack.io' }
}
}
Step 2. Add the dependency
dependencies {
compile 'com.github.deviant-studio:bindingtools:{latest_version}'
}
Let's say you have an Activity:
class MainActivity : AppCompatActivity() {
private lateinit var textLabel: TextView
private val viewModel = MainViewModel()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
textLabel = findViewById(R.id.text)
bindViews()
}
private fun bindViews() {
// ...
}
}and a ViewModel:
class MainViewModel {
var text: String = ""
fun sayHello() {
text = "Hello, World!"
}
}It would be nice if we can bind text field to the view. Let's modify ViewModel:
class MainViewModel : Bindable {
var text: String by binding("")
fun sayHello() {
text = "Hello, World!"
}
}and Activity:
private fun bindViews() = withBindable(viewModel) {
bind(::text, textLabel::setText, textLabel::getText)
}Thats it! Now we can set TextView's text like:
viewModel.sayHello()Also library allows you to simplify TextView/EditText bindings to this:
withBindable(viewModel) {
bind(::text, textLabel)
}+ don't have to write BindingAdapters
+ no code generation (no more missed BR.id, don't have to force clean in any unclear situation)
+ great code completion (compared to XML)
+ clean XML files
+ can bind anything to anything, not only the View
+ can be used with Anko (and any programmatically created views)
+ much cleaner way to implement 2-way bindings
- some reflection
- not from Google
- only for Kotlin apps
- no observables (yet?)
It's so annoying to deal with SharedPreferences directly:
final String ageKey = "age";
final String userNameKey = "userName";
final String adminKey = "admin";
SharedPreferences prefs = getSharedPreferences("main_prefs", Context.MODE_PRIVATE);
SharedPreferences.Editor editor = prefs.edit();
editor.putInt(ageKey, 12);
editor.putString(userNameKey, "Luke");
editor.putBoolean(adminKey,true);
editor.apply();Fortunately now we have Kotlin and the bindingtools!
First, declare the PreferencesAware class
class Prefs(ctx: Context) : PreferencesAware {
override val forcePersistDefaults = true
override val sharedPreferences: SharedPreferences = ctx.getSharedPreferences("main_prefs", Context.MODE_PRIVATE)
var age by pref(0)
var userName by pref("")
var isAdmin by pref(false)
}Now you can use preferences like this:
val prefs = Prefs(this)
prefs.age = 12
prefs.userName = "Ani Lorak"
prefs.isAdmin = true
println("the name is ${prefs.userName}")Dealing with args bundle has never been such simple before. Let's declare another one activity:
class SecondActivity : AppCompatActivity() {
val userName: String by arg("")
val age: String by arg("")
val country: String? by arg()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_second)
println("$userName $age $country") // that's it. just read the properties
}
}
Start activity with convenient bundle builder:
startActivity<SecondActivity> {
SecondActivity::userName to "Ivo Bobul"
SecondActivity::age to 99
SecondActivity::code to 65536
}or build the bundle separately:
val args = bundle {
SecondActivity::userName to "Slavko Vakarchuk"
SecondActivity::code to 100500
}Same rules can be used when using resources:
private val appName: String by res(R.string.app_name)
...
println(appName)