Android-Kotlin-Commons
Small library that contains common extensions for Android. Aims:
- Provide the shortest way to do things
- Reduce count of "Compat" and "Utils" classes
- Remove boilerplate code
Getting started
Add library as dependency to your build.gradle.
compile 'com.dewarder:akommons:0.0.4' Features
Views
Visibility
override fun onCreate(savedInstanceState: Bundle) {
...
firstView.isVisible = true
secondView.isVisible = false
...
}
Before
override fun onCreate(savedInstanceState: Bundle) {
...
firstView.visibility = View.VISIBLE
secondView.visibility = View.GONE
...
}
Auto-casting
private lateinit var linearLayout: LinearLayout
override fun onCreate(savedInstanceState: Bundle) {
linearLayout = getViewById(R.id.linearLayout)
}
Before
private lateinit var linearLayout: LinearLayout override fun onCreate(savedInstanceState: Bundle) {
linearLayout = findViewById(R.id.linearLayout) as LinearLayout
}
Padding
override fun onCreate(savedInstanceState: Bundle) {
...
firstView.setOptionalPadding(bottom = 16)
secondView.setAllPadding(16)
...
}
Before
override fun onCreate(savedInstanceState: Bundle) {
...
firstView.setPadding(firstView.paddingLeft, firstView.paddingTop, firstView.paddingRight, 16)
secondView.setPadding(16, 16, 16, 16)
...
}
Post runnables
override fun onCreate(savedInstanceState: Bundle) {
...
refreshLayout.postDelayedApply(3000) {
isRefreshing = false
clearAnimation()
}
...
}
Before
override fun onCreate(savedInstanceState: Bundle) {
...
refreshLayout.postDelayed({
refreshLayout.isRefreshing = false
refreshLayout.clearAnimation()
}
, 3000)
...
}
Also see postApply, postLet, postDelayedLet
Shared preferences
Delegates
class AccountRepository : SharedPreferencesProvider {
override val sharedPreferences: SharedPreferences
var currentUserId by PreferencesDelegates.int()
constructor(context: Context) {
this.sharedPreferences = context.defaultSharedPreferences
}
}
Before
class AccountRepository {
val sharedPreferences: SharedPreferences constructor(context: Context) {
this.sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context)
}
var currentUserId: Int = 0
get() = sharedPreferences.getInt(CURRENT_USER_ID, 0)
set(value) {
sharedPreferences.edit().putInt(CURRENT_USER_ID, value).apply()
field = value
}
companion object {
const val CURRENT_USER_ID = "CURRENT_USER_ID"
}
}
Shortcuts
sharedPreferences.save(CURRENT_USER_ID, userId)
...
sharedPreferences.save(BEARER_TOKEN, token, force = true)Before
sharedPreferences.edit()
.putInt(CURRENT_USER_ID, userId)
.apply() ... sharedPreferences.edit() .putString(BEARER_TOKEN, token) .commit()Context
Compat
override fun onCreate(savedInstanceState: Bundle) {
...
val color = getThemedColor(R.color.cyan)
val drawable = getThemedDrawable(R.drawable.background)
val stateList = getThemedColorStateList(R.drawable.state_list)
...
}
Before
override fun onCreate(savedInstanceState: Bundle) {
...
val color = ContextCompat.getColor(this, R.color.cyan)
val drawable = ContextCompat.getDrawable(this, R.drawable.background)
val stateList = ContextCompat.getColorStateList(this, R.drawable.state_list)
...
}
Services
override fun onCreate(savedInstanceState: Bundle) {
...
val inflater = layoutInflater
val sharedPreferences = defaultSharedPreferences
...
}
Before
override fun onCreate(savedInstanceState: Bundle) {
...
val inflater = getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
val sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this)
...
}
Toasts
override fun onCreate(savedInstanceState: Bundle) {
...
showShortToast("Hi!")
showLongToast(R.string.hello)
...
}
Before
override fun onCreate(savedInstanceState: Bundle) {
...
Toast.makeText(this, "Hi!", Toast.LENGTH_SHORT).show()
Toast.makeText(this, R.string.hello, Toast.LENGTH_LONG).show()
...
}
Permissions
override fun onCreate(savedInstanceState: Bundle) {
...
if (isPermissionsGranted(Permission.WRITE_EXTERNAL_STORAGE, Permission.ACCESS_FINE_LOCATION)) {
...
}
...
}
Before
override fun onCreate(savedInstanceState: Bundle) {
...
if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED &&
ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
...
}
...
}
SQLiteDatabase
Queries
val db: SQLiteDatabase
override fun getAllUsers() {
...
val cursor = db.executeQuery(table = TABLE_USERS, orderBy = COLUMN_NAME)
...
db.executeDelete(table = TABLE_USERS)
...
}
Before
val db: SQLiteDatabase override fun getAllUsers() {
... val cursor = db.query(TABLE_USERS, null, null, null, null, null, COLUMN_NAME) ... db.delete(TABLE_USERS, null, null) ...
}
Also see executeInsert, executeUpdate.
Use with SQLiteDatabase and Cursor
fun runQuery(helper: SQLiteOpenHelper) = helper.writableDatabase.use {
db ->
db.query( ... ).use {
cursor ->
}
}
Before
fun runQuery(helper: SQLiteOpenHelper) {
val db = helper.writableDatabase
val cursor = db.query( ... )
...
cursor.close()
db.close()
}
Important: you should use extension method, not from kotlin-stlib because you can get ClassCastException. See this link.
License
Copyright (C) 2017 Artem Glugovsky Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.