# Kau :core
> The framework of everything
## Contents
* [KPrefs](#kprefs)
* [Changelog XML](#changelog)
* [Ripple Canvas](#ripple-canvas)
* [Timber Logger](#timber-logger)
* [Email Builder](#email-builder)
* [Extensions](#extensions)
## KPrefs
A typical SharedPreference contains items that look like so:
```Java
class MyPrefs {
public static final String TEXT_COLOR = "TEXT_COLOR";
private static SharedPreference prefs = ...
public static void setTextColor(int color) {
prefs.edit().putInt(TEXT_COLOR, color).apply();
}
public static int getTextColor() {
prefs.getInt(TEXT_COLOR, Color.WHITE);
}
}
```
KPrefs greatly simplifies it by using Kotlin's object pattern and delegates to achieve the following:
```Kotlin
object MyPrefs : KPref() {
var textColor: Int by kpref("TEXT_COLOR", Color.WHITE)
var bgColor: Int by kpref("BG_COLOR", Color.BLACK)
var isFirstLaunch: Boolean by kpref("IS_FIRST_LAUNCH", true)
...
}
```
By using `KPrefSample.textColor = Color.RED` or `textView.setTextColor(KPrefSample.textColor)` we can effectively set and save the value.
The values are retrieved lazily and are only done so once; future retrievals will be done with a local value, and updating a preference will both save it in the SharedPreference and update it locally.
The object inherits the initializer method `fun initialize(c: Context, preferenceName: String)`, which must be invoked (preferably in the Application class) before using a preference.
There is also a `reset()` method to clear the local values and have them retrieve from the SharedPreference again.
In shared preferences, we often require a boolean that returns true once, so we can use it to showcase views or display prompts on the first load.
Kpref supports special preferences like these through the `KPrefSingleDelgate`
It can be used in a KPref like so:
```Kotlin
object MyPrefs : KPref() {
val displayHelper: Boolean by kprefSingle("KEY_HERE")
...
}
```
Notice that it is a `val` and takes no default. It will return true the first time and false for all subsequent calls.
## Changelog XML
Create an xml resource with the following structure:
```xml