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This repository was archived by the owner on Nov 14, 2018. It is now read-only.
Generic set & get method for SharedPreferences.Editor #435
Description
Is it possible to have generic set & get method for SharedPreferences.Editor?
sharedPreferences.edit {
putBoolean("key", value)
putString("key",value)
}
Instead of that can we have some thing like below to set preference.
Idea is to get ride of putBoolean, putString, putLong instead only use set.
prefs.edit{
set("Test" to "Blame")
set("Rest" to 12)
set("Best" to 12.30f)
}
Similar way for getting preferences instead of getString, getBoolean, getLong we should call something like below.
prefs.get("Test" to null)
Also my proposal is as below.
For setting values in preference.
fun <T: Any>SharedPreferences.Editor.set(pair: Pair<String,T>){
when(pair.second){
is String -> putString(pair.first,pair.second as String)
is Int -> putInt(pair.first,pair.second as Int)
is Long -> putLong(pair.first,pair.second as Long)
is Float -> putFloat(pair.first,pair.second as Float)
}
}
For getting values from preference
fun <T: Any>get(key: String , defaultVal: T?): Serializable? {
val preference = getSharedPreferences()
return when(defaultVal){
is String,null -> preference.getString(key,defaultVal.toString())
is Int -> preference.getInt(key,defaultVal.toInt())
is Float -> preference.getFloat(key,defaultVal.toFloat())
is Long -> preference.getLong(key,defaultVal.toLong())
else -> IllegalArgumentException("Type mismatch")
}
}
Activity
dovahkiin98 commentedon Mar 14, 2018
Most extensions are inline, also, set would be better if you use a key and a value, looks like an indexer
JakeWharton commentedon Mar 14, 2018
I don't think we want to encourage a reduction in type safety inside of a lambda block where we're not forced to. The current preference interaction is fairly concise. I'm not sure what we gain from changing it?
dovahkiin98 commentedon Mar 14, 2018
We can make getting and setting values easier.
I would like to use this concept in Intent and Bundle too, makes interacting with values easy and quick
JakeWharton commentedon Mar 14, 2018
It's not any easier, you're just code golfing character count and reducing type safety.
rongi commentedon Mar 15, 2018
It's easier because you no longer need to think which method to use:
putString()orputBoolean(), orputInt(). Just use a genericset(), orput(), or whatever, and you are golden.pinakinkansara commentedon Mar 29, 2018
@JakeWharton
While looking at android-ktx code base, I found out that Bundle
are also implemented as Feature I demanded for.
If type safety is the only concern for SharePreference to apply generic set & get method then it should also be concern for Bundle as well.
JakeWharton commentedon Mar 29, 2018
AllanWang commentedon Jun 22, 2018
In light of a more "generic" get & set, one thing I did was a delegation pattern much like that of the bundle.
(README and Source)
The implementation essentially allows us to do something like:
Where kpref is defined for the supported types and backed by a general class that checks instance types.
You would then be able to get and set your preferences much as you would get and set a normal variable: