Were you ever in a situation where you had to access Drawables based on their names (for example if the Drawable names are stored in a DB) and you had to write long lookup tables converting the names into R.drawable.ids? And maintaining them?
This library is offering a way around it by using reflection to access the Drawable directly by name. You only need to include them as normal into your Res folder tree. It has been benchmarked at up to 5x faster than the platform's Resources.getIdentifier() method.
It is using LRU caching to mitigate the reflection time overhead.
It also includes a few convenience functions to help change Drawable colour based on a hex colour value.
Sample app available on the Play Store
To use:
- Download a copy of the ReflectiveDrawableLoader library and reference it in your project.
- Get an Instance of the ReflectiveDrawableLoader by calling
ReflectiveDrawableLoader.getInstance(Context); - Start getting your Drawable ids by calling any of the getDrawable functions.
Drawable families
The library is using a concept of icon families to distinguish between different variations of similar icons. For example, icons in Android can come in a Holo Light and Holo Dark variant.
So, if you call getDrawableId("submarine", "yellow", R.drawable.ic_list_fallback) then the library will try to look for an icon called yellow_submarine and return its Id if it exists, or R.drawable.ic_list_fallback otherwise.
Similarly, if you call getDrawableId("submarine", null, R.drawable.ic_list_fallback) or getDrawableId("submarine", R.drawable.ic_list_fallback) then the library will try to look for an icon called submarine and return its Id if it exists, or R.drawable.ic_list_fallback otherwise.
Of course, nothing stops you from calling getDrawableId("yellow_submarine", null, R.drawable.ic_list_fallback) to get the yellow_submarine icon as well.
Convenience Functions and Drawable naming conventions
The convenience functions in the library assume that Drawables are named using the convention described here Icon Design Guidelines.
So for example,
If you call getListDrawableId("submarine", "yellow", R.drawable.ic_list_fallback); then the library will try to look for an icon called ic_list_yellow_submarine and return its Id if it exists, or R.drawable.ic_list_fallback otherwise.
If you ask for a Colorised Icon by calling getColorisedListDrawable("table", "furniture", "#c0c0c0", R.drawable.ic_list_fallback); instead of an Id you will get a DrawableResourceContainer object which will contain the Id of the Drawable to use, the colour to use as and Integer and a couple convenience functions to use to colourise the Drawable. If there was an error parsing the colour, the Integer will be null.
For sample code on how this works and the different between the two convenience color filtering functions have a look at ColorisedDrawableArrayAdapter.java in the Sample App project.
Also, the convenience functions do not apply the colorFilter to the Drawable directly, but to the ImageView holding it.
Feel free to expand the DrawableResourceContainer to add other colour filters or behaviours.
Type ant jar at the root of the Library Project to produce a Jar file.
ProGuard users must ensure that the R class, its inner drawable class and all fields are not obfuscated for the runtime reflection to work. Add the following to your your proguard-project.txt file:
-keepattributes InnerClasses
-keep class **.R
-keep class **.R$* {
<fields>;
}
- v0.0.1 First public release
- v0.0.2 Bugfixes, added caching of the resource classes in ReflectionUtils.
- v0.0.3 Added caching of non-existing drawable requests.
- No permissions required
Author: Alexandros Schillings.
Based on code by Jeff Gilfelt, who showed me that contrary to my academic reservations, reflectively loading icons is not that bad :)
All logos are the property of their respective owners.
The icons used for the example app were downloaded from here: Android Design
The code in this project is licensed under the Apache Software License 2.0.
Copyright (c) 2013 Alexandros Schillings.