Access resource defined in theme and attrs.xml android
Solution 1
I think you can get the Drawable with this code:
TypedArray a = getTheme().obtainStyledAttributes(R.style.AppTheme, new int[] {R.attr.homeIcon});
int attributeResourceId = a.getResourceId(0, 0);
Drawable drawable = getResources().getDrawable(attributeResourceId);
a.recycle();
Solution 2
Another possible way to do it:
public static int getResIdFromAttribute(final Activity activity,final int attr) {
if(attr==0)
return 0;
final TypedValue typedvalueattr=new TypedValue();
activity.getTheme().resolveAttribute(attr,typedvalueattr,true);
return typedvalueattr.resourceId;
}
Or in Kotlin:
@JvmStatic
fun getResIdFromAttribute(activity: Activity, attr: Int): Int {
if (attr == 0)
return 0
val typedValue = TypedValue()
activity.theme.resolveAttribute(attr, typedValue, true)
return typedValue.resourceId
}
no need to recycle anything here...
usage:
int drawableResId=getResIdFromAttribute(this,R.attr.homeIcon);
Drawable drawable = getResources().getDrawable(drawableResId);
Solution 3
I used below method to get resource id form style attribute. Then it can be used for drawable, string, dimension so on.
TypedArray typedArray = context.getTheme().obtainStyledAttributes(new int[] { R.attr.attrName });
int resourceId = typedArray.getResourceId(0, defaultResourceId);
typedArray.recycle();
cheers :-)
Solution 4
If you are using support / design library easier way to get drawables now is -
Context.getDrawable(int)
or
ContextCompat.getDrawable(Context, int)
reference - https://plus.google.com/+BenjaminWeiss/posts/M1dYFaobyBM
Solution 5
Here are the results of my investigation, regarding this topic.
If we have declare-stylable
then we can override those values in themes.
So far the best way that I found how to get them is the following.
TypedArray a = context.getTheme().obtainStyledAttributes(R.styleable.AppTheme);
a.getDrawable(R.styleable.AppTheme_homeIcon);
By using R.styleable.AppTheme_homeIcon
we are referencing exactly that attribute that we want. For example if we would have few more attributes, then we can reference them as follows:
a.getColor(R.styleable.AppTheme_color,defaultValue);
a.getDimension(R.styleable.AppTheme_width,defaultWidth);
And if in current theme those attributes were not defined you will get default values and no Exceptions.
Shardul
Updated on July 20, 2021Comments
-
Shardul almost 3 years
I have a scenario in which I want to set a
Drawable
depending upon the theme defined.To explain this further, Here is what I have in code:
\res\values\attrs.xml
<resources> <declare-styleable name="AppTheme"> <attr name="homeIcon" format="reference" /> </declare-styleable> </resources>
res\values\styles.xml
<resources> <style name="AppTheme" parent="android:style/Theme"> <item name="attr/homeIcon">@drawable/ic_home</item> </style> </resources>
AndroidManifest.xml
<application android:label="@string/app_name" android:theme="@style/AppTheme"> <activity android:name=".MainActivity" android:label="@string/app_name"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application>
So as you have noticed I am defining a custom attr homeIcon and setting the attribute value in AppTheme.
When I define this attribute in a layout XML and try to access it it works smoothly
<ImageView android:id="@+id/img" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:src="?attr/homeIcon" />
and renders the
Drawable
ic_home in anImageView
.But I am not able to figure out how to access the
Drawable
programmatically.I tried to do this with a work around, by defining a holder
LayerList Drawable
, which results in resource not found exception:<?xml version="1.0" encoding="utf-8"?> <layer-list xmlns:android="http://schemas.android.com/apk/res/android" > <item android:drawable="?attr/homeIcon" /> </layer-list>
Summary I want to access the
Drawable
defined in a custom definedTheme
programmatically. -
Aswathy P Krishnan about 11 yearsWorked for me to..! Thanks! :)
-
Alexey about 11 yearsIt wokrs, but you should call a.recycle(); after you're done. Also, first parameter in obtainStyledAttributes is optional.
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Alex Semeniuk over 10 yearsWell, this may be simplified even more: just
Drawable drawable = a.getDrawable(0);
is enough (where 0 is the index of requeired attribute in new int[] array). -
Olumide Oyetoke over 9 yearsit worked for me. but why is there no need to recycle?
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android developer over 9 years@OlumideOyetoke Check the docs: developer.android.com/reference/android/util/TypedValue.html . There is no recycle function there...
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Roman Nazarevych about 7 yearsIf you plan to override those attributes in another themes don
t use
R.style.AppTheme` because values will always be taken from this Theme. Just useobtainStyledAttributes(new int[] {R.attr.homeIcon});
and then as @AlexSemeniuk mentioneda.getDrawable(0)