问题描述
我有一个场景,我想根据定义的主题设置 Drawable.
为了进一步解释这一点,这是我在代码中的内容:
esvaluesattrs.xml
<declare-styleable name="AppTheme"><attr name="homeIcon" format="reference"/></declare-styleable></资源>
resvaluesstyles.xml
<style name="AppTheme" parent="android:style/Theme"><item name="attr/homeIcon">@drawable/ic_home</item></风格></资源>
AndroidManifest.xml
<application android:label="@string/app_name"android:theme="@style/AppTheme"><activity android:name=".MainActivity" android:label="@string/app_name"><意图过滤器><action android:name="android.intent.action.MAIN"/><类别 android:name="android.intent.category.LAUNCHER"/></意图过滤器></活动></应用程序>
正如您所注意到的,我正在定义一个自定义 attr homeIcon 并在 AppTheme 中设置属性值.
当我在布局 XML 中定义此属性并尝试访问它时,它工作顺利
<ImageView android:id="@+id/img"android:layout_width="wrap_content"android:layout_height="wrap_content"安卓:layout_gravity="center"android:src="?attr/homeIcon"/>
并在 ImageView 中呈现 Drawable ic_home.
但我无法弄清楚如何以编程方式访问 Drawable.
我试图通过定义一个持有者LayerList Drawable来解决这个问题,这会导致找不到资源异常:
<?xml version="1.0" encoding="utf-8"?><层列表xmlns:android="http://schemas.android.com/apk/res/android" ><项目android:drawable="?attr/homeIcon"/></层列表>
<块引用>
总结我想以编程方式访问自定义 Theme 中定义的 Drawable.
我想你可以用这段代码获得 Drawable:
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();
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:
esvaluesattrs.xml
<resources> <declare-styleable name="AppTheme"> <attr name="homeIcon" format="reference" /> </declare-styleable> </resources>
resvaluesstyles.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 an ImageView.
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 defined Theme programmatically.
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();