How do you get "android:" tag values in a Custom View

Question

There seems to be a lot of "similar" questions and answers to this scattered around which all refer to how to get a custom attribute from an AttributeSet. What I haven't been able to find so far is how to get an android: namespace tag:

    <com.custom.view.StatusThumbnail
        android:id="@+id/statusThumbnailContainer"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_margin="5dp"
        android:layout_weight="1"/>

I would like to pull back the layout_height attribute from this custom component. Unfortunately from what I've read the closest I've got to how to do this is:

public StatusThumbnail(Context context, AttributeSet attrs) {
    super(context, attrs);

    String height = attrs.getAttributeValue("android", "layout_height");

But this returns null.

Surely this isn't a rare thing to try and do?

score 66 · Accepted Answer · edited Oct 25 '11 at 10:07

66

The namespace should be "http://schemas.android.com/apk/res/android" android is an alias declared in your xml file

edited Oct 25 '11 at 10:07

Reno

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answered Oct 24 '11 at 14:53

jqpubliq

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What about the case that we need multiple namespaces in one single xml file. For example I've created a custom view as well as some new attributes for that custom view. Now I wanna set attributes using my own defined and android predefined attrs. in such case your approach still returns null. it sounds i can not access android predefined attrs. How may I resolve such this case? – anonim Jun 10 '12 at 20:11
9

Superb ! finally this worked : `attrs.getAttributeIntValue("http://schemas.android.com/apk/res/android", "maxLength", 100)` – user1060418 Jun 15 '14 at 18:49
Thanks! That wokrs for me! – Lagix Jan 13 '22 at 12:48

score -5 · Answer 2 · answered Oct 24 '11 at 15:02

-5

First declare required attributes in :

res\attrs.xml

    <declare-styleable name="StatusThumbnail">
        <attr name="statusThumbnailattr" format="string"/>
    </declare-styleable>

then in your XML layout declaration use the same attribute

<com.custom.view.StatusThumbnail
        android:id="@+id/statusThumbnailContainer"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_margin="5dp"
        statusThumbnailattr="some value"
        android:layout_weight="1"/>

Access using

public StatusThumbnail(Context context, AttributeSet attrs) {
    super(context, attrs);
TypedArray a=context.obtainStyledAttributes(attrs,R.styleable.StatusThumbnail);
this.mdColorDialogTitle=a.getString(R.styleable.StatusThumbnail_statusThumbnailattr);
}

answered Oct 24 '11 at 15:02

Shardul

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Specifically didn't want custom tags - as mentioned in the question. Far too much pollution on this subject by similar answers. – Graeme Oct 24 '11 at 15:34
1

I was trying to explain you additional implementation, anyways if feel like down voting I don't mind. – Shardul Oct 29 '11 at 16:03
2

Remember to do `try { ... } finally { a.recycle(); }` as described on [TypedArray](https://developer.android.com/reference/android/content/res/TypedArray.html) – Wernight Feb 04 '15 at 19:31

How do you get "android:" tag values in a Custom View

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