How to get a string from attr with reference forma

问题:

I have my custom attr.xml document in which I specified declare-styleable:

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <declare-styleable name="EditTextValidateablePreference">
        <attr name="errorMessage" format="reference" />
    </declare-styleable>

</resources>

Then in layout I set:

<com.xx.yy.EditTextValidateablePreference
    ...
    ns:errorMessage="@string/validation_email_mail_server_invalid"
    />

And in EditTextValidateablePreference.class I get it with:

    String validatorErrorMessage = attrs.getAttributeValue(PREFERENCE_NS, "errorMessage");

validatorErrorMessage has a value like: @2131099700

How can I get its integer value to use it with:

context.getResources().getString(messageId)

?

Thanks !

回答1:

There's an excellent general answer which I recommend you to refer to: Declaring a custom android UI element using XML

In particular, you should use Context.obtainStyledAttributes(AttributeSet set, int[] attrs) and TypedArray.getString(int index) instead of AttributeSet.getAttributeValue(...):

TypedArray ta = activityContext.obtainStyledAttributes(attrs, R.styleable.EditTextValidateablePreference);
String theString = ta.getString(R.styleable.EditTextValidateablePreference_errorMessage);
ta.recycle();

回答2:

TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.EditTextValidateablePreference);
int resID = array.getResourceId(R.styleable.EditTextValidateablePreference_errorMessage, R.string.default_text);

And from this int, you can get the string by saying...

getResources().getString(resID);