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Custom attributes in Android fragments

Posted by: admin April 23, 2020 Leave a comment

Questions:

I’d like to define custom attributes in Android fragment using XML (without using bundle additional parameters) like declare-styleable in custom controls. But there are no constructors with AttrSet parameters, so is it possible? Can i just override public void onInflate(android.app.Activity activity, android.util.AttributeSet attrs, android.os.Bundle savedInstanceState) in order to get attributes support?

How to&Answers:

The Link for Support4Demos is changed or can be changed so posting the complete solution. Here it goes.

  1. Create attrs.xml file in res/values folder. Or add the below content if file already exists.

    <?xml version="1.0" encoding="utf-8"?>
    <resources>
    <declare-styleable name="MyFragment">
        <attr name="my_string" format="string"/>
        <attr name="my_integer" format="integer"/>
    </declare-styleable> 
    

  2. Override the onInflate delegate of fragment and read attributes in it

    /**
     * Parse attributes during inflation from a view hierarchy into the
     * arguments we handle.
     */
    @Override
    public void onInflate(Activity activity, AttributeSet attrs, Bundle savedInstanceState) {
        super.onInflate(activity, attrs, savedInstanceState);
        Log.v(TAG,"onInflate called");
    
        TypedArray a = activity.obtainStyledAttributes(attrs,R.styleable.MyFragment);
    
        CharSequence myString = a.getText(R.styleable.MyFragment_my_string);
        if(myString != null) {
            Log.v(TAG, "My String Received : " + myString.toString());
        }
    
        int myInteger = a.getInt(R.styleable.AdFragment_my_integer, -1);
        if(myInteger != -1) {
            Log.v(TAG,"My Integer Received :" + myInteger);
        }
    
        a.recycle();
    }
    
  3. Pass these attributes in your layout file as following. Just an example

    <?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
    
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="This is android activity" />
    
        <fragment
            android:id="@+id/ad_fragment"
            android:name="com.yourapp.packagename.MyFragment"
            android:layout_width="fill_parent"
            android:layout_height="50dp"
            android:layout_alignParentBottom="true"
            app:my_string="Hello This is HardCoded String. Don't use me"
            app:my_integer="30" />
    
    </RelativeLayout>
    

Thats all. Its a working solution.

While doing this if you see any namespace error in xml.
try project cleaning again and again.
This is pathetic but eclipse and adt misbehaves sometimes.

Hope it helps others 🙂

Cheers

Answer:

@Override
public void onInflate(Activity activity, AttributeSet attrs, Bundle savedInstanceState) {
    super.onInflate(activity, attrs, savedInstanceState); 
    // Your code here to process the attributes
}