Changing color in a shape inside a layer-list programmatically

Question

I am trying to change programmatically the color of the selectable_kachel_shape. Here is the xml file:

kachel_ticked_style.xml

<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >


    <item>
        <shape
            android:id="@+id/selectable_kachel_shape"
            android:shape="rectangle" >
            <stroke
                android:width="5dp"
                android:color="@color/headrbar_color" />
        </shape>
    </item>
    <item>
        <rotate
            android:fromDegrees="45"
            android:pivotX="120%"
            android:pivotY="100%"
            android:toDegrees="45" >
            <shape android:shape="line" >
                <stroke
                    android:width="40dp"
                    android:color="@color/headrbar_color" />
            </shape>
        </rotate>
    </item>
    <item
        android:right="5dp"
        android:top="5dp">
        <bitmap
            android:gravity="top|right"
            android:src="@drawable/selectable_tiles_check" />
    </item>

</layer-list>

I am calling inside a Fragment the following code

LayerDrawable layers = (LayerDrawable)  this.getActivity().getResources().getDrawable(R.drawable.kachel_ticked_style);

GradientDrawable shape = (GradientDrawable) (layers.findDrawableByLayerId(R.id.selectable_kachel_shape));
                       shape.setColor(this.getActivity().getResources().getColor(android.R.color.background_dark);

1.Why am I geting a NullPointerException in shape.setColor?

2.How would it be possible to change the color inside a shape, that is inside a layer list, programmatically?

Sella

Answer 1

Ok I found the answer, I just had to put the id of the shape inside the item not in the shape kachel_ticked_style.xml:

<item 
    android:id="@+id/selectable_kachel_shape">
        <shape
             android:shape="rectangle" >
            <stroke
                android:width="5dp"
                android:color="@color/headrbar_color" />
        </shape>
    </item>

And then you can change either the color of the shape calling shape.setColor or the color of the stroke calling shape.setStroke(strokeWidth,strokeColor)

Sella

But am having the same problem.This doesnt work for me – Albescent

Well @jincyabraham you can get the view then its background drawable then get the shape as a gradiendrawable as in here link – Intuition

Can you please show what steps you did to acquire the the shape object, it is unclear. – Eruct

This works for a GradientDrawable, but not for a RotateDrawable which color I try to define at runtime. Any ideas? – Karat