angle attribute in android gradient

Gradient basically represents the variation in space(in a direction) of any quantity. With color it represents the variation of color intensity in a direction represented by angle. Here are some diagrams to represent this concept:

Here the figure shows the color variation in horizontal direction (angle is set 0).
XML code:

    <shape xmlns:android="http://schemas.android.com/apk/res/android">    <gradient        android:startColor="#000000"        android:angle="0"/>   </shape>

Here the figure shows the color variation in vertical direction (angle is set 90).
XML code:

<shape xmlns:android="http://schemas.android.com/apk/res/android"><gradient    android:startColor="#000000"    android:angle="90"/> </shape>

You can also use different color as start, center and end colors. The code you attached contains all these elements.

Specifies a gradient color for the shape.attributes:

android:angleInteger. The angle for the gradient, in degrees. 0 is left to right, 90 is bottom to top. It must be a multiple of 45. Default is 0.

It seems that the description in the documentation contradict to karn's answer??

You can find more details in the documentation

you might wanna create diagonal gradient from code. It's much easier and you have a lot of options open from there. This snippet helped me

public void SetGradient(View view) {        GradientDrawable gd = new GradientDrawable(                GradientDrawable.Orientation.TL_BR,                new int[]{0xFF141a24, 0xFF293f49, 0xFF72554c});        view.setBackground(gd);    }

available directions from GradientDrawable class

/*public enum Orientation {        *//** draw the gradient from the top to the bottom *//*        TOP_BOTTOM,        *//** draw the gradient from the top-right to the bottom-left *//*        TR_BL,        *//** draw the gradient from the right to the left *//*        RIGHT_LEFT,        *//** draw the gradient from the bottom-right to the top-left *//*        BR_TL,        *//** draw the gradient from the bottom to the top *//*        BOTTOM_TOP,        *//** draw the gradient from the bottom-left to the top-right *//*        BL_TR,        *//** draw the gradient from the left to the right *//*        LEFT_RIGHT,        *//** draw the gradient from the top-left to the bottom-right *//*        TL_BR,    }*/

and you call the method from onCreate or onCreateView in fragment and pass parent view(in my case).

 @Override    public View onCreateView(LayoutInflater inflater, ViewGroup container,                             Bundle savedInstanceState) {        View view = inflater.inflate(R.layout.dialog_view_parent, container);                   ...        SetGradient(view);        return view;    }