how to set status bar background as gradient color or a drawable in android

Add this code in onCreate

getWindow().addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
getWindow().setStatusBarColor(Color.TRANSPARENT);
android.graphics.drawable.Drawable background = MainActivity.this.getResources().getDrawable(R.drawable.status);
getWindow().setBackgroundDrawable(background);

Now add a file with name status in drawable folder and put this code

<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item><!-- Edit hex colors as you like -->
<shape android:shape="rectangle" >
<gradient
android:angle="180"
android:endColor="#806AF8"
android:startColor="#F16EB5" />
</shape></item></layer-list>

Here how you do it without any Java code,

Gradient drawable file drawable/bg_toolbar.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <gradient
        android:type="linear"
        android:angle="0"
        android:startColor="#11998e"
        android:endColor="#38ef7d" />
</shape>

add this in your values/style.xml

<item name="android:windowBackground">@drawable/bg_toolbar</item>
<item name="toolbarStyle">@style/Widget.Toolbar</item>
<item name="android:statusBarColor">#00000000</item>

make a new file for your toolbar Gradient values/toolbar.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <style name="Widget.Toolbar" parent="@style/Widget.AppCompat.Toolbar">
        <item name="contentInsetStart">0dp</item>
        <item name="android:background">@drawable/bg_toolbar</item>
    </style>
</resources> 

Edit: Add background android:background="#ffffff" in your Activity Layout file.

For some one who want to set gradient color to status bar background you can use following method in your activity before setContentView()

For Java

@TargetApi(Build.VERSION_CODES.LOLLIPOP)
public static void setStatusBarGradiant(Activity activity) {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        Window window = activity.getWindow();
        Drawable background = activity.getResources().getDrawable(R.drawable.gradient_theme);
        window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
        
        window.setStatusBarColor(activity.getResources().getColor(android.R.color.transparent));
        window.setNavigationBarColor(activity.getResources().getColor(android.R.color.transparent));
        window.setBackgroundDrawable(background);
    }
}

For Kotlin

@TargetApi(Build.VERSION_CODES.LOLLIPOP)
fun setStatusBarGradiant(activity: Activity) {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        val window: Window = activity.window
        val background =ContextCompat.getDrawable(activity, R.drawable.gradient_theme)
        window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS)
        
        window.statusBarColor = ContextCompat.getColor(activity,android.R.color.transparent)
        window.navigationBarColor = ContextCompat.getColor(activity,android.R.color.transparent)
        window.setBackgroundDrawable(background)
    }
}

Thanks every one for your help

EDIT

If the above code don't work, try to add this in your styles.xml:

<style name="AppTheme.NoActionBar">
    <!-- Customize your theme here. -->
    <item name="windowActionBar">false</item>
    <item name="windowNoTitle">true</item>
</style>

If you want to override status bar with your view then use window.addFlags(WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS);

an extension to the sushant's answer since getColor is deprecated and in kotlin language.

@RequiresApi(Build.VERSION_CODES.LOLLIPOP)
fun backGroundColor() {
    window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS)
    window.statusBarColor = ContextCompat.getColor(this, android.R.color.transparent)
    window.navigationBarColor = ContextCompat.getColor(this, android.R.color.transparent)
    window.setBackgroundDrawableResource(R.drawable.ic_drawable_vertical_background)
}

The idea is to make transparent status bar and setting a background to the whole window which will also cover the status bar in the same background.