Summary: Nested Classes | Constants | Methods | Inherited Methods

ShadowOverlayHelper

Kotlin |Java

public final class ShadowOverlayHelper
extends Object

java.lang.Object
↳	androidx.leanback.widget.ShadowOverlayHelper

ShadowOverlayHelper is a helper class for shadow, overlay color and rounded corner. There are many choices to implement Shadow, overlay color. Initialize it with ShadowOverlayHelper.Builder and it decides the best strategy based on options user choose and current platform version.

For shadow: it may use 9-patch with opticalBounds or Z-value based shadow for API >= 21. When 9-patch is used, it requires a ShadowOverlayContainer to include 9-patch views.
For overlay: it may use ShadowOverlayContainer which overrides draw() or it may use setForeground(new ColorDrawable()) for API>=23. The foreground support might be disabled if rounded corner is applied due to performance reason.
For rounded-corner: it uses a ViewOutlineProvider for API>=21.

There are two different strategies: use Wrapper with a ShadowOverlayContainer; or apply rounded corner, overlay and rounded-corner to the view itself. Below is an example of how helper is used.


 ShadowOverlayHelper mHelper = new ShadowOverlayHelper.Builder().
         .needsOverlay(true).needsRoundedCorner(true).needsShadow(true)
         .build();
 mHelper.prepareParentForShadow(parentView); // apply optical-bounds for 9-patch shadow.
 mHelper.setOverlayColor(view, Color.argb(0x80, 0x80, 0x80, 0x80));
 mHelper.setShadowFocusLevel(view, 1.0f);
 ...
 View initializeView(View view) {
     if (mHelper.needsWrapper()) {
         ShadowOverlayContainer wrapper = mHelper.createShadowOverlayContainer(context);
         wrapper.wrap(view);
         return wrapper;
     } else {
         mHelper.onViewCreated(view);
         return view;
     }
 }
 ...

Summary

Nested classes
`class`	`ShadowOverlayHelper.Builder` Builder for creating ShadowOverlayHelper.
`class`	`ShadowOverlayHelper.Options` Option values for ShadowOverlayContainer.

Constants
`int`	`SHADOW_DYNAMIC` Shadows depend on the size, shape, and position of the view.
`int`	`SHADOW_NONE` No shadow.
`int`	`SHADOW_STATIC` Shadows are fixed.

Public methods
`ShadowOverlayContainer`	`createShadowOverlayContainer(Context context)` Create ShadowOverlayContainer for this helper.
`int`	`getShadowType()`
`boolean`	`needsOverlay()`
`boolean`	`needsRoundedCorner()`
`boolean`	`needsWrapper()` Returns true if a "wrapper" ShadowOverlayContainer is needed.
`void`	`onViewCreated(View view)` Must be called when view is created for cases `needsWrapper()` is false.
`void`	`prepareParentForShadow(ViewGroup parent)` `prepareParentForShadow(ViewGroup)` must be called on parent of container before using shadow.
`static void`	`setNoneWrapperOverlayColor(View view, int color)` Set overlay color for view other than ShadowOverlayContainer.
`static void`	`setNoneWrapperShadowFocusLevel(View view, float level)` Set shadow focus level (0 to 1).
`void`	`setOverlayColor(View view, int color)` Set overlay color for view, it can be a ShadowOverlayContainer if needsWrapper() is true, or other view type.
`void`	`setShadowFocusLevel(View view, float level)` Set shadow focus level (0 to 1).
`static boolean`	`supportsDynamicShadow()` Returns true if the platform sdk supports dynamic shadows.
`static boolean`	`supportsForeground()` Returns true if view.setForeground() is supported.
`static boolean`	`supportsRoundedCorner()` Returns true if the platform sdk supports rounded corner through outline.
`static boolean`	`supportsShadow()` Return true if the platform sdk supports shadow.

Inherited methods

From class


        
          java.lang.Object

`Object`	`clone()`
`boolean`	`equals(Object arg0)`
`void`	`finalize()`
`final Class<?>`	`getClass()`
`int`	`hashCode()`
`final void`	`notify()`
`final void`	`notifyAll()`
`String`	`toString()`
`final void`	`wait(long arg0, int arg1)`
`final void`	`wait(long arg0)`
`final void`	`wait()`

Constants

SHADOW_DYNAMIC

public static final int SHADOW_DYNAMIC

Shadows depend on the size, shape, and position of the view.

Constant Value: 3 (0x00000003)

SHADOW_NONE

public static final int SHADOW_NONE

No shadow.

Constant Value: 1 (0x00000001)

SHADOW_STATIC

public static final int SHADOW_STATIC

Shadows are fixed.

Constant Value: 2 (0x00000002)

Public methods

createShadowOverlayContainer

public ShadowOverlayContainer createShadowOverlayContainer (Context context)

Create ShadowOverlayContainer for this helper.

Parameters
`context`	`Context`: Context to create view.

Returns
`ShadowOverlayContainer`	ShadowOverlayContainer.

getShadowType

public int getShadowType ()

Returns
`int`

needsOverlay

public boolean needsOverlay ()

Returns
`boolean`

needsRoundedCorner

public boolean needsRoundedCorner ()

Returns
`boolean`

needsWrapper

public boolean needsWrapper ()

Returns true if a "wrapper" ShadowOverlayContainer is needed. When needsWrapper() is true, call createShadowOverlayContainer(Context) to create the wrapper.

Returns
`boolean`

onViewCreated

public void onViewCreated (View view)

Must be called when view is created for cases needsWrapper() is false.

prepareParentForShadow

public void prepareParentForShadow (ViewGroup parent)

prepareParentForShadow(ViewGroup) must be called on parent of container before using shadow. Depending on Shadow type, optical bounds might be applied.

Parameters
`parent`	`ViewGroup`

setNoneWrapperOverlayColor

public static void setNoneWrapperOverlayColor (View view, 
                int color)

Set overlay color for view other than ShadowOverlayContainer. See also ShadowOverlayContainer.setOverlayColor(int).

Parameters
`view`	`View`
`color`	`int`

setNoneWrapperShadowFocusLevel

public static void setNoneWrapperShadowFocusLevel (View view, 
                float level)

Set shadow focus level (0 to 1). 0 for unfocused, 1 for fully focused. This is for view other than ShadowOverlayContainer. See also ShadowOverlayContainer.setShadowFocusLevel(float).

Parameters
`view`	`View`
`level`	`float`

setOverlayColor

public void setOverlayColor (View view, 
                int color)

Set overlay color for view, it can be a ShadowOverlayContainer if needsWrapper() is true, or other view type.

Parameters
`view`	`View`
`color`	`int`

setShadowFocusLevel

public void setShadowFocusLevel (View view, 
                float level)

Set shadow focus level (0 to 1). 0 for unfocused, 1 for fully focused.

Parameters
`view`	`View`
`level`	`float`

supportsDynamicShadow

public static boolean supportsDynamicShadow ()

Returns true if the platform sdk supports dynamic shadows.

Returns
`boolean`

supportsForeground

public static boolean supportsForeground ()

Returns true if view.setForeground() is supported.

Returns
`boolean`

supportsRoundedCorner

public static boolean supportsRoundedCorner ()

Returns true if the platform sdk supports rounded corner through outline.

Returns
`boolean`

supportsShadow

public static boolean supportsShadow ()

Return true if the platform sdk supports shadow.

Returns
`boolean`

ShadowOverlayHelper

Summary

Nested classes

Constants

Public methods

Inherited methods

Constants

SHADOW_DYNAMIC

SHADOW_NONE

SHADOW_STATIC

Public methods

createShadowOverlayContainer

getShadowType

needsOverlay

needsRoundedCorner

needsWrapper

onViewCreated

prepareParentForShadow

setNoneWrapperOverlayColor

setNoneWrapperShadowFocusLevel

setOverlayColor

setShadowFocusLevel

supportsDynamicShadow

supportsForeground

supportsRoundedCorner

supportsShadow