# ShadowOverlayHelper

Artifact: [androidx.leanback:leanback](https://developer.android.com/jetpack/androidx/releases/leanback) [View Source](https://cs.android.com/search?q=file:androidx/leanback/widget/ShadowOverlayHelper.java+class:androidx.leanback.widget.ShadowOverlayHelper) Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/leanback#1.1.0)

*** ** * ** ***


```
public final class ShadowOverlayHelper
```

<br />

*** ** * ** ***

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 types |
|---|
| `public final class https://developer.android.com/reference/androidx/leanback/widget/ShadowOverlayHelper.Builder` Builder for creating ShadowOverlayHelper. |
| `public final class https://developer.android.com/reference/androidx/leanback/widget/ShadowOverlayHelper.Options` Option values for ShadowOverlayContainer. |

| ### Constants |
|---|---|
| `static final int` | `https://developer.android.com/reference/androidx/leanback/widget/ShadowOverlayHelper#SHADOW_DYNAMIC() = 3` Shadows depend on the size, shape, and position of the view. |
| `static final int` | `https://developer.android.com/reference/androidx/leanback/widget/ShadowOverlayHelper#SHADOW_NONE() = 1` No shadow. |
| `static final int` | `https://developer.android.com/reference/androidx/leanback/widget/ShadowOverlayHelper#SHADOW_STATIC() = 2` Shadows are fixed. |

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

## Constants

### SHADOW_DYNAMIC

Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/leanback#1.1.0)

```
public static final int SHADOW_DYNAMIC = 3
```

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

### SHADOW_NONE

Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/leanback#1.1.0)

```
public static final int SHADOW_NONE = 1
```

No shadow.

### SHADOW_STATIC

Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/leanback#1.1.0)

```
public static final int SHADOW_STATIC = 2
```

Shadows are fixed.

## Public methods

### createShadowOverlayContainer

Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/leanback#1.1.0)

```
public ShadowOverlayContainer createShadowOverlayContainer(Context context)
```

Create ShadowOverlayContainer for this helper.

| Parameters |
|---|---|
| `https://developer.android.com/reference/android/content/Context.html context` | Context to create view. |

| Returns |
|---|---|
| `https://developer.android.com/reference/androidx/leanback/widget/ShadowOverlayContainer` | ShadowOverlayContainer. |

### getShadowType

Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/leanback#1.1.0)

```
public int getShadowType()
```

### needsOverlay

Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/leanback#1.1.0)

```
public boolean needsOverlay()
```

### needsRoundedCorner

Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/leanback#1.1.0)

```
public boolean needsRoundedCorner()
```

### needsWrapper

Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/leanback#1.1.0)

```
public boolean needsWrapper()
```

Returns true if a "wrapper" ShadowOverlayContainer is needed. When needsWrapper() is true, call `https://developer.android.com/reference/androidx/leanback/widget/ShadowOverlayHelper#createShadowOverlayContainer(android.content.Context)` to create the wrapper.

### onViewCreated

Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/leanback#1.1.0)

```
public void onViewCreated(View view)
```

Must be called when view is created for cases `https://developer.android.com/reference/androidx/leanback/widget/ShadowOverlayHelper#needsWrapper()` is false.

| Parameters |
|---|---|
| `https://developer.android.com/reference/android/view/View.html view` |   |

### prepareParentForShadow

Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/leanback#1.1.0)

```
public void prepareParentForShadow(ViewGroup parent)
```

`https://developer.android.com/reference/androidx/leanback/widget/ShadowOverlayHelper#prepareParentForShadow(android.view.ViewGroup)` must be called on parent of container before using shadow. Depending on Shadow type, optical bounds might be applied.

### setNoneWrapperOverlayColor

Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/leanback#1.1.0)

```
public static void setNoneWrapperOverlayColor(View view, int color)
```

Set overlay color for view other than ShadowOverlayContainer. See also `https://developer.android.com/reference/androidx/leanback/widget/ShadowOverlayContainer#setOverlayColor(int)`.

### setNoneWrapperShadowFocusLevel

Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/leanback#1.1.0)

```
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 `https://developer.android.com/reference/androidx/leanback/widget/ShadowOverlayContainer#setShadowFocusLevel(float)`.

### setOverlayColor

Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/leanback#1.1.0)

```
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.

### setShadowFocusLevel

Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/leanback#1.1.0)

```
public void setShadowFocusLevel(View view, float level)
```

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

### supportsDynamicShadow

Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/leanback#1.1.0)

```
public static boolean supportsDynamicShadow()
```

Returns true if the platform sdk supports dynamic shadows.

### supportsForeground

Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/leanback#1.1.0)

```
public static boolean supportsForeground()
```

Returns true if view.setForeground() is supported.

### supportsRoundedCorner

Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/leanback#1.1.0)

```
public static boolean supportsRoundedCorner()
```

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

### supportsShadow

Added in [1.1.0](https://developer.android.com/jetpack/androidx/releases/leanback#1.1.0)

```
public static boolean supportsShadow()
```

Return true if the platform sdk supports shadow.