PreviewView

Added in 1.1.0

Kotlin |Java

public final class PreviewView extends FrameLayout

java.lang.Object
↳	android.view.View
	↳	android.view.ViewGroup
		↳	android.widget.FrameLayout
			↳	androidx.camera.view.PreviewView

Custom View that displays the camera feed for CameraX's Preview use case.

This class manages the preview Surface's lifecycle. It internally uses either a TextureView or SurfaceView to display the camera feed, and applies required transformations on them to correctly display the preview, this involves correcting their aspect ratio, scale and rotation.

If PreviewView uses a SurfaceView to display the preview stream, be careful when overlapping a View that's initially not visible (either INVISIBLE or GONE) on top of it. When the SurfaceView is attached to the display window, it calls requestTransparentRegion which requests a computation of the transparent regions on the display. At this point, the View isn't visible, causing the overlapped region between the SurfaceView and the View to be considered transparent. Later if the View becomes visible, it will not be displayed on top of SurfaceView. A way around this is to call requestTransparentRegion right after making the View visible, or initially hiding the View by setting its opacity to 0, then setting it to 1.0F to show it.

There are some limitations of transition animations to SurfaceView and TextureView, which applies to PreviewView as well.

See also
`Limitations`

Summary

Nested types
`public enum PreviewView.ImplementationMode` The implementation mode of a `PreviewView`.
`public enum PreviewView.ScaleType` Options for scaling the preview vis-à-vis its container `PreviewView`.
`public enum PreviewView.StreamState` Definitions for the preview stream state.

Public constructors
`@UiThread PreviewView(@NonNull Context context)`
`@UiThread PreviewView(@NonNull Context context, @Nullable AttributeSet attrs)`
`@UiThread PreviewView( @NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr )`
`@UiThread PreviewView( @NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes )`

Public methods
`@Nullable Bitmap`	`@UiThread getBitmap()` Returns a `Bitmap` representation of the content displayed on the `PreviewView`, or `null` if the camera preview hasn't started yet.
`@Nullable CameraController`	`@UiThread getController()` Get the `CameraController`.
`@NonNull PreviewView.ImplementationMode`	`@UiThread getImplementationMode()` Returns the `ImplementationMode`.
`@NonNull MeteringPointFactory`	`@UiThread getMeteringPointFactory()` Gets the `MeteringPointFactory` for the camera currently connected to the `PreviewView`, if any.
`@Nullable OutputTransform`	`getOutputTransform()` Gets the `OutputTransform` associated with the `PreviewView`.
`@NonNull LiveData<PreviewView.StreamState>`	`getPreviewStreamState()` Gets a `LiveData` for the preview `StreamState`.
`@NonNull PreviewView.ScaleType`	`@UiThread getScaleType()` Returns the `ScaleType` currently applied to the preview.
`@Nullable ImageCapture.ScreenFlash`	`@UiThread getScreenFlash()` Returns an `ImageCapture.ScreenFlash` implementation based on the `Window` instance set via `setScreenFlashWindow`.
`@Nullable Matrix`	`@UiThread getSensorToViewTransform()` Gets the transformation matrix from camera sensor to `PreviewView`.
`@NonNull Preview.SurfaceProvider`	`@UiThread getSurfaceProvider()` Gets a `Preview.SurfaceProvider` to be used with `setSurfaceProvider`.
`@Nullable ViewPort`	`@UiThread getViewPort()` Gets a `ViewPort` based on the current status of `PreviewView`.
`@Nullable ViewPort`	`@UiThread getViewPort(int targetRotation)` Gets a `ViewPort` with custom target rotation.
`boolean`	`onTouchEvent(@NonNull MotionEvent event)`
`boolean`	`performClick()`
`void`	`@UiThread setController(@Nullable CameraController cameraController)` Sets the `CameraController`.
`void`	`@UiThread setImplementationMode( @NonNull PreviewView.ImplementationMode implementationMode )` Sets the `ImplementationMode` for the `PreviewView`.
`void`	`@UiThread setScaleType(@NonNull PreviewView.ScaleType scaleType)` Applies a `ScaleType` to the preview.
`void`	`setScreenFlashOverlayColor(@ColorInt int color)` Sets the color of the top overlay view during screen flash.
`void`	`@UiThread setScreenFlashWindow(@Nullable Window screenFlashWindow)` Sets a `Window` instance for subsequent photo capture requests with `FLASH_MODE_SCREEN` set.

Protected methods
`void`	`onAttachedToWindow()`
`void`	`onDetachedFromWindow()`

Inherited Constants

From android.view.View

`static final int`	`ACCESSIBILITY_DATA_SENSITIVE_AUTO = 0`
`static final int`	`ACCESSIBILITY_DATA_SENSITIVE_NO = 2`
`static final int`	`ACCESSIBILITY_DATA_SENSITIVE_YES = 1`
`static final int`	`ACCESSIBILITY_LIVE_REGION_ASSERTIVE = 2`
`static final int`	`ACCESSIBILITY_LIVE_REGION_NONE = 0`
`static final int`	`ACCESSIBILITY_LIVE_REGION_POLITE = 1`
`static final Property<View, Float>`	`ALPHA`
`static final int`	`AUTOFILL_FLAG_INCLUDE_NOT_IMPORTANT_VIEWS = 1`
`static final String`	`AUTOFILL_HINT_CREDIT_CARD_EXPIRATION_DATE = "creditCardExpirationDate"`
`static final String`	`AUTOFILL_HINT_CREDIT_CARD_EXPIRATION_DAY = "creditCardExpirationDay"`
`static final String`	`AUTOFILL_HINT_CREDIT_CARD_EXPIRATION_MONTH = "creditCardExpirationMonth"`
`static final String`	`AUTOFILL_HINT_CREDIT_CARD_EXPIRATION_YEAR = "creditCardExpirationYear"`
`static final String`	`AUTOFILL_HINT_CREDIT_CARD_NUMBER = "creditCardNumber"`
`static final String`	`AUTOFILL_HINT_CREDIT_CARD_SECURITY_CODE = "creditCardSecurityCode"`
`static final String`	`AUTOFILL_HINT_EMAIL_ADDRESS = "emailAddress"`
`static final String`	`AUTOFILL_HINT_NAME = "name"`
`static final String`	`AUTOFILL_HINT_PASSWORD = "password"`
`static final String`	`AUTOFILL_HINT_PHONE = "phone"`
`static final String`	`AUTOFILL_HINT_POSTAL_ADDRESS = "postalAddress"`
`static final String`	`AUTOFILL_HINT_POSTAL_CODE = "postalCode"`
`static final String`	`AUTOFILL_HINT_USERNAME = "username"`
`static final int`	`AUTOFILL_TYPE_DATE = 4`
`static final int`	`AUTOFILL_TYPE_LIST = 3`
`static final int`	`AUTOFILL_TYPE_NONE = 0`
`static final int`	`AUTOFILL_TYPE_TEXT = 1`
`static final int`	`AUTOFILL_TYPE_TOGGLE = 2`
`static final int`	`CONTENT_SENSITIVITY_AUTO = 0`
`static final int`	`CONTENT_SENSITIVITY_NOT_SENSITIVE = 2`
`static final int`	`CONTENT_SENSITIVITY_SENSITIVE = 1`
`static final int`	`DRAG_FLAG_ACCESSIBILITY_ACTION = 1024`
`static final int`	`DRAG_FLAG_GLOBAL = 256`
`static final int`	`DRAG_FLAG_GLOBAL_PERSISTABLE_URI_PERMISSION = 64`
`static final int`	`DRAG_FLAG_GLOBAL_PREFIX_URI_PERMISSION = 128`
`static final int`	`DRAG_FLAG_GLOBAL_SAME_APPLICATION = 4096`
`static final int`	`DRAG_FLAG_GLOBAL_URI_READ = 1`
`static final int`	`DRAG_FLAG_GLOBAL_URI_WRITE = 2`
`static final int`	`DRAG_FLAG_HIDE_CALLING_TASK_ON_DRAG_START = 16384`
`static final int`	`DRAG_FLAG_OPAQUE = 512`
`static final int`	`DRAG_FLAG_START_INTENT_SENDER_ON_UNHANDLED_DRAG = 8192`
`static final int`	`DRAWING_CACHE_QUALITY_AUTO = 0` This field is deprecated.
`static final int`	`DRAWING_CACHE_QUALITY_HIGH = 1048576` This field is deprecated.
`static final int`	`DRAWING_CACHE_QUALITY_LOW = 524288` This field is deprecated.
`static final int[]`	`EMPTY_STATE_SET`
`static final int[]`	`ENABLED_FOCUSED_SELECTED_STATE_SET`
`static final int[]`	`ENABLED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`ENABLED_FOCUSED_STATE_SET`
`static final int[]`	`ENABLED_FOCUSED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`ENABLED_SELECTED_STATE_SET`
`static final int[]`	`ENABLED_SELECTED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`ENABLED_STATE_SET`
`static final int[]`	`ENABLED_WINDOW_FOCUSED_STATE_SET`
`static final int`	`FIND_VIEWS_WITH_CONTENT_DESCRIPTION = 2`
`static final int`	`FIND_VIEWS_WITH_TEXT = 1`
`static final int`	`FOCUSABLE = 1`
`static final int`	`FOCUSABLES_ALL = 0`
`static final int`	`FOCUSABLES_TOUCH_MODE = 1`
`static final int`	`FOCUSABLE_AUTO = 16`
`static final int[]`	`FOCUSED_SELECTED_STATE_SET`
`static final int[]`	`FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`FOCUSED_STATE_SET`
`static final int[]`	`FOCUSED_WINDOW_FOCUSED_STATE_SET`
`static final int`	`FOCUS_BACKWARD = 1`
`static final int`	`FOCUS_DOWN = 130`
`static final int`	`FOCUS_FORWARD = 2`
`static final int`	`FOCUS_LEFT = 17`
`static final int`	`FOCUS_RIGHT = 66`
`static final int`	`FOCUS_UP = 33`
`static final int`	`GONE = 8`
`static final int`	`HAPTIC_FEEDBACK_ENABLED = 268435456`
`static final int`	`IMPORTANT_FOR_ACCESSIBILITY_AUTO = 0`
`static final int`	`IMPORTANT_FOR_ACCESSIBILITY_NO = 2`
`static final int`	`IMPORTANT_FOR_ACCESSIBILITY_NO_HIDE_DESCENDANTS = 4`
`static final int`	`IMPORTANT_FOR_ACCESSIBILITY_YES = 1`
`static final int`	`IMPORTANT_FOR_AUTOFILL_AUTO = 0`
`static final int`	`IMPORTANT_FOR_AUTOFILL_NO = 2`
`static final int`	`IMPORTANT_FOR_AUTOFILL_NO_EXCLUDE_DESCENDANTS = 8`
`static final int`	`IMPORTANT_FOR_AUTOFILL_YES = 1`
`static final int`	`IMPORTANT_FOR_AUTOFILL_YES_EXCLUDE_DESCENDANTS = 4`
`static final int`	`IMPORTANT_FOR_CONTENT_CAPTURE_AUTO = 0`
`static final int`	`IMPORTANT_FOR_CONTENT_CAPTURE_NO = 2`
`static final int`	`IMPORTANT_FOR_CONTENT_CAPTURE_NO_EXCLUDE_DESCENDANTS = 8`
`static final int`	`IMPORTANT_FOR_CONTENT_CAPTURE_YES = 1`
`static final int`	`IMPORTANT_FOR_CONTENT_CAPTURE_YES_EXCLUDE_DESCENDANTS = 4`
`static final int`	`INVISIBLE = 4`
`static final int`	`KEEP_SCREEN_ON = 67108864`
`static final int`	`LAYER_TYPE_HARDWARE = 2`
`static final int`	`LAYER_TYPE_NONE = 0`
`static final int`	`LAYER_TYPE_SOFTWARE = 1`
`static final int`	`LAYOUT_DIRECTION_INHERIT = 2`
`static final int`	`LAYOUT_DIRECTION_LOCALE = 3`
`static final int`	`LAYOUT_DIRECTION_LTR = 0`
`static final int`	`LAYOUT_DIRECTION_RTL = 1`
`static final int`	`MEASURED_HEIGHT_STATE_SHIFT = 16`
`static final int`	`MEASURED_SIZE_MASK = 16777215`
`static final int`	`MEASURED_STATE_MASK = -16777216`
`static final int`	`MEASURED_STATE_TOO_SMALL = 16777216`
`static final int`	`NOT_FOCUSABLE = 0`
`static final int`	`NO_ID = -1`
`static final int`	`OVER_SCROLL_ALWAYS = 0`
`static final int`	`OVER_SCROLL_IF_CONTENT_SCROLLS = 1`
`static final int`	`OVER_SCROLL_NEVER = 2`
`static final int[]`	`PRESSED_ENABLED_FOCUSED_SELECTED_STATE_SET`
`static final int[]`	`PRESSED_ENABLED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`PRESSED_ENABLED_FOCUSED_STATE_SET`
`static final int[]`	`PRESSED_ENABLED_FOCUSED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`PRESSED_ENABLED_SELECTED_STATE_SET`
`static final int[]`	`PRESSED_ENABLED_SELECTED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`PRESSED_ENABLED_STATE_SET`
`static final int[]`	`PRESSED_ENABLED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`PRESSED_FOCUSED_SELECTED_STATE_SET`
`static final int[]`	`PRESSED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`PRESSED_FOCUSED_STATE_SET`
`static final int[]`	`PRESSED_FOCUSED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`PRESSED_SELECTED_STATE_SET`
`static final int[]`	`PRESSED_SELECTED_WINDOW_FOCUSED_STATE_SET`
`static final int[]`	`PRESSED_STATE_SET`
`static final int[]`	`PRESSED_WINDOW_FOCUSED_STATE_SET`
`static final float`	`REQUESTED_FRAME_RATE_CATEGORY_DEFAULT`
`static final float`	`REQUESTED_FRAME_RATE_CATEGORY_HIGH = -4.0f`
`static final float`	`REQUESTED_FRAME_RATE_CATEGORY_LOW = -2.0f`
`static final float`	`REQUESTED_FRAME_RATE_CATEGORY_NORMAL = -3.0f`
`static final float`	`REQUESTED_FRAME_RATE_CATEGORY_NO_PREFERENCE = -1.0f`
`static final Property<View, Float>`	`ROTATION`
`static final Property<View, Float>`	`ROTATION_X`
`static final Property<View, Float>`	`ROTATION_Y`
`static final Property<View, Float>`	`SCALE_X`
`static final Property<View, Float>`	`SCALE_Y`
`static final int`	`SCREEN_STATE_OFF = 0`
`static final int`	`SCREEN_STATE_ON = 1`
`static final int`	`SCROLLBARS_INSIDE_INSET = 16777216`
`static final int`	`SCROLLBARS_INSIDE_OVERLAY = 0`
`static final int`	`SCROLLBARS_OUTSIDE_INSET = 50331648`
`static final int`	`SCROLLBARS_OUTSIDE_OVERLAY = 33554432`
`static final int`	`SCROLLBAR_POSITION_DEFAULT = 0`
`static final int`	`SCROLLBAR_POSITION_LEFT = 1`
`static final int`	`SCROLLBAR_POSITION_RIGHT = 2`
`static final int`	`SCROLL_AXIS_HORIZONTAL = 1`
`static final int`	`SCROLL_AXIS_NONE = 0`
`static final int`	`SCROLL_AXIS_VERTICAL = 2`
`static final int`	`SCROLL_CAPTURE_HINT_AUTO = 0`
`static final int`	`SCROLL_CAPTURE_HINT_EXCLUDE = 1`
`static final int`	`SCROLL_CAPTURE_HINT_EXCLUDE_DESCENDANTS = 4`
`static final int`	`SCROLL_CAPTURE_HINT_INCLUDE = 2`
`static final int`	`SCROLL_INDICATOR_BOTTOM = 2`
`static final int`	`SCROLL_INDICATOR_END = 32`
`static final int`	`SCROLL_INDICATOR_LEFT = 4`
`static final int`	`SCROLL_INDICATOR_RIGHT = 8`
`static final int`	`SCROLL_INDICATOR_START = 16`
`static final int`	`SCROLL_INDICATOR_TOP = 1`
`static final int[]`	`SELECTED_STATE_SET`
`static final int[]`	`SELECTED_WINDOW_FOCUSED_STATE_SET`
`static final int`	`SOUND_EFFECTS_ENABLED = 134217728`
`static final int`	`STATUS_BAR_HIDDEN = 1` This field is deprecated.
`static final int`	`STATUS_BAR_VISIBLE = 0` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_FULLSCREEN = 4` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_HIDE_NAVIGATION = 2` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_IMMERSIVE = 2048` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_IMMERSIVE_STICKY = 4096` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN = 1024` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION = 512` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_LAYOUT_STABLE = 256` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_LIGHT_NAVIGATION_BAR = 16` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_LIGHT_STATUS_BAR = 8192` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_LOW_PROFILE = 1` This field is deprecated.
`static final int`	`SYSTEM_UI_FLAG_VISIBLE = 0` This field is deprecated.
`static final int`	`SYSTEM_UI_LAYOUT_FLAGS = 1536` This field is deprecated.
`static final int`	`TEXT_ALIGNMENT_CENTER = 4`
`static final int`	`TEXT_ALIGNMENT_GRAVITY = 1`
`static final int`	`TEXT_ALIGNMENT_INHERIT = 0`
`static final int`	`TEXT_ALIGNMENT_TEXT_END = 3`
`static final int`	`TEXT_ALIGNMENT_TEXT_START = 2`
`static final int`	`TEXT_ALIGNMENT_VIEW_END = 6`
`static final int`	`TEXT_ALIGNMENT_VIEW_START = 5`
`static final int`	`TEXT_DIRECTION_ANY_RTL = 2`
`static final int`	`TEXT_DIRECTION_FIRST_STRONG = 1`
`static final int`	`TEXT_DIRECTION_FIRST_STRONG_LTR = 6`
`static final int`	`TEXT_DIRECTION_FIRST_STRONG_RTL = 7`
`static final int`	`TEXT_DIRECTION_INHERIT = 0`
`static final int`	`TEXT_DIRECTION_LOCALE = 5`
`static final int`	`TEXT_DIRECTION_LTR = 3`
`static final int`	`TEXT_DIRECTION_RTL = 4`
`static final Property<View, Float>`	`TRANSLATION_X`
`static final Property<View, Float>`	`TRANSLATION_Y`
`static final Property<View, Float>`	`TRANSLATION_Z`
`static final String`	`VIEW_LOG_TAG = "View"`
`static final int`	`VISIBLE = 0`
`static final int[]`	`WINDOW_FOCUSED_STATE_SET`
`static final Property<View, Float>`	`X`
`static final Property<View, Float>`	`Y`
`static final Property<View, Float>`	`Z`

From android.view.ViewGroup

`static final int`	`CLIP_TO_PADDING_MASK = 34`
`static final int`	`FOCUS_AFTER_DESCENDANTS = 262144`
`static final int`	`FOCUS_BEFORE_DESCENDANTS = 131072`
`static final int`	`FOCUS_BLOCK_DESCENDANTS = 393216`
`static final int`	`LAYOUT_MODE_CLIP_BOUNDS = 0`
`static final int`	`LAYOUT_MODE_OPTICAL_BOUNDS = 1`
`static final int`	`PERSISTENT_ALL_CACHES = 3` This field is deprecated.
`static final int`	`PERSISTENT_ANIMATION_CACHE = 1` This field is deprecated.
`static final int`	`PERSISTENT_NO_CACHE = 0` This field is deprecated.
`static final int`	`PERSISTENT_SCROLLING_CACHE = 2` This field is deprecated.

Inherited methods

From android.widget.FrameLayout

`boolean`	`checkLayoutParams(ViewGroup.LayoutParams p)`
`FrameLayout.LayoutParams`	`generateDefaultLayoutParams()`
`FrameLayout.LayoutParams`	`generateLayoutParams(AttributeSet attrs)`
`CharSequence`	`getAccessibilityClassName()`
`boolean`	`getConsiderGoneChildrenWhenMeasuring()` This method is deprecated.
`boolean`	`getMeasureAllChildren()`
`void`	`onLayout(boolean changed, int left, int top, int right, int bottom)`
`void`	`onMeasure(int widthMeasureSpec, int heightMeasureSpec)`
`void`	`setForegroundGravity(int foregroundGravity)`
`void`	`setMeasureAllChildren(boolean measureAll)`
`boolean`	`shouldDelayChildPressedState()`

From android.view.View

`void`	`addOnAttachStateChangeListener( View.OnAttachStateChangeListener listener )`
`void`	`addOnLayoutChangeListener(View.OnLayoutChangeListener listener)`
`void`	`addOnUnhandledKeyEventListener( View.OnUnhandledKeyEventListener listener )`
`ViewPropertyAnimator`	`animate()`
`void`	`announceForAccessibility(CharSequence text)` This method is deprecated.
`void`	`autofill(SparseArray<AutofillValue> values)`
`boolean`	`awakenScrollBars()`
`void`	`bringToFront()`
`void`	`buildDrawingCache()` This method is deprecated.
`void`	`buildLayer()`
`boolean`	`callOnClick()`
`boolean`	`canResolveLayoutDirection()`
`boolean`	`canResolveTextAlignment()`
`boolean`	`canResolveTextDirection()`
`boolean`	`canScrollHorizontally(int direction)`
`boolean`	`canScrollVertically(int direction)`
`final void`	`cancelDragAndDrop()`
`void`	`cancelLongPress()`
`final void`	`cancelPendingInputEvents()`
`boolean`	`checkInputConnectionProxy(View view)`
`void`	`clearAnimation()`
`void`	`clearPendingCredentialRequest()`
`void`	`clearViewTranslationCallback()`
`static int`	`combineMeasuredStates(int curState, int newState)`
`int`	`computeHorizontalScrollExtent()`

PreviewView

Summary

Nested types

Public constructors

Public methods

Protected methods

Inherited Constants

Inherited methods