B4A Library CameraView - Take Pictures, record Video with the Camera

DonManfred · Aug 26, 2017

this is a quick (and incomplete) hack for this github project.

CameraView
Version: 1

CameraView
Events:
- onCameraClosed ( As )
- onCameraOpened (options As Object)
- onExposureCorrectionChanged (newValue As Float, bounds() As Float, fingers() As Object)
- onFocusEnd (success As Boolean, x As Int, y As Int)
- onFocusStart (x As Int, y As Int)
- onOrientationChanged (orientation As Int)
- onPictureTaken (jpeg() As Byte)
- onVideoTaken (path As String, filename As String)
- onZoomChanged (newValue As Float, bounds() As Float, fingers() As Object)
Fields:
- ba As BA
Methods:
- BringToFront
- DesignerCreateView (base As PanelWrapper, lw As LabelWrapper, props As Map)
- Initialize (EventName As String)
- Invalidate
- Invalidate2 (arg0 As Rect)
- Invalidate3 (arg0 As Int, arg1 As Int, arg2 As Int, arg3 As Int)
- IsInitialized As Boolean
- RemoveView
- RequestFocus As Boolean
- SendToBack
- SetBackgroundImageNew (arg0 As Bitmap) As BitmapDrawable
- SetColorAnimated (arg0 As Int, arg1 As Int, arg2 As Int)
- SetLayout (arg0 As Int, arg1 As Int, arg2 As Int, arg3 As Int)
- SetLayoutAnimated (arg0 As Int, arg1 As Int, arg2 As Int, arg3 As Int, arg4 As Int)
- SetVisibleAnimated (arg0 As Int, arg1 As Boolean)
- capturePicture
  Asks the camera to capture an image of the current scene.
  This will trigger {@link CameraListener#onPictureTaken(byte[])} if a listener
  was registered.
  
  Note that if sessionType is {@link SessionType#VIDEO}, this
  might fall back to {@link #captureSnapshot()} (that is, we might capture a preview frame).
- captureSnapshot
  Asks the camera to capture a snapshot of the current preview.
  This eventually triggers {@link CameraListener#onPictureTaken(byte[])} if a listener
  was registered.
  
  The difference with {@link #capturePicture()} is that this capture is faster, so it might be
  better on slower cameras, though the result can be generally blurry or low quality.
- clearCameraListeners
  Clears the list of {@link CameraListener} that are registered
  to camera events.
- destroy
- pause
  Stops the current preview, if any was started.
  This should be called onPause().
- setLocation (latitude As Double, longitude As Double)
  Set location coordinates to be found later in the jpeg EXIF header
  latitude: current latitude
  longitude: current longitude
- setSessionPicture
- setSessionVideo
- start
  Starts the camera preview, if not started already.
  This should be called onResume(), or when you are ready with permissions.
- startAutoFocus (x As Float, y As Float)
  Starts an autofocus process at the given coordinates, with respect
  to the view width and height.
  x: should be between 0 and getWidth()
  y: should be between 0 and getHeight()
- startCapturingVideo (path As String, filename As String)
  Starts recording a video with selected options. Video will be written to the given file,
  so callers should ensure they have appropriate permissions to write to the file.
  file: a file where the video will be saved
- stop
  Stops the current preview, if any was started.
  This should be called onPause().
- stopCapturingVideo
  Stops capturing video, if there was a video record going on.
  This will fire {@link CameraListener#onVideoTaken(File)}.
- toggleFacing As Facing
  Toggles the facing value between {@link Facing#BACK}
  and {@link Facing#FRONT}.
  Return type: @return:the new facing value
- toggleFlash As Flash
  Toggles the flash mode between {@link Flash#OFF},
  {@link Flash#ON} and {@link Flash#AUTO}, in this order.
  Return type: @return:the new flash value
Properties:
- Background As Drawable
- CameraOptions As CameraOptions [read only]
  Returns a {@link CameraOptions} instance holding supported options for this camera
  session. This might change over time. It's better to hold a reference from
  {@link CameraListener#onCameraOpened(CameraOptions)}.
- CaptureSize As Size [read only]
  Returns the size used for the capture,
  or null if it hasn't been computed yet (for example if the surface is not ready).
- Color As Int [write only]
- CropOutput As Boolean [write only]
  Whether we should crop the picture output to match CameraView aspect ratio.
  This is only relevant if CameraView dimensions were somehow constrained
  (e.g. by fixed value or MATCH_PARENT) and do not match internal aspect ratio.
  
  Please note that this requires additional computations after the picture is taken.
- Enabled As Boolean
- ExposureCorrection As Float
  Returns the current exposure correction value, typically 0
  at start-up.
- ExtraProperties As ExtraProperties [read only]
  If present, returns a collection of extra properties from the current camera
  session.
- Facing As Facing
  Gets the facing camera currently being used.
- Flash As Flash
  Gets the current flash mode.
- Grid As Grid
  Gets the current grid mode.
- Height As Int
- JpegQuality As Int [write only]
  Sets the JPEG compression quality for image outputs.
- Left As Int
- Padding()() As Int
- Parent As Object [read only]
- PreviewSize As Size [read only]
  Returns the size used for the preview,
  or null if it hasn't been computed (for example if the surface is not ready).
- SessionType As SessionType
  Gets the current session type.
- SnapshotSize As Size [read only]
  Returns the size used for capturing snapshots.
  This is equal to {@link #getPreviewSize()}.
- Started As Boolean [read only]
  Returns whether the camera has started showing its preview.
- Tag As Object
- Top As Int
- VideoQuality As String
  Gets the current video quality.
- Visible As Boolean
- WhiteBalance As WhiteBalance
  Returns the current white balance behavior.
- Width As Int
- Zoom As Float
  Returns the current zoom value, something between 0 and 1.

nicolino33 · Jul 18, 2018

No, this library is very good, come on, implement this feature, you did 30 make 31!

cliv · Dec 4, 2018

How can i use autofocus?
This code ...

B4X:

Sub Cam_onFocusStart(x As Int, y As Int)
    Log($"Cam_onFocusStart(${x},${y})"$)
End Sub
Sub btnFocus_Click
    cam.startAutoFocus(cam.Width/2,cam.Height/2)
End Sub

... generate error:

B4X:

java.lang.Exception: Sub cam_onfocusstart signature does not match expected signature.
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:193)
    at anywheresoftware.b4a.BA$2.run(BA.java:365)
    at android.os.Handler.handleCallback(Handler.java:815)
    at android.os.Handler.dispatchMessage(Handler.java:104)
    at android.os.Looper.loop(Looper.java:207)
    at android.app.ActivityThread.main(ActivityThread.java:5769)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:679)

Ivan Aldaz · Dec 4, 2018

Probably the error is generated because the Sub Cam_onFocusStart is expecting Int values, and is receiving non-Int values

DonManfred · Dec 4, 2018

try

B4X:

Sub Cam_onFocusStart(x As Float, y As Float)
    Log($"Cam_onFocusStart(${x},${y})"$)
End Sub

cliv · Dec 5, 2018

DonManfred said:
try

B4X:

Sub Cam_onFocusStart(x As Float, y As Float) Log($"Cam_onFocusStart(${x},${y})"$) End Sub

I already try this, same error, only difference ...error after Cam_onFocusStart(540.0,760.5) event.
Before (with x As Int and y As Int) onFocusStart event is not triggered.

B4X:

Cam_onOrientationChanged(0)
Cam_onCameraOpened()
Cam_onFocusStart(540.0,760.5)
java.lang.Exception: Sub cam_onfocusend signature does not match expected signature.
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:193)
    at anywheresoftware.b4a.BA$2.run(BA.java:365)
    at android.os.Handler.handleCallback(Handler.java:815)
    at android.os.Handler.dispatchMessage(Handler.java:104)
    at android.os.Looper.loop(Looper.java:207)
    at android.app.ActivityThread.main(ActivityThread.java:5769)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:679)

Shalu Samtani · Feb 6, 2019

why i cant turn on flash?

DonManfred · Feb 6, 2019

The lib does not support it.

MphammadHosien · Dec 20, 2020

can I use this library to take photo in background service? How?

idrotelapp · Jul 29, 2023

Dear Erel,
I am working on a widget and after clicking on widget I want to use cameraview to take a photo but cameraview does not start in widget . I tested the cameraview in new app without widget and it works properly !
How i can use cameraview in widget ?
many tanks for your kind help.

DonManfred · Jul 30, 2023

idrotelapp said:
How i can use cameraview in widget ?

you can´t use cameraview in a widget

idrotelapp · Jul 30, 2023

thnx DonManfred , which lib is suitable for camera in widget?

B4A Library CameraView - Take Pictures, record Video with the Camera

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