Please help: I want camerax preview use case to fill the whole size of the screen in compose, I am u...

# compose

[Shivam Sethi]

Please help: I want camerax preview use case to fill the whole size of the screen in compose, I am using a PreviewView in AndroidView and it is not filling the full screen, I tried creating same activity with xml (no compose) and is working as expected ? Or is there a direct way in compose to not use PreviewView() at all to show a preview use case full screen ?

In xml I had it match_parent for height and width not sure how can achieve that here, it just put black screen top and bottom but preview size remains the same if I do Modifier.fillmaxSize()

[jaqxues]

You should probably set the layout params to get the expected behaviour

[Shivam Sethi]

okay, but the question is which layout params should be used ? it is pure compose activity ?

[Shivam Sethi]

tried

LinearLayout.LayoutParams(MATCH_PARENT, MATCH_PARENT)

but no effect

[jaqxues]

Uhm I doubt that the Preview inherits from LinearLayout. Guessing here, but still pretty sure that would not even compile

[jaqxues]

How are you setting it? And is that all the setup you need for the preview? Doubt that too

[Shivam Sethi]

well this is the setting of preview, used the same setting in xml PeviewView

[Shivam Sethi]

private fun startCamera() {
    val cameraProviderFuture = ProcessCameraProvider.getInstance(this)

    cameraProviderFuture.addListener({
        // Used to bind the lifecycle of cameras to the lifecycle owner
        val cameraProvider: ProcessCameraProvider = cameraProviderFuture.get()

        // Preview
        val preview = Preview.Builder()
            .build()
            .also {
                it.setSurfaceProvider(previewView.surfaceProvider)
            }

        // Select back camera as a default
        val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA

        try {
            // Unbind use cases before rebinding
            cameraProvider.unbindAll()

            // Bind use cases to camera
            cameraProvider.bindToLifecycle(
                this, cameraSelector, preview
            )

        } catch (exc: Exception) {
            Log.e(DEBUG_TAG, "Use case binding failed", exc)
        }

    }, ContextCompat.getMainExecutor(this))
}

[Neal Sanche]

You might try setting previewView.implementationMode = PreviewView.ImplementationMode.COMPATIBLE which seems to be more stable for me. I've put in a bug report for a similar problem: https://issuetracker.google.com/issues/179291080

[Neal Sanche]

I tried some of your code, mixed with a few of the things that I've tried.

Untitled.kt

[Neal Sanche]

This is the Android View layout I used.

res_layout_preview_host_xml.xml

[Cyril Find]

Untitled

[Cyril Find]

mine looks like this ⬆️
i had issues with the ratio of the preview on some devices and previewView.implementationMode = PreviewView.ImplementationMode.COMPATIBLE fixed it
(i don't remember why i didn't use the update lambda in the end 😅)

[Neal Sanche]

I think initially, the update lambda didn't exist. But, it's also going to restart the camera use cases, which might not be what you want.

[Shivam Sethi]

Thanks @Neal Sanche @Cyril Find you guys saved the refactor back to xml.