如何在合成中初始化摄像机-移动开发问题

How to initialize camera in compose(如何在合成中初始化摄像机)

本文介绍了如何在合成中初始化摄像机的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我想通过合成androidView获得相机视图，但以下代码似乎不适合我。

@Composable
fun CameraPreviewScreen() {
    val lifecycleOwner = LifecycleOwnerAmbient.current
    val context = ContextAmbient.current
    val cameraProviderFuture = remember { ProcessCameraProvider.getInstance(context) }
    val previewView = remember { PreviewView(context) }
    AndroidView(viewBlock = { previewView }) {
        cameraProviderFuture.addListener(Runnable {
            val cameraProvider = cameraProviderFuture.get()
            val preview = Preview.Builder().build()
            preview.setSurfaceProvider(it.surfaceProvider)
            val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA
            try {
                cameraProvider.unbindAll()
                cameraProvider.bindToLifecycle(
                    lifecycleOwner, cameraSelector, preview)
            } catch(exc: Exception) {
                Log.e(TAG, "Use case binding failed", exc)
            }
        }, ContextCompat.getMainExecutor(context))
    }
}

下面的快照。

报告错误。

拒绝权限：无法使用摄像头
没有相机权限(代码1)，无法打开相机&0&q；

推荐答案

由于您的问题似乎与摄像机权限有关，您可以使用Permissions APIs来自Accompanist库向用户请求权限。

文档显示了一个使用摄像头的示例

@Composable
private fun FeatureThatRequiresCameraPermission(
    navigateToSettingsScreen: () -> Unit
) {
    // Track if the user doesn't want to see the rationale any more.
    var doNotShowRationale by rememberSaveable { mutableStateOf(false) }

    val cameraPermissionState = rememberPermissionState(android.Manifest.permission.CAMERA)
    PermissionRequired(
        permissionState = cameraPermissionState,
        permissionNotGrantedContent = {
            if (doNotShowRationale) {
                Text("Feature not available")
            } else {
                Column {
                    Text("The camera is important for this app. Please grant the permission.")
                    Spacer(modifier = Modifier.height(8.dp))
                    Row {
                        Button(onClick = { cameraPermissionState.launchPermissionRequest() }) {
                            Text("Ok!")
                        }
                        Spacer(Modifier.width(8.dp))
                        Button(onClick = { doNotShowRationale = true }) {
                            Text("Nope")
                        }
                    }
                }
            }
        },
        permissionNotAvailableContent = {
            Column {
                Text(
                    "Camera permission denied. See this FAQ with information about why we " +
                        "need this permission. Please, grant us access on the Settings screen."
                )
                Spacer(modifier = Modifier.height(8.dp))
                Button(onClick = navigateToSettingsScreen) {
                    Text("Open Settings")
                }
            }
        }
    ) {
        Text("Camera permission Granted")
    }
}

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