Question

我正在学习CameraX API，CameraXBasic是办公室示例代码。

CameraXBasic 中的

CameraFragment.kt 显示了真实的摄像机预览，我希望添加一个 Switch 按钮冻结当前预览，通过即使移动手机相机镜头，图片也不会改变。

如何使用CameraX API？谢谢！

CameraFragment.kt

private lateinit var viewFinder: TextureView

private fun bindCameraUseCases() {
    // Get screen metrics used to setup camera for full screen resolution
    val metrics = DisplayMetrics().also { viewFinder.display.getRealMetrics(it) }
    val screenAspectRatio = Rational(metrics.widthPixels, metrics.heightPixels)
    Log.d(TAG, "Screen metrics: ${metrics.widthPixels} x ${metrics.heightPixels}")

    // Set up the view finder use case to display camera preview
    val viewFinderConfig = PreviewConfig.Builder().apply {
        setLensFacing(lensFacing)
        // We request aspect ratio but no resolution to let CameraX optimize our use cases
        setTargetAspectRatio(screenAspectRatio)
        // Set initial target rotation, we will have to call this again if rotation changes
        // during the lifecycle of this use case
        setTargetRotation(viewFinder.display.rotation)
    }.build()

    // Use the auto-fit preview builder to automatically handle size and orientation changes
    preview = AutoFitPreviewBuilder.build(viewFinderConfig, viewFinder)

 ....

 CameraX.bindToLifecycle(
            viewLifecycleOwner, preview, imageCapture, imageAnalyzer)
}

Answer 1

在PreviewOutputUpdateListener上添加Preview，然后可以决定是否更新TextureView：

Java：

preview.setOnPreviewOutputUpdateListener(
        previewOutput -> {
            if(!frozen){
               textureView.setSurfaceTexture(previewOutput.getSurfaceTexture());
            }
});

科特琳：

preview.setOnPreviewOutputUpdateListener {
    previewOutput: Preview.PreviewOutput? ->
        if(!frozen)
        textureView.setSurfaceTexture(previewOutput.getSurfaceTexture());
}

From Preview Documentation：

预览用例产生一个SurfaceTexture，用于传输相机输入。它还提供了有关视图进行裁剪，缩放或旋转以正确显示的其他信息。

当相机处于活动状态时，图像预览将流式传输到此SurfaceTexture。 SurfaceTexture可以连接到TextureView或GLSurfaceView。

因此Preview本身不会呈现任何内容，仅提供要渲染的Texture，由您决定如何处理由{ Texture 。

如何在Android Studio中使用CameraX API冻结相机的图片？

1 个答案: