相机预览与上面的透明图像

问题描述

我想在Camera SurfaceView \preview顶部看到一个图像。
我如何做到这一点？任何示例？

I would like to see an image on top of Camera SurfaceView\preview.How do I do that? Any examples?

推荐答案

一个很好的示例可以在 library，应用程序。

A great example can be found in ZXing library, Barcode Scanner application.

他们使用 FrameLayout $ c> SurfaceView 及其自定义 ViewfinderView ，以便 SurfaceView 和 ViewfinderView 覆盖全屏：

What they do is they use FrameLayout for SurfaceView and their custom ViewfinderView so that both SurfaceView and ViewfinderView are covering full screen:

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
             android:layout_width="fill_parent"
             android:layout_height="fill_parent">

  <SurfaceView android:id="@+id/preview_view"
               android:layout_width="fill_parent"
               android:layout_height="fill_parent"
               android:layout_centerInParent="true"/>

  <com.google.zxing.client.android.ViewfinderView
      android:id="@+id/viewfinder_view"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent"
      android:background="@color/transparent"/>

</FrameLayout>

请注意<$ c中的 fill_parent $ c> layout_height 和 layout_width 。

Note the fill_parent values in layout_height and layout_width for both views.

方法，只是在相机预览显示的顶部。

And then they draw custom things in ViewfinderView.onDraw() method, just on top of what is being displayed by camera preview.

如果你不想绘制任何东西，而是使用预定义的图像，那么使用 ImageView code> ViewfinderView 。您可以考虑调用 setAlpha 方法使图像透明（如果drawable本身不是透明的）。

If you don't want to draw anything, but just use predefined image, then use ImageView instead of ViewfinderView. You might consider calling setAlpha method to make your image transparent (if drawable wasn't already transparent by itself).

以下是条码扫描器的屏幕截图：

Here is a screenshot from Barcode Scanner:

img src =https://i.stack.imgur.com/CQ9Dq.pngalt =输入图片说明here>>

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