android - 从非 Activity 中拍照

Question

我在我的代码中使用了虚拟表面。它在运行 4.2.1 的 Canvas HD 中运行良好，但是当在我的 nexus 5/S 3 上部署相同的应用程序时，它在 camera.takepicture 上出现 RunTimeException

这是我的代码

  {
    camera = Camera.open(cameraId);
    if (camera != null)
   {
    SurfaceView dummy = new SurfaceView(context);
    try {
    camera.setPreviewDisplay(dummy.getHolder());
    } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    }
    camera.startPreview();
    camera.takePicture(null, null, new PhotoHandler(context));

    }

日志:

07-17 22:46:49.281: E/AndroidRuntime(481): FATAL EXCEPTION: main
07-17 22:46:49.281: E/AndroidRuntime(481): Process: com.example.ex, PID: 481
07-17 22:46:49.281: E/AndroidRuntime(481): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.ex/com.example.ex.MainActivity}: java.lang.RuntimeException: takePicture failed
07-17 22:46:49.281: E/AndroidRuntime(481):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2184)
07-17 22:46:49.281: E/AndroidRuntime(481):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
07-17 22:46:49.281: E/AndroidRuntime(481):  at android.app.ActivityThread.access$800(ActivityThread.java:135)
07-17 22:46:49.281: E/AndroidRuntime(481):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
07-17 22:46:49.281: E/AndroidRuntime(481):  at android.os.Handler.dispatchMessage(Handler.java:102)
07-17 22:46:49.281: E/AndroidRuntime(481):  at android.os.Looper.loop(Looper.java:136)
07-17 22:46:49.281: E/AndroidRuntime(481):  at android.app.ActivityThread.main(ActivityThread.java:5001)
07-17 22:46:49.281: E/AndroidRuntime(481):  at java.lang.reflect.Method.invokeNative(Native Method)
07-17 22:46:49.281: E/AndroidRuntime(481):  at java.lang.reflect.Method.invoke(Method.java:515)
07-17 22:46:49.281: E/AndroidRuntime(481):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
07-17 22:46:49.281: E/AndroidRuntime(481):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
07-17 22:46:49.281: E/AndroidRuntime(481):  at dalvik.system.NativeStart.main(Native Method)
07-17 22:46:49.281: E/AndroidRuntime(481): Caused by: java.lang.RuntimeException: takePicture failed
07-17 22:46:49.281: E/AndroidRuntime(481):  at android.hardware.Camera.native_takePicture(Native Method)
07-17 22:46:49.281: E/AndroidRuntime(481):  at android.hardware.Camera.takePicture(Camera.java:1245)
07-17 22:46:49.281: E/AndroidRuntime(481):  at android.hardware.Camera.takePicture(Camera.java:1190)
07-17 22:46:49.281: E/AndroidRuntime(481):  at com.example.ex.MainActivity.capturephoto(MainActivity.java:63)
07-17 22:46:49.281: E/AndroidRuntime(481):  at com.example.ex.MainActivity.onCreate(MainActivity.java:26)
07-17 22:46:49.281: E/AndroidRuntime(481):  at android.app.Activity.performCreate(Activity.java:5231)
07-17 22:46:49.281: E/AndroidRuntime(481):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
07-17 22:46:49.281: E/AndroidRuntime(481):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148)

在 stackoverflow 上搜索和搜索许多问题后，我找到了 this和 this但是这两个 fragment 都在 Activity 中使用。

我怎样才能在我的应用程序中使用这样的代码，以便我可以从背景中捕获图片

Answer 1

您可以使用虚拟 SurfaceTexture 代替 SurfaceView。这是可靠的，并且在旧相机 API 上运行良好:

mDummyTexture = new SurfaceTexture(1); // pick a random argument for texture id
mCamera.setPreviewTexture(mDummyTexture);
mCamera.startPreview();
mCamera.takePicture(...);

只要确保将 mDummyTexture 保留为您的类的成员，否则您可能会遇到废弃的表面错误。

只要不调用 SurfaceTexture#updateTexImage()，就不需要 OpenGL 上下文。