从非活动中拍照 [英] Taking picture from non-activity
问题描述
我在代码中使用了虚拟表面。在运行4.2.1的Canvas HD中可以正常工作，但是当在我的nexus 5 / S 3上部署相同的应用程序时，它会在camera.takepicture上给出RunTimeException
I am using dummy surface in my code.It's working fine in Canvas HD running 4.2.1 but when the same app is deployed on my nexus 5/S 3 it gives RunTimeException on camera.takepicture
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));
}
Logcat：
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)
在搜寻并搜索了许多关于stackoverflow的问题后，我发现此和 ，但这两个代码段都用于活动中。
After googling and searching many questions on stackoverflow I found this and this but both snippets are used in activties .
我该如何在我的应用中使用这样的代码，以便可以从背景中捕获图片
How could I use such code in my app so that I can capture picture from background
推荐答案
您不应使用虚拟的SurfaceView，因为Android会检查是否在屏幕上显示了SurfaceView。
You shouldn't use a dummy SurfaceView as Android checks is the SurfaceView is displayed on the screen.
相反，使用WindowManager在类型为SYSTEM_OVERLAY的SurfaceView上显示预览。将您的SurfaceView宽度和高度设置为1px，将不透明度设置为0以隐藏预览，就是这样！
Instead, display the preview on a SurfaceView with WindowManager, with type SYSTEM_OVERLAY. Set your SurfaceView width and height to 1px and the opacity to 0 to hide the preview, and that's it!
如果您计划仅支持5.0+设备，或者即将推出的新应用，您应该考虑使用新的android Camera2 API，该API修复了旧API的许多错误。
If you plan to support only 5.0+ devices, or it's a new app that won't be available too soon, you should consider using the new android Camera2 API, which fixed many mistakes of the older API.
希望它会为您提供帮助：）
Hope it will help you :)
这篇关于从非活动中拍照的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
