hasSystemFeature（PackageManager.FEATURE_CAMERA）用于设备返回true，没有摄像头 [英] hasSystemFeature(PackageManager.FEATURE_CAMERA) returns true for device with no camera

问题描述

我有它的功能，它使用相机功能中有一个应用程序，但部分也可以不带摄像功能的运行。所以我必须把这个在我的清单。

I have a application which uses camera functionality in it but part of its functionality can also run without camera feature. SO I have put this in my manifest.

<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera"  android:required="false"/> 

在我的code我检查设备是否有相机或不使用这种

and in my code I check whether the device has camera or not using this

final boolean deviceHasCameraFlag = pm.hasSystemFeature(PackageManager.FEATURE_CAMERA);

现在我测试我的code上运行Android 4.0（ICS），并没有摄像头平板电脑。但我仍然得到 deviceHasCameraFlag 真正的价值。被这个奇怪的还是我失去了一些东西。

Now I am testing my code on a tablet which runs Android 4.0(ICS) and has no camera. But still I get True value for the deviceHasCameraFlag. Is this weird or am I missing something.

我尝试不同的东西，甚至试图在同样的事情上蓝牙功能的平板电脑，甚至不具备蓝牙功能。它工作正常的蓝牙，但给了我真正的相机。

I tried different things and even tried the same thing on Bluetooth feature as Tablet even doesn't have Bluetooth feature. It works fine for Bluetooth but gives me true for camera.

推荐答案

哪个设备是什么呢？你得到的答案是一个bug，和4.0已经很老了时下。仍然运行此版本的许多平板电脑都无法正确雕琢，无论是硬件还是软件配备多个问题。

Which device is it? The answer you get is a bug, and 4.0 is very old nowadays. Many tablets that still run this version were not crafted correctly, both hardware and software featuring multiple problems.

无论如何，你应该总是ppared处理失败$ P $关于 Camera.open（）或 Camera.open（0）：例如，在某些情况下，设备上的其他软件将不正常释放相机。

Regardless, you should always be prepared to handle failure on Camera.open() or Camera.open(0): for example, in some cases other software on your device will not release the camera gracefully.

所以，你的情况，你有一个假阳性，您尝试打开摄像头，它失败了，你继续，如果有设备上没有摄像头，即使软件包管理系统认为< STRONG> PackageManager.FEATURE_CAMERA 是速效。

So, in your case you have a false positive, you try to open the camera, it fails, and you continue as if there is no camera on the device, even if PackageManager thinks that PackageManager.FEATURE_CAMERA is availabe.

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