Flutter：PlatformExceptionno_available_camera，没有可用于拍照的相机，null，null

问题描述

伙计们！我正在面对这个相机版本。合并项目后发生了。它说没有可用的摄像头，但当时运行良好。请看看！

E/Flutter: [ERROR:Flutter/lib/ui/ui_dart_state.cc(177)] Unhandled Exception: PlatformException(no_available_camera,No cameras available for taking pictures.,null,null)
    #0      StandardMethodCodec.decodeEnvelope (package:Flutter/src/services/message_codecs.dart:582:7)
    #1      MethodChannel._invokeMethod (package:Flutter/src/services/platform_channel.dart:159:18)
    <asynchronous suspension>
    #2      MethodChannel.invokeMethod (package:Flutter/src/services/platform_channel.dart:332:12)
    #3      MethodChannelImagePicker.pickImagePath (package:image_picker_platform_interface/src/method_channel/method_channel_image_picker.dart:62:21)
    #4      MethodChannelImagePicker.pickImage (package:image_picker_platform_interface/src/method_channel/method_channel_image_picker.dart:30:25)
    #5      ImagePicker.getimage (package:image_picker/image_picker.dart:101:21)
    #6      _ImageEvaluationState.getimage (package:PhotoEarn/screens/camera/image_evaluation.dart:201:38)
    #7      _ImageEvaluationState.build.<anonymous closure> (package:PhotoEarn/screens/camera/image_evaluation.dart:1099:33)
    #8      _InkResponseState._handleTap (package:Flutter/src/material/ink_well.dart:993:19)
    #9      _InkResponseState.build.<anonymous closure> (package:Flutter/src/material/ink_well.dart:1111:38)
    #10     GestureRecognizer.invokeCallback (package:Flutter/src/gestures/recognizer.dart:183:24)
    #11     TapGestureRecognizer.handleTapUp (package:Flutter/src/gestures/tap.dart:598:11)
    #12     BaseTapGestureRecognizer._checkUp (package:Flutter/src/gestures/tap.dart:287:5)
    #13     BaseTapGestureRecognizer.acceptGesture (package:Flutter/src/gestures/tap.dart:259:7)
    #14     GestureArenaManager.sweep (package:Flutter/src/gestures/arena.dart:157:27)
    #15     GestureBinding.handleEvent (package:Flutter/src/gestures/binding.dart:362:20)
    #16     GestureBinding.dispatchEvent (package:Flutter/src/gestures/binding.dart:338:22)
    #17     RendererBinding.dispatchEvent (package:Flutter/src/rendering/binding.dart:267:11)
    #18     GestureBinding._handlePointerEvent (package:Flutter/src/gestures/binding.dart:295:7)
    #19     GestureBinding._flushPointerEventQueue (package:Flutter/src/gestures/binding.dart:240:7)
    #20     GestureBinding._handlePointerDataPacket (package:Flutter/src/gestures/binding.dart:213:7)
    #21     _rootRunUnary (dart:async/zone.dart:1206:13)
    #22     _CustomZone.runUnary (dart:async/zone.dart:1100:19)
    #23     _CustomZone.runUnaryguarded (dart:async/zone.dart:1005:7)
    #24     _invoke1 (dart:ui/hooks.dart:265:10)
    #25     _dispatchPointerDataPacket (dart:ui/hooks.dart:174:5)

请查看此错误消息并提供帮助。我希望听到大家的来信。预先谢谢你。

解决方法

鉴于目标是仅访问相机，我不确定添加 QUERY_ALL_PACKAGES 是正确的解决方案。如果 targetSdkVersion=30（或更高），将 <queries> 添加到您的 AndroidManifest.xml 看起来是这里的首选解决方案 - https://stackoverflow.com/a/63246789/268156

<manifest package="com.example">
    <queries>
        <intent>
            <action android:name="android.media.action.IMAGE_CAPTURE" />
        </intent>
    </queries>
    ...
</manifest>

如果您的compileSdkVersion和targetSdkVersion为30（或更高），则将以下内容添加到Android清单中：

<uses-permission android:name="android.permission.QUERY_ALL_PACKAGES"/>

那应该可以解决您的问题。

在Github issue中，有两种方法可以解决此问题

使用flutter upgrade更新到最新的flutter版本，然后运行您的应用。如果这不起作用，请使用flutter channel master切换到Flutter主频道并运行该应用。
如果上述方法不能解决问题，则应将compileSdkVersion和targetSdkVersion都设置为29。

我面临同样的问题。对于android，您需要在AndroidManifest.xml 文件中添加Camera 权限和Query all packages 权限，如下所示：

<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.QUERY_ALL_PACKAGES"/>

如果您的目标是 android 11/android sdk 30 或更高版本，则需要在 android manifest xml 文件中添加以下权限。

<uses-permission android:name="android.permission.QUERY_ALL_PACKAGES"/>

它可能会引发另一个警告，但您可以暂时忽略它。问候。

我在 Emulator 上进行测试，当我切换到 Real device 时，一切正常。

android-camera android-permissions imagepicker