错误：无法连接到相机服务@Android marshmallow

Question

我正在尝试构建一个相机应用程序（我对此很陌生） 当我在真实设备上运行应用程序时，它给了我这个错误：

    05-26 13:16:37.504 14076-14076/involved.pose9 E/AndroidRuntime: FATAL EXCEPTION: main
                                                            Process: involved.pose9, PID: 14076
                                                            java.lang.RuntimeException: Fail to connect to camera service
                                                                at android.hardware.Camera.<init>(Camera.java:511)
                                                                at android.hardware.Camera.open(Camera.java:368)
                                                                at involved.pose9.CameraActivity.surfaceCreated(CameraActivity.java:63)
                                                                at android.view.SurfaceView.updateWindow(SurfaceView.java:582)
                                                                at android.view.SurfaceView$3.onPreDraw(SurfaceView.java:177)
                                                                at android.view.ViewTreeObserver.dispatchOnPreDraw(ViewTreeObserver.java:944)
                                                                at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2067)
                                                                at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1119)
                                                                at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6060)
                                                                at android.view.Choreographer$CallbackRecord.run(Choreographer.java:858)
                                                                at android.view.Choreographer.doCallbacks(Choreographer.java:670)
                                                                at android.view.Choreographer.doFrame(Choreographer.java:606)
                                                                at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:844)
                                                                at android.os.Handler.handleCallback(Handler.java:746)
                                                                at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                at android.os.Looper.loop(Looper.java:148)
                                                                at android.app.ActivityThread.main(ActivityThread.java:5443)
                                                                at java.lang.reflect.Method.invoke(Native Method)
                                                                at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:728)
                                                                at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)

这是我的课

    import android.graphics.PixelFormat;
    import android.hardware.Camera;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.SurfaceHolder;
    import android.view.SurfaceView;
    import android.view.Window;
    import android.view.WindowManager;

    import java.io.IOException;

    public class CameraActivity extends AppCompatActivity implements SurfaceHolder.Callback {

SurfaceHolder mSurfaceHolder;
SurfaceView mSurfaceView;
public Camera mCamera;
boolean mPreviewRunning;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);


    getWindow().setFormat(PixelFormat.TRANSLUCENT);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
            WindowManager.LayoutParams.FLAG_FULLSCREEN);
    setContentView(R.layout.activity_camera);
    mSurfaceView = (SurfaceView) findViewById(R.id.surface_camera);
    mSurfaceHolder = mSurfaceView.getHolder();
    mSurfaceHolder.addCallback(this);
    mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}

@Override
public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) {
    // TODO Auto-generated method stub


    if (mPreviewRunning) {
        mCamera.stopPreview();
    }
    Camera.Parameters p = mCamera.getParameters();
    //p.setPreviewSize(w, h);
    mCamera.setParameters(p);
    try {
        mCamera.setPreviewDisplay(arg0);
    } catch (IOException e) {
        e.printStackTrace();
    }
    mCamera.startPreview();
    mPreviewRunning = true;
}

@Override
public void surfaceCreated(SurfaceHolder holder) {
    // TODO Auto-generated method stub
    mCamera = Camera.open();
}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
    // TODO Auto-generated method stub
    mCamera.stopPreview();
    mPreviewRunning = false;
    mCamera.release();
}

Camera.PictureCallback mPictureCallback = new Camera.PictureCallback() {
    public void onPictureTaken(byte[] imageData, Camera c) {
    }
};
}

这里有什么问题？提前谢谢..

我还在 manifest.xml 中声明了权限

    <uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.Camera" />
<uses-feature android:name="android.hardware." />

Answer 1

您需要以编程方式授予android.hardware.Camera 权限。

清单权限在 Android 6 上不起作用

使用棉花糖（最新版本的 Android）。我们有一些 使用 Sensitive 权限的限制，例如： 存储、联系人访问等。在版本中授予这些权限 manifest，我们需要在 Runtime 向用户请求它们。

更多详情请参考：Android M permissions

在您的活动中添加此代码：

@Override
protected void onStart() {
    super.onStart();

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {

        int hasCameraPermission = checkSelfPermission(Manifest.permission.CAMERA);

        List<String> permissions = new ArrayList<String>();

        if (hasCameraPermission != PackageManager.PERMISSION_GRANTED) {
            permissions.add(Manifest.permission.CAMERA);

        } 
        if (!permissions.isEmpty()) {
            requestPermissions(permissions.toArray(new String[permissions.size()]), 111);
        }
    }


}

在onActivityResult之后添加这个：

@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
    switch (requestCode) {
        case 111: {
            for (int i = 0; i < permissions.length; i++) {
                if (grantResults[i] == PackageManager.PERMISSION_GRANTED) {
                    System.out.println("Permissions --> " + "Permission Granted: " + permissions[i]);


                } else if (grantResults[i] == PackageManager.PERMISSION_DENIED) {
                    System.out.println("Permissions --> " + "Permission Denied: " + permissions[i]);

                }
            }
        }
        break;
        default: {
            super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        }
    }
}

Answer 2

从 marshmellow 开始，操作系统权限应该在运行时获得。相机权限也必须在运行时获取请查看以下链接以了解如何在运行时请求权限。 https://developer.android.com/training/permissions/requesting.html

快速解决方案： 这是一个修复，但您可以用于当前的 marshmellow 版本 尝试将其添加到您的 build.gradle 文件中

targetSdkVersion 22

Answer 3

在 Marshmallow 上，您必须在运行时请求用户授予权限，例如

int permissionCheck = ContextCompat.checkSelfPermission(thisActivity,
        Manifest.permission.WRITE_CALENDAR);

if(permissionCheck == PackageManager.PERMISSION_GRANTED){
//user granted you
}else{
//the user denied your permission
}