Android上的相机应用

Question

I am beginner in android developing and I am trying to make a camera app. The camera app is opening but camera hardware is not detecting this is the code of main activity code. Now what am I missing to added to detect camera hardware please describe it and help me to solve it

public class CamTestActivity extends Activity {
    private static final String TAG = "CamTestActivity";
    Preview preview;
    Button buttonClick;
    Camera camera;
    Activity act;
    Context ctx;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ctx = this;
        act = this;
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);

        setContentView(R.layout.main);

        preview = new Preview(this, (SurfaceView)findViewById(R.id.surfaceView));
        preview.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
        ((FrameLayout) findViewById(R.id.layout)).addView(preview);
        preview.setKeepScreenOn(true);

        preview.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View arg0) {
                camera.takePicture(shutterCallback, rawCallback, jpegCallback);
            }
        });

        Toast.makeText(ctx, getString(R.string.take_photo_help), Toast.LENGTH_LONG).show();

        buttonClick = (Button) findViewById(R.id.btnCapture);

        buttonClick.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                try {
                    preview.mCamera.takePicture(shutterCallback, rawCallback, jpegCallback);
                    camera.takePicture(shutterCallback, rawCallback, jpegCallback);
                }catch (Exception e)
                {
                    Toast.makeText(ctx, getString(R.string.camera_not_found), Toast.LENGTH_LONG).show();
                }
            }
        });

        buttonClick.setOnLongClickListener(new OnLongClickListener(){
            @Override
            public boolean onLongClick(View arg0) {
                camera.autoFocus(new Camera.AutoFocusCallback(){
                    @Override
                    public void onAutoFocus(boolean arg0, Camera arg1) {
                        //camera.takePicture(shutterCallback, rawCallback, jpegCallback);
                    }
                });
                return true;
            }
        });
    }

    @Override
    protected void onResume() {
        super.onResume();
        int numCams = Camera.getNumberOfCameras();
        if(numCams > 0){
            try{
                camera = Camera.open(1);
                camera.startPreview();
                preview.setCamera(camera);
            } catch (RuntimeException ex){
                Toast.makeText(ctx, getString(R.string.camera_not_found), Toast.LENGTH_LONG).show();
            }
        }
    }

    @Override
    protected void onPause() {
        if(camera != null) {
            camera.stopPreview();
            preview.setCamera(null);
            camera.release();
            camera = null;
        }
        super.onPause();
    }

    private void resetCam() {
        camera.startPreview();
        preview.setCamera(camera);
    }

    private void refreshGallery(File file) {
        Intent mediaScanIntent = new Intent( Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
        mediaScanIntent.setData(Uri.fromFile(file));
        sendBroadcast(mediaScanIntent);
    }

    ShutterCallback shutterCallback = new ShutterCallback() {
        public void onShutter() {
            //           Log.d(TAG, "onShutter'd");
        }
    };

    PictureCallback rawCallback = new PictureCallback() {
        public void onPictureTaken(byte[] data, Camera camera) {
            //           Log.d(TAG, "onPictureTaken - raw");
        }
    };

    PictureCallback jpegCallback = new PictureCallback() {
        public void onPictureTaken(byte[] data, Camera camera) {
            new SaveImageTask().execute(data);
            resetCam();
            Log.d(TAG, "onPictureTaken - jpeg");
        }
    };

    private class SaveImageTask extends AsyncTask<byte[], Void, Void> {

        @Override
        protected Void doInBackground(byte[]... data) {
            FileOutputStream outStream = null;

            // Write to SD Card
            try {
                File sdCard = Environment.getExternalStorageDirectory();
                File dir = new File (sdCard.getAbsolutePath() + "/camtest");
                dir.mkdirs();

                String fileName = String.format("%d.jpg", System.currentTimeMillis());
                File outFile = new File(dir, fileName);

                outStream = new FileOutputStream(outFile);
                outStream.write(data[0]);
                outStream.flush();
                outStream.close();

                Log.d(TAG, "onPictureTaken - wrote bytes: " + data.length + " to " + outFile.getAbsolutePath());

                refreshGallery(outFile);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
            }
            return null;
        }
        }
}

this is the manifest code

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.niit.cameraapp">
    <uses-sdk android:minSdkVersion="9" />

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

    <application
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:label="@string/app_name"
            android:name=".CamTestActivity"
            android:screenOrientation="portrait" >
            <intent-filter >
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

this is the logcat error

04-26 12:20:13.694 9167-9167/com.example.niit.cameraapp I/zygote64: Late-enabling -Xcheck:jni
04-26 12:20:13.969 9167-9167/com.example.niit.cameraapp I/InstantRun: starting instant run server: is main process
04-26 12:20:14.142 9167-9167/com.example.niit.cameraapp W/.niit.cameraapp: type=1400 audit(0.0:84362): avc: denied { read } for name="u:object_r:camera_prop:s0" dev="tmpfs" ino=6271 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:object_r:camera_prop:s0 tclass=file permissive=0
04-26 12:20:14.149 9167-9167/com.example.niit.cameraapp E/libc: Access denied finding property "camera.hal1.packagelist"
04-26 12:20:14.152 9167-9167/com.example.niit.cameraapp W/CameraBase: An error occurred while connecting to camera 1: Status(-8): '1: validateClientPermissionsLocked:920: Caller "com.example.niit.cameraapp" (PID 10190, UID 9167) cannot open camera "1" without camera permission'
04-26 12:20:14.181 9167-9330/com.example.niit.cameraapp D/OpenGLRenderer: HWUI GL Pipeline
04-26 12:20:14.233 9167-9330/com.example.niit.cameraapp I/Adreno: QUALCOMM build                   : 7f08991, I8a9bdcf8d3
04-26 12:20:14.236 9167-9330/com.example.niit.cameraapp I/vndksupport: sphal namespace is not configured for this process. Loading /vendor/lib64/hw/gralloc.msm8953.so from the current namespace instead.
04-26 12:20:14.232 9167-9167/com.example.niit.cameraapp W/RenderThread: type=1400 audit(0.0:84363): avc: denied { search } for name="proc" dev="debugfs" ino=5174 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:object_r:qti_debugfs:s0 tclass=dir permissive=0
04-26 12:20:14.244 9167-9330/com.example.niit.cameraapp I/Adreno: PFP: 0x005ff087, ME: 0x005ff063
04-26 12:20:14.249 9167-9330/com.example.niit.cameraapp I/OpenGLRenderer: Initialized EGL, version 1.4
04-26 12:20:14.249 9167-9330/com.example.niit.cameraapp D/OpenGLRenderer: Swap behavior 2
04-26 12:20:14.309 9167-9330/com.example.niit.cameraapp I/vndksupport: sphal namespace is not configured for this process. Loading /vendor/lib64/hw/gralloc.msm8953.so from the current namespace instead.
04-26 12:20:17.316 9167-9202/com.example.niit.cameraapp I/zygote64: Debugger is no longer active

screenshot of the deployed app

Answer 1

The issue is most likely that, while you have asked for the Camera permission in the manifest, you also need to ask at runtime. The reason is that in older versions of Android (I think < Android 6.0), you only needed to declare permissions in the manifest. However, now the user can turn permissions on and off after the app has been installed. So now you are supposed to check during runtime whether you have permission for the feature you require. If you don't have it, then you should ask the user to enable it.

You can find code for this online. But first we need to verify that that is indeed the problem. The simplest way of doing that is by going to your Android Settings app. Then in there, there should be an Apps options. Find your app and click on it. In there, there should be a section with the Permissions. If the camera permission is not checked there, then check it and rerun your app.

If this fixes your issue, then you need to find code to ask the user to grant you the permission after the app opens. One such way of doing this is simply on the splash screen, as demonstrated here .

Answer 2

I assume you are running the app on a device with Android 6 or higher. So, you should additionally check for the runtime permissions to use the camera:

https://developer.android.com/training/permissions/requesting

If you don't add this permission check, Android will block the access to the camera hardware. It will also block hardware detection, because it requires also the camera permission. So, everytime you make a call on camera it will fail with a permission denied exception, which is logged in you logcat:

04-26 12:20:14.152 9167-9167/com.example.niit.cameraapp W/CameraBase: An error occurred while connecting to camera 1: Status(-8): '1: validateClientPermissionsLocked:920: Caller "com.example.niit.cameraapp" (PID 10190, UID 9167) cannot open camera "1" without camera permission'

Additionally, it seems you are using the deprecated camera api instead of the camera2 api:

https://developer.android.com/reference/android/hardware/camera2/package-summary