如何在不使用相机应用程序的情况下在后台捕获图像 [英] how to capture an image in background without using the camera application
本文介绍了如何在不使用相机应用程序的情况下在后台捕获图像的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我有一个由 Button 组成的 android 应用程序.
当您点击按钮时，无需打开相机应用程序即可从相机中捕获图像(图像应在后台捕获).
如何实现这个功能?
任何建议都会有很大帮助.
提前非常感谢.
I have an android app which consists of a Button.
When you click on Button, an image should be captured from the camera without opening the camera application (the image should be captured in background).
How to implement this feature?
Any suggestions will be of great help.
Thanks a lot in advance.
推荐答案
这是我的整个工作项目，即如何在没有 SurfaceView 的情况下在后台捕获图像.
Here is my whole working project of How to capture image in background without SurfaceView.
//您可以启动您的服务以在任何您不希望从活动中捕获图像.
// You can start your service to capturing image wherever you want not should from activity.
还需要在您的 Activity 中询问需要权限
also need to ask need permission in your Activity
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && !Settings.canDrawOverlays(this)) {
Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION,
Uri.parse("package:" + getPackageName()));
startActivityForResult(intent, APP_PERMISSION_REQUEST);
}
在点击或您需要的地方处理意图
handle intent in click or where you needed
Intent front_translucent = new Intent(getApplication()
.getApplicationContext(), CameraService.class);
front_translucent.putExtra("Front_Request", true);
front_translucent.putExtra("Quality_Mode",
camCapture.getQuality());
getApplication().getApplicationContext().startService(
front_translucent);
public class CamerService extends Service implements
SurfaceHolder.Callback {
// Camera variables
// a surface holder
// a variable to control the camera
private Camera mCamera;
// the camera parameters
private Parameters parameters;
private Bitmap bmp;
FileOutputStream fo;
private String FLASH_MODE;
private int QUALITY_MODE = 0;
private boolean isFrontCamRequest = false;
private Camera.Size pictureSize;
SurfaceView sv;
private SurfaceHolder sHolder;
private WindowManager windowManager;
WindowManager.LayoutParams params;
public Intent cameraIntent;
SharedPreferences pref;
Editor editor;
int width = 0, height = 0;
/** Called when the activity is first created. */
@Override
public void onCreate() {
super.onCreate();
}
private Camera openFrontFacingCameraGingerbread() {
if (mCamera != null) {
mCamera.stopPreview();
mCamera.release();
}
int cameraCount = 0;
Camera cam = null;
Camera.CameraInfo cameraInfo = new Camera.CameraInfo();
cameraCount = Camera.getNumberOfCameras();
for (int camIdx = 0; camIdx < cameraCount; camIdx++) {
Camera.getCameraInfo(camIdx, cameraInfo);
if (cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
try {
cam = Camera.open(camIdx);
} catch (RuntimeException e) {
Log.e("Camera",
"Camera failed to open: " + e.getLocalizedMessage());
/*
* Toast.makeText(getApplicationContext(),
* "Front Camera failed to open", Toast.LENGTH_LONG)
* .show();
*/
}
}
}
return cam;
}
private void setBesttPictureResolution() {
// get biggest picture size
width = pref.getInt("Picture_Width", 0);
height = pref.getInt("Picture_height", 0);
if (width == 0 | height == 0) {
pictureSize = getBiggesttPictureSize(parameters);
if (pictureSize != null)
parameters
.setPictureSize(pictureSize.width, pictureSize.height);
// save width and height in sharedprefrences
width = pictureSize.width;
height = pictureSize.height;
editor.putInt("Picture_Width", width);
editor.putInt("Picture_height", height);
editor.commit();
} else {
// if (pictureSize != null)
parameters.setPictureSize(width, height);
}
}
private Camera.Size getBiggesttPictureSize(Camera.Parameters parameters) {
Camera.Size result = null;
for (Camera.Size size : parameters.getSupportedPictureSizes()) {
if (result == null) {
result = size;
} else {
int resultArea = result.width * result.height;
int newArea = size.width * size.height;
if (newArea > resultArea) {
result = size;
}
}
}
return (result);
}
/** Check if this device has a camera */
private boolean checkCameraHardware(Context context) {
if (context.getPackageManager().hasSystemFeature(
PackageManager.FEATURE_CAMERA)) {
// this device has a camera
return true;
} else {
// no camera on this device
return false;
}
}
/** Check if this device has front camera */
private boolean checkFrontCamera(Context context) {
if (context.getPackageManager().hasSystemFeature(
PackageManager.FEATURE_CAMERA_FRONT)) {
// this device has front camera
return true;
} else {
// no front camera on this device
return false;
}
}
Handler handler = new Handler();
private class TakeImage extends AsyncTask<Intent, Void, Void> {
@Override
protected Void doInBackground(Intent... params) {
takeImage(params[0]);
return null;
}
@Override
protected void onPostExecute(Void result) {
}
}
private synchronized void takeImage(Intent intent) {
if (checkCameraHardware(getApplicationContext())) {
Bundle extras = intent.getExtras();
if (extras != null) {
String flash_mode = extras.getString("FLASH");
FLASH_MODE = flash_mode;
boolean front_cam_req = extras.getBoolean("Front_Request");
isFrontCamRequest = front_cam_req;
int quality_mode = extras.getInt("Quality_Mode");
QUALITY_MODE = quality_mode;
}
if (isFrontCamRequest) {
// set flash 0ff
FLASH_MODE = "off";
// only for gingerbread and newer versions
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.GINGERBREAD) {
mCamera = openFrontFacingCameraGingerbread();
if (mCamera != null) {
try {
mCamera.setPreviewDisplay(sv.getHolder());
} catch (IOException e) {
handler.post(new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(),
"API dosen't support front camera",
Toast.LENGTH_LONG).show();
}
});
stopSelf();
}
Camera.Parameters parameters = mCamera.getParameters();
pictureSize = getBiggesttPictureSize(parameters);
if (pictureSize != null)
parameters
.setPictureSize(pictureSize.width, pictureSize.height);
// set camera parameters
mCamera.setParameters(parameters);
mCamera.startPreview();
mCamera.takePicture(null, null, mCall);
// return 4;
} else {
mCamera = null;
handler.post(new Runnable() {
@Override
public void run() {
Toast.makeText(
getApplicationContext(),
"Your Device dosen't have Front Camera !",
Toast.LENGTH_LONG).show();
}
});
stopSelf();
}
/*
* sHolder = sv.getHolder(); // tells Android that this
* surface will have its data // constantly // replaced if
* (Build.VERSION.SDK_INT < 11)
*
* sHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS)
*/
} else {
if (checkFrontCamera(getApplicationContext())) {
mCamera = openFrontFacingCameraGingerbread();
if (mCamera != null) {
try {
mCamera.setPreviewDisplay(sv.getHolder());
} catch (IOException e) {
handler.post(new Runnable() {
@Override
public void run() {
Toast.makeText(
getApplicationContext(),
"API dosen't support front camera",
Toast.LENGTH_LONG).show();
}
});
stopSelf();
}
Camera.Parameters parameters = mCamera.getParameters();
pictureSize = getBiggesttPictureSize(parameters);
if (pictureSize != null)
parameters
.setPictureSize(pictureSize.width, pictureSize.height);
// set camera parameters
mCamera.setParameters(parameters);
mCamera.startPreview();
mCamera.takePicture(null, null, mCall);
// return 4;
} else {
mCamera = null;
/*
* Toast.makeText(getApplicationContext(),
* "API dosen't support front camera",
* Toast.LENGTH_LONG).show();
*/
handler.post(new Runnable() {
@Override
public void run() {
Toast.makeText(
getApplicationContext(),
"Your Device dosen't have Front Camera !",
Toast.LENGTH_LONG).show();
}
});
stopSelf();
}
// Get a surface
/*
* sHolder = sv.getHolder(); // tells Android that this
* surface will have its data // constantly // replaced
* if (Build.VERSION.SDK_INT < 11)
*
* sHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS
* );
*/
}
}
} else {
if (mCamera != null) {
mCamera.stopPreview();
mCamera.release();
mCamera = Camera.open();
} else
mCamera = getCameraInstance();
try {
if (mCamera != null) {
mCamera.setPreviewDisplay(sv.getHolder());
parameters = mCamera.getParameters();
if (FLASH_MODE == null || FLASH_MODE.isEmpty()) {
FLASH_MODE = "auto";
}
parameters.setFlashMode(FLASH_MODE);
// set biggest picture
setBesttPictureResolution();
// log quality and image format
Log.d("Qaulity", parameters.getJpegQuality() + "");
Log.d("Format", parameters.getPictureFormat() + "");
// set camera parameters
mCamera.setParameters(parameters);
mCamera.startPreview();
Log.d("ImageTakin", "OnTake()");
mCamera.takePicture(null, null, mCall);
} else {
handler.post(new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(),
"Camera is unavailable !",
Toast.LENGTH_LONG).show();
}
});
}
// return 4;
} catch (IOException e) {
// TODO Auto-generated catch block
Log.e("TAG", "CmaraHeadService()::takePicture", e);
}
// Get a surface
/*
* sHolder = sv.getHolder(); // tells Android that this surface
* will have its data constantly // replaced if
* (Build.VERSION.SDK_INT < 11)
*
* sHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
*/
}
} else {
// display in long period of time
/*
* Toast.makeText(getApplicationContext(),
* "Your Device dosen't have a Camera !", Toast.LENGTH_LONG)
* .show();
*/
handler.post(new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(),
"Your Device dosen't have a Camera !",
Toast.LENGTH_LONG).show();
}
});
stopSelf();
}
// return super.onStartCommand(intent, flags, startId);
}
@SuppressWarnings("deprecation")
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
// sv = new SurfaceView(getApplicationContext());
cameraIntent = intent;
Log.d("ImageTakin", "StartCommand()");
pref = getApplicationContext().getSharedPreferences("MyPref", 0);
editor = pref.edit();
windowManager = (WindowManager) getSystemService(WINDOW_SERVICE);
params = new WindowManager.LayoutParams(
WindowManager.LayoutParams.WRAP_CONTENT,
WindowManager.LayoutParams.WRAP_CONTENT,
WindowManager.LayoutParams.TYPE_PHONE,
WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,
PixelFormat.TRANSLUCENT);
params.gravity = Gravity.TOP | Gravity.LEFT;
params.width = 1;
params.height = 1;
params.x = 0;
params.y = 0;
sv = new SurfaceView(getApplicationContext());
windowManager.addView(sv, params);
sHolder = sv.getHolder();
sHolder.addCallback(this);
// tells Android that this surface will have its data constantly
// replaced
if (Build.VERSION.SDK_INT < 11)
sHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
return 1;
}
Camera.PictureCallback mCall = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
// decode the data obtained by the camera into a Bitmap
Log.d("ImageTakin", "Done");
if (bmp != null)
bmp.recycle();
System.gc();
bmp = decodeBitmap(data);
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
if (bmp != null && QUALITY_MODE == 0)
bmp.compress(Bitmap.CompressFormat.JPEG, 70, bytes);
else if (bmp != null && QUALITY_MODE != 0)
bmp.compress(Bitmap.CompressFormat.JPEG, QUALITY_MODE, bytes);
File imagesFolder = new File(
Environment.getExternalStorageDirectory(), "MYGALLERY");
if (!imagesFolder.exists())
imagesFolder.mkdirs(); // <----
File image = new File(imagesFolder, System.currentTimeMillis()
+ ".jpg");
// write the bytes in file
try {
fo = new FileOutputStream(image);
} catch (FileNotFoundException e) {
Log.e("TAG", "FileNotFoundException", e);
// TODO Auto-generated catch block
}
try {
fo.write(bytes.toByteArray());
} catch (IOException e) {
Log.e("TAG", "fo.write::PictureTaken", e);
// TODO Auto-generated catch block
}
// remember close de FileOutput
try {
fo.close();
if (Build.VERSION.SDK_INT < 19)
sendBroadcast(new Intent(
Intent.ACTION_MEDIA_MOUNTED,
Uri.parse("file://"
+ Environment.getExternalStorageDirectory())));
else {
MediaScannerConnection
.scanFile(
getApplicationContext(),
new String[] { image.toString() },
null,
new MediaScannerConnection.OnScanCompletedListener() {
public void onScanCompleted(
String path, Uri uri) {
Log.i("ExternalStorage", "Scanned "
+ path + ":");
Log.i("ExternalStorage", "-> uri="
+ uri);
}
});
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if (mCamera != null) {
mCamera.stopPreview();
mCamera.release();
mCamera = null;
}
/*
* Toast.makeText(getApplicationContext(),
* "Your Picture has been taken !", Toast.LENGTH_LONG).show();
*/
com.integreight.onesheeld.Log.d("Camera", "Image Taken !");
if (bmp != null) {
bmp.recycle();
bmp = null;
System.gc();
}
mCamera = null;
handler.post(new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(),
"Your Picture has been taken !", Toast.LENGTH_SHORT)
.show();
}
});
stopSelf();
}
};
@Override
public IBinder onBind(Intent intent) {
return null;
}
public static Camera getCameraInstance() {
Camera c = null;
try {
c = Camera.open(); // attempt to get a Camera instance
} catch (Exception e) {
// Camera is not available (in use or does not exist)
}
return c; // returns null if camera is unavailable
}
@Override
public void onDestroy() {
if (mCamera != null) {
mCamera.stopPreview();
mCamera.release();
mCamera = null;
}
if (sv != null)
windowManager.removeView(sv);
Intent intent = new Intent("custom-event-name");
// You can also include some extra data.
intent.putExtra("message", "This is my message!");
LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
super.onDestroy();
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO Auto-generated method stub
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
if (cameraIntent != null)
new TakeImage().execute(cameraIntent);
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
if (mCamera != null) {
mCamera.stopPreview();
mCamera.release();
mCamera = null;
}
}
public static Bitmap decodeBitmap(byte[] data) {
Bitmap bitmap = null;
BitmapFactory.Options bfOptions = new BitmapFactory.Options();
bfOptions.inDither = false; // Disable Dithering mode
bfOptions.inPurgeable = true; // Tell to gc that whether it needs free
// memory, the Bitmap can be cleared
bfOptions.inInputShareable = true; // Which kind of reference will be
// used to recover the Bitmap data
// after being clear, when it will
// be used in the future
bfOptions.inTempStorage = new byte[32 * 1024];
if (data != null)
bitmap = BitmapFactory.decodeByteArray(data, 0, data.length,
bfOptions);
return bitmap;
}
}
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