New to Android programming here.
I have had a look around and have found this to be a common issue, but I don't really see an easy fix... I am trying to run the following code on a Nexus 7 (have tried AVD & physical device) with no luck whatsoever. It seems to be the:
camera.setPreviewDisplay(SurfaceHolder);
But I could be wrong. Here is the current code:
public class MainActivity extends Activity implements SurfaceHolder.Callback{
Camera camera;
SurfaceView surfaceView;
SurfaceHolder surfaceHolder;
boolean previewing = false;;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.cameralayout);
getWindow().setFormat(PixelFormat.UNKNOWN);
surfaceView = (SurfaceView)findViewById(R.id.surfaceview);
surfaceHolder = surfaceView.getHolder();
surfaceHolder.addCallback(this);
}
public void onClick() {
// TODO Auto-generated method stub
if(!previewing){
camera = Camera.open();
if (camera != null){
try {
camera.setPreviewDisplay(surfaceHolder);
camera.startPreview();
previewing = true;
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
Any ideas folks? Thank you for your help!
From android documentation about Camera.open()
Creates a new Camera object to access the first back-facing camera on
the device. If the device does not have a back-facing camera, this
returns null.
It gives you only an access to back-facing Camera.
I am trying to run the following code on a Nexus 7
Camera.open() returns null because Nexus 7 doesn't have a back camera, only a front camera.
You could try this method
public Camera getCamera()
{
for(int i = 0; i < Camera.getNumberOfCameras(); i++)
return Camera.open(i);
return null;
}
To apply,
camera = getCamera();
Related
I'm new in android.
I found previous questions, but are quite old, actually I'm using API 23 or higher.
I'm interested in a way to obtaining a picture from a camera, without displaying the preview and without any touch or interaction of the user.
I used an intent to access to a camera app but don't let me to take a picture automatically in the way I need.
This only let me to use camera app.
Intent intentTakePic = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
if(intentTakePic.resolveActivity(getPackageManager()) != null){
startActivityForResult(intentTakePic, GET_THE_PICTURE);
}
In future I probably need also to record the audio in the same way (without interaction).
Does anyone has suggestion for me ?
You need to use the CameraAPI to take pictures without opening another camera app. https://developer.android.com/guide/topics/media/camera
You'll basically make a camera app.
// in the activity onCreate, but doesn't have to be there
// needs explicit permission
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (checkSelfPermission(Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
requestPermissions(new String[] {Manifest.permission.CAMERA}, 1);
}
}
final Camera camera = Camera.open();
CameraPreview cameraPreview = new CameraPreview(this, camera);
// preview is required. But you can just cover it up in the layout.
FrameLayout previewFL = findViewById(R.id.preview_layout);
previewFL.addView(cameraPreview);
camera.startPreview();
// take picture button
findViewById(R.id.take_picture_button).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
camera.takePicture(null, null, new Camera.PictureCallback() {
#Override
public void onPictureTaken(byte[] data, Camera camera) {
// path of where you want to save it
File pictureFile = new File(getFilesDir() + "/images/pic0");
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
});
}
});
CameraPreview class
import android.content.Context;
import android.hardware.Camera;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import java.io.IOException;
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
private SurfaceHolder mHolder;
private Camera mCamera;
public CameraPreview(Context context, Camera camera) {
super(context);
mCamera = camera;
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = getHolder();
mHolder.addCallback(this);
// deprecated setting, but required on Android versions prior to 3.0
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, now tell the camera where to draw the preview.
try {
mCamera.setPreviewDisplay(holder);
mCamera.startPreview();
} catch (IOException e) {
e.printStackTrace();
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
// empty. Take care of releasing the Camera preview in your activity.
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
if (mHolder.getSurface() == null){
// preview surface does not exist
return;
}
// stop preview before making changes
try {
mCamera.stopPreview();
} catch (Exception e){
// ignore: tried to stop a non-existent preview
}
// set preview size and make any resize, rotate or
// reformatting changes here
// start preview with new settings
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
} catch (Exception e){
e.printStackTrace();
}
}
}
I found these useful guide:
https://zatackcoder.com/android-camera-2-api-example-without-preview/
https://inducesmile.com/android/android-camera2-api-example-tutorial/
https://github.com/googlesamples/android-Camera2Basic
I took the Google example for using ImageReader from here.
The code uses Camera2 API and ImageReader to such that querying image runs in different thread than previewing it.
As I want to target Android KitKat (API 20), I need to modify the code to use older Camera API with keeping the ImageReader part as is.
Here is the part of original code that sets onImageAvailableListener:
/**
* THIS IS CALLED WHEN OPENING CAMERA
* Sets up member variables related to camera.
*
* #param width The width of available size for camera preview
* #param height The height of available size for camera preview
*/
private void setUpCameraOutputs(int width, int height) {
Activity activity = getActivity();
CameraManager manager = (CameraManager) activity.getSystemService(Context.CAMERA_SERVICE);
try {
for (String cameraId : manager.getCameraIdList()) {
CameraCharacteristics characteristics
= manager.getCameraCharacteristics(cameraId);
// We don't use a front facing camera in this sample.
Integer facing = characteristics.get(CameraCharacteristics.LENS_FACING);
if (facing != null && facing == CameraCharacteristics.LENS_FACING_FRONT) {
continue;
}
StreamConfigurationMap map = characteristics.get(
CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
if (map == null) {
continue;
}
// For still image captures, we use the largest available size.
Size largest = Collections.max(
Arrays.asList(map.getOutputSizes(ImageFormat.JPEG)),
new CompareSizesByArea());
mImageReader = ImageReader.newInstance(largest.getWidth(), largest.getHeight(),
ImageFormat.JPEG, /*maxImages*/2);
mImageReader.setOnImageAvailableListener(
mOnImageAvailableListener, mBackgroundHandler);
.
.
.
.
}
Now I was able to use older Camera API. But I am lost in connecting it with ImageReader. So I don't know how should I set onImageListener so that I can access it once the image is delivered.
Here is my modification :
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
mTextureView = (AutoFitTextureView) v.findViewById(R.id.texture);
mTextureView.setSurfaceTextureListener(new SurfaceTextureListener() {
#Override
public void onSurfaceTextureUpdated(SurfaceTexture surface) {
}
#Override
public void onSurfaceTextureSizeChanged(SurfaceTexture surface,
int width, int height) {
}
#Override
public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
return true;
}
#Override
public void onSurfaceTextureAvailable(SurfaceTexture surface,
int width, int height) {
mCamera = Camera.open();
try {
Camera.Parameters parameters = mCamera.getParameters();
if (getActivity().getResources().getConfiguration().orientation != Configuration.ORIENTATION_LANDSCAPE) {
// parameters.set("orientation", "portrait"); // For
// Android Version 2.2 and above
mCamera.setDisplayOrientation(90);
// For Android Version 2.0 and above
parameters.setRotation(90);
}
mCamera.setParameters(parameters);
mCamera.setPreviewTexture(surface);
} catch (IOException exception) {
mCamera.release();
}
mCamera.startPreview();
setUpCameraOutputs(width, height);
tfPreviewListener.initialize(getActivity().getAssets(), scoreView);
}
});
}
My question is how should I add ImageReader in the code above to make it work properly?
Thanks in advance.
I'm a complete noob . I've managed to write and understand this code after reading this http://developer.android.com/guide/topics/media/camera.html .
But now i want to get the byte array for preview and then convert it to bitmap . But i want to do this in real time without be forced to save a picture file in storage . Please , help!
Here is my program code.
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
private SurfaceHolder mHolder;
private Camera mCamera;
public CameraPreview(Context context, Camera camera) {
super(context);
mCamera = camera;
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = getHolder();
mHolder.addCallback(this);
// deprecated setting, but required on Android versions prior to 3.0
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, now tell the camera where to draw the preview.
try {
mCamera.setPreviewDisplay(holder);
mCamera.startPreview();
} catch (IOException e) {
String TAG = null;
Log.d(TAG, "Error setting camera preview: " + e.getMessage());
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
// empty. Take care of releasing the Camera preview in your activity.
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
mCamera.setDisplayOrientation(90);
// set preview size and make any resize, rotate or
// reformatting changes here
// start preview with new settings
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
} catch (Exception e){
String TAG = null;
Log.d(TAG, "Error starting camera preview: " + e.getMessage());
}
}
private PictureCallback mPicture = new PictureCallback(){
#Override
public void onPictureTaken(byte[] data, Camera camera)
{
// TODO: Implement this method
}
};
}
And main activity :
public class MainActivity extends Activity
{ private Camera mCamera;
private CameraPreview mPreview;
int i;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mCamera = getCameraInstance();
mPreview = new CameraPreview(this, mCamera);
FrameLayout preview = (FrameLayout) findViewById(R.id.frame);
preview.addView(mPreview);
}
public static Camera getCameraInstance()
{
Camera c = null;
try
{
c = Camera.open();}
catch (Exception e)
{ System.out.println("blamjjjh");}
return c;
}
public void releasec(){
mCamera.release();
}
#Override
protected void onStop()
{
super.onStop();
releasec();
}
}
As detailed in the Android Developer docs here (which you might have already read), add an implementation of the PictureCallback interface (see the example below) to your Activity. Also you can use BitmapFactory to then convert the byte array that gets passed back to a Bitmap. Then you can use this as required.
NOTE:
I would also read the docs here on handling Bitmaps efficiently in relation to memory as you might get OutOfMemory errors if you're manipulating Bitmaps.
private PictureCallback mPicture = new PictureCallback() {
#Override
public void onPictureTaken(byte[] data, Camera camera) {
//create a Bitmap from the byte array
Bitmap bitmap = BitmapFactory.decodeByteArray(data , 0, data.length);
//use your Bitmap
}
};
You then need to pass this into the takePicture() method against your camera instance e.g.
// Add a listener to the Capture button
Button captureButton = (Button) findViewById(id.button_capture);
captureButton.setOnClickListener(
new View.OnClickListener() {
#Override
public void onClick(View v) {
// get an image from the camera
mCamera.takePicture(null, null, mPicture);
}
}
);
Hope this helps! :-)
I have the following java method:
private Camera openFrontFacingCameraGingerbread() {
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) {
Toast.makeText(debug, "failed", Toast.LENGTH_LONG).show();
}
}
}
and what I'm looking forward to do is mirror the camera in the screen. This is, as soon as I open the app I would like the user to see himself but I'm not being able to accomplish this.
Here is the onCreate method of the same class:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.activity_main);
openFrontFacingCameraGingerbread();
}
Can someone help me on this one? Thank you very much
You need to include a SurfaceView in your layout, and use setPreviewDisplay() and startPreview(). This will draw the camera's input in your Activity.
You should check the developer guides, and also take a look at Android - Camera Preview
I'm using a Nexus One and the Camera displays horizontal when it should be vertical and vice versa. I've no idea what's wrong. The code works fine on a HTC tattoo. Anyone have any idea what's wrong?
class Preview extends SurfaceView implements SurfaceHolder.Callback {
SurfaceHolder mHolder;
Camera mCamera;
Preview(Context context) {
super(context);
// Install a SurfaceHolder.Callback so we get notified when
//the
// underlying surface is created and destroyed.
mHolder = getHolder();
mHolder.addCallback(this);
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, acquire the camera and tell
//it where
// to draw.
mCamera = Camera.open();
try {
mCamera.setPreviewDisplay(holder);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
// Surface will be destroyed when we return, so stop the
//preview.
// Because the CameraDevice object is not a shared resource,
//it's very
// important to release it when the activity is paused.
mCamera.stopPreview();
mCamera = null;
}
public void surfaceChanged(SurfaceHolder holder, int format, int
w, int h) {
// Now that the size is known, set up the camera parameters
//and begin
// the preview.
Camera.Parameters parameters = mCamera.getParameters();
parameters.setPreviewSize(800, 480);
mCamera.setParameters(parameters);
mCamera.startPreview();
}
Got it working. I added..
parameters.set("orientation", "portrait");
CommonsWare gave me the idea it was that kind of issue thanks man :)