Android camera , onPictureTaken(byte[] imgData, Camera camer

问题描述

我有一个自定义相机应用程序，它可以在 SurfaceView 上预览相机视频输出并尝试拍照，这些照片应该由xzing"扫描仪 API 处理，以解码图像中的任何条形码.

I have a custom camera app , that previews the camera video output on SurfaceView and attempts to take pictures , the pics should be will be processed by "xzing "scanner API to decode any barcodes in the image.

我的应用可以正确预览并且不会抛出任何错误或期望，但是我的 onPictureTaken(byte[] imgData, Camera camera) 方法和PictureCallback 永远不会被调用，因此我无法获取图像 &继续进一步扫描.

My app previews correctly and does not throw any errors or expectations, however my onPictureTaken(byte[] imgData, Camera camera) method & PictureCallback are never called, therefore I’m unable to get the image & continue with further scanning.

以下是负责相机逻辑的活动的实际代码.onPictureTaken(byte[] imgData, Camera camera) 方法 &PictureCallback 都在这个类中(ScanVinFromBarcodeActivity.java)见吹:

package com.ty.tyownerspoc.barcode;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.ChecksumException;
import com.google.zxing.FormatException;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.NotFoundException;
import com.google.zxing.RGBLuminanceSource; 
import com.google.zxing.Reader;
import com.google.zxing.Result;
import com.google.zxing.common.HybridBinarizer;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.pm.PackageManager;
import android.content.res.Configuration;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.ImageFormat;
import android.graphics.Matrix;
import android.graphics.Point;
import android.hardware.Camera;
import android.hardware.Camera.CameraInfo;
import android.hardware.Camera.Parameters;
import android.hardware.Camera.PictureCallback;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.Display;
import android.view.SurfaceView;
import android.view.View;
import android.widget.FrameLayout;
import android.widget.TextView;
import android.widget.Toast;
import com.ty.tyownerspoc.R;

public class ScanVinFromBarcodeActivity extends Activity {

    private Camera globalCamera;
    private int cameraId = 0;
    private TextView VINtext = null;
    private View scanButton = null;
    // bitmap from camera
    private Bitmap bmpOfTheImageFromCamera = null;
    // global flag whether a camera has been detected
    private boolean isThereACamera = false;
    // surfaceView for preview object
    private FrameLayout frameLayoutBarcodeScanner = null;
    private CameraPreview newCameraPreview = null;
    private SurfaceView surfaceViewBarcodeScanner = null;
    private int counter = 0; 
    private volatile boolean finishedPictureTask  = false;
    /*
     * This method , finds FEATURE_CAMERA, opens the camera, set parameters ,
     * add CameraPreview to layout, set camera surface holder, start preview
     */
    private void initializeGlobalCamera() {
        try {
            if (!getPackageManager().hasSystemFeature(
                    PackageManager.FEATURE_CAMERA)) {
                Toast.makeText(this, "No camera on this device",
                        Toast.LENGTH_LONG).show();
            } else { // check for front camera ,and get the ID
                cameraId = findFrontFacingCamera();
                if (cameraId < 0) {

                    Toast.makeText(this, "No front facing camera found.",
                            Toast.LENGTH_LONG).show();
                } else {

                    Log.d("ClassScanViewBarcodeActivity",
                            "camera was found , ID: " + cameraId);
                    // camera was found , set global camera flag to true
                    isThereACamera = true;
                    // OPEN
                    globalCamera = Camera.open(cameraId);

                    // pass surfaceView to CameraPreview
                    newCameraPreview = new CameraPreview(this, globalCamera);
                    // pass CameraPreview to Layout
                    frameLayoutBarcodeScanner.addView(newCameraPreview);
                    try {
                        globalCamera
                                .setPreviewDisplay(surfaceViewBarcodeScanner
                                        .getHolder());
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                    // PREVIEW
                    globalCamera.startPreview();

                    Log.d("ClassScanViewBarcodeActivity",
                            "camera opened & previewing");
                }
            }// end else ,check for front camera
        }// end try
        catch (Exception exc) {

            // in case of exception release resources & cleanup
            if (globalCamera != null) {
                globalCamera.stopPreview();
                globalCamera.setPreviewCallback(null);
                globalCamera.release();
                globalCamera = null;

            }
            Log.d("ClassScanViewBarcodeActivity initializeGlobalCamera() exception:",
                    exc.getMessage());
        }// end catch
    }

    // onCreate, instantiates layouts & surfaceView used for video preview
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_barcode_vin_scanner);
        Log.d("ClassScanViewBarcodeActivity", "onCreate ");

        // create surfaceView for previewing of camera image
        frameLayoutBarcodeScanner = (FrameLayout) findViewById(R.id.FrameLayoutForPreview);
        surfaceViewBarcodeScanner = (SurfaceView) findViewById(R.id.surfaceViewBarcodeScanner);

        initializeGlobalCamera();

        // create text area & scan button
        VINtext = (TextView) findViewById(R.id.mytext);
        scanButton = findViewById(R.id.webbutton);
        // on click listener, onClick take a picture
        scanButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                try {

                    // if true take a picture
                    if (isThereACamera) {
                        Log.d("ClassScanViewBarcodeActivity",
                                "setOnClickListener() isThereACamera: "+ isThereACamera);

                        //set picture format to JPEG, everytime makesure JPEg callback is called 
                         Parameters parameters = globalCamera.getParameters();              
                         parameters.setPictureFormat(ImageFormat.JPEG);
                         globalCamera.setParameters(parameters);                         
                         //take pic , should call Callback 
                        globalCamera.takePicture(null, null, jpegCallback);
                        // wait 1 sec , than start preview again
                        Thread.sleep(1000);
                        //STOP
                        globalCamera.stopPreview();
                        //start previewing again onthe SurfaceView in case use wants to take another pic/scan
                        globalCamera.startPreview();

                    }

                }// end try
                catch (Exception exc) {

                    // in case of exception release resources & cleanup
                    if (globalCamera != null) {
                        globalCamera.stopPreview();
                        globalCamera.setPreviewCallback(null);
                        globalCamera.release();
                        globalCamera = null;

                    }
                    Log.d("ClassScanViewBarcodeActivity setOnClickListener() exceprtion:",
                            exc.getMessage());
                }// end catch

            }// end on Click
        });// end OnClickListener() implementation

    }// end onCreate

    @Override
    protected void onResume() {

        Log.d("ClassScanViewBarcodeActivity, onResume() globalCamera:",
                String.valueOf(globalCamera));

        if (globalCamera != null) {
            // START PREVIEW
            globalCamera.startPreview();
        } else {
            initializeGlobalCamera();
        }

        super.onResume();
    }

    @Override
    protected void onStop() {

        if (globalCamera != null) {
            globalCamera.stopPreview();
            globalCamera.setPreviewCallback(null);
            globalCamera.release();
            globalCamera = null;
        }
        super.onStop();
    }

    //callback used by takePicture()
    PictureCallback jpegCallback = new PictureCallback() {



        public void onPictureTaken(byte[] imgData, Camera camera) {
            BinaryBitmap bitmap = null;
            try {



                Log.d("ClassScanViewBarcodeActivity" ,"onPictureTaken()");

                //save image to sd card 
                savePicture(imgData);

                // get the bitmap from camera imageData
                bmpOfTheImageFromCamera = BitmapFactory.decodeByteArray(
                        imgData, 0, imgData.length);


                if (bmpOfTheImageFromCamera != null) {
                    //Galaxy S3 , incorrect rotation issue rotate to correct rotation
                    Matrix matrix = new Matrix();
                    matrix.postRotate(90);
                    Bitmap rotatedBitmap = Bitmap.createBitmap(bmpOfTheImageFromCamera, 0, 0, bmpOfTheImageFromCamera.getWidth(), bmpOfTheImageFromCamera.getHeight(), matrix, true);
                    // convert bitmap to binary bitmap
                    bitmap = cameraBytesToBinaryBitmap(rotatedBitmap);


                    if (bitmap != null) {
                        // decode the VIN
                        String VIN = decodeBitmapToString(bitmap);
                        Log.d("***ClassScanViewBarcodeActivity ,onPictureTaken(): VIN ",
                                VIN);
                        VINtext.setText(VIN);
                    } else {
                        Log.d("ClassScanViewBarcodeActivity ,onPictureTaken(): bitmap=",String.valueOf(bitmap));

                    }
                } else {
                    Log.d("ClassScanViewBarcodeActivity , onPictureTaken(): bmpOfTheImageFromCamera = ",
                            String.valueOf(bmpOfTheImageFromCamera));

                }
            }// end try

            catch (Exception exc) {
                exc.getMessage();

                Log.d("ClassScanViewBarcodeActivity , scanButton.setOnClickListener(): exception = ",
                        exc.getMessage());
            }

        }// end onPictureTaken()
    };// jpegCallback implementation


    /*
     * created savePicture(byte [] data) for testing 
     */
    public void savePicture(byte [] data)
    {
        Log.d( "ScanVinFromBarcodeActivity " , "savePicture(byte [] data)");
        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyymmddhhmmss");
        String date = dateFormat.format(new Date());
        String photoFile = "Picture_"+counter+"_"+ date + ".jpg";

        File sdDir = Environment
                  .getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);


        String filename =sdDir + File.separator + photoFile;

        File pictureFile = new File(filename);

        try {
          FileOutputStream fos = new FileOutputStream(pictureFile);
          fos.write(data);
          fos.close();

          Toast.makeText(this, "New Image saved:" + photoFile,
              Toast.LENGTH_LONG).show();

        } catch (Exception error) {
            Log.d( "File not saved: " , error.getMessage());
          Toast.makeText(this, "Image could not be saved.",
              Toast.LENGTH_LONG).show();
        }
        counter++;
      }



    private int findFrontFacingCamera() {
        int cameraId = -1;
        // Search for the front facing camera
        int numberOfCameras = Camera.getNumberOfCameras();
        for (int i = 0; i < numberOfCameras; i++) {
            CameraInfo info = new CameraInfo();
            Camera.getCameraInfo(i, info);
            if (info.facing == CameraInfo.CAMERA_FACING_BACK) {
                Log.d("ClassScanViewBarcodeActivity , findFrontFacingCamera(): ",
                        "Camera found");
                cameraId = i;
                break;
            }
        }
        return cameraId;
    }// end findFrontFacingCamera()

    @Override
    protected void onPause() {
        if (globalCamera != null) {
            globalCamera.stopPreview();
            globalCamera.setPreviewCallback(null);
            globalCamera.release();
            globalCamera = null;
        }
        super.onPause();
    }// end onPause()

    public String decodeBitmapToString(BinaryBitmap bitmap) {
        Reader reader = null;
        Result result = null;
        String textResult = null;
        try {

            reader = new MultiFormatReader();
            if (bitmap != null) {
                result = reader.decode(bitmap);
                if (result != null) {
                    textResult = result.getText();
                } else {
                    Log.d("ClassScanViewBarcodeActivity , String decodeBitmapToString (BinaryBitmap bitmap): result = ",
                            String.valueOf(result));
                }
            } else {
                Log.d("ClassScanViewBarcodeActivity , String decodeBitmapToString (BinaryBitmap bitmap): bitmap = ",
                        String.valueOf(bitmap));
            }
            /*
             * byte[] rawBytes = result.getRawBytes(); BarcodeFormat format =
             * result.getBarcodeFormat(); ResultPoint[] points =
             * result.getResultPoints();
             */

        } catch (NotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (ChecksumException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (FormatException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();

        }

        return textResult;
    }// end decodeBitmapToString (BinaryBitmap bitmap)

    public BinaryBitmap cameraBytesToBinaryBitmap(Bitmap bitmap) {
        BinaryBitmap binaryBitmap = null;
        if (bitmap != null) {

            int[] pixels = new int[bitmap.getHeight() * bitmap.getWidth()];
            bitmap.getPixels(pixels, 0, 0, bitmap.getWidth() - 1,
                    bitmap.getHeight() - 1, bitmap.getWidth(),
                    bitmap.getHeight());

            RGBLuminanceSource source = new RGBLuminanceSource(
                    bitmap.getWidth(), bitmap.getHeight(), pixels);

            HybridBinarizer bh = new HybridBinarizer(source);
            binaryBitmap = new BinaryBitmap(bh);
        } else {
            Log.d("ClassScanViewBarcodeActivity , cameraBytesToBinaryBitmap (Bitmap bitmap): bitmap = ",
                    String.valueOf(bitmap));
        }

        return binaryBitmap;
    }

    @SuppressLint("NewApi")
    @SuppressWarnings("deprecation")
    /*
     * The method getScreenOrientation() return screen orientation either
     * landscape or portrait. IF width < height , than orientation = portrait,
     * ELSE landscape For backwards compatibility we use to methods to detect
     * the orientation. The first method is for API versions prior to 13 or
     * HONEYCOMB.
     */
    public int getScreenOrientation() {

        int currentapiVersion = android.os.Build.VERSION.SDK_INT;
        // if API version less than 13
        Display getOrient = getWindowManager().getDefaultDisplay();
        int orientation = Configuration.ORIENTATION_UNDEFINED;

        if (currentapiVersion < android.os.Build.VERSION_CODES.HONEYCOMB) {
            // Do something for API version less than HONEYCOMB

            if (getOrient.getWidth() == getOrient.getHeight()) {
                orientation = Configuration.ORIENTATION_SQUARE;
            } else {
                if (getOrient.getWidth() < getOrient.getHeight()) {
                    orientation = Configuration.ORIENTATION_PORTRAIT;
                } else {
                    orientation = Configuration.ORIENTATION_LANDSCAPE;
                }
            }
        } else {
            // Do something for API version greater or equal to HONEYCOMB

            Point size = new Point();
            this.getWindowManager().getDefaultDisplay().getSize(size);
            int width = size.x;
            int height = size.y;

            if (width < height) {
                orientation = Configuration.ORIENTATION_PORTRAIT;
            } else {
                orientation = Configuration.ORIENTATION_LANDSCAPE;
            }
        }

        return orientation;

    }// end getScreenOrientation()
}// end class ScanVinFromBarcodeActivity

用于在 SurfaceView 上显示实时摄像头的预览类 (CameraPreview.java):

package com.ty.tyownerspoc.barcode;

import java.io.IOException;
import java.util.List;

import android.content.Context;
import android.hardware.Camera;
import android.hardware.Camera.Size;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.ViewGroup;
import android.hardware.Camera.CameraInfo;

/** A basic Camera preview class */
public class CameraPreview extends SurfaceView implements
        SurfaceHolder.Callback {
    private SurfaceHolder mHolder;
    private Camera mCamera;
    private Context context;

    public CameraPreview(Context context, Camera camera) {
        super(context);
        mCamera = camera;
        this.context = context;

        // 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) {

        }
    }

    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
        }
                Camera.Parameters p = mCamera.getParameters();

        // get width & height of the SurfaceView
        int SurfaceViewWidth = this.getWidth();
        int SurfaceViewHeight = this.getHeight();

        List<Size> sizes = p.getSupportedPreviewSizes();
         Size optimalSize = getOptimalPreviewSize(sizes, SurfaceViewWidth, SurfaceViewHeight);


        // set parameters
        p.setPreviewSize(optimalSize.width, optimalSize.height);

        /*rotate the image by 90 degrees clockwise , in order to correctly displayed the image , images seem to be -90 degrees (counter clockwise) rotated 
         * I even tried setting it to  p.setRotation(0); , but still no effect.
         */
        mCamera.setDisplayOrientation(90);

        mCamera.setParameters(p);

        // start preview with new settings
        try {
            mCamera.setPreviewDisplay(mHolder);
            mCamera.startPreview();

        } catch (Exception e) {
            Log.d("CameraPreview ,  surfaceCreated() , orientation: ",
                    String.valueOf(e.getMessage()));
        }
    }// end surfaceChanged()
     static Size getOptimalPreviewSize(List <Camera.Size>sizes, int w, int h) {
            final double ASPECT_TOLERANCE = 0.1;
            final double MAX_DOWNSIZE = 1.5;

            double targetRatio = (double) w / h;
            if (sizes == null) return null;

            Size optimalSize = null;
            double minDiff = Double.MAX_VALUE;

            int targetHeight = h;

            // Try to find an size match aspect ratio and size
            for (Camera.Size size : sizes) {
              double ratio = (double) size.width / size.height;
              double downsize = (double) size.width / w;
              if (downsize > MAX_DOWNSIZE) {
                //if the preview is a lot larger than our display surface ignore it
                //reason - on some phones there is not enough heap available to show the larger preview sizes
                continue;
              }
              if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue;
              if (Math.abs(size.height - targetHeight) < minDiff) {
                optimalSize = size;
                minDiff = Math.abs(size.height - targetHeight);
              }
            }
            // Cannot find the one match the aspect ratio, ignore the requirement
            //keep the max_downsize requirement
            if (optimalSize == null) {
              minDiff = Double.MAX_VALUE;
              for (Size size : sizes) {
                double downsize = (double) size.width / w;
                if (downsize > MAX_DOWNSIZE) {
                  continue;
                }
                if (Math.abs(size.height - targetHeight) < minDiff) {
                  optimalSize = size;
                  minDiff = Math.abs(size.height - targetHeight);
                }
              }
            }
            //everything else failed, just take the closest match
            if (optimalSize == null) {
              minDiff = Double.MAX_VALUE;
              for (Size size : sizes) {
                if (Math.abs(size.height - targetHeight) < minDiff) {
                  optimalSize = size;
                  minDiff = Math.abs(size.height - targetHeight);
                }
              }
            }
            return optimalSize;
          }

}//end Preview class

ScanVinFromBarcodeActivity"活动的布局 (activity_barcode_vin_scanner.xml):

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    android:padding="20dip" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:gravity="center_horizontal"
        android:padding="20dip"
        android:text="@string/decode_label"
        android:textColor="@color/mbackground1" />

    <TextView
        android:id="@+id/mytext"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@color/mbackground2"
        android:gravity="center_horizontal"
        android:padding="20dip"
        android:textColor="@color/mytextcolor" />

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:gravity="center_horizontal"
        android:padding="20dip"
        android:text="@string/continue_label"
        android:textColor="@color/mytextcolor" />

    <Button
        android:id="@+id/webbutton"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/web_button"
        android:textColor="@color/mytextcolor" />

    <FrameLayout
    android:id="@+id/FrameLayoutForPreview"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_weight="1">

        <SurfaceView
            android:id="@+id/surfaceViewBarcodeScanner"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />

    </FrameLayout>
</LinearLayout>

任何帮助将不胜感激.

谢谢

Updated & working onTakePicturen method, the that works , the PictureCallback returns (stopPreview & StartPreview were moved to inside this method in its finally block).


    public void onPictureTaken(byte[] imgData, Camera camera) {
        BinaryBitmap bitmap;
        try {



            Log.d("ClassScanViewBarcodeActivity" ,"onPictureTaken()");

            //save image to sd card 
            savePicture(imgData);

            // get the bitmap from camera imageData

            BitmapFactory.Options options = new BitmapFactory.Options();
              options.inSampleSize = 8; 
              //down sample
            bmpOfTheImageFromCamera = BitmapFactory.decodeByteArray(
                    imgData, 0, imgData.length,options);


            if (bmpOfTheImageFromCamera != null) {

                Log.d("***ClassScanViewBarcodeActivity ,onPictureTaken(): bmpOfTheImageFromCamera getByteCount(): ",
                        String.valueOf(bmpOfTheImageFromCamera.getByteCount()));
                //Galaxy S3 , incorrect rotation issue rotate to correct rotation
                /*Matrix matrix = new Matrix();
                matrix.postRotate(90);
                Bitmap rotatedBitmap = Bitmap.createBitmap(bmpOfTheImageFromCamera, 0, 0, bmpOfTheImageFromCamera.getWidth(), bmpOfTheImageFromCamera.getHeight(), matrix, true);*/
                // convert bitmap to binary bitmap
                bitmap = cameraBytesToBinaryBitmap(bmpOfTheImageFromCamera);


                if (bitmap != null) {
                    // decode the VIN
                    String VIN = decodeBitmapToString(bitmap);
                    Log.d("***ClassScanViewBarcodeActivity ,onPictureTaken(): VIN ",
                            VIN);
                    VINtext.setText(VIN);
                } else {
                    Log.d("ClassScanViewBarcodeActivity ,onPictureTaken(): bitmap=",String.valueOf(bitmap));

                }
            } else {
                Log.d("ClassScanViewBarcodeActivity , onPictureTaken(): bmpOfTheImageFromCamera = ",
                        String.valueOf(bmpOfTheImageFromCamera));

            }


        }// end try

        catch (Exception exc) {
            exc.getMessage();

            Log.d("ClassScanViewBarcodeActivity , scanButton.setOnClickListener(): exception = ",
                    exc.getMessage());
        }

        finally
        {
            globalCamera.stopPreview();
            //start previewing again onthe SurfaceView in case use wants to take another pic/scan
            globalCamera.startPreview();
        }

    }// end onPictureTaken()
};// jpegCallback implementation

推荐答案

我能找到的唯一可能是罪魁祸首的是，您在 jpegCallback 返回之前再次开始预览.根据 javadoc，这是不允许的:

The only thing I can find that might be the culprit is that you're starting the preview again before the jpegCallback has returned. According to the javadoc, this is not allowed:

调用此方法后，在 JPEG 回调返回之前，不得调用 startPreview() 或拍摄另一张照片.

After calling this method, you must not call startPreview() or take another picture until the JPEG callback has returned.

回调实际上是放在 UI 线程队列中 - 它将在您的 Thread.sleep() 中暂停，并且同一个线程将调用 stopPreview() 并且startPreview() 在真正进入回调之前.一般来说，如果你在 UI 线程上调用 Thread.sleep() - 你做错了.因此，希望如果您删除 sleep() 并将其后的内容放入 jpegCallback 您的问题应该得到解决.

The callback is actually put on the UI thread queue - which will be suspended in your Thread.sleep() and the same thread will have called stopPreview() and startPreview() before actually coming to the callback. Generally speaking, if you call Thread.sleep() on the UI thread - you're doing it wrong. So, hopefully if you remove the sleep() and put what comes after it in the jpegCallback your problem should be solved.

这篇关于Android camera , onPictureTaken(byte[] imgData, Camera camera) 方法 &PictureCallback 从未调用过的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持跟版网！