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我正在开发一个 android 应用程序，它允许用户检查 QR 码内容并根据读取结果执行某些操作。

为了提高性能，我想实现两种方法：

  • onClickFocus（允许用户在点击屏幕时聚焦相机）
  • 打开/关闭闪光灯（允许用户打开/关闭闪光灯）

我已经进行了一些挖掘并发现要管理相机和闪光灯，我需要能够管理Cameraas 对象本身。

这就是噩梦开始的地方。

我正在使用以下代码来显示相机结果并跟踪 QR 码。

    import android.app.FragmentTransaction;
import android.content.Context;


import android.os.Bundle;
import android.os.Vibrator;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.util.SparseArray;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.widget.TextView;

import com.google.android.gms.vision.Detector;
import com.google.android.gms.vision.barcode.Barcode;
import com.google.android.gms.vision.barcode.BarcodeDetector;
import java.io.IOException;



public class MainReadActivity extends AppCompatActivity {


    public SurfaceView cameraView;
    private TextView barcodeInfo;
    public BarcodeDetector barcodeDetector;
    public CameraSource cameraSource;
    public Vibrator v;
    public String textInfo;
    public DrawerLayout mDrawerLayout;




    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_read);
        v = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);

        mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout_main);


        getSupportFragmentManager().findFragmentById(R.id.drawer_layout_main);

        cameraView = (SurfaceView) findViewById(R.id.camera_view);


        //barcodeInfo = (TextView) findViewById(R.id.code_info);

        barcodeDetector = new BarcodeDetector.Builder(this)
                .setBarcodeFormats(Barcode.QR_CODE)
                .build();


        cameraSource = new CameraSource.Builder(this, barcodeDetector).build();



        cameraView.getHolder().addCallback(new SurfaceHolder.Callback() {

            @Override
            public void surfaceCreated(SurfaceHolder holder) {


                try {
                    cameraSource.start(cameraView.getHolder());
                } catch (IOException ie) {
                    Log.e("CAMERA SOURCE", ie.getMessage());
                }

            }


            @Override
            public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
            }

            @Override
            public void surfaceDestroyed(SurfaceHolder holder) {
                cameraSource.stop();
            }

        });


        barcodeDetector.setProcessor(new Detector.Processor<Barcode>() {

            @Override
            public void release() {

            }


            @Override
            public void receiveDetections(Detector.Detections<Barcode> detections) {
                final SparseArray<Barcode> barcodes = detections.getDetectedItems();

                if (barcodes.size() != 0) {


                    new Runnable() {    // Use the post method of the TextView
                        public void run() {


                            v.vibrate(500);
                          // textInfo = barcodes.valueAt(0).displayValue;

                            MyFragmentDialog newf = new MyFragmentDialog();
                            FragmentTransaction transaction = getFragmentManager().beginTransaction();
                            transaction.replace(R.id.fragment_container, newf);

                            transaction.addToBackStack("tag");
                            transaction.commit();

                        }
                    };
                }
            }

        });







    }

    public void onBackPressed() {
        // do nothing
    }
}

所以，我需要从 CameraSource 访问相机（对吗？！）一旦不可能，我尝试使用 GoogleSamples 的 git 中的这个CameraSource类，它允许使用 setFocusMode 方法......但不幸的是我不是成功的。

我还尝试使用 API 21，因为 API 22不再支持Camera 和 CameraPreferences。

我很确定这不仅是我的问题，而且找不到解决方法。

任何人都可以帮忙吗？

固定的：

只需使用这个 CameraSource (github.com/googlesamples/android-vision/blob/master/visionSamples/barcode-reader/app/src/main/java/com/google/android/gms/samples/vision/barcodereader/ui/camera /CameraSource.java) 。是的，我知道，我已经建议了...但是这次我解决了我的问题！因此，如果您要使用它，请确保您的编译看起来像这样：

compile 'com.google.android.gms:play-services:8.1.0'
4

3 回答 3

3

初始化这些并定义它们OnCreate

Camera.Parameters params;
Camera camera;
CameraSource cameraSource;
SurfaceView cameraView;
boolean isFlash = false;

调用changeFlashStatus()方法来打开闪光灯并再次调用它来关闭闪光灯

public void changeFlashStatus() {
    Field[] declaredFields = CameraSource.class.getDeclaredFields();

    for (Field field : declaredFields) {
        if (field.getType() == Camera.class) {
            field.setAccessible(true);
            try {
                camera = (Camera) field.get(cameraSource);
                if (camera != null) {
                    params = camera.getParameters();
                    if (!isFlash) {
                        params.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
                        flashImage.setColorFilter(getResources().getColor(R.color.yellow));
                        isFlash = true;
                    } else {
                        params.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
                        flashImage.setColorFilter(getResources().getColor(R.color.greyLight));
                        isFlash = false;
                    }
                    camera.setParameters(params);
                }

            } catch (IllegalAccessException e) {
                e.printStackTrace();
            }

            break;
        }
    }
}

要让相机对焦，您需要一个特定区域 ( Rect) 将其传递给 Camera 以使该区域对焦。所以我们必须实现onTouchListener()，surfaceView所以当我们触摸surfaceView我们创建的内容时MotionEvent，它会确定您触摸的确切位置，surfaceView然后我们可以从中Rect提取MotionEvent。

调用initCameraFocusListener()您的 OnCreate。相机启动后安全调用它

private void initCameraFocusListener() {
    cameraView.setOnTouchListener(new View.OnTouchListener() {

        @Override
        public boolean onTouch(View v, MotionEvent event) {

            cameraFocus(event, cameraSource, Camera.Parameters.FOCUS_MODE_AUTO);

            return false;
        }
    });
}

private boolean cameraFocus(MotionEvent event, @NonNull CameraSource cameraSource, @NonNull String focusMode) {
    Field[] declaredFields = CameraSource.class.getDeclaredFields();

    int pointerId = event.getPointerId(0);
    int pointerIndex = event.findPointerIndex(pointerId);
    // Get the pointer's current position
    float x = event.getX(pointerIndex);
    float y = event.getY(pointerIndex);

    float touchMajor = event.getTouchMajor();
    float touchMinor = event.getTouchMinor();

    Rect touchRect = new Rect((int)(x - touchMajor / 2), (int)(y - touchMinor / 2), (int)(x + touchMajor / 2), (int)(y + touchMinor / 2));

    Rect focusArea = new Rect();

    focusArea.set(touchRect.left * 2000 / cameraView.getWidth() - 1000,
            touchRect.top * 2000 / cameraView.getHeight() - 1000,
            touchRect.right * 2000 / cameraView.getWidth() - 1000,
            touchRect.bottom * 2000 / cameraView.getHeight() - 1000);

    // Submit focus area to camera

    ArrayList<Camera.Area> focusAreas = new ArrayList<Camera.Area>();
    focusAreas.add(new Camera.Area(focusArea, 1000));

    for (Field field : declaredFields) {
        if (field.getType() == Camera.class) {
            field.setAccessible(true);
            try {
                camera = (Camera) field.get(cameraSource);
                if (camera != null) {
                    params = camera.getParameters();
                    params.setFocusMode(focusMode);
                    params.setFocusAreas(focusAreas);
                    camera.setParameters(params);

                    // Start the autofocus operation

                    camera.autoFocus(new Camera.AutoFocusCallback() {
                        @Override
                        public void onAutoFocus(boolean b, Camera camera) {
                            // currently set to auto-focus on single touch
                        }
                    });
                    return true;
                }

                return false;
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            }

            break;
        }
    }
    return false;
}
于 2017-05-09T15:15:30.227 回答
0

在这里回答：Google Vision API 示例：让 CameraSource 聚焦

自动对焦使用 .setAutoFocusEnabled(true)您的CameraSource.Builder()

于 2016-04-16T20:40:09.590 回答
0

我使用这个库，它工作得很好，而且很容易实现

https://github.com/dm77/barcodescanner

于 2016-04-16T20:30:24.693 回答