如何从另一个类（相机）获取当前路径

Question

我正在开发应用程序，该应用程序从我的自定义相机类中拍摄照片，然后将路径放入 Activity 上的 imageView 中，就像预览图像一样，现在我创建了一个类来处理相机功能并将路径发送到 Activity预览结果。但我的结果不是我拍摄的正确照片。示例：我第一次拍照时，我的“currentPicpath”为空，但在第二次拍照时，它给了我之前拍摄的第一张照片。

所以，在第 2 课中，我创建了一个获取当前路径但钢不给出 null 的方法，除非拍摄了一张新照片。

还有一个问题。为什么图像保存后它们是相反的？ 我的课：

MainActivity:
@Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.dialog_additem);

        d_image_pre1 = (ImageView) findViewById(R.id.d_image1);


        d_BTakePicture = (Button) findViewById(R.id.d_bTakePicture);
        bOpenCamera = (Button) findViewById(R.id.bOpenCamera);
        d_BTakePicture.setOnClickListener(this);
        bOpenCamera.setOnClickListener(this);

        take = new TakeApicture(this);

    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
        case R.id.bOpenCamera:
        take.openCam();
            break;
        case R.id.d_bTakePicture:

            take.makeFolder("myTest");
            take.captureImage();
            String path = take.getCurrentPicPath(); 

            BitmapFactory.Options options = new BitmapFactory.Options();
            options.inSampleSize = 2;
            Bitmap bm = BitmapFactory.decodeFile(path, options);
            d_image_pre1.setImageBitmap(bm); 

            break;

        default:
            break;
        }       
    }

第 2 类：

public class TakeApicture implements SurfaceHolder.Callback{

    Activity context;

    Camera camera;
    SurfaceView surface;
    SurfaceHolder holder;

    PictureCallback jpegCallback;

    File myGeneralFolder;
    FileOutputStream outStream = null;

    private String fullPathFolder;
    String currentPicPath = "No image path";


    @SuppressWarnings("deprecation")
    public TakeApicture(Activity context) {
        super();
        this.context = context;

        surface  = (SurfaceView)context.findViewById(R.id.surfaceView);
        holder = surface.getHolder();
        holder.addCallback(this);
         holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

           jpegCallBack();


    }


       public void captureImage() {
            camera.takePicture(null, null, jpegCallback);
        }



    public void makeFolder(String itemFolderName) {
        fullPathFolder = Environment.getExternalStorageDirectory()+File.separator+"mySalesImages"+File.separator+itemFolderName;
        myGeneralFolder = new  File(fullPathFolder);
        myGeneralFolder.mkdirs();
    }



    public void jpegCallBack(){
        jpegCallback = new PictureCallback() {
            @Override
            public void onPictureTaken(byte[] data, Camera camera) {
                    try {
                        getPicPath(data);

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



    public void getPicPath(byte[] data) throws IOException{
        currentPicPath = String.format(myGeneralFolder+"/%d.jpg",(System.currentTimeMillis()));
        outStream = new FileOutputStream(currentPicPath);
        outStream.write(data); 
        outStream.close();
    }

    public String getCurrentPicPath() {
        return currentPicPath;
    }


    @SuppressWarnings("deprecation")
    public void openCam(){
        try {
        camera = Camera.open();
        Camera.Parameters param;
        param = camera.getParameters();
        //modify parameter
        camera.setDisplayOrientation(90);
        param.setPreviewFrameRate(20);
        param.setPreviewSize(176, 144);
        camera.setParameters(param);

        camera.setPreviewDisplay(holder);
        camera.startPreview();

        } catch (Exception e) {
            // TODO: handle exception
        }

    }


    public void closeCam(){
        camera.stopPreview();
        camera.release();
    }




    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        // TODO Auto-generated method stub

    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width,
            int height) {
        // TODO Auto-generated method stub

    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        closeCam();
    }


}

这是正确的解决方案？？？

    take.captureImage();

    new Handler().postDelayed(new Runnable() {
        @Override
        public void run() {
    String path = take.getCurrentPicPath(); 


    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inSampleSize = 2;
    Bitmap bm = BitmapFactory.decodeFile(path, options);
    d_image_pre1.setImageBitmap(bm); 

        }
    }, 1000);

Answer 1

take.captureImage(); 行启动了一个异步的拍照过程。一段时间后，Android 系统将调用您的onPictureTaken() 回调，您将计算一个新的图像路径（并相应地写入照片）。但是这条线

String path = take.getCurrentPicPath(); 

将已经被执行。

您可以同步计算路径，但即便如此，您的 Activity 也必须等待实际图像写入磁盘。因此，您别无选择，只能将其提取出来

String path = take.getCurrentPicPath(); 

BitmapFactory.Options options = new BitmapFactory.Options();
options.inSampleSize = 2;
Bitmap bm = BitmapFactory.decodeFile(path, options);
d_image_pre1.setImageBitmap(bm); 

变成一个单独的方法。您可以直接从onPictureTaken() 调用这个新方法，也可以使用post()（无需从onPictureTaken() 调用postDelayed()）异步执行。

---

因此，快速而肮脏的修复（为简洁起见删除了异常处理）如下：

在MainActivity.java：

public void onClick(View v) {
  switch (v.getId()) {
    case R.id.bOpenCamera:
      take.openCam();
      break;
    case R.id.d_bTakePicture:
      take.makeFolder("myTest");
      take.captureImage();
      break;
  }       
}

public void setImage(String path) {
  BitmapFactory.Options options = new BitmapFactory.Options();
  options.inSampleSize = 2;
  Bitmap bm = BitmapFactory.decodeFile(path, options);
  d_image_pre1.setImageBitmap(bm); 
}

在TakeApicture.java：

public void jpegCallBack() {
  jpegCallback = new PictureCallback() {
    public void onPictureTaken(byte[] data, Camera camera) {
      getPicPath(data);
      (MainActivity)context.setImage(currentPicPath);
    }
  };
}