Question

这几天困扰我的人都知道了。问题是，我不知道自己是否朝着正确的方向前进。

我的开始活动是ImageDisplay类，它为CustomCamera活动调用startActivityForRestult。拍摄照片后，用户将返回到ImageDisplay并显示捕获图像，但不会显示。我做错了什么？

第二件事，我猜它真的很重要，那时相机应该被释放？

ImageDisplay：

public class ImageDisplay extends Activity{

ImageView imageHolder;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.al_imagedisplay);
    imageHolder = (ImageView) findViewById(R.id.imageView1);

    Intent intent = new Intent(this, CustomCamera.class);
    startActivityForResult(intent, 0); 
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    // TODO Auto-generated method stub
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == 0 && resultCode == RESULT_OK) {  

        Bitmap photo = (Bitmap) data.getExtras().get("result");
        imageHolder.setImageBitmap(photo);
    }
}

}

CustomCamera：

public class CustomCamera extends Activity {

private Camera mCamera;
private NewItemSurfaceView mPreview;
Button captureButton;
public static final int MEDIA_TYPE_IMAGE = 1;
public static final int MEDIA_TYPE_VIDEO = 2;
public static final String MY_CAMERRA_APP = "MyCameraApp";

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.al_newitem_camera);

    captureButton = (Button) findViewById(R.id.buttonClick);

    // Create an instance of Camera
    mCamera = getCameraInstance();
    mCamera.setDisplayOrientation(90);

    // Create our Preview view and set it as the content of our activity.
    mPreview = new NewItemSurfaceView(this, mCamera);
    FrameLayout preview = (FrameLayout) findViewById(R.id.flCamera);
    preview.addView(mPreview);

    // Add a listener to the Capture button
    captureButton.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            // get an image from the camera
            mCamera.takePicture(null, null, mPicture);
        }
    });
}

/** A safe way to get an instance of the Camera object. */
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
}

private PictureCallback mPicture = new PictureCallback() {

    @Override
    public void onPictureTaken(byte[] data, Camera camera) {

        File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE);
        if (pictureFile == null) {
            Log.d("Camera error",
                    "Error creating media file, check storage permissions: ");
            return;
        }
        Log.i("Picture", pictureFile.toString());
        try {
            FileOutputStream fos = new FileOutputStream(pictureFile);
            fos.write(data);
            fos.close();
        } catch (FileNotFoundException e) {
            Log.d("Camera error", "File not found: " + e.getMessage());
        } catch (IOException e) {
            Log.d("Camera error", "Error accessing file: " + e.getMessage());
        }



        Intent returnIntent = new Intent();
        returnIntent.putExtra("result", pictureFile);
        setResult(RESULT_OK, returnIntent);
        finish();

    }

};

/** Create a File for saving an image or video */
private static File getOutputMediaFile(int type) {
    // To be safe, you should check that the SDCard is mounted
    // using Environment.getExternalStorageState() before doing this.

    File mediaStorageDir = new File(
            Environment
                    .getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM),
            "MyCameraApp");
    // This location works best if you want the created images to be shared
    // between applications and persist after your app has been uninstalled.

    // Create the storage directory if it does not exist
    if (!mediaStorageDir.exists()) {
        if (!mediaStorageDir.mkdirs()) {
            Log.i("MyCameraApp", "failed to create directory");
            return null;
        }
    }

    // Create a media file name
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss")
            .format(new Date());
    File mediaFile;
    if (type == MEDIA_TYPE_IMAGE) {
        mediaFile = new File(mediaStorageDir.getPath() + File.separator
                + "IMG_" + timeStamp + ".jpg");
    } else if (type == MEDIA_TYPE_VIDEO) {
        mediaFile = new File(mediaStorageDir.getPath() + File.separator
                + "VID_" + timeStamp + ".mp4");
    } else {
        return null;
    }

    return mediaFile;
}

}

Answer 1

像这样修改onActivityResult方法

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    // TODO Auto-generated method stub
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == 0 && resultCode == RESULT_OK) {  

        String photoPath = (String) data.getExtras().get("result");
        imageHolder.setImageBitmap(BitmapFactory.decodeFile("photoPath"));
    }
}

在你的onPictureTaken方法中进行一些修改

 Intent returnIntent = getIntent();
        returnIntent.putExtra("result", pictureFile.getAbsolutePath());
        setResult(RESULT_OK, returnIntent);
        finish();

使用自定义相机应用捕获和显示图像

1 个答案: