Android：捕获和存储图片

Question

我正在关注this tutorial 拍摄照片、显示缩略图并将完整照片存储在仅对我的应用程序可用的本地公共存储中。

问题：尝试访问我的应用程序的本地存储时 EACCESS（权限被拒绝）

11-12 10:36:30.765    3746-3746/com.test.example.photo W/System.err﹕ java.io.IOException: open failed: EACCES (Permission denied)
11-12 10:36:30.765    3746-3746/com.test.example.photo W/System.err﹕ at java.io.File.createNewFile(File.java:948)
11-12 10:36:30.765    3746-3746/com.test.example.photo W/System.err﹕ at java.io.File.createTempFile(File.java:1013)

我查看了this question，但它似乎已经过时，因为今天没有任何解决方案可以工作。 This question 也没有提供有效的解决方案。我看到并尝试过的其他结果和解决方案似乎只是模糊相关。

我的清单权限

</application>
    <!-- PERMISSIONS -->
    <permission
        android:name="android.hardware.Camera.any"
        android:required="true" />
    <permission
        android:name="android.permission.WRITE_EXTERNAL_STORAGE"
        android:required="true" />
    <!-- android:maxSdkVersion="18" seemingly does nothing-->
</manifest>

崩溃的方法

private File createImageFile() throws IOException {
    // Create an image file name
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    String imageFileName = "JPEG_" + timeStamp + "_";

    //THIS IS WHERE IT CRASHES
    File storageDir = Environment.getExternalStoragePublicDirectory(
            Environment.DIRECTORY_PICTURES);
    File image = File.createTempFile(
        imageFileName,  /* prefix */
        ".jpg",         /* suffix */
        storageDir      /* directory */
    );

    // Save a file: path for use with ACTION_VIEW intents
    mCurrentPhotoPath = "file:" + image.getAbsolutePath();
    return image;
}

我正在使用 i9250 Galaxy Nexus 3 手机来运行示例，因为我的模拟器没有摄像头并且会自动删除元素。我的目标 SDK 是 16，我已将我的构建工具和 Android Studio 更新到最新版本。

我觉得我在这里遗漏了一些明显的东西，因为拍照在应用程序中是如此普遍，我无法想象它不适用于每个人，但我被困住了，我很感激你的指导。我对android很陌生，我主要使用的文献是Beginning Android 4 Game Programming，Beginning Android 4 and Pro Android 4。

感谢您的宝贵时间！

Answer 1

感谢大家的帮助，现在可以了！

显然我使用的是需要权限的 SD 卡存储，如 permission vs uses-permisson 中所述，而不是从 API 级别 19 开始不需要权限的本地沙盒存储。

SD卡访问，需要写权限：Environment.getExternalStoragePublicDirectory

应用的沙盒本地存储：getExternalFilesDir

我将此代码用于 API 级别 16，它应该需要很少的努力来实现和更改，但如果您遇到问题，请留言，我会尽力帮助或澄清。

大部分解释都在代码中作为注释

    //OnClick hook, requires implements View.OnClickListener to work
    public void takePicture(View v) {
        dispatchTakePictureIntent();
    }

    private void dispatchTakePictureIntent() {
        //Create intent to capture an image from the camera
        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        // Ensure that there's a camera activity to handle the intent
        if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
            // Create the directory File where the photo should go, do NOT try to create the image file itself
            File photoFile = null;
            try {
                //mCurrentPhotoPath is a File outside of the methods, so all methods know the last directory for the last picture taken
                mCurrentPhotoPath = createImageFile();
                photoFile = mCurrentPhotoPath;
            } catch (IOException ex) {
                // Error occurred while creating the File
                ex.printStackTrace();
            }
            // Continue only if the File was successfully created
            if (photoFile != null) {
                //photoFile MUST be a directory or the camera will hang on an internal
                //error and will refuse to store the picture,
                //resulting in not being able to to click accept
                //MediaStore will automatically store a jpeg for you in the specific directory and add the filename to the path
                takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(photoFile));
                startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE);
            }
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
            //unique name, can be pretty much whatever you want
            imageId = generateImageId(); 
            //Get file.jpg as bitmap from MediaStore's returned File object
            Bitmap imageBitmap = BitmapFactory.decodeFile(mCurrentPhotoPath.getAbsolutePath()); 
            //resize it to fit the screen
            imageBitmap = Bitmap.createScaledBitmap(imageBitmap,300,300,false); 
            //Some ImageView in your layout.xml
            ImageView imageView = (ImageView)findViewById(R.id.imageView); 
            imageView.setImageBitmap(imageBitmap);
            Bitmap thumbnail =  makeThumbnail(mCurrentPhotoPath);
            ImageView thumbnail = (ImageView)findViewById(R.id.thumbnail); 
            thumbnail.setImageBitmap(imageBitmap);
        }
    }

    private File createImageFile() throws IOException {
        // Create an image file name
        String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
        File storageDir = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
        //completely optional subdirectory structure
        storageDir = new File(storageDir, "custom_directory");
        return storageDir;
    }    

    private Bitmap makeThumbnail(File currentPhotoPath) {
        // Get the dimensions of the View, I strongly recommend creating a <dimens> resource for dip scaled pixels
        int targetW = 45;
        int targetH = 80;

        // Get the dimensions of the bitmap
        BitmapFactory.Options bmOptions = new BitmapFactory.Options();
        bmOptions.inJustDecodeBounds = true;
        BitmapFactory.decodeFile(currentPhotoPath.getAbsolutePath(), bmOptions);
        int photoW = bmOptions.outWidth;
        int photoH = bmOptions.outHeight;

        // Determine how much to scale down the image
        int scaleFactor = Math.min(photoW/targetW, photoH/targetH);

        // Decode the image file into a Bitmap sized to fill the View
        bmOptions.inJustDecodeBounds = false;
        bmOptions.inSampleSize = scaleFactor;
        bmOptions.inPurgeable = true;

        Bitmap bitmap = BitmapFactory.decodeFile(currentPhotoPath.getAbsolutePath(), bmOptions);
        return bitmap;
    }

    private long generateImageId() {
        return Calendar.getInstance().getTimeInMillis();
    }

Android 5.0，API 21，将使用 Camera2 API，据我所知，所有这些都将被隐藏得很远。你可以阅读它here

Answer 2

试试这个：

private File getDir() {
File sdDir = Environment
  .getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
return new File(sdDir, "Your_photo_dir_here");

}

然后：

 File pictureFileDir = getDir();

if (!pictureFileDir.exists() && !pictureFileDir.mkdirs()) {

  Log.d("TAG", "Can't create directory to save image.");
  return;

}


SimpleDateFormat dateFormat = new SimpleDateFormat("yyyymmddhhmmss");
String date = dateFormat.format(new Date());
String photoFile = "myphoto_" + date + ".jpg";

String filename = pictureFileDir.getPath() + File.separator + photoFile;

File pictureFile = new File(filename);

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

} catch (Exception error) {
  Log.d("TAG", "File" + filename + "not saved: "
      + error.getMessage());

}

Answer 3

使用uses-permission代替权限标签 在清单中添加这个

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />