Question

我关注Android应用程序的Google Camera Tutorial。此时，我可以拍照，保存，显示路径并将位图显示到ImageView中。

当我要求我拍摄的照片的绝对路径时，这是logcat的一个例子：

D/PATH:: /storage/emulated/0/Pictures/JPEG_20160210_140144_217642556.jpg

现在，我想通过USB在PC上传输它。当我浏览设备存储时，我可以看到我之前在代码中使用变量Picture调用的公用文件夹Environment.DIRECTORY_PICTURES。但是，此文件夹中没有任何内容。

我无法在我的设备中插入SD卡进行测试。此外，我不想将图片放入缓存目录以防止被删除。

以下是我在Manifest中的权限：

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera.autofocus" />

当用户点击相机按钮时：

dispatchTakePictureIntent();
[...]
private void dispatchTakePictureIntent() {
    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 File where the photo should go
        File photoFile = null;
        try {
            photoFile = createImageFile();
        } catch (IOException ex) {
            // Error occurred while creating the File
        }
        // Continue only if the File was successfully created
        if (photoFile != null) {
            takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT,
                    Uri.fromFile(photoFile));
            startActivityForResult(takePictureIntent, REQUEST_TAKE_PHOTO);
        }
    }
}

这是创建文件的方法

private File createImageFile() throws IOException {
    // Create an image file name
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    String imageFileName = "JPEG_" + timeStamp + "_";
    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();
    Log.d("PATH:", image.getAbsolutePath());
    return image;
}

我想我误解了External Storage的一些事情。 有人可以解释一下为什么我无法保存图片并在PC上访问它吗？谢谢！

- 编辑 -

在阅读下面的答案后，我尝试将文件放在OnActivityResult中并使用Java IO保存。不幸的是，当我查看资源管理器时，图片文件夹中没有文件。

if (requestCode == REQUEST_TAKE_PHOTO) {
        Log.d("AFTER", absolutePath);

       // Bitmap bitmap = BitmapFactory.decodeFile(absolutePath);
       // imageTest.setImageBitmap(Bitmap.createScaledBitmap(bitmap, 2100, 3100, false));

        moveFile(absolutePath, Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES).toString());
    }

private void moveFile(String inputFile, String outputPath) {

    InputStream in = null;
    OutputStream out = null;
    try {

        //create output directory if it doesn't exist
        File dir = new File (outputPath);
        if (!dir.exists())
        {
            dir.mkdirs();
        }


        in = new FileInputStream(inputFile);
        out = new FileOutputStream(outputPath + imageFileName + ".jpg");

        byte[] buffer = new byte[1024];
        int read;
        while ((read = in.read(buffer)) != -1) {
            out.write(buffer, 0, read);
        }
        in.close();
        in = null;

        // write the output file
        out.flush();
        out.close();
        out = null;

        // delete the original file
        new File(inputFile).delete();


    }

Answer 1

您目前正在将文件保存为临时文件，因此在应用程序生命周期后它不会在磁盘上保留。使用类似的东西：

ByteArrayOutputStream bytes = new ByteArrayOutputStream();
imageBitmap.compress(Bitmap.CompressFormat.JPEG, 90, bytes);
File f = new File(Environment.getExternalStorageDirectory() + [filename])

然后创建一个FileOutputStream来写入它。

FileOutStream fo = new FileOutputStream(f);
fo.write(bytes.toByteArray());

Answer 2

要解决我的问题，我必须将文件写入应用程序的数据文件夹并使用MediaScannerConnection。我已经把.txt文件用于测试，但是在它工作之后你可以放任何其他文件。

我会为遇到类似问题的人分享解决方案：

try
    {
        // Creates a trace file in the primary external storage space of the
        // current application.
        // If the file does not exists, it is created.
        File traceFile = new File(((Context)this).getExternalFilesDir(null), "TraceFile.txt");
        if (!traceFile.exists())
            traceFile.createNewFile();
        // Adds a line to the trace file
        BufferedWriter writer = new BufferedWriter(new FileWriter(traceFile, true /*append*/));
        writer.write("This is a test trace file.");
        writer.close();
        // Refresh the data so it can seen when the device is plugged in a
        // computer. You may have to unplug and replug the device to see the
        // latest changes. This is not necessary if the user should not modify
        // the files.
        MediaScannerConnection.scanFile((Context)(this),
                new String[] { traceFile.toString() },
                null,
                null);

    }
    catch (IOException e)
    {
        Log.d("FileTest", "Unable to write to the TraceFile.txt file.");
    }

如何保存图片并在PC上访问？

2 个答案: