如何将位图等图像文件写入特定的文件路径？

Question

我想制作一个附件功能，允许用户从图库中拍摄照片或选择图像，然后在附件列表视图中显示。

然后，当用户选择了他的图像时，结果是FileSchemeUri还是ContentSchemeUri。所以我尝试降低位图的大小并获取单击的文件路径以查看图像/在attachmnet列表视图中设置图标，方法是使用此函数获取outputFilePath：

    private File uriToFile(Uri uri, File sdImageMainDirectory) throws IOException{

    /*InputStream inputStream = getContentResolver().openInputStream(uri);
    Bitmap bitmap = BitmapFactory.decodeStream(inputStream);*/

    Bitmap bitmap = MediaStore.Images.Media.getBitmap(getContentResolver(), uri);
    OutputStream stream = new FileOutputStream(sdImageMainDirectory);

    int bitmapWidth = bitmap.getWidth();
    int bitmapHeight = bitmap.getHeight();
    int maxSize = 640;

    float bitmapRatio = (float) bitmapWidth / (float) bitmapHeight;

    if(bitmapRatio > 0){
        bitmapWidth = maxSize;
        bitmapHeight = (int) (bitmapWidth / bitmapRatio);
    }
    else{
        bitmapHeight = maxSize;
        bitmapWidth = (int) (bitmapHeight * bitmapRatio);
    }
    bitmap.createScaledBitmap(bitmap, bitmapWidth, bitmapHeight, true);
    bitmap.compress(Bitmap.CompressFormat.JPEG, 50, stream);
   File outputFile = new File(String.valueOf(stream));
    stream.flush();
    stream.close();
    return outputFile;
}

我想要做的是将位图写入名为sdImageMainDirectory的特定路径。它失败了，因为outputFile的值是这样的事情：java.IO.FileOutputStream@438571。我看了看我的目录文件夹，那些图像变成了0kb图像（坏了）。我想问一下如何将位图写入那些目录？请帮忙。

调试：

Answer 1

这是我选择的图像方法，请看一下：

  private void imageChooserDialog() {

    //region Create folder 'eLeaveAttachmentFolder'
    // Define a file name "root", which is a path of the user's phone's image directory, and create a file called "eLeaveAttachmentFolder"
    final File root = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES) + File.separator + "eLeaveAttachmentFolder" + File.separator);

    // In the file object "root" (path), if the folder eLeaveAttachmentFolder is not exist, create one.
    root.mkdirs();
    //endregion

    //region Define where the result should save at
    // Define a string name claimfilename, which is used to store an image's name while it's created/selected.
    final String claimfilename = getUniqueImageFilenameForFilename();

    // Define a file name sdImageMainDirectory which is exactly the image's path (e.g. emulated\0\Pictures\eLeaveAttachmentFolder\Screenshot_08122015_160952.jpg)
    sdImageMainDirectory = new File(root, claimfilename);
    //endregion


    // Assign the path 'sdImageMainDirectory' to the outputFileUri(Image in uri format)
    outputFileUri = Uri.fromFile(sdImageMainDirectory);

    //Camera

    // Create an arraylist to save types of intent (camera or gallery)
    final List<Intent> cameraIntents = new ArrayList<>();

    // Create the intent of camera
    final Intent captureIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);

    // PackageManager manages uri installing and uninstalling
    final PackageManager packageManager = getPackageManager();

    // ?? What is ResolveInfo?  packageManager.queryIntentActivities(captureIntent, 0) ??
    final List<ResolveInfo> listCam = packageManager.queryIntentActivities(captureIntent, 0);

    // "res" is to get all objects from the array "listCam"
    for (ResolveInfo res : listCam) {

        // ?? ????
        final String packageName = res.activityInfo.packageName;

        // Create the intent for saving the captureIntent
        final Intent intent = new Intent(captureIntent);

        //
        intent.setComponent(new ComponentName(res.activityInfo.packageName, res.activityInfo.name));
        intent.setPackage(packageName);

        // Bundle the outputFileUri to onActivityResult
        intent.putExtra(MediaStore.EXTRA_OUTPUT, outputFileUri);

        // Set the quality of the image
        intent.putExtra(MediaStore.EXTRA_VIDEO_QUALITY, 1);

        // Add the whole camera properties into one intent called cameraIntents
        cameraIntents.add(intent);
    }

    // Filesystem.
    final Intent galleryIntent = new Intent();
    galleryIntent.setType("image/*");
    galleryIntent.setAction(Intent.ACTION_GET_CONTENT);

    // Chooser of filesystem options.
    final Intent chooserIntent = Intent.createChooser(galleryIntent, "Select Source");

    // Add the camera options.
    chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS, cameraIntents.toArray(new Parcelable[cameraIntents.size()]));


    startActivityForResult(chooserIntent, SELECT_PICTURE); // Activity to pop up the dialog, bundle the selectedImage Data to show at the onActivityResult
}
//endregion

//region onActivityResult
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data){
    if (resultCode == RESULT_OK) {
        if (requestCode == SELECT_PICTURE) {

            Uri selectedImageUri = data.getData();


            //Camera
            if (selectedImageUri == null) {
                //selectedImageUri = outputFileUri;
             try{uriToFile(outputFileUri, sdImageMainDirectory);}
             catch(IOException e){}
            }

            else {
                try{uriToFile(selectedImageUri, sdImageMainDirectory);}
                catch(IOException e){}
            }
            }

            try {imageOutputStream = new FileOutputStream(sdImageMainDirectory); }
            catch (FileNotFoundException e) {}

            claimattachmentfilename = getUniqueImageFilenameForShowing();
            claimattachmentpathname = getUniqueImageFilenameForFilename();

             /*try{claimattachmentbitmap = UriToBitmap(claimattachmenturi);}
             catch (FileNotFoundException e){}
            catch(IOException e){}*/

            newAttachment = new AttachmentListResult();
            // newAttachment.setBitmap(claimattachmentbitmap);
            newAttachment.setDirectory(sdImageMainDirectory);
            newAttachment.setFilename(claimattachmentfilename);
        //    newAttachment.setPathname(claimattachmentpathname);
          //  newAttachment.setByteArray(claimattachmentbytearray);
            if (lastAdapter != null) {attachmentarray = lastAdapter.getAttachmentArray();}

            attachmentarray.add(newAttachment);

            listViewUpdate();
        }
    }



//endregion