从相册获取图片并转换为文件数组并上传

程序从一个dialog开始：

private void show() {
        final Dialog dialog = new Dialog(this, R.style.ActionSheetDialogStyle);
        View inflate = LayoutInflater.from(this).inflate(R.layout.dialog_item, null);
        //相册
        Button bt_camera = inflate.findViewById(R.id.bt_camera);
        //取消
        Button bt_cancel = inflate.findViewById(R.id.bt_cancel);
        dialog.setContentView(inflate);
        Window dialogWindow = dialog.getWindow();
        dialogWindow.setGravity(Gravity.BOTTOM);
        WindowManager.LayoutParams lp = dialogWindow.getAttributes();
        lp.y = 20;
        dialogWindow.setAttributes(lp);
        //取消按钮
        bt_cancel.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                dialog.dismiss();
            }
        });
        //从相册选取
        bt_camera.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                dialog.dismiss();
                if (ContextCompat.checkSelfPermission(FeedbackDetails.this,
                        android.Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
                    ActivityCompat.requestPermissions(FeedbackDetails.this, new String[]{android.Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
                } else {
                    openAlbum();
                }
            }
        });
        dialog.show();
    }

 private void openAlbum() {
        Intent intent = new Intent("android.intent.action.GET_CONTENT");
        intent.setType("image/*");
        startActivityForResult(intent, CHOOSE_PHOTO);//打开相册
    }

    //相册
    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode) {
            case 1:
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    openAlbum();
                } else {
                    Toast.makeText(this, "你拒绝了权限申请，可能无法打开相册哟", Toast.LENGTH_SHORT).show();
                }
                break;
            default:
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch (requestCode) {
            case CHOOSE_PHOTO:
                if (resultCode == RESULT_OK) {
                    // 判断手机系统版本号
                    if (Build.VERSION.SDK_INT >= 19) {
                        // 4.4及以上系统使用这个方法处理图片
                        handleImageOnKitKat(data);
                    } else {
                        // 4.4以下系统使用这个方法处理图片
                        handleImageBeforeKitKat(data);
                    }
                }
                break;
            default:
                break;
        }
    }

    @TargetApi(19)
    private void handleImageOnKitKat(Intent data) {
        String imagePath = null;
        Uri uri = data.getData();
        if (DocumentsContract.isDocumentUri(this, uri)) {
            // 如果是document类型的Uri，则通过document id处理
            String docId = DocumentsContract.getDocumentId(uri);
            if ("com.android.providers.media.documents".equals(uri.getAuthority())) {
                String id = docId.split(":")[1]; // 解析出数字格式的id
                String selection = MediaStore.Images.Media._ID + "=" + id;
                imagePath = getImagePath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, selection);
            } else if ("com.android.providers.downloads.documents".equals(uri.
                    getAuthority())) {
                Uri contentUri = ContentUris.withAppendedId(Uri.parse("content: downloads/public_downloads"), Long.valueOf(docId));
                imagePath = getImagePath(contentUri, null);
            }
        } else if ("content".equalsIgnoreCase(uri.getScheme())) {
            // 如果是content类型的Uri，则使用普通方式处理
            imagePath = getImagePath(uri, null);
        } else if ("file".equalsIgnoreCase(uri.getScheme())) {
            // 如果是file类型的Uri，直接获取图片路径即可
            imagePath = uri.getPath();
        }

        displayImage(imagePath); // 根据图片路径显示图片

    }

    private void handleImageBeforeKitKat(Intent data) {
        Uri uri = data.getData();
        String imagePath = getImagePath(uri, null);
        displayImage(imagePath);

    }

    private String getImagePath(Uri uri, String selection) {
        String path = null;
        // 通过Uri和selection来获取真实的图片路径
        Cursor cursor = getContentResolver().query(uri, null, selection, null, null);
        if (cursor != null) {
            if (cursor.moveToFirst()) {
                path = cursor.getString(cursor.getColumnIndex(MediaStore.
                        Images.Media.DATA));
            }
            cursor.close();
        }
        return path;
    }
    //获取图片地址
    private void displayImage(String imagePath) {
        if (imagePath != null) {
            Bitmap bitmap = BitmapFactory.decodeFile(imagePath);
            headFile = saveMyBitmap(bitmap, "head");
            setsend("", headFile);
        } else {
            Toast.makeText(this, "获取图片失败", Toast.LENGTH_SHORT).show();
        }
    }

    //将bitmap转化为png格式
    public File saveMyBitmap(Bitmap mBitmap, String prefix) {
        File storageDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM);
        File file = null;
        try {
            file = File.createTempFile(
                    prefix,  /* prefix */
                    ".jpg",         /* suffix */
                    storageDir      /* directory */
            );
            FileOutputStream fos = new FileOutputStream(file);
            mBitmap.compress(Bitmap.CompressFormat.JPEG, 10, fos);
            fos.flush();
            fos.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return file;
    }