android - 如何从 InputStream 而不是 File 获取 Exif 数据？

Question

我问这个的原因是因为文件选择器 Intent 的回调返回一个 Uri。

通过 Intent 打开文件选择器:

Intent intent = new Intent();
intent.setType("image/*");
intent.setAction(Intent.ACTION_GET_CONTENT);
startActivityForResult(Intent.createChooser(intent, "Select Picture"), CHOOSE_IMAGE_REQUEST);

回调:

@Override
public void onActivityResult(int requestCode, int resultCode, final Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (requestCode == CHOOSE_IMAGE_REQUEST && resultCode == Activity.RESULT_OK) {

        if (data == null) {
            // Error
            return;
        }

        Uri fileUri = data.getData();
        InputStream in = getContentResolver().openInputStream(fileUri);

        // How to determine image orientation through Exif data here?
    }
}

一种方法是将 InputStream 写入实际的 File，但这对我来说似乎是一个糟糕的解决方法。

Answer 1

引入 25.1.0 支持库后，现在可以通过 InputStream 从 URI 内容(content://或 file://)读取 exif 数据。

例子:首先将这一行添加到您的 gradle 文件中:

compile 'com.android.support:exifinterface:25.1.0'

Uri uri; // the URI you've received from the other app
InputStream in;
try {
  in = getContentResolver().openInputStream(uri);
  ExifInterface exifInterface = new ExifInterface(in);
  // Now you can extract any Exif tag you want
  // Assuming the image is a JPEG or supported raw format
} catch (IOException e) {
  // Handle any errors
} finally {
  if (in != null) {
    try {
      in.close();
    } catch (IOException ignored) {}
  }
}

更多信息请查看:Introducing the ExifInterface Support Library , ExifInterface .