Android Firebase 存储：getFile() 失败并创建 0 字节的文件

Question

我在 Android (SDK 34) 上使用 Firebase API 将文件从我的存储桶下载到我的共享下载文件夹。但是，当我调用

StorageReference.getFile(Uri uri)

时，创建0字节文件后失败。但是，如果我使用

getBytes

并自己将字节写入文件，则效果很好。

这是无法工作的代码：

// This does not. See the exception details below
public void download(String remotePath, Uri localUri) {
  StorageReference fileRef = storageRef.child(remotePath);
  fileRef
  .getFile(localUri)
  .addOnFailureListener(
      error -> {
        System.out.println(error.getMessage());
      });
}

错误消息和堆栈跟踪：

error = {StorageException@26984} "com.google.firebase.storage.StorageException: An unknown error occurred, please check the HTTP result code and inner exception for server response."
 cause = {IOException@26987} "java.io.IOException: No such file or directory"
  backtrace = null
  cause = {IOException@26987} "java.io.IOException: No such file or directory"
   backtrace = null
   cause = {IOException@26987} "java.io.IOException: No such file or directory"
   detailMessage = "No such file or directory"
   stackTrace = {StackTraceElement[14]@26998} 
    0 = {StackTraceElement@27003} "java.io.UnixFileSystem.createFileExclusively0(Native Method)"
    1 = {StackTraceElement@27004} "java.io.UnixFileSystem.createFileExclusively(UnixFileSystem.java:349)"
    2 = {StackTraceElement@27005} "java.io.File.createNewFile(File.java:1006)"
    3 = {StackTraceElement@27006} "com.google.firebase.storage.FileDownloadTask.processResponse(FileDownloadTask.java:136)"
    4 = {StackTraceElement@27007} "com.google.firebase.storage.FileDownloadTask.run(FileDownloadTask.java:228)"
    5 = {StackTraceElement@27008} "com.google.firebase.storage.StorageTask.lambda$getRunnable$7$com-google-firebase-storage-StorageTask(StorageTask.java:1077)"
    6 = {StackTraceElement@27009} "com.google.firebase.storage.StorageTask$$ExternalSyntheticLambda7.run(Unknown Source:2)"
    7 = {StackTraceElement@27010} "com.google.firebase.concurrent.LimitedConcurrencyExecutor.lambda$decorate$0$com-google-firebase-concurrent-LimitedConcurrencyExecutor(LimitedConcurrencyExecutor.java:65)"
    8 = {StackTraceElement@27011} "com.google.firebase.concurrent.LimitedConcurrencyExecutor$$ExternalSyntheticLambda0.run(Unknown Source:4)"
    9 = {StackTraceElement@27012} "java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)"
    10 = {StackTraceElement@27013} "java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)"
    11 = {StackTraceElement@27014} "com.google.firebase.concurrent.CustomThreadFactory.lambda$newThread$0$com-google-firebase-concurrent-CustomThreadFactory(CustomThreadFactory.java:47)"
    12 = {StackTraceElement@27015} "com.google.firebase.concurrent.CustomThreadFactory$$ExternalSyntheticLambda0.run(Unknown Source:4)"
    13 = {StackTraceElement@27016} "java.lang.Thread.run(Thread.java:1012)"

但是，这段代码可以工作：

public void download(String remotePath, Uri localUri) {
  StorageReference fileRef = storageRef.child(remotePath);
  fileRef
      .getBytes(1024 * 1024 * 16)
      .addOnSuccessListener(
          result -> {
            try {
              ContentResolver resolver = context.getContentResolver();
              OutputStream stream = resolver.openOutputStream(localUri);
              stream.write(result);
              stream.close();
            } catch (Exception e) {
              System.out.println(e.getMessage());
            }
          });
}

这就是我创建

localUri

的方式：

ContentResolver resolver = context.getContentResolver();
String fileName = UUID.randomUUID().toString().toUpperCase();
Uri imagesUri = MediaStore.Images.Media.getContentUri(MediaStore.VOLUME_EXTERNAL_PRIMARY);

ContentValues values = new ContentValues();
values.put(MediaStore.MediaColumns.DISPLAY_NAME, fileName);
values.put(MediaStore.MediaColumns.MIME_TYPE, "image/png");

Uri localUri = resolver.insert(imagesUri, values);

你知道这里出了什么问题吗？谢谢！

Answer 1

fileRef.getFile(uri) 尝试将远程文件从存储下载到传递给它的本地文件 URI。它必须是一个特定的文件路径，如文档所述（强调我的）：

将此 StorageReference 处的对象异步下载到

指定的系统文件路径。

但是您将 URI 传递给 ContentProvider，而这不受支持。 SDK 不会尝试下载文件并将其放入 ContentProvider 中。 URI 必须标识一个文件。您可能更容易只传递 File 参数，并确保它指向应用程序可写入的位置，例如其

内部存储位置。