本頁面由 Cloud Translation API 翻譯而成。

在 Android 裝置上使用 Cloud Storage 上傳檔案

Cloud Storage for Firebase 可讓您輕鬆快速地將檔案上傳至由 Firebase 提供及管理的 Cloud Storage 值區。

上傳檔案

如要將檔案上傳至 Cloud Storage，您必須先建立檔案完整路徑的參照，包括檔案名稱。

Kotlin+KTX

// Create a storage reference from our app
val storageRef = storage.reference

// Create a reference to "mountains.jpg"
val mountainsRef = storageRef.child("mountains.jpg")

// Create a reference to 'images/mountains.jpg'
val mountainImagesRef = storageRef.child("images/mountains.jpg")

// While the file names are the same, the references point to different files
mountainsRef.name == mountainImagesRef.name // true
mountainsRef.path == mountainImagesRef.path // falseStorageActivity.kt

Java

// Create a storage reference from our app
StorageReference storageRef = storage.getReference();

// Create a reference to "mountains.jpg"
StorageReference mountainsRef = storageRef.child("mountains.jpg");

// Create a reference to 'images/mountains.jpg'
StorageReference mountainImagesRef = storageRef.child("images/mountains.jpg");

// While the file names are the same, the references point to different files
mountainsRef.getName().equals(mountainImagesRef.getName());    // true
mountainsRef.getPath().equals(mountainImagesRef.getPath());    // falseStorageActivity.java

建立適當的參照後，請呼叫 putBytes()、putFile() 或 putStream() 方法，將檔案上傳至 Cloud Storage。

您無法上傳參照 Cloud Storage 值區根目錄的資料。您的參照必須指向子網址。

從記憶體中的資料上傳

如要將檔案上傳至 Cloud Storage，使用 putBytes() 方法是最簡單的方法。putBytes() 會接受 byte[] 並傳回 UploadTask，供您管理及監控上傳作業狀態。

Kotlin+KTX

// Get the data from an ImageView as bytes
imageView.isDrawingCacheEnabled = true
imageView.buildDrawingCache()
val bitmap = (imageView.drawable as BitmapDrawable).bitmap
val baos = ByteArrayOutputStream()
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos)
val data = baos.toByteArray()

var uploadTask = mountainsRef.putBytes(data)
uploadTask.addOnFailureListener {
    // Handle unsuccessful uploads
}.addOnSuccessListener { taskSnapshot ->
    // taskSnapshot.metadata contains file metadata such as size, content-type, etc.
    // ...
}StorageActivity.kt

Java

// Get the data from an ImageView as bytes
imageView.setDrawingCacheEnabled(true);
imageView.buildDrawingCache();
Bitmap bitmap = ((BitmapDrawable) imageView.getDrawable()).getBitmap();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);
byte[] data = baos.toByteArray();

UploadTask uploadTask = mountainsRef.putBytes(data);
uploadTask.addOnFailureListener(new OnFailureListener() {
    @Override
    public void onFailure(@NonNull Exception exception) {
        // Handle unsuccessful uploads
    }
}).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
    @Override
    public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
        // taskSnapshot.getMetadata() contains file metadata such as size, content-type, etc.
        // ...
    }
});StorageActivity.java

由於 putBytes() 接受 byte[]，因此應用程式會要求應用程式一次將整個檔案的內容保存在記憶體中。請考慮使用 putStream() 或 putFile() 來減少記憶體。

從串流上傳

putStream() 方法是將檔案上傳至 Cloud Storage 最多元的方法。putStream() 會接受 InputStream 並傳回 UploadTask，供您管理及監控上傳作業狀態。

Kotlin+KTX

val stream = FileInputStream(File("path/to/images/rivers.jpg"))

uploadTask = mountainsRef.putStream(stream)
uploadTask.addOnFailureListener {
    // Handle unsuccessful uploads
}.addOnSuccessListener { taskSnapshot ->
    // taskSnapshot.metadata contains file metadata such as size, content-type, etc.
    // ...
}StorageActivity.kt

Java

InputStream stream = new FileInputStream(new File("path/to/images/rivers.jpg"));

uploadTask = mountainsRef.putStream(stream);
uploadTask.addOnFailureListener(new OnFailureListener() {
    @Override
    public void onFailure(@NonNull Exception exception) {
        // Handle unsuccessful uploads
    }
}).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
    @Override
    public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
        // taskSnapshot.getMetadata() contains file metadata such as size, content-type, etc.
        // ...
    }
});StorageActivity.java

從本機檔案上傳

您可以使用 putFile() 方法上傳裝置上的本機檔案，例如相機中的相片和影片。putFile() 會接受 File 並傳回 UploadTask，供您管理及監控上傳作業狀態。

Kotlin+KTX

var file = Uri.fromFile(File("path/to/images/rivers.jpg"))
val riversRef = storageRef.child("images/${file.lastPathSegment}")
uploadTask = riversRef.putFile(file)

// Register observers to listen for when the download is done or if it fails
uploadTask.addOnFailureListener {
    // Handle unsuccessful uploads
}.addOnSuccessListener { taskSnapshot ->
    // taskSnapshot.metadata contains file metadata such as size, content-type, etc.
    // ...
}StorageActivity.kt

Java

Uri file = Uri.fromFile(new File("path/to/images/rivers.jpg"));
StorageReference riversRef = storageRef.child("images/"+file.getLastPathSegment());
uploadTask = riversRef.putFile(file);

// Register observers to listen for when the download is done or if it fails
uploadTask.addOnFailureListener(new OnFailureListener() {
    @Override
    public void onFailure(@NonNull Exception exception) {
        // Handle unsuccessful uploads
    }
}).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
    @Override
    public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
        // taskSnapshot.getMetadata() contains file metadata such as size, content-type, etc.
        // ...
    }
});StorageActivity.java

取得下載網址

上傳檔案後，您可以在 StorageReference 上呼叫 getDownloadUrl() 方法，取得下載檔案的網址：

Kotlin+KTX

val ref = storageRef.child("images/mountains.jpg")
uploadTask = ref.putFile(file)

val urlTask = uploadTask.continueWithTask { task ->
    if (!task.isSuccessful) {
        task.exception?.let {
            throw it
        }
    }
    ref.downloadUrl
}.addOnCompleteListener { task ->
    if (task.isSuccessful) {
        val downloadUri = task.result
    } else {
        // Handle failures
        // ...
    }
}StorageActivity.kt

Java

final StorageReference ref = storageRef.child("images/mountains.jpg");
uploadTask = ref.putFile(file);

Task<Uri> urlTask = uploadTask.continueWithTask(new Continuation<UploadTask.TaskSnapshot, Task<Uri>>() {
    @Override
    public Task<Uri> then(@NonNull Task<UploadTask.TaskSnapshot> task) throws Exception {
        if (!task.isSuccessful()) {
            throw task.getException();
        }

        // Continue with the task to get the download URL
        return ref.getDownloadUrl();
    }
}).addOnCompleteListener(new OnCompleteListener<Uri>() {
    @Override
    public void onComplete(@NonNull Task<Uri> task) {
        if (task.isSuccessful()) {
            Uri downloadUri = task.getResult();
        } else {
            // Handle failures
            // ...
        }
    }
});StorageActivity.java

新增檔案中繼資料

您也可以在上傳檔案時加入中繼資料。這個中繼資料包含一般檔案中繼資料屬性，例如 name、size 和 contentType (通常稱為 MIME 類型)。putFile() 方法會從 File 擴充功能自動推論 MIME 類型，但您可以在中繼資料中指定 contentType，覆寫自動偵測的類型。如未提供 contentType，且 Cloud Storage 無法從副檔名推斷預設值，Cloud Storage 會使用 application/octet-stream。如要進一步瞭解檔案中繼資料，請參閱使用檔案中繼資料一節。

Kotlin+KTX

// Create file metadata including the content type
var metadata = storageMetadata {
    contentType = "image/jpg"
}

// Upload the file and metadata
uploadTask = storageRef.child("images/mountains.jpg").putFile(file, metadata)StorageActivity.kt

Java

// Create file metadata including the content type
StorageMetadata metadata = new StorageMetadata.Builder()
        .setContentType("image/jpg")
        .build();

// Upload the file and metadata
uploadTask = storageRef.child("images/mountains.jpg").putFile(file, metadata);StorageActivity.java

管理上傳項目

除了開始上傳作業，您還可以使用 pause()、resume() 和 cancel() 方法暫停、繼續及取消上傳作業。暫停和繼續事件會分別引發 pause 和 progress 狀態變更。取消上傳會導致上傳失敗，並顯示錯誤，通知您上傳作業已取消。

Kotlin+KTX

uploadTask = storageRef.child("images/mountains.jpg").putFile(file)

// Pause the upload
uploadTask.pause()

// Resume the upload
uploadTask.resume()

// Cancel the upload
uploadTask.cancel()StorageActivity.kt

Java

uploadTask = storageRef.child("images/mountains.jpg").putFile(file);

// Pause the upload
uploadTask.pause();

// Resume the upload
uploadTask.resume();

// Cancel the upload
uploadTask.cancel();StorageActivity.java

監控上傳進度

您可以新增事件監聽器，處理上傳工作中的成功、失敗、進度或暫停：

監聽器類型	一般用量
`OnProgressListener`	系統會在資料傳輸過程中定期呼叫這個事件監聽器，並用來填入上傳/下載指標。
`OnPausedListener`	工作暫停時，系統就會呼叫此事件監聽器。
`OnSuccessListener`	工作順利完成後，系統就會呼叫此事件監聽器。
`OnFailureListener`	上傳失敗時，系統就會呼叫此事件監聽器。可能的原因包括網路逾時、授權失敗或是您取消工作。

系統會透過 Exception 執行個體呼叫 OnFailureListener。系統會使用 UploadTask.TaskSnapshot 物件呼叫其他事件監聽器。此物件是事件發生時，工作的不可變更檢視畫面。UploadTask.TaskSnapshot 包含下列屬性：

屬性	類型	說明
`getDownloadUrl`	`String`	可用來下載物件的網址。這個網址是可公開檢索的公開網址，可與其他客戶分享。上傳完成後，系統就會填入這個值。
`getError`	`Exception`	如果工作失敗，這會造成原因為「例外狀況」。
`getBytesTransferred`	`long`	擷取這個快照時已傳輸的位元組總數。
`getTotalByteCount`	`long`	預計上傳的位元組總數。
`getUploadSessionUri`	`String`	透過對 putFile 發出的其他呼叫，可用來繼續這項工作的 URI。
`getMetadata`	`StorageMetadata`	上傳完成之前，系統會將中繼資料傳送至伺服器。上傳完成之後，這是伺服器傳回的中繼資料。
`getTask`	`UploadTask`	建立這張快照的工作。透過這項工作取消、暫停或繼續上傳作業。
`getStorage`	`StorageReference`	用來建立 `UploadTask` 的 `StorageReference`。

UploadTask 事件監聽器可讓您以簡單又有效的方式監控上傳事件。

Kotlin+KTX

// Observe state change events such as progress, pause, and resume
// You'll need to import com.google.firebase.storage.component1 and
// com.google.firebase.storage.component2
uploadTask.addOnProgressListener { (bytesTransferred, totalByteCount) ->
    val progress = (100.0 * bytesTransferred) / totalByteCount
    Log.d(TAG, "Upload is $progress% done")
}.addOnPausedListener {
    Log.d(TAG, "Upload is paused")
}StorageActivity.kt

Java

// Observe state change events such as progress, pause, and resume
uploadTask.addOnProgressListener(new OnProgressListener<UploadTask.TaskSnapshot>() {
    @Override
    public void onProgress(UploadTask.TaskSnapshot taskSnapshot) {
        double progress = (100.0 * taskSnapshot.getBytesTransferred()) / taskSnapshot.getTotalByteCount();
        Log.d(TAG, "Upload is " + progress + "% done");
    }
}).addOnPausedListener(new OnPausedListener<UploadTask.TaskSnapshot>() {
    @Override
    public void onPaused(UploadTask.TaskSnapshot taskSnapshot) {
        Log.d(TAG, "Upload is paused");
    }
});StorageActivity.java

處理活動生命週期變更

即使活動生命週期有所變更 (例如顯示對話方塊或旋轉畫面)，上傳作業仍會在背景繼續執行。您附加的所有事件監聽器也會保持連接。如果在活動停止後呼叫，可能會產生非預期的結果。

如要解決這個問題，您可以使用活動範圍訂閱事件監聽器，以便在活動停止時自動取消註冊。接著，在活動重新啟動時使用 getActiveUploadTasks 方法，取得仍在執行或最近完成的上傳工作。

下例示範了這個做法，並示範如何保存所使用的儲存空間參照路徑。

Kotlin+KTX

override fun onSaveInstanceState(outState: Bundle) {
    super.onSaveInstanceState(outState)

    // If there's an upload in progress, save the reference so you can query it later
    outState.putString("reference", storageRef.toString())
}

override fun onRestoreInstanceState(savedInstanceState: Bundle) {
    super.onRestoreInstanceState(savedInstanceState)

    // If there was an upload in progress, get its reference and create a new StorageReference
    val stringRef = savedInstanceState.getString("reference") ?: return

    storageRef = Firebase.storage.getReferenceFromUrl(stringRef)

    // Find all UploadTasks under this StorageReference (in this example, there should be one)

    val tasks = storageRef.activeUploadTasks

    if (tasks.size > 0) {
        // Get the task monitoring the upload
        val task = tasks[0]

        // Add new listeners to the task using an Activity scope
        task.addOnSuccessListener(this) {
            // Success!
            // ...
        }
    }
}UploadActivity.kt

Java

@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);

    // If there's an upload in progress, save the reference so you can query it later
    if (mStorageRef != null) {
        outState.putString("reference", mStorageRef.toString());
    }
}

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);

    // If there was an upload in progress, get its reference and create a new StorageReference
    final String stringRef = savedInstanceState.getString("reference");
    if (stringRef == null) {
        return;
    }
    mStorageRef = FirebaseStorage.getInstance().getReferenceFromUrl(stringRef);

    // Find all UploadTasks under this StorageReference (in this example, there should be one)
    List<UploadTask> tasks = mStorageRef.getActiveUploadTasks();
    if (tasks.size() > 0) {
        // Get the task monitoring the upload
        UploadTask task = tasks.get(0);

        // Add new listeners to the task using an Activity scope
        task.addOnSuccessListener(this, new OnSuccessListener<UploadTask.TaskSnapshot>() {
            @Override
            public void onSuccess(UploadTask.TaskSnapshot state) {
                // Success!
                // ...
            }
        });
    }
}UploadActivity.java

getActiveUploadTasks 會在提供的參照位置內及下方擷取所有進行中的上傳工作，因此您可能需要處理多項工作。

繼續跨程序重新啟動上傳

如果程序關閉，所有進行中的上傳作業都會中斷。不過，您可以在程序重新啟動後，透過伺服器繼續上傳工作階段繼續上傳。這有助於節省時間和頻寬，因為不用從檔案開頭開始上傳。

如要這麼做，請透過 putFile 開始上傳。在產生的 StorageTask 上呼叫 getUploadSessionUri，並將產生的值儲存在永久儲存空間 (例如 SharedPreferences)。

Kotlin+KTX

uploadTask = storageRef.putFile(localFile)
uploadTask.addOnProgressListener { taskSnapshot ->
    sessionUri = taskSnapshot.uploadSessionUri
    if (sessionUri != null && !saved) {
        saved = true
        // A persisted session has begun with the server.
        // Save this to persistent storage in case the process dies.
    }
}UploadActivity.kt

Java

uploadTask = mStorageRef.putFile(localFile);
uploadTask.addOnProgressListener(new OnProgressListener<UploadTask.TaskSnapshot>() {
    @Override
    public void onProgress(UploadTask.TaskSnapshot taskSnapshot) {
        Uri sessionUri = taskSnapshot.getUploadSessionUri();
        if (sessionUri != null && !mSaved) {
            mSaved = true;
            // A persisted session has begun with the server.
            // Save this to persistent storage in case the process dies.
        }
    }
});UploadActivity.java

程序因上傳作業中斷而重新啟動後，請再次呼叫 putFile。但這次也會傳送已儲存的 URI。

Kotlin+KTX

// resume the upload task from where it left off when the process died.
// to do this, pass the sessionUri as the last parameter
uploadTask = storageRef.putFile(
    localFile,
    storageMetadata { },
    sessionUri,
)UploadActivity.kt

Java

//resume the upload task from where it left off when the process died.
//to do this, pass the sessionUri as the last parameter
uploadTask = mStorageRef.putFile(localFile,
        new StorageMetadata.Builder().build(), sessionUri);UploadActivity.java

上週的工作階段。如果您在工作階段過期或發生錯誤，嘗試繼續工作階段，您會收到失敗回呼。您有責任確保檔案在上傳後不會變更。

處理錯誤

導致上傳發生錯誤的原因有很多，包括本機檔案不存在，或使用者沒有上傳所需檔案的權限。如要進一步瞭解錯誤，請參閱說明文件的處理錯誤一節。

完整範例

下列是含有進度監控和錯誤處理的上傳的完整範例：

Kotlin+KTX

// File or Blob
file = Uri.fromFile(File("path/to/mountains.jpg"))

// Create the file metadata
metadata = storageMetadata {
    contentType = "image/jpeg"
}

// Upload file and metadata to the path 'images/mountains.jpg'
uploadTask = storageRef.child("images/${file.lastPathSegment}").putFile(file, metadata)

// Listen for state changes, errors, and completion of the upload.
// You'll need to import com.google.firebase.storage.component1 and
// com.google.firebase.storage.component2
uploadTask.addOnProgressListener { (bytesTransferred, totalByteCount) ->
    val progress = (100.0 * bytesTransferred) / totalByteCount
    Log.d(TAG, "Upload is $progress% done")
}.addOnPausedListener {
    Log.d(TAG, "Upload is paused")
}.addOnFailureListener {
    // Handle unsuccessful uploads
}.addOnSuccessListener {
    // Handle successful uploads on complete
    // ...
}StorageActivity.kt

Java

// File or Blob
file = Uri.fromFile(new File("path/to/mountains.jpg"));

// Create the file metadata
metadata = new StorageMetadata.Builder()
        .setContentType("image/jpeg")
        .build();

// Upload file and metadata to the path 'images/mountains.jpg'
uploadTask = storageRef.child("images/"+file.getLastPathSegment()).putFile(file, metadata);

// Listen for state changes, errors, and completion of the upload.
uploadTask.addOnProgressListener(new OnProgressListener<UploadTask.TaskSnapshot>() {
    @Override
    public void onProgress(UploadTask.TaskSnapshot taskSnapshot) {
        double progress = (100.0 * taskSnapshot.getBytesTransferred()) / taskSnapshot.getTotalByteCount();
        Log.d(TAG, "Upload is " + progress + "% done");
    }
}).addOnPausedListener(new OnPausedListener<UploadTask.TaskSnapshot>() {
    @Override
    public void onPaused(UploadTask.TaskSnapshot taskSnapshot) {
        Log.d(TAG, "Upload is paused");
    }
}).addOnFailureListener(new OnFailureListener() {
    @Override
    public void onFailure(@NonNull Exception exception) {
        // Handle unsuccessful uploads
    }
}).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
    @Override
    public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
        // Handle successful uploads on complete
        // ...
    }
});StorageActivity.java

上傳檔案後，不妨進一步瞭解如何從 Cloud Storage 下載這些檔案。