上传到Firebase Storeage等待上传完成，然后上传到Firebase并返回任务

Question

我正试图将一个自定义对象上传到Firebase Firestore，但Firestore对象应该包含一个下载图像url。我必须这样做的想法是先上传图像，等待完成，获得下载url的引用，更新我的自定义类，然后将其上传到Firestore。然后，我想在最后一次上传(上传到Firestore(完成时通知我的视图。我想通过返回一个任务来完成此操作。这是我上传图片的方法：

ref.putFile(file).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
@Override
public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
ref.getDownloadUrl().addOnSuccessListener(new OnSuccessListener<Uri>() {
@Override
public void onSuccess(Uri uri) {
//use uri to update object and then upload to firestore
mObject.setImageUri(uri)
uploadToFirestore(myObject);
}
Log.d(TAG, "onSuccess: uri= "+ uri.toString());
}
});
}
});`

我不知道如何返回Firstore上传的最终任务，因为它是在图像上传任务中完成的。我的目标是监听uploadToFireStore((何时完成，然后通知我的视图。如有任何建议，我们将不胜感激。谢谢

编辑：我有这样的结构-View已从用户处获取信息，并将其作为自定义对象传递给viewmodel。然后视图模型调用数据库来执行上载。我的想法是将一个任务从db返回到viewmodel，它将把所述任务返回到view。视图检查是否完成，然后停止加载程序。这是一个很好的思考方式吗？

Answer 1

我的工作示例。

public class SomeClass {
private String downloadUrl;
private final FirebaseStorage storage = FirebaseStorage.getInstance();
private int count = 0;
public interface Callback {
void callingBack();
void getReady();
}
public int getCount() {
return count;
}
private Callback callback;
public void registerCallBack(Callback callback) {
this.callback = callback;
}

public String getImageUri () {
return downloadUrl;
}
public void uploadImage (String srcPath, String fileName, Context context, int size) {
StorageReference storageRef = storage.getReference();
StorageReference imageRef = storageRef.child(fileName);
try {
InputStream inputStream = new FileInputStream(new File(srcPath));
imageRef.putStream(inputStream)
.continueWithTask(task -> imageRef.getDownloadUrl())
.addOnCompleteListener(task -> {
downloadUrl = task.getResult().toString();
callback.callingBack();
this.count++;
if (this.count == size) {
callback.getReady();
this.count = 0;
}
});
} catch (Exception e) {
Toast.makeText(context, "Connection error", Toast.LENGTH_LONG).show();
}
}    
}

活动代码

public void someMehtod() {
String fileName;
String filePath;
int size = YOUR_SIZE;
String[] imgUrlList = new String[size];
for (int i = 0; i < size; i++) {
fileName = "img_" + i + ".jpg"; // set target file name
filePath = "/storage/emulated/0/Download/images_" + i + ".jpg"; // for example (u need get your real source file paths)
getImageUri.registerCallBack(new GetImageUri.Callback() {
@Override
public void callingBack() {
imgUrlList [getImageUri.getCount()] = getImageUri.getImageUri();
}
}

@Override
public void getReady() {
// here u can use your URLs
for (int k = 0; k < size; k ++) {
Log.d(TAG, "getReady: " + imgUrlList [k]);    
}
});
getImageUri.uploadImage(filePath, fileName, this.getContext(), imgListCount);
}
}

Answer 2

我想好了如何解决这个问题。使用回调。创建一个类似的界面

public interface Callback {
void result(Result result);
void url(Uri downloadUrl);
}

注意：result是一个枚举类，有两个值FAILED和SUCCESS然后在你的视图中调用这样的视图模型

ViewModel.saveoBJECT(mObject, new Callback() {
@Override
public void result(Result result) {
switch (result){
case SUCCESS:
mProgressbar.setVisibility(View.GONE);
break;
case FAILED:
Log.v(TAG, "Failed");
Toast.makeText(getApplicationContext(), "OOPS ERROR!", Toast.LENGTH_LONG).show();
break;
}
}
@Override
public void url(Uri downloadUrl) { }
});

在你的数据库里做一些类似的事情

uploadImage(Uri.parse(imageString), prepend, new Callback() {
@Override
public void result(Result result) {}
@Override
public void uri(Uri downloadUrl) {
saveObjectInDB(downloadUrl, new Callback() {
@Override
public void result(Result result) {
callback.result(result);
}
@Override
public void url(Uri downloadUrl) { }
});
}
});

在上传图像功能中

ref.putFile(file).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
@Override
public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
ref.getDownloadUrl().addOnSuccessListener(new OnSuccessListener<Uri>() {
@Override
public void onSuccess(Uri uri) {
callback.journey(uri);
Log.d(TAG, "onSuccess: uri= "+ uri.toString());
}
});
}
});

在saveObjectInDB函数中，您可以执行此

db.collection(DATABASE).add(O)
.addOnSuccessListener(new OnSuccessListener<DocumentReference>() {
@Override
public void onSuccess(DocumentReference documentReference) {
Log.w(TAG, "Document upload complete");
callback.result(Result.SUCCESS);
}
})
.addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
Log.w(TAG, "Error adding uploading document", e);
callback.result(Result.FAILED);
}
});