Question

我目前在Android应用中有一项功能，可让我发布评论并附上照片。评论将上传到Cloud Firestore，并通过其下载URL引用对Firebase存储的评论。

我遇到的问题是，在第一次调用该方法时，它似乎没有检索下载URL，但是当我进行第二次调用时，它成功检索到它。下面我已经包含了这个方法，只需在按钮点击监听器中调用即可。

 protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_event_comments);

    submitComment.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            newComment();
        }
    });



        private void newComment() {

    Date date = new Date();
    EventComment mcomment = new EventComment();
    mcomment.setComment(commentText.getText().toString());
    mcomment.setDate_created(date);
   // mcomment.setUsername(firebaseAuth.getCurrentUser().getEmail());

    String commentID = Long.toHexString(Double.doubleToLongBits(Math.random()));

    StorageReference filePath = firebaseStorage.child("Photos").child(imageUri.getLastPathSegment());

    filePath.putFile(imageUri).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
        @Override
        public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {

            if(taskSnapshot.getDownloadUrl() != null){
                imgDownloadUri = taskSnapshot.getDownloadUrl();

            } else if(taskSnapshot.getMetadata().getDownloadUrl() != null) {
                imgDownloadUri = taskSnapshot.getMetadata().getDownloadUrl();
            }
            Toast.makeText(getApplicationContext(), "Image uploaded", Toast.LENGTH_SHORT).show();
        }


    }).addOnFailureListener(new OnFailureListener() {
        @Override
        public void onFailure(@NonNull Exception e) {
            Toast.makeText(getApplicationContext(), e.getMessage(), Toast.LENGTH_SHORT).show();

        }
    });

    if (imgDownloadUri != null) {
        mcomment.setImageUri(imgDownloadUri.toString());

    }

    firestore.collection("events").document(event_id).collection("comments").document(commentID)
            .set(mcomment, SetOptions.merge()).addOnCompleteListener(new OnCompleteListener<Void>() {
        @Override
        public void onComplete(@NonNull Task<Void> task) {
            Toast.makeText(EventCommentsActivity.this, "Comment posted successfully", Toast.LENGTH_SHORT).show();
        }

    });


}

    firestore.collection("events").document(event_id).collection("comments").document(commentID)
            .set(mcomment, SetOptions.merge()).addOnCompleteListener(new OnCompleteListener<Void>() {
        @Override
        public void onComplete(@NonNull Task<Void> task) {
            Toast.makeText(EventCommentsActivity.this, "Comment posted successfully", Toast.LENGTH_SHORT).show();
        }

    });

我已经多次调试了这个，我不确定是什么导致了这个。或许它可以做回调的工作方式，并在一个方法中使用它可能会导致问题？

任何反馈都将不胜感激。

干杯

Answer 1

我在代码中解释，看看代码内的注释，如果您有任何疑问，请询问！

private void newComment() {
        StorageReference filePath = firebaseStorage.child("Photos").child(imageUri.getLastPathSegment());
         //start progessbar here

        filePath.putFile(imageUri).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
            @Override
            public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {

                if(taskSnapshot.getDownloadUrl() != null){
                    imgDownloadUri = taskSnapshot.getDownloadUrl();

                } else if(taskSnapshot.getMetadata().getDownloadUrl() != null) {
                    imgDownloadUri = taskSnapshot.getMetadata().getDownloadUrl();
                }
                if (imgDownloadUri != null) {
                   //close progessbar here
            mcomment.setImageUri(imgDownloadUri.toString());

                }
                Toast.makeText(getApplicationContext(), "Image uploaded", Toast.LENGTH_SHORT).show();
            }


        }).addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                Toast.makeText(getApplicationContext(), e.getMessage(), Toast.LENGTH_SHORT).show();

            }
        });



        firestore.collection("events").document(event_id).collection("comments").document(commentID)
                .set(mcomment, SetOptions.merge()).addOnCompleteListener(new OnCompleteListener<Void>() {
            @Override
            public void onComplete(@NonNull Task<Void> task) {
                Toast.makeText(EventCommentsActivity.this, "Comment posted successfully", Toast.LENGTH_SHORT).show();
            }

        });


    }

Android - Firebase存储getDownloadUrl在第一次调用时返回null

1 个答案: