java - 上传具有不同扩展名的多个文件 firebase storage

Question

我的目标是添加新产品，每个产品都包含图片和 pdf 文件到 firebase 存储，然后将每个链接保存到 firebase 数据库。

我在上传图片和 pdf 时遇到问题。我无法从每个文件获取下载 URL，并返回 null 我尝试发布到数据库。

代码:

private void bukafilemanager(View view) {
    switch (view.getId()){
        case R.id.pilih_gambar:
            Intent gambar = new Intent();
            gambar.setType("image/*");
            gambar.setAction(Intent.ACTION_GET_CONTENT);
            startActivityForResult(gambar, PICK_IMAGE_REQUEST);
            break;

        case R.id.pilih_pdf:
            Intent pdf = new Intent();
            pdf.setType("application/*");
            pdf.setAction(Intent.ACTION_GET_CONTENT);
            startActivityForResult(pdf, PICK_FILE_REQUEST);
    }
}

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

    if (requestCode == PICK_IMAGE_REQUEST && resultCode == RESULT_OK && data != null && data.getData()!= null){
        URI_Image = data.getData();
        daftarupload.add(URI_Image);
        Glide.with(this).load(URI_Image).into(preview_gambar);
        preview_gambar.setImageURI(URI_Image);

    } else if (requestCode == PICK_FILE_REQUEST && resultCode == RESULT_OK && data != null && data.getData()!= null){
        URI_File = data.getData();
        daftarupload.add(URI_File);
    }
}

public String getMimeType(Context context, Uri uri) {
    String extension;

    //Check uri format to avoid null
    if (uri.getScheme().equals(ContentResolver.SCHEME_CONTENT)) {
        //If scheme is a content
        MimeTypeMap mime = MimeTypeMap.getSingleton();
        extension = mime.getExtensionFromMimeType(context.getContentResolver().getType(uri));
    } else {
        //If scheme is a File
        //This will replace white spaces with %20 and also other special characters. This will avoid returning null values on file name with spaces and special characters.
        extension = MimeTypeMap.getFileExtensionFromUrl(Uri.fromFile(new File(uri.getPath())).toString());
    }
    return extension;
}

protected void uploadfile(ArrayList<Uri> daftarupload){

    progressDialog.setMessage("Harap Tunggu...");
    progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
    progressDialog.setIndeterminate(true);
    progressDialog.setProgress(count);
    progressDialog.setMax(daftarupload.size());
    progressDialog.show();

    String nama_produk = namaproduk.getText().toString();
    String ket_produk = ketproduk.getText().toString();
    if(!TextUtils.isEmpty(nama_produk) && !TextUtils.isEmpty(ket_produk)) {
        for (Uri uri : daftarupload) {
            switch (getMimeType(getBaseContext(), uri)) {
                case "jpg":
                    final StorageReference lokasijpg = storage.child(id_produk + ".jpg");
                    lokasijpg
                            .putFile(uri)
                            .addOnCompleteListener(new OnCompleteListener<UploadTask.TaskSnapshot>() {
                                @Override
                                public void onComplete(@NonNull Task<UploadTask.TaskSnapshot> task) {
                                    if (task.isComplete()){
                                        lokasijpg
                                                .getDownloadUrl()
                                                .addOnSuccessListener(new OnSuccessListener<Uri>() {
                                                    @Override
                                                    public void onSuccess(Uri uri) {
                                                        URL_JPG = uri;
                                                        count += 1;
                                                        progressDialog.setProgress(count);
                                                    }
                                                });
                                    }
                                }
                            });
                    break;
                case "pdf":
                    final StorageReference lokasipdf = storage.child(id_produk + ".pdf");
                    lokasipdf
                            .putFile(uri)
                            .addOnCompleteListener(new OnCompleteListener<UploadTask.TaskSnapshot>() {
                                @Override
                                public void onComplete(@NonNull Task<UploadTask.TaskSnapshot> task) {
                                    if(task.isComplete()){
                                            lokasipdf
                                                    .getDownloadUrl()
                                                    .addOnSuccessListener(new OnSuccessListener<Uri>() {
                                                    @Override
                                                    public void onSuccess(Uri uri) {
                                                        URL_PDF = uri;
                                                        count += 1;
                                                        progressDialog.setProgress(count);
                                                    }
                                                });
                                    }
                                }
                            });
                    break;

                default:
                    progressDialog.dismiss();
                    Toast.makeText(getBaseContext(), "Format Tidak Sesuai", Toast.LENGTH_LONG).show();
                    break;

            }
        }

        simpandata(id_produk, nama_produk, ket_produk , URL_JPG, URL_PDF);
        progressDialog.dismiss();

    } else {
        progressDialog.dismiss();
        Toast.makeText(tambahproduk.this,"Semua data harus diisi lengkap!", Toast.LENGTH_LONG).show();
    }
}

protected void simpandata(String id_produk, final String nama_produk, String ket_produk, Uri URL_JPG, Uri URL_PDF){

        produk produk = new produk(id_produk,nama_produk,ket_produk,URL_JPG.toString(),URL_PDF.toString());
        database.child(id_produk).setValue(produk).addOnSuccessListener(new OnSuccessListener<Void>() {
            @Override
            public void onSuccess(Void aVoid) {
                progressDialog.dismiss();
                Toast.makeText(tambahproduk.this, "Produk "+nama_produk.toString()+" Berhasil Ditambahkan", Toast.LENGTH_LONG).show();
                finish();
            }
        }).addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                progressDialog.dismiss();
                Toast.makeText(tambahproduk.this, e.toString(), Toast.LENGTH_LONG).show();
            }
        });
}

错误:

E/AndroidRuntime: FATAL EXCEPTION: main
              Process: com.user.katalog.lulu.user, PID: 27391
              java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.net.Uri.toString()' on a null object reference
                  at com.user.katalog.lulu.user.tambahproduk.simpandata(tambahproduk.java:237)
                  at com.user.katalog.lulu.user.tambahproduk.uploadfile(tambahproduk.java:226)
                  at com.user.katalog.lulu.user.tambahproduk$3.onClick(tambahproduk.java:102)
                  at android.view.View.performClick(View.java:5198)
                  at android.view.View$PerformClick.run(View.java:21147)
                  at android.os.Handler.handleCallback(Handler.java:739)
                  at android.os.Handler.dispatchMessage(Handler.java:95)
                  at android.os.Looper.loop(Looper.java:148)
                  at android.app.ActivityThread.main(ActivityThread.java:5417)
                  at java.lang.reflect.Method.invoke(Native Method)
                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

Answer 1

根据您的评论，我了解到您收到该错误是由于以下代码行:

produk produk = new produk(id_produk,nama_produk,ket_produk,URL_JPG.toString(),URL_PDF.toString());

这是因为您无法将 URL_PDF 变量创建为全局变量并期望正常工作。您现在无法使用尚未加载的内容。换句话说，您不能简单地在 onComplete() 方法之外使用 URL_PDF 对象，因为由于此方法的异步行为，它始终为 null方法。这意味着当您尝试在该方法之外使用该结果时，数据尚未完成从数据库的加载，这就是无法访问的原因。解决此问题的一个快速解决方案是仅在 onComplete() 方法中使用 URL_PDF 变量，否则我建议您查看此 中我的答案的最后部分> post 其中我解释了如何使用自定义回调来完成它。您还可以看看这个video 为了更好地理解。