使用 firebase 時任務尚未完成

Question

我正在創建將音樂從設備存儲到 firebase 的應用程序。 我正在使用 Firebase 存儲和數據庫，一切正常，但是當我上傳它時，它向我顯示進度條，在該應用程序崩潰后，我發現文件已上傳到存儲中，但沒有出現在數據庫中

收到以下錯誤：

2020-07-08 13:57:47.766 32456-32456/xyz.hannanshaikh.firebasemusic E/AndroidRuntime: FATAL EXCEPTION: main
    Process: xyz.hannanshaikh.firebasemusic, PID: 32456
    java.lang.IllegalStateException: Task is not yet complete
        at com.google.android.gms.common.internal.Preconditions.checkState(Unknown Source:29)
        at com.google.android.gms.tasks.zzu.zzb(Unknown Source:121)
        at com.google.android.gms.tasks.zzu.getResult(Unknown Source:12)
        at xyz.hannanshaikh.firebasemusic.MainActivity$3.onSuccess(MainActivity.java:105)
        at xyz.hannanshaikh.firebasemusic.MainActivity$3.onSuccess(MainActivity.java:98)
        at com.google.firebase.storage.StorageTask.lambda$new$0(com.google.firebase:firebase-storage@@19.1.1:123)
        at com.google.firebase.storage.StorageTask$$Lambda$1.raise(Unknown Source:6)
        at com.google.firebase.storage.TaskListenerImpl.lambda$onInternalStateChanged$2(com.google.firebase:firebase-storage@@19.1.1:90)
        at com.google.firebase.storage.TaskListenerImpl$$Lambda$3.run(Unknown Source:6)
        at android.os.Handler.handleCallback(Handler.java:873)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:201)
        at android.app.ActivityThread.main(ActivityThread.java:6823)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:547)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:873)

這是代碼：

package xyz.hannanshaikh.firebasemusic;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;

import android.Manifest;
import android.app.ProgressDialog;
import android.content.Intent;
import android.database.Cursor;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.provider.OpenableColumns;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toast;

import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.storage.FirebaseStorage;
import com.google.firebase.storage.OnProgressListener;
import com.google.firebase.storage.StorageReference;
import com.google.firebase.storage.UploadTask;
import com.karumi.dexter.Dexter;
import com.karumi.dexter.PermissionToken;
import com.karumi.dexter.listener.PermissionDeniedResponse;
import com.karumi.dexter.listener.PermissionGrantedResponse;
import com.karumi.dexter.listener.PermissionRequest;
import com.karumi.dexter.listener.single.PermissionListener;

import java.util.Objects;

public class MainActivity extends AppCompatActivity {
    private static final String LOG_TAG = "MainActivity";
    private boolean checkPermission = false;
    Uri uri;
    String songName, songUrl;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
        if (item.getItemId() == R.id.nav_upload) {
            if (validatePermission()) {
                pickSongs();
            }
        }
        return super.onOptionsItemSelected(item);
    }

    private void pickSongs() {
        Intent intent_upload = new Intent();
        intent_upload.setType("audio/*");
        intent_upload.setAction(Intent.ACTION_GET_CONTENT);
        startActivityForResult(intent_upload, 1);
        Log.d(LOG_TAG,"Intent sent for result");
    }

    @RequiresApi(api = Build.VERSION_CODES.O)
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {

        if (requestCode == 1) {
            if (resultCode == RESULT_OK) {
                uri = data.getData();

                Cursor mCursor = getApplicationContext().getContentResolver()
                        .query(uri, null, null, null);

                int indexedName = Objects.requireNonNull(mCursor).getColumnIndex(OpenableColumns.DISPLAY_NAME);
                mCursor.moveToFirst();
                songName = mCursor.getString(indexedName);
                mCursor.close();
                uploadToFirebaseStorage();
            }
        }
        super.onActivityResult(requestCode, resultCode, data);
    }

    private void uploadToFirebaseStorage() {
        Log.d(LOG_TAG,"Method: uploadToFirebaseStorage");
        StorageReference storageReference = FirebaseStorage.getInstance().getReference()
                .child("Songs").child(Objects.requireNonNull(uri.getLastPathSegment()));

        final ProgressDialog progressDialog = new ProgressDialog(this);
        progressDialog.show();

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

                Task<Uri> uriTask = taskSnapshot.getStorage().getDownloadUrl();

                while (!uriTask.isSuccessful()) {
                    Uri urlSong = uriTask.getResult();
                    songUrl = Objects.requireNonNull(urlSong).toString();

                    uploadDetailsToDatabase();
                    progressDialog.dismiss();
                }

            }
        }).addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                Toast.makeText(MainActivity.this, e.getMessage(), Toast.LENGTH_SHORT).show();
                progressDialog.dismiss();
            }
        }).addOnProgressListener(new OnProgressListener<UploadTask.TaskSnapshot>() {
            @Override
            public void onProgress(@NonNull UploadTask.TaskSnapshot taskSnapshot) {
                double progress = (100.0 * taskSnapshot.getBytesTransferred()) / taskSnapshot.getTotalByteCount();
                int currentProgress = (int) progress;
                progressDialog.setMessage("Uploaded: " + currentProgress + "%");
            }
        });
    }

    private void uploadDetailsToDatabase() {
        Songs songObj = new Songs(songName, songUrl);

        FirebaseDatabase.getInstance().getReference("Songs")
                .push().setValue(songObj).addOnCompleteListener(new OnCompleteListener<Void>() {
            @Override
            public void onComplete(@NonNull Task<Void> task) {
                if (task.isSuccessful()){
                    Toast.makeText(MainActivity.this,"Song Uploaded",Toast.LENGTH_SHORT).show();
                }
            }
        }).addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                Toast.makeText(MainActivity.this, e.getMessage(),Toast.LENGTH_SHORT).show();
            }
        });

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.custom_menu, menu);
        return super.onCreateOptionsMenu(menu);
    }

    //Validate permission with Dexter library
    private boolean validatePermission() {
        Dexter.withContext(MainActivity.this)
                .withPermission(Manifest.permission.READ_EXTERNAL_STORAGE)
                .withListener(new PermissionListener() {
                    @Override
                    public void onPermissionGranted(PermissionGrantedResponse permissionGrantedResponse) {
                        checkPermission = true;
                    }

                    @Override
                    public void onPermissionDenied(PermissionDeniedResponse permissionDeniedResponse) {
                        checkPermission = false;
                    }

                    @Override
                    public void onPermissionRationaleShouldBeShown(PermissionRequest permissionRequest, PermissionToken permissionToken) {
                        permissionToken.continuePermissionRequest();
                    }
                }).check();
        return checkPermission;
    }
}

Answer 1

您應該避免在回調偵聽器中使用 while 循環，相反，您可以檢查其他偵聽器方法 onComplete() 是否上傳成功。

Answer 2

我認為您嘗試將歌曲上傳到數據庫（我想是在實時數據庫中）的方式是錯誤的。 在方法uploadDetailsToDatabase中，編寫：

1. 在 class 的開頭聲明引用：

DatabaseReference songsDatabase;

2. 在onCreate()方法中使用數據庫中歌曲表的路徑初始化引用：

songsDatabase = FirebaseDatabase.getInstance().getReference("songs");

3. 在實時數據庫中添加歌曲 object：

Songs songObj = new Songs(songName, songUrl);

DatabaseReference ref = FirebaseDatabase.getInstance().getReference();
songsDatabase.child(songName).setValue(songObj).addOnCompleteListener(new OnCompleteListener<Void>() {
            @Override
            public void onComplete(@NonNull Task<Void> task) {
                if (task.isSuccessful()){
                    Toast.makeText(MainActivity.this,"Song Uploaded",Toast.LENGTH_SHORT).show();
                }
            }
        }).addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                Toast.makeText(MainActivity.this, e.getMessage(),Toast.LENGTH_SHORT).show();
            }
        });

這樣，您在實時數據庫中創建一個數據（表），將歌曲名稱作為該表的名稱（songName）。 在此表中，您有 2 個字段：歌曲名稱和歌曲的 url。

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