将 ProgressBar 与 DownloadManager 一起使用

Question

在我的应用中，我使用 DownloadManager 从 Firebase 下载文件。

import static android.os.Environment.DIRECTORY_DOWNLOADS;

public class Physics extends AppCompatActivity {
PDFView pdfView;
FirebaseStorage firebaseStorage;
StorageReference storageReference;
StorageReference ref;
File file;
File files;
ProgressBar progressBar;
private Context context;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_SECURE, WindowManager.LayoutParams.FLAG_SECURE);
    setContentView(R.layout.activity_physics1);

    pdfView = findViewById(R.id.pdfview);
    progressBar = (ProgressBar) findViewById(R.id.progressBar);


    Context mContext = getApplicationContext();
    String path = mContext.getFilesDir().getAbsolutePath() + "/storage/emulated/0/Android/data/com.impwala.impwala/files/Download/asd.nomedia";
    File file = new File("/storage/emulated/0/Android/data/com.impwala.impwala/files/Download/asd.nomedia");

    if (file.exists()) {
        files = new File("/storage/emulated/0/Android/data/com.impwala.impwala/files/Download/asd.nomedia");
        pdfView.fromFile(files).load();
    } else {
        if (haveNetwork()) {
            download();
        } else if (!haveNetwork()) {
            final Intent mainIntent = new Intent(Physics.this, Nointernet.class);
            Physics.this.startActivity(mainIntent);
            Physics.this.finish();
        }
    }
}

// Indicate that we would like to update download progress
private static final int UPDATE_DOWNLOAD_PROGRESS = 1;

// Use a background thread to check the progress of downloading
private final ExecutorService executor = Executors.newFixedThreadPool(1);

// Use a hander to update progress bar on the main thread
private final Handler mainHandler = new Handler(Looper.getMainLooper(), new Handler.Callback() {
    @Override
    public boolean handleMessage(@NonNull Message msg) {
        if (msg.what == UPDATE_DOWNLOAD_PROGRESS) {
            int downloadProgress = msg.arg1;

            // Update your progress bar here.
            progressBar.setProgress(downloadProgress);

        }
        return true;
    }

});

public boolean haveNetwork () {
    boolean have_WIFI = false;
    boolean have_MobileData = false;

    ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(CONNECTIVITY_SERVICE);
    NetworkInfo[] networkInfos = connectivityManager.getAllNetworkInfo();

    for (NetworkInfo info : networkInfos) {
        if (info.getTypeName().equalsIgnoreCase("WIFI"))
            if (info.isConnected())
                have_WIFI = true;
        if (info.getTypeName().equalsIgnoreCase("MOBILE"))
            if (info.isConnected())
                have_MobileData = true;
    }
    return have_MobileData || have_WIFI;
}

public void download () {

    storageReference = FirebaseStorage.getInstance().getReference();
    ref = storageReference.child("asd.pdf");

    ref.getDownloadUrl()
            .addOnSuccessListener(new OnSuccessListener<Uri>() {
                @Override
                public void onSuccess(Uri uri) {
                    String url = uri.toString();
                    downloadFile(Physics.this, "asd", ".nomedia", DIRECTORY_DOWNLOADS, url); // Successfully downloaded data to local file
                    // ...
                }
            })
            .addOnFailureListener(new OnFailureListener() {
                @Override
                public void onFailure(@NonNull Exception e) {
                    // Handle failed download
                    // ...
                }
            });
}

public void downloadFile (Context context, String fileName, String fileExtension, String destinationDirectory, String url)
    {
        final DownloadManager downloadManager = (DownloadManager) context.
                getSystemService(Context.DOWNLOAD_SERVICE);

    Uri uri = Uri.parse(url);
    DownloadManager.Request request = new DownloadManager.Request(uri);
  request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
    request.setDestinationInExternalFilesDir(context, destinationDirectory, fileName + fileExtension);

      final long downloadId = downloadManager.enqueue(request);
    //Run a task in a background thread to check download progress
    executor.execute(new Runnable() {
        @Override
        public void run() {
            int progress = 0;
            boolean isDownloadFinished = false;
            while (!isDownloadFinished) {
                Cursor cursor = downloadManager.query(new DownloadManager.Query().setFilterById(downloadId));
                if (cursor.moveToFirst()) {
                    int downloadStatus = cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_STATUS));
                    switch (downloadStatus) {
                        case DownloadManager.STATUS_RUNNING:
                            long totalBytes = cursor.getLong(cursor.getColumnIndex(DownloadManager.COLUMN_TOTAL_SIZE_BYTES));
                            if (totalBytes > 0) {
                                long downloadedBytes = cursor.getLong(cursor.getColumnIndex(DownloadManager.COLUMN_BYTES_DOWNLOADED_SO_FAR));
                                progress = (int) (downloadedBytes * 100 / totalBytes);
                            }

                            break;
                        case DownloadManager.STATUS_SUCCESSFUL:
                            progress = 100;
                            isDownloadFinished = true;
                            break;
                        case DownloadManager.STATUS_PAUSED:
                        case DownloadManager.STATUS_PENDING:
                            break;
                        case DownloadManager.STATUS_FAILED:
                            isDownloadFinished = true;
                            break;
                    }
                    Message message = Message.obtain();
                    message.what = UPDATE_DOWNLOAD_PROGRESS;
                    message.arg1 = progress;
                    mainHandler.sendMessage(message);


                }
            }
        }
    });
    executor.shutdown();
    mainHandler.removeCallbacksAndMessages(null);
}
}

我想显示一个进度条来指示下载进度，但我不知道如何实现它。

我根据@Son Truong 的建议编辑了我的代码并在 XML

中有一个进度条

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/gradient"
    tools:context=".Physics">

    <ProgressBar
        android:id="@+id/progressBar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:progress="0"
        android:max="100"/>

    <com.github.barteksc.pdfviewer.PDFView
        android:id="@+id/pdfview"
        android:layout_width="match_parent"
        android:layout_height="478dp"
        android:layout_gravity="bottom"
        />

</FrameLayout>

但是下载开始时进度条没有开始，下载完成后也没有结束。另外，没有文字显示完成了多少百分比。

Answer 1

解决方案

步骤 1. 在 class

中声明以下变量

// Indicate that we would like to update download progress
private static final int UPDATE_DOWNLOAD_PROGRESS = 1;

// Use a background thread to check the progress of downloading
private final ExecutorService executor = Executors.newFixedThreadPool(1);

// Use a hander to update progress bar on the main thread
private final Handler mainHandler = new Handler(Looper.getMainLooper(), new Handler.Callback() {
    @Override
    public boolean handleMessage(@NonNull Message msg) {
        if (msg.what == UPDATE_DOWNLOAD_PROGRESS) {
            int downloadProgress = msg.arg1;

            // Update your progress bar here.
            progressBar.setProgress(downloadProgress);
        }
        return true;
    }
});

步骤 2.修改您的 downloadFile() 方法

public void downloadFile(Context context, String fileName, String fileExtension, String destinationDirectory, String url) {
    DownloadManager downloadManager = (DownloadManager) context.
            getSystemService(Context.DOWNLOAD_SERVICE);

    Uri uri = Uri.parse(url);
    DownloadManager.Request request = new DownloadManager.Request(uri);

    request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
    request.setDestinationInExternalFilesDir(context, destinationDirectory, fileName + fileExtension);

    long downloadId = downloadManager.enqueue(request);

    // Run a task in a background thread to check download progress
    executor.execute(new Runnable() {
        @Override
        public void run() {
            int progress = 0;
            boolean isDownloadFinished = false;
            while (!isDownloadFinished) {
                Cursor cursor = downloadManager.query(new DownloadManager.Query().setFilterById(downloadId));
                if (cursor.moveToFirst()) {
                    int downloadStatus = cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_STATUS));
                    switch (downloadStatus) {
                        case DownloadManager.STATUS_RUNNING:
                            long totalBytes = cursor.getLong(cursor.getColumnIndex(DownloadManager.COLUMN_TOTAL_SIZE_BYTES));
                            if (totalBytes > 0) {
                                long downloadedBytes = cursor.getLong(cursor.getColumnIndex(DownloadManager.COLUMN_BYTES_DOWNLOADED_SO_FAR));
                                progress = (int) (downloadedBytes * 100 / totalBytes);
                            }

                            break;
                        case DownloadManager.STATUS_SUCCESSFUL:
                            progress = 100;
                            isDownloadFinished = true;
                            break;
                        case DownloadManager.STATUS_PAUSED:
                        case DownloadManager.STATUS_PENDING:
                            break;
                        case DownloadManager.STATUS_FAILED:
                            isDownloadFinished = true;
                            break;
                    }
                    Message message = Message.obtain();
                    message.what = UPDATE_DOWNLOAD_PROGRESS;
                    message.arg1 = progress;
                    mainHandler.sendMessage(message);
                }
            }
        }
    });
}

注意：下载完成后记得释放executor和handler

executor.shutdown();
mainHandler.removeCallbacksAndMessages(null);

将 ProgressBar 与 DownloadManager 一起使用

Using ProgressBar with DownloadManager

android

firebase-storage

android-download-manager