检查下载管理器是否下载了文件 [英] Check if Download Manager downloaded the file

问题描述

如何检查文件是否已下载并运行安装?我有一个代码:

How can I check if file has been downloaded and run its installation? I have a code:

public void downloadUpdate(String url){

    DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
    request.setDescription("Downloading...");
    request.setTitle("App Update");
    request.allowScanningByMediaScanner();
    request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);

    String name = URLUtil.guessFileName(url, null, MimeTypeMap.getFileExtensionFromUrl(url));

    request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, name);

    DownloadManager manager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
    manager.enqueue(request);
}

推荐答案

要检查下载管理器是否下载了文件，您必须实现您的 BroatcastReceiver.

To check whether the download manager downloaded the file, you must implements your BroatcastReceiver.

@Override
public void onReceive(Context context, Intent intent) {
    String action = intent.getAction();
    if (action.equals(DownloadManager.ACTION_DOWNLOAD_COMPLETE)) {
        DownloadManager.Query query = new DownloadManager.Query();
        query.setFilterById(intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, 0));
        DownloadManager manager = (DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE);
        Cursor cursor = manager.query(query);
        if (cursor.moveToFirst()) {
            if (cursor.getCount() > 0) {
                int status = cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_STATUS));
                if (status == DownloadManager.STATUS_SUCCESSFUL) {
                    String file = cursor.getString(cursor.getColumnIndex(DownloadManager.COLUMN_LOCAL_FILENAME));
                    // So something here on success
                } else {
                    int message = cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_REASON));
                    // So something here on failed.
                }
            }
        }
    }
}

但是，我不确定您是否可以通过编程方式安装 APK.出于安全原因，我认为你不能.对于应用程序更新，我认为您应该使用 google 版本控制.当您使用不同的版本号重新部署您的应用程序时，用户应该能够自动更新(除非用户在 google play 上关闭).希望这会有所帮助.

However, I am not sure whether you can install the APK programmatically. For security reason, I don't think you can. For application update, I think you should use google versioning control. When you re-deploy your app using different version number, the users should able to update automatically (unless user turn off at google play). Hope that this will help.

更新

你不需要调用我提到的方法.您只需要在清单 xml 文件中声明广播接收器，下载完成后 DownloadManager 将调用 at.xml 如下所示:

You do not need to call the method that I mention. You just need to declare your broadcast receiver at your manifest xml file and DownloadManager will call at when download complete. The xml look something like below:

    <receiver
        android:name=".BroadcastReceiver"
        android:enabled="true"
        android:exported="true" >
        <intent-filter>
            <action android:name="android.intent.action.DOWNLOAD_COMPLETE" />
            <action android:name="android.intent.action.DOWNLOAD_NOTIFICATION_CLICKED" />
        </intent-filter>
    </receiver>

这篇关于检查下载管理器是否下载了文件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！