如何启用 Android 下载管理器

Question

我正在使用 Android 下载管理器来下载文件列表。最近我看到一个崩溃报告说

Unknown java.lang.IllegalArgumentException: Unknown URL content://downloads/my_downloads

后来，我发现原因是因为用户禁用了 Android 下载管理器。我通过使用下面的代码检查它的包名称来检查下载管理器是否被禁用。

int state = this.getPackageManager().getApplicationEnabledSetting("com.android.providers.downloads");

现在，如果下载管理器被禁用，我需要找到一种方法来启用它。我尝试使用清单中的权限设置它的启用状态，但我不断收到安全异常。

this.getPackageManager().setApplicationEnabledSetting("com.android.providers.downloads", PackageManager.COMPONENT_ENABLED_STATE_DEFAULT, 0);

<uses-permission android:name="android.permission.CHANGE_COMPONENT_ENABLED_STATE"/>

所以我认为它可能无法访问，因为它是一个系统应用程序。 （Google Play 应用程序会这样做）。

有没有办法将用户重定向到下载管理器应用程序信息视图？让用户启用它？如果无法以编程方式在运行时启用它。

Answer 1

可能对你有帮助。

downloadManager = (DownloadManager)getSystemService(DOWNLOAD_SERVICE);
   DownloadManager.Request request = new DownloadManager.Request(Download_Uri);
   //Restrict the types of networks over which this download may proceed.
   request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI | DownloadManager.Request.NETWORK_MOBILE);
   //Set whether this download may proceed over a roaming connection.
   request.setAllowedOverRoaming(false);
   //Set the title of this download, to be displayed in notifications (if enabled).
   request.setTitle("My Data Download");
   //Set a description of this download, to be displayed in notifications (if enabled)
   request.setDescription("Android Data download using DownloadManager.");
   //Set the local destination for the downloaded file to a path within the application's external files directory
   request.setDestinationInExternalFilesDir(this,Environment.DIRECTORY_DOWNLOADS,"CountryList.json");

   //Enqueue a new download and same the referenceId
   downloadReference = downloadManager.enqueue(request);

http://www.mysamplecode.com/2012/09/android-downloadmanager-example.html

Answer 2

如果无效，请编辑我的答案

检查下载管理器是否可用：

   int state = this.getPackageManager().getApplicationEnabledSetting("com.android.providers.downloads");

if(state==PackageManager.COMPONENT_ENABLED_STATE_DISABLED||
state==PackageManager.COMPONENT_ENABLED_STATE_DISABLED_USER
||state==PackageManager.COMPONENT_ENABLED_STATE_DISABLED_UNTIL_USED){

// Cannot download using download manager
}

            else {
                request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, fileName);
                request.setDescription(fileName);   
                manager.enqueue(request); 
            }

尝试启用下载管理器的解决方案是：

packageName = "com.android.providers.downloads"

try {
    //Open the specific App Info page:
    Intent intent = new Intent(android.provider.Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
    intent.setData(Uri.parse("package:" + packageName));
    startActivity(intent);

} catch ( ActivityNotFoundException e ) {
    //e.printStackTrace();

    //Open the generic Apps page:
    Intent intent = new Intent(android.provider.Settings.ACTION_MANAGE_APPLICATIONS_SETTINGS);
    startActivity(intent);

}

Answer 3

有些人正在寻找这个问题的答案，而我刚刚意识到对这个问题的回答不知何故被删除了。所以我想回答我自己的问题。

无法直接激活/停用下载管理器，因为它是系统应用程序，我们无权访问它。

唯一的选择是将用户重定向到下载管理器应用程序的信息页面。

try {
     //Open the specific App Info page:
     Intent intent = new Intent(android.provider.Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
     intent.setData(Uri.parse("package:" + "com.android.providers.downloads"));
     startActivity(intent);

} catch ( ActivityNotFoundException e ) {
     e.printStackTrace();

     //Open the generic Apps page:
     Intent intent = new Intent(android.provider.Settings.ACTION_MANAGE_APPLICATIONS_SETTINGS);
     startActivity(intent);
}

Answer 4

Google Gmail Inbox 已经检查了 DownloadManager 是否被禁用，如果是，则显示一个 AlertDialog 告诉用户在设置中启用 DownloadManager。截图如下：

我写了一个名为DownloadManagerResolver 的类来解决这个问题，希望这可以帮助你。:)

public final class DownloadManagerResolver {

private static final String DOWNLOAD_MANAGER_PACKAGE_NAME = "com.android.providers.downloads";

/**
 * Resolve whether the DownloadManager is enable in current devices.
 *
 * @return true if DownloadManager is enable,false otherwise.
 */
public static boolean resolve(Context context) {
    boolean enable = resolveEnable(context);
    if (!enable) {
        AlertDialog alertDialog = createDialog(context);
        alertDialog.show();
    }
    return enable;
}

/**
 * Resolve whether the DownloadManager is enable in current devices.
 *
 * @param context
 * @return true if DownloadManager is enable,false otherwise.
 */
private static boolean resolveEnable(Context context) {
    int state = context.getPackageManager()
            .getApplicationEnabledSetting(DOWNLOAD_MANAGER_PACKAGE_NAME);

    if (Build.VERSION.SDK_INT > Build.VERSION_CODES.JELLY_BEAN_MR2) {
        return !(state == PackageManager.COMPONENT_ENABLED_STATE_DISABLED ||
                state == PackageManager.COMPONENT_ENABLED_STATE_DISABLED_USER
                || state == PackageManager.COMPONENT_ENABLED_STATE_DISABLED_UNTIL_USED);
    } else {
        return !(state == PackageManager.COMPONENT_ENABLED_STATE_DISABLED ||
                state == PackageManager.COMPONENT_ENABLED_STATE_DISABLED_USER);
    }
}

private static AlertDialog createDialog(final Context context) {
    AppCompatTextView messageTextView = new AppCompatTextView(context);
    messageTextView.setTextSize(16f);
    messageTextView.setText("DownloadManager is disabled. Please enable it.");
    return new AlertDialog.Builder(context)
            .setView(messageTextView, 50, 30, 50, 30)
            .setPositiveButton("ok", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    enableDownloadManager(context);
                }
            })
            .setCancelable(false)
            .create();
}

/**
 * Start activity to Settings to enable DownloadManager.
 */
private static void enableDownloadManager(Context context) {
    try {
        //Open the specific App Info page:
        Intent intent = new Intent(android.provider.Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
        intent.setData(Uri.parse("package:" + DOWNLOAD_MANAGER_PACKAGE_NAME));
        context.startActivity(intent);
    } catch (ActivityNotFoundException e) {
        e.printStackTrace();

        //Open the generic Apps page:
        Intent intent = new Intent(android.provider.Settings.ACTION_MANAGE_APPLICATIONS_SETTINGS);
        context.startActivity(intent);
    }
}
}