Android Q (10) 使用 DownloadManager 和 FileProvider 下载后打开 PDF
Open PDF after download with DownloadManager and FileProvider on Android Q (10)
targetSdkVersion: 30
在我们的应用程序中,我们有一个功能,我们将文件(主要是 pdf)下载到 public 下载文件夹,然后启动一个 intent 来打开它。我们的代码适用于 api >= 28 和 >= 30 的 android 应用程序。只有我们在 Android 10(sdkVersion 29)上的应用程序将尝试打开文档并立即关闭 activity 试图显示 pdf。 logcat 显示以下错误:
22-03-17 14:23:42.486 12161-15168/? E/DisplayData: openFd: java.io.FileNotFoundException: open failed: EACCES (Permission denied)
22-03-17 14:23:42.486 12161-15168/? E/PdfLoader: Can't load file (doesn't open) Display Data [PDF : download.pdf] +ContentOpenable, uri: content://com.example.fileprovider/Download/download.pdf
如果我在应用程序设置中授予文件权限,它将完美运行,但如果我正确理解 android 文档,这应该没有必要,因为 Android 10。特别是因为没有Android 11 和 Android 12 台设备上没有此权限的问题。在所有 Android 版本中,文件将被正确下载,用户可以从其设备的下载部分手动打开它。
这是文件提供者的Android清单部分
<provider
android:name="androidx.core.content.FileProvider"
android:authorities="${applicationId}.fileprovider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/filepaths" />
</provider>
文件路径 XML 文件
<?xml version="1.0" encoding="utf-8"?>
<paths>
<external-files-path
name="external_files"
path="." />
<external-path
name="Download"
path="Download/"/>
<files-path
name="files"
path="." />
<external-cache-path
name="external_cache"
path="." />
</paths>
这是使用 DownloadManager 下载文件的代码
public static long downloadFile(Context context, String url, String fileName) {
DownloadManager downloadManager = (DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE);
try {
DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
request.setTitle(fileName)
.setDescription(Localization.getStringClient("file_download_progress"))
.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, fileName)
.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
return downloadManager.enqueue(request);
} catch (Exception e) {
e.printStackTrace();
Toast.makeText(context, Localization.getStringClient("error_downloading_asset"), Toast.LENGTH_SHORT).show();
}
return -1;
}
监听下载进度的广播接收器
public class DownloadBroadcastReceiver extends BroadcastReceiver {
private long downloadId = -2;
public void setDownloadId(long downloadId) {
this.downloadId = downloadId;
}
@Override
public void onReceive(Context context, Intent intent) {
long id = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1);
if (id == downloadId) {
DownloadManager downloadManager = (DownloadManager) context.getSystemService(DOWNLOAD_SERVICE);
DownloadManager.Query query = new DownloadManager.Query();
query.setFilterById(id);
Cursor c = downloadManager.query(query);
if (c != null) {
c.moveToFirst();
int columnIndex = c.getColumnIndex(DownloadManager.COLUMN_STATUS);
if (DownloadManager.STATUS_SUCCESSFUL == c.getInt(columnIndex)) {
String uriString = c.getString(c.getColumnIndex(DownloadManager.COLUMN_LOCAL_URI));
String mediaType = c.getString(c.getColumnIndex(DownloadManager.COLUMN_MEDIA_TYPE));
Uri fileUri = Uri.parse(uriString);
DownloadUtils.openFile(context, fileUri, mediaType);
} else if (DownloadManager.STATUS_FAILED == c.getInt(columnIndex)) {
Toast.makeText(context, Localization.getStringClient("error_downloading_asset"), Toast.LENGTH_SHORT).show();
}
c.close();
}
}
}
}
打开文件的代码。仅在 Android 10 时,应用程序再次立即关闭 activity。
public static void openFile(Context context, Uri fileUri, String mediaType) {
File file = new File(fileUri.getPath());
Uri uri = FileProvider.getUriForFile(
context,
context.getApplicationContext().getPackageName() + ".fileprovider",
file
);
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(uri, mediaType);
intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
try {
context.startActivity(intent);
} catch (ActivityNotFoundException e) {
e.printStackTrace();
Toast.makeText(context, Localization.getStringClient("open_file_no_activity"), Toast.LENGTH_SHORT).show();
}
}
下载调用看起来像这样
@Override
public void startPDFDownload(String pdfDownloadUrl, String fileName) {
long downloadId = DownloadUtils.downloadFile(requireContext(), pdfDownloadUrl, fileName);
if (downloadId > -1) {
DownloadBroadcastReceiver receiver = new DownloadBroadcastReceiver();
receiver.setDownloadId(downloadId);
requireContext().registerReceiver(receiver, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));
}
}
我想我对 Android10 中文件处理的工作方式有错误的理解,但我不知道我必须在哪里调整代码或配置。非常感谢您的帮助。目前,作为一种解决方法,我们要求 WRITE_EXTERNAL_STORAGE 获得在 Android 10 上打开下载文件的权限。但我更愿意以正确的方式进行操作。
解法:
我将BroadcastReceiver调整为如下代码。我从光标中删除了 LOCAL_URI 并使用了 DownloadManager 方法中的 URI。
public class DownloadBroadcastReceiver extends BroadcastReceiver {
private long downloadId = -2;
public void setDownloadId(long downloadId) {
this.downloadId = downloadId;
}
@Override
public void onReceive(Context context, Intent intent) {
long id = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1);
if (id == downloadId) {
DownloadManager downloadManager = (DownloadManager) context.getSystemService(DOWNLOAD_SERVICE);
DownloadManager.Query query = new DownloadManager.Query();
query.setFilterById(id);
Cursor c = downloadManager.query(query);
if (c != null) {
c.moveToFirst();
int columnIndex = c.getColumnIndex(DownloadManager.COLUMN_STATUS);
if (DownloadManager.STATUS_SUCCESSFUL == c.getInt(columnIndex)) {
String mediaType = c.getString(c.getColumnIndex(DownloadManager.COLUMN_MEDIA_TYPE));
DownloadUtils.openFile(context, downloadManager.getUriForDownloadedFile(id), mediaType);
} else if (DownloadManager.STATUS_FAILED == c.getInt(columnIndex)) {
Toast.makeText(context, Localization.getStringClient("error_downloading_asset"), Toast.LENGTH_SHORT).show();
}
c.close();
}
}
}
}
并且我将使用uri打开文件的方法调整为以下代码。我删除了 FileProvider 代码并使用了 DownloadManager 中的 uri。
public static void openFile(Context context, Uri fileUri, String mediaType) {
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(fileUri, mediaType);
intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
try {
context.startActivity(intent);
} catch (ActivityNotFoundException e) {
e.printStackTrace();
Toast.makeText(context, Localization.getStringClient("open_file_no_activity"), Toast.LENGTH_SHORT).show();
}
}
其他方法代码不变
您不应使用 FileProvider 获取文件的 uri。
您可以从 DownloadManager 获取 uri 并使用它来提供您的文件。
所有 Android 版本的代码都相同。
不需要任何权限。
targetSdkVersion: 30
在我们的应用程序中,我们有一个功能,我们将文件(主要是 pdf)下载到 public 下载文件夹,然后启动一个 intent 来打开它。我们的代码适用于 api >= 28 和 >= 30 的 android 应用程序。只有我们在 Android 10(sdkVersion 29)上的应用程序将尝试打开文档并立即关闭 activity 试图显示 pdf。 logcat 显示以下错误:
22-03-17 14:23:42.486 12161-15168/? E/DisplayData: openFd: java.io.FileNotFoundException: open failed: EACCES (Permission denied)
22-03-17 14:23:42.486 12161-15168/? E/PdfLoader: Can't load file (doesn't open) Display Data [PDF : download.pdf] +ContentOpenable, uri: content://com.example.fileprovider/Download/download.pdf
如果我在应用程序设置中授予文件权限,它将完美运行,但如果我正确理解 android 文档,这应该没有必要,因为 Android 10。特别是因为没有Android 11 和 Android 12 台设备上没有此权限的问题。在所有 Android 版本中,文件将被正确下载,用户可以从其设备的下载部分手动打开它。
这是文件提供者的Android清单部分
<provider
android:name="androidx.core.content.FileProvider"
android:authorities="${applicationId}.fileprovider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/filepaths" />
</provider>
文件路径 XML 文件
<?xml version="1.0" encoding="utf-8"?>
<paths>
<external-files-path
name="external_files"
path="." />
<external-path
name="Download"
path="Download/"/>
<files-path
name="files"
path="." />
<external-cache-path
name="external_cache"
path="." />
</paths>
这是使用 DownloadManager 下载文件的代码
public static long downloadFile(Context context, String url, String fileName) {
DownloadManager downloadManager = (DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE);
try {
DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
request.setTitle(fileName)
.setDescription(Localization.getStringClient("file_download_progress"))
.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, fileName)
.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
return downloadManager.enqueue(request);
} catch (Exception e) {
e.printStackTrace();
Toast.makeText(context, Localization.getStringClient("error_downloading_asset"), Toast.LENGTH_SHORT).show();
}
return -1;
}
监听下载进度的广播接收器
public class DownloadBroadcastReceiver extends BroadcastReceiver {
private long downloadId = -2;
public void setDownloadId(long downloadId) {
this.downloadId = downloadId;
}
@Override
public void onReceive(Context context, Intent intent) {
long id = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1);
if (id == downloadId) {
DownloadManager downloadManager = (DownloadManager) context.getSystemService(DOWNLOAD_SERVICE);
DownloadManager.Query query = new DownloadManager.Query();
query.setFilterById(id);
Cursor c = downloadManager.query(query);
if (c != null) {
c.moveToFirst();
int columnIndex = c.getColumnIndex(DownloadManager.COLUMN_STATUS);
if (DownloadManager.STATUS_SUCCESSFUL == c.getInt(columnIndex)) {
String uriString = c.getString(c.getColumnIndex(DownloadManager.COLUMN_LOCAL_URI));
String mediaType = c.getString(c.getColumnIndex(DownloadManager.COLUMN_MEDIA_TYPE));
Uri fileUri = Uri.parse(uriString);
DownloadUtils.openFile(context, fileUri, mediaType);
} else if (DownloadManager.STATUS_FAILED == c.getInt(columnIndex)) {
Toast.makeText(context, Localization.getStringClient("error_downloading_asset"), Toast.LENGTH_SHORT).show();
}
c.close();
}
}
}
}
打开文件的代码。仅在 Android 10 时,应用程序再次立即关闭 activity。
public static void openFile(Context context, Uri fileUri, String mediaType) {
File file = new File(fileUri.getPath());
Uri uri = FileProvider.getUriForFile(
context,
context.getApplicationContext().getPackageName() + ".fileprovider",
file
);
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(uri, mediaType);
intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
try {
context.startActivity(intent);
} catch (ActivityNotFoundException e) {
e.printStackTrace();
Toast.makeText(context, Localization.getStringClient("open_file_no_activity"), Toast.LENGTH_SHORT).show();
}
}
下载调用看起来像这样
@Override
public void startPDFDownload(String pdfDownloadUrl, String fileName) {
long downloadId = DownloadUtils.downloadFile(requireContext(), pdfDownloadUrl, fileName);
if (downloadId > -1) {
DownloadBroadcastReceiver receiver = new DownloadBroadcastReceiver();
receiver.setDownloadId(downloadId);
requireContext().registerReceiver(receiver, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));
}
}
我想我对 Android10 中文件处理的工作方式有错误的理解,但我不知道我必须在哪里调整代码或配置。非常感谢您的帮助。目前,作为一种解决方法,我们要求 WRITE_EXTERNAL_STORAGE 获得在 Android 10 上打开下载文件的权限。但我更愿意以正确的方式进行操作。
解法:
我将BroadcastReceiver调整为如下代码。我从光标中删除了 LOCAL_URI 并使用了 DownloadManager 方法中的 URI。
public class DownloadBroadcastReceiver extends BroadcastReceiver {
private long downloadId = -2;
public void setDownloadId(long downloadId) {
this.downloadId = downloadId;
}
@Override
public void onReceive(Context context, Intent intent) {
long id = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1);
if (id == downloadId) {
DownloadManager downloadManager = (DownloadManager) context.getSystemService(DOWNLOAD_SERVICE);
DownloadManager.Query query = new DownloadManager.Query();
query.setFilterById(id);
Cursor c = downloadManager.query(query);
if (c != null) {
c.moveToFirst();
int columnIndex = c.getColumnIndex(DownloadManager.COLUMN_STATUS);
if (DownloadManager.STATUS_SUCCESSFUL == c.getInt(columnIndex)) {
String mediaType = c.getString(c.getColumnIndex(DownloadManager.COLUMN_MEDIA_TYPE));
DownloadUtils.openFile(context, downloadManager.getUriForDownloadedFile(id), mediaType);
} else if (DownloadManager.STATUS_FAILED == c.getInt(columnIndex)) {
Toast.makeText(context, Localization.getStringClient("error_downloading_asset"), Toast.LENGTH_SHORT).show();
}
c.close();
}
}
}
}
并且我将使用uri打开文件的方法调整为以下代码。我删除了 FileProvider 代码并使用了 DownloadManager 中的 uri。
public static void openFile(Context context, Uri fileUri, String mediaType) {
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(fileUri, mediaType);
intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
try {
context.startActivity(intent);
} catch (ActivityNotFoundException e) {
e.printStackTrace();
Toast.makeText(context, Localization.getStringClient("open_file_no_activity"), Toast.LENGTH_SHORT).show();
}
}
其他方法代码不变
您不应使用 FileProvider 获取文件的 uri。
您可以从 DownloadManager 获取 uri 并使用它来提供您的文件。
所有 Android 版本的代码都相同。
不需要任何权限。