我遇到通过 DownloadManager API 成功下载后打开下载文件的问题。在我的代码中：
Uri uri=Uri.parse("http://www.nasa.gov/images/content/206402main_jsc2007e113280_hires.jpg");
Environment
.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS)
.mkdirs();
lastDownload = mgr.enqueue(new DownloadManager.Request(uri)
.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI |
DownloadManager.Request.NETWORK_MOBILE)
.setAllowedOverRoaming(false)
.setTitle("app update")
.setDescription("New version 1.1")
.setShowRunningNotification(true)
.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, "a.apk"));
Cursor c=mgr.query(new DownloadManager.Query().setFilterById(lastDownload));
if(c.getInt(c.getColumnIndex(DownloadManager.COLUMN_STATUS)) == 8) {
try {
mgr.openDownloadedFile(c.getLong(c.getColumnIndex(DownloadManager.COLUMN_ID)));
} catch (NumberFormatException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.d("MGR", "Error");
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.d("MGR", "Error");
}
}
问题是
if(c.getInt(c.getColumnIndex(DownloadManager.COLUMN_STATUS))==8)DownloadManager APIAPK编辑：我发现status = 8是在成功下载之后。您可能有不同的“检查成功下载”方法
谢谢
问题
Android DownloadManager API - 下载后打开文件？
解决方案
/**
* Used to download the file from url.
* <p/>
* 1. Download the file using Download Manager.
*
* @param url Url.
* @param fileName File Name.
*/
public void downloadFile(final Activity activity, final String url, final String fileName) {
try {
if (url != null && !url.isEmpty()) {
Uri uri = Uri.parse(url);
activity.registerReceiver(attachmentDownloadCompleteReceive, new IntentFilter(
DownloadManager.ACTION_DOWNLOAD_COMPLETE));
DownloadManager.Request request = new DownloadManager.Request(uri);
request.setMimeType(getMimeType(uri.toString()));
request.setTitle(fileName);
request.setDescription("Downloading attachment..");
request.allowScanningByMediaScanner();
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, fileName);
DownloadManager dm = (DownloadManager) activity.getSystemService(Context.DOWNLOAD_SERVICE);
dm.enqueue(request);
}
} catch (IllegalStateException e) {
Toast.makeText(activity, "Please insert an SD card to download file", Toast.LENGTH_SHORT).show();
}
}
/**
* Used to get MimeType from url.
*
* @param url Url.
* @return Mime Type for the given url.
*/
private String getMimeType(String url) {
String type = null;
String extension = MimeTypeMap.getFileExtensionFromUrl(url);
if (extension != null) {
MimeTypeMap mime = MimeTypeMap.getSingleton();
type = mime.getMimeTypeFromExtension(extension);
}
return type;
}
/**
* Attachment download complete receiver.
* <p/>
* 1. Receiver gets called once attachment download completed.
* 2. Open the downloaded file.
*/
BroadcastReceiver attachmentDownloadCompleteReceive = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (DownloadManager.ACTION_DOWNLOAD_COMPLETE.equals(action)) {
long downloadId = intent.getLongExtra(
DownloadManager.EXTRA_DOWNLOAD_ID, 0);
openDownloadedAttachment(context, downloadId);
}
}
};
/**
* Used to open the downloaded attachment.
*
* @param context Content.
* @param downloadId Id of the downloaded file to open.
*/
private void openDownloadedAttachment(final Context context, final long downloadId) {
DownloadManager downloadManager = (DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE);
DownloadManager.Query query = new DownloadManager.Query();
query.setFilterById(downloadId);
Cursor cursor = downloadManager.query(query);
if (cursor.moveToFirst()) {
int downloadStatus = cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_STATUS));
String downloadLocalUri = cursor.getString(cursor.getColumnIndex(DownloadManager.COLUMN_LOCAL_URI));
String downloadMimeType = cursor.getString(cursor.getColumnIndex(DownloadManager.COLUMN_MEDIA_TYPE));
if ((downloadStatus == DownloadManager.STATUS_SUCCESSFUL) && downloadLocalUri != null) {
openDownloadedAttachment(context, Uri.parse(downloadLocalUri), downloadMimeType);
}
}
cursor.close();
}
/**
* Used to open the downloaded attachment.
* <p/>
* 1. Fire intent to open download file using external application.
*
* 2. Note:
* 2.a. We can't share fileUri directly to other application (because we will get FileUriExposedException from Android7.0).
* 2.b. Hence we can only share content uri with other application.
* 2.c. We must have declared FileProvider in manifest.
* 2.c. Refer - https://developer.android.com/reference/android/support/v4/content/FileProvider.html
*
* @param context Context.
* @param attachmentUri Uri of the downloaded attachment to be opened.
* @param attachmentMimeType MimeType of the downloaded attachment.
*/
private void openDownloadedAttachment(final Context context, Uri attachmentUri, final String attachmentMimeType) {
if(attachmentUri!=null) {
// Get Content Uri.
if (ContentResolver.SCHEME_FILE.equals(attachmentUri.getScheme())) {
// FileUri - Convert it to contentUri.
File file = new File(attachmentUri.getPath());
attachmentUri = FileProvider.getUriForFile(activity, "com.freshdesk.helpdesk.provider", file);;
}
Intent openAttachmentIntent = new Intent(Intent.ACTION_VIEW);
openAttachmentIntent.setDataAndType(attachmentUri, attachmentMimeType);
openAttachmentIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
try {
context.startActivity(openAttachmentIntent);
} catch (ActivityNotFoundException e) {
Toast.makeText(context, context.getString(R.string.unable_to_open_file), Toast.LENGTH_LONG).show();
}
}
}
初始化 FileProvider 详细信息
在AndroidManifest中声明FileProvider
<provider
android:name="android.support.v4.content.FileProvider"
android:authorities="com.freshdesk.helpdesk.provider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/file_path"/>
</provider>
添加以下文件“res -> xml -> file_path.xml”
<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
<external-path name="attachment_file" path="."/>
</paths>
注意
为什么使用FileProvider
使用“DownloadManager.getUriForDownloadedFile(long id)”的问题
参考
下载完成后您需要注册一个接收器：
registerReceiver(onComplete, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));
和 BroadcastReciever 处理程序
BroadcastReceiver onComplete=new BroadcastReceiver() {
public void onReceive(Context ctxt, Intent intent) {
// Do Something
}
};
购买而不是我抄袭一切，我建议你检查一下这个。
编辑：
作为一个建议，我暂时不建议使用 API 9：
http://developer.android.com/resources/dashboard/platform-versions.html有很多方法可以解决这个问题，通过创建你自己的下载处理程序，就像我所做的那样，因为我们不想疏远我们的大多数 Android 用户群，为此你需要： 创建处理文件下载的AsyncTask。
我会建议创建某种下载对话框（如果你说这是一个大文件，我会让它出现在通知区域中）。
然后您需要处理文件的打开：
protected void openFile(String fileName) {
Intent install = new Intent(Intent.ACTION_VIEW);
install.setDataAndType(Uri.fromFile(new File(fileName)),
"MIME-TYPE");
startActivity(install);
}
对我来说，帮助添加了
Intent.FLAG_GRANT_READ_URI_PERMISSION对于 Kotlin，您可以轻松地使用
URL.openStream()如果你想做更多更奇特的事情，比如后台线程。 你应该看看 Eye 在 Medium 上的文章。
private fun downloadVcfFile() {
CoroutineScope(Dispatchers.IO).launch {
val url = "https://srv-store5.gofile.io/download/JXLVFW/vcard.vcf"
val path = "${Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS)}/contacts.vcf"
URL(url).openStream().use { input ->
FileOutputStream(File(path)).use { output ->
input.copyTo(output)
val file = File(path)
file.createNewFile()
onMain { saveVcfFile(file) }
}
}
}
}
记住将
<uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES" />