如何在API 29或Android Q中使用DownloadManager下载文件? [英] How to Download File Using DownloadManager in API 29 or Android Q?
本文介绍了如何在API 29或Android Q中使用DownloadManager下载文件?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
由于我是Android开发的新手，因此我正在尝试使用DownloadManager简化App.
As I am new in Android Development, I am trying to simple App using DownloadManager.
这是代码
public class MainActivity extends AppCompatActivity implements ActivityCompat.OnRequestPermissionsResultCallback{
Button btn;
private long referenceID;
private DownloadManager downloadManager;
private static final int PERMISSION_REQUEST_CODE = 1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn = findViewById(R.id.btn);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M){
if (checkPermission())
{
/*** If Storage Permission Is Given, Check External storage is available for read and write***/
Uri image_uri = Uri.parse("https://unifiedclothes.com/Unifiedclothes/App_Gallery/thumb_8_121432471036-1432471036-SC-505.jpg");
referenceID = DownloadImage(image_uri);
} else {
requestPermission();
}
}
else{
Toast.makeText(MainActivity.this,"Permission Is Granted..",Toast.LENGTH_SHORT).show();
}
}
});
registerReceiver(receiver,new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));
}
private BroadcastReceiver receiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (DownloadManager.ACTION_DOWNLOAD_COMPLETE.equals(action)){
DownloadManager.Query ImageDownloadQuery = new DownloadManager.Query();
//set the query filter to our previously Enqueued download
ImageDownloadQuery.setFilterById(referenceID);
//Query the download manager about downloads that have been requested.
Cursor cursor = downloadManager.query(ImageDownloadQuery);
if(cursor.moveToFirst()){
Toast.makeText(MainActivity.this,DownloadStatus(cursor),Toast.LENGTH_SHORT).show();
}
}
}
};
private String DownloadStatus(Cursor cursor){
//column for download status
int columnIndex = cursor.getColumnIndex(DownloadManager.COLUMN_STATUS);
int status = cursor.getInt(columnIndex);
//column for reason code if the download failed or paused
int columnReason = cursor.getColumnIndex(DownloadManager.COLUMN_REASON);
int reason = cursor.getInt(columnReason);
String statusText = "";
String reasonText = "";
switch(status){
case DownloadManager.STATUS_FAILED:
statusText = "STATUS_FAILED";
switch(reason){
case DownloadManager.ERROR_CANNOT_RESUME:
reasonText = "ERROR_CANNOT_RESUME";
break;
case DownloadManager.ERROR_DEVICE_NOT_FOUND:
reasonText = "ERROR_DEVICE_NOT_FOUND";
break;
case DownloadManager.ERROR_FILE_ALREADY_EXISTS:
reasonText = "ERROR_FILE_ALREADY_EXISTS";
break;
case DownloadManager.ERROR_FILE_ERROR:
reasonText = "ERROR_FILE_ERROR";
break;
case DownloadManager.ERROR_HTTP_DATA_ERROR:
reasonText = "ERROR_HTTP_DATA_ERROR";
break;
case DownloadManager.ERROR_INSUFFICIENT_SPACE:
reasonText = "ERROR_INSUFFICIENT_SPACE";
break;
case DownloadManager.ERROR_TOO_MANY_REDIRECTS:
reasonText = "ERROR_TOO_MANY_REDIRECTS";
break;
case DownloadManager.ERROR_UNHANDLED_HTTP_CODE:
reasonText = "ERROR_UNHANDLED_HTTP_CODE";
break;
case DownloadManager.ERROR_UNKNOWN:
reasonText = "ERROR_UNKNOWN";
break;
}
break;
case DownloadManager.STATUS_PAUSED:
statusText = "STATUS_PAUSED";
switch(reason){
case DownloadManager.PAUSED_QUEUED_FOR_WIFI:
reasonText = "PAUSED_QUEUED_FOR_WIFI";
break;
case DownloadManager.PAUSED_UNKNOWN:
reasonText = "PAUSED_UNKNOWN";
break;
case DownloadManager.PAUSED_WAITING_FOR_NETWORK:
reasonText = "PAUSED_WAITING_FOR_NETWORK";
break;
case DownloadManager.PAUSED_WAITING_TO_RETRY:
reasonText = "PAUSED_WAITING_TO_RETRY";
break;
}
break;
case DownloadManager.STATUS_PENDING:
statusText = "STATUS_PENDING";
break;
case DownloadManager.STATUS_SUCCESSFUL:
statusText = "Image Saved Successfully";
//reasonText = "Filename:\n" + filename;
Toast.makeText(MainActivity.this, "Download Status:" + "\n" + statusText + "\n" + reasonText, Toast.LENGTH_SHORT).show();
break;
}
return statusText + reasonText;
}
private long DownloadImage(Uri uri){
long downloadReference;
downloadManager = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
DownloadManager.Request request = new DownloadManager.Request(uri);
//Setting title of request
request.setTitle("Image Download");
//Setting description of request
request.setDescription("Image download using DownloadManager.");
request.setDestinationInExternalPublicDir(getExternalFilesDir(Environment.DIRECTORY_PICTURES) + "/NewFile","sample2.jpg");
//request.allowScanningByMediaScanner();
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
downloadReference = downloadManager.enqueue(request);
return downloadReference;
}
private boolean checkPermission() {
int result = ContextCompat.checkSelfPermission(MainActivity.this, android.Manifest.permission.WRITE_EXTERNAL_STORAGE);
if (result == PackageManager.PERMISSION_GRANTED) {
return true;
} else {
return false;
}
}
private void requestPermission() {
ActivityCompat.requestPermissions(MainActivity.this, new String[]{android.Manifest.permission.WRITE_EXTERNAL_STORAGE}, PERMISSION_REQUEST_CODE);
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == PERMISSION_REQUEST_CODE) {
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
Uri image_uri = Uri.parse("https://www.dccomics.com/sites/default/files/Char_GetToKnow_Batman80_5ca54cb83a27a6.53173051.png");
referenceID = DownloadImage(image_uri);
}
else {
Toast.makeText(MainActivity.this, "Permission Denied... \n You Should Allow External Storage Permission To Download Images.", Toast.LENGTH_LONG).show();
}
}
}
}
当我在低于API 29的任何设备上运行它时，它运行良好(我的测试设备是Nexus 5X，ApI 28仿真器).但是，当我在Nexus 5X上运行它时，API 29该应用程序崩溃了.这是日志:
It works well when i run it on any device below API 29(My testing device was Nexus 5X ,ApI 28 emulator). But when I run it on Nexus 5X ,API 29 The app gets crashed. Here is the Logs:
2019-09-24 20:51:46.354 11322-11344/? E/DatabaseUtils: Writing exception to parcel
java.lang.IllegalStateException: Not one of standard directories: /storage/emulated/0/Android/data/com.blz.prisoner.downloadmanager/files/Pictures/NewFile
at com.android.providers.downloads.DownloadProvider.call(DownloadProvider.java:651)
at android.content.ContentProvider.call(ContentProvider.java:2152)
at android.content.ContentProvider$Transport.call(ContentProvider.java:477)
at android.content.ContentProviderNative.onTransact(ContentProviderNative.java:277)
at android.os.Binder.execTransactInternal(Binder.java:1021)
at android.os.Binder.execTransact(Binder.java:994)
2019-09-24 20:51:46.355 15023-15023/com.blz.prisoner.downloadmanager D/AndroidRuntime:关闭VM
2019-09-24 20:51:46.355 15023-15023/com.blz.prisoner.downloadmanager D/AndroidRuntime: Shutting down VM
--------- beginning of crash
2019-09-24 20:51:46.360 15023-15023/com.blz.prisoner.downloadmanager E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.blz.prisoner.downloadmanager, PID: 15023
java.lang.IllegalStateException: Not one of standard directories: /storage/emulated/0/Android/data/com.blz.prisoner.downloadmanager/files/Pictures/NewFile
at android.os.Parcel.createException(Parcel.java:2079)
at android.os.Parcel.readException(Parcel.java:2039)
at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:188)
at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:140)
at android.content.ContentProviderProxy.call(ContentProviderNative.java:658)
at android.content.ContentProviderClient.call(ContentProviderClient.java:558)
at android.content.ContentProviderClient.call(ContentProviderClient.java:546)
at android.app.DownloadManager$Request.setDestinationInExternalPublicDir(DownloadManager.java:567)
at com.blz.prisoner.downloadmanager.MainActivity.DownloadImage(MainActivity.java:206)
at com.blz.prisoner.downloadmanager.MainActivity.access$200(MainActivity.java:29)
at com.blz.prisoner.downloadmanager.MainActivity$1.onClick(MainActivity.java:60)
at android.view.View.performClick(View.java:7140)
at android.view.View.performClickInternal(View.java:7117)
at android.view.View.access$3500(View.java:801)
at android.view.View$PerformClick.run(View.java:27351)
at android.os.Handler.handleCallback(Handler.java:883)
at android.os.Handler.dispatchMessage(Handler.java:100)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7356)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
我认为问题出在 DownloadImage(Uri uri)中的" request.setDestinationInExternalPublicDir(getExternalFilesDir(Environment.DIRECTORY_PICTURES)+"/NewFile"，"sample2.jpg"); ")功能.如何解决问题?
I think the problem is on line " request.setDestinationInExternalPublicDir(getExternalFilesDir(Environment.DIRECTORY_PICTURES) + "/NewFile","sample2.jpg");" in DownloadImage(Uri uri) function. How to solve the problem??
另一个问题是，当我在低于API 29的设备上运行该应用程序时，它运行良好，但是当我在完成下载后单击通知时，它无法打开图库中/保存在其上的图像.
Another Problem is when I run the app on the device below API 29 it runs well but when I click on notification after completing the download it doesn't open the image on gallery/on the folder it was saved.
推荐答案
我只是使用以下方法解决了:
I solved just by using:
setDestinationInExternalFilesDir(context, relativePath, filename);
代替:
setDestinationInExternalPublicDir(relativePath, filename);
我的相对路径是:
Environment.getExternalStorageDirectory().getPath() + "MyExternalStorageAppPath"
我的清单中也有
android:requestLegacyExternalStorage="true"
要使用旧版存储管理(共享存储)，而不是Android 10及更高版本中使用的新存储管理(范围存储).
To use Legacy storage management (Shared Storage) instead of new storage management (Scoped Storage) used from Android 10 and above.
请记住，通过使用"setDestinationInExternalFilesDir"文件将下载到专用于您的应用的外部存储器中，因此:"external/Android/data/your_app_name/path_you_used_on_function".如果要将其下载到其他位置，则需要在使用Input&输出流.要使用Android 10或更高版本的另一个应用打开文件，您必须使用FileProvider.
Remember that by using "setDestinationInExternalFilesDir" files will be download to the external memory dedicated to your app, so: "external/Android/data/your_app_name/path_you_used_on_function". If you want to download it to another place you need to move It after you downloaded It by using Input & Output streams. To open the file with another app in Android version 10 or above you must use FileProvider.
如果有人需要，这是移动代码(移动而不是复制.因此原始文件将被删除.如果要复制文件而不删除文件，则删除"source.delete();").源文件)从一个位置到另一个位置的文件:
If someone need it, this is the code to move (move, not copy. So the original file will be deleted. Remove "source.delete();" if you want to copy the file and not delete the source file) a file from one location to another:
public static boolean moveFile(File source, String destPath){
if(source.exists()){
File dest = new File(destPath);
checkMakeDirs(dest.getParent());
try (FileInputStream fis = new FileInputStream(source);
FileOutputStream fos = new FileOutputStream(dest)){
if(!dest.exists()){
dest.createNewFile();
}
writeToOutputStream(fis, fos);
source.delete();
return true;
} catch (IOException ioE){
Log.e(TAG, ioE.getMessage());
}
}
return false;
}
private static void writeToOutputStream(InputStream is, OutputStream os) throws IOException {
byte[] buffer = new byte[1024];
int length;
if (is != null) {
while ((length = is.read(buffer)) > 0x0) {
os.write(buffer, 0x0, length);
}
}
os.flush();
}
用法(源"是您需要移动的文件，路径"是目标):
Usage ("source" is the File you need to move, "path" is the destination):
if(FilesUtils.moveFile(source, path)) {
// Success Moving File, do what you need with it
}
DownloadManager完成时的广播接收器:
private static class DownloadFileReceiver extends BroadcastReceiver {
private DownloadManager mDownloadManager;
private String mPath;
private DownloadFileReceiver(DownloadManager dManager, String path){
mDownloadManager = dManager;
mPath = path;
}
/** Override BroadcastReceiver Methods **/
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (DownloadManager.ACTION_DOWNLOAD_COMPLETE.equals(action)) {
Bundle extras = intent.getExtras();
DownloadManager.Query q = new DownloadManager.Query();
q.setFilterById(extras.getLong(DownloadManager.EXTRA_DOWNLOAD_ID));
Cursor c = mDownloadManager.query(q);
if (c.moveToFirst()) {
int status = c.getInt(c.getColumnIndex(DownloadManager.COLUMN_STATUS));
if (status == DownloadManager.STATUS_SUCCESSFUL) {
String fullPath = null; File source = null;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
fullPath = c.getString(c.getColumnIndex(DownloadManager.COLUMN_LOCAL_URI));
source = new File(Uri.parse(fullPath).getPath());
} else {
fullPath = c.getString(c.getColumnIndex(DownloadManager.COLUMN_LOCAL_FILENAME));
source = new File(fullPath);
}
}
}
c.close();
}
Objects.requireNonNull(context).unregisterReceiver(this);
}
}
将其注册到DownloadManager实例:
context.registerReceiver(new DownloadFileReceiver(downloadManager, path),
new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));
checkMakeDirs(检查目录是否存在或是否可以成功创建目录)和makeDirs(仅在不进行检查的情况下进行创建)代码:
public static boolean checkMakeDirs(String dirPath){
try {
File dir = new File(dirPath);
return dir.exists() || dir.mkdirs();
} catch (Exception e) {
Log.e(TAG, e.getMessage());
}
return false;
}
public static void makeDirs(String dirPath){
try {
File dir = new File(dirPath);
if(!dir.exists()){
dir.mkdirs();
}
} catch (Exception e){
Log.e(TAG, e.getMessage());
}
}
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