Java 分离类的正确方法-下载管理器
我可以在单独的Java 分离类的正确方法-下载管理器,java,android,class,android-download-manager,Java,Android,Class,Android Download Manager,我可以在单独的类中分离DownloadManager吗？我想在我的几个类中重复使用它。在Volley中，我们可以创建一个class扩展StringRequest或ImageRequest 例如： public class VolleyStringRequest extends StringRequest{ public VolleyStringRequest(Response.Listenter<String> listener,
类中分离DownloadManager
吗？类中重复使用它。在Volley
中，我们可以创建一个class
扩展StringRequest
或ImageRequest
例如：
public class VolleyStringRequest extends StringRequest{
public VolleyStringRequest(Response.Listenter<String> listener,
Response.ErrorListener errorListener)
{
super(Method.POST, " " , listener, errorListener);
} }
您可以创建一个扩展应用程序类的全局下载类，并声明一个将Uri作为输入的公共方法
class DownloadClass extends Application {
public void startDownload(String url)
{
DownloadManager dm= (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
DownloadManager.Request request = new
DownloadManager.Request(Uri.parse(url));
dm.enqueue(request);
}
}
然后，无论何时需要访问此数据，都可以通过以下方式获取应用程序对象：
DownloadClass download=(DownloadClass)context.getApplication();
download.startDownload("https://www.google.com.tw/images/srpr/logo4w.png");
在类中包装以下downloadThroughManager（String imageUrl，Context Context）
方法，以便您可以在项目中的多个位置使用它。
public static void downloadThroughManager(String imageUrl, Context context) {
File path = new File(imageUrl);
String fileName = path.getName();
final DownloadManager downloadManager = (DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE);
Uri uri = Uri.parse(imageUrl);
DownloadManager.Request request = new DownloadManager.Request(uri);
request.setTitle(fileName);
request.setDescription(fileName);
request.setVisibleInDownloadsUi(true);
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, fileName);
long ref = downloadManager.enqueue(request);
IntentFilter filter = new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE);
final BroadcastReceiver receiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
long downloadReference = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1);
Log.i("GenerateTurePDfAsync", "Download completed");
DownloadManager.Query query = new DownloadManager.Query();
query.setFilterById(downloadReference);
Cursor cur = downloadManager.query(query);
if (cur.moveToFirst()) {
int columnIndex = cur.getColumnIndex(DownloadManager.COLUMN_STATUS);
if (DownloadManager.STATUS_SUCCESSFUL == cur.getInt(columnIndex)) {
String uriString = cur.getString(cur.getColumnIndex(DownloadManager.COLUMN_LOCAL_URI));
Toast.makeText(context, "File has been downloaded successfully.", Toast.LENGTH_SHORT).show();
} else if (DownloadManager.STATUS_FAILED == cur.getInt(columnIndex)) {
int columnReason = cur.getColumnIndex(DownloadManager.COLUMN_REASON);
int reason = cur.getInt(columnReason);
switch(reason){
case DownloadManager.ERROR_FILE_ERROR:
Toast.makeText(context, "Download Failed.File is corrupt.", Toast.LENGTH_LONG).show();
break;
case DownloadManager.ERROR_HTTP_DATA_ERROR:
Toast.makeText(context, "Download Failed.Http Error Found.", Toast.LENGTH_LONG).show();
break;
case DownloadManager.ERROR_INSUFFICIENT_SPACE:
Toast.makeText(context, "Download Failed due to insufficient space in internal storage", Toast.LENGTH_LONG).show();
break;
case DownloadManager.ERROR_UNHANDLED_HTTP_CODE:
Toast.makeText(context, "Download Failed. Http Code Error Found.", Toast.LENGTH_LONG).show();
break;
case DownloadManager.ERROR_UNKNOWN:
Toast.makeText(context, "Download Failed.", Toast.LENGTH_LONG).show();
break;
case DownloadManager.ERROR_CANNOT_RESUME:
Toast.makeText(context, "ERROR_CANNOT_RESUME", Toast.LENGTH_LONG).show();
break;
case DownloadManager.ERROR_TOO_MANY_REDIRECTS:
Toast.makeText(context, "ERROR_TOO_MANY_REDIRECTS", Toast.LENGTH_LONG).show();
break;
case DownloadManager.ERROR_DEVICE_NOT_FOUND:
Toast.makeText(context, "ERROR_DEVICE_NOT_FOUND", Toast.LENGTH_LONG).show();
break;
}
}
}
}
};
context.registerReceiver(receiver, filter);
}
我将把它包括在我的Singleton
类中。问题是我想对该类执行文件
外部操作。例如：公共类DownloadMyManager扩展DownloadManager{}为此，我需要扩展DownloadManager
？如果我用一个类来包装它？在同一个类中，我将执行文件
路径。你有了“我的问题”的想法。@RoCk你不需要扩展DownloadManager
，只需将此代码粘贴到任何自定义类中，并在方法中传递context
和url
。
public static void downloadThroughManager(String imageUrl, Context context) {
File path = new File(imageUrl);
String fileName = path.getName();
final DownloadManager downloadManager = (DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE);
Uri uri = Uri.parse(imageUrl);
DownloadManager.Request request = new DownloadManager.Request(uri);
request.setTitle(fileName);
request.setDescription(fileName);
request.setVisibleInDownloadsUi(true);
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, fileName);
long ref = downloadManager.enqueue(request);
IntentFilter filter = new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE);
final BroadcastReceiver receiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
long downloadReference = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1);
Log.i("GenerateTurePDfAsync", "Download completed");
DownloadManager.Query query = new DownloadManager.Query();
query.setFilterById(downloadReference);
Cursor cur = downloadManager.query(query);
if (cur.moveToFirst()) {
int columnIndex = cur.getColumnIndex(DownloadManager.COLUMN_STATUS);
if (DownloadManager.STATUS_SUCCESSFUL == cur.getInt(columnIndex)) {
String uriString = cur.getString(cur.getColumnIndex(DownloadManager.COLUMN_LOCAL_URI));
Toast.makeText(context, "File has been downloaded successfully.", Toast.LENGTH_SHORT).show();
} else if (DownloadManager.STATUS_FAILED == cur.getInt(columnIndex)) {
int columnReason = cur.getColumnIndex(DownloadManager.COLUMN_REASON);
int reason = cur.getInt(columnReason);
switch(reason){
case DownloadManager.ERROR_FILE_ERROR:
Toast.makeText(context, "Download Failed.File is corrupt.", Toast.LENGTH_LONG).show();
break;
case DownloadManager.ERROR_HTTP_DATA_ERROR:
Toast.makeText(context, "Download Failed.Http Error Found.", Toast.LENGTH_LONG).show();
break;
case DownloadManager.ERROR_INSUFFICIENT_SPACE:
Toast.makeText(context, "Download Failed due to insufficient space in internal storage", Toast.LENGTH_LONG).show();
break;
case DownloadManager.ERROR_UNHANDLED_HTTP_CODE:
Toast.makeText(context, "Download Failed. Http Code Error Found.", Toast.LENGTH_LONG).show();
break;
case DownloadManager.ERROR_UNKNOWN:
Toast.makeText(context, "Download Failed.", Toast.LENGTH_LONG).show();
break;
case DownloadManager.ERROR_CANNOT_RESUME:
Toast.makeText(context, "ERROR_CANNOT_RESUME", Toast.LENGTH_LONG).show();
break;
case DownloadManager.ERROR_TOO_MANY_REDIRECTS:
Toast.makeText(context, "ERROR_TOO_MANY_REDIRECTS", Toast.LENGTH_LONG).show();
break;
case DownloadManager.ERROR_DEVICE_NOT_FOUND:
Toast.makeText(context, "ERROR_DEVICE_NOT_FOUND", Toast.LENGTH_LONG).show();
break;
}
}
}
}
};
context.registerReceiver(receiver, filter);
}