使用DownloadManager时,ListView中的Android ProgressBar

Question

我有一个ListView,其中每个项目代表一个PDF文件.当用户单击某个项目时,该应用程序必须在外部存储上下载该文件.现在下载无法正常运行,但这不是问题.我想要一个ProgressBar,旋转轮样式,在下载文件时出现在列表的每个项目旁边.

我的问题是:我找不到如何使纺车出现.在下载管理器之前,我尝试使用AsyncTask并且旋转轮工作.

这是我的代码:

CategoryActivity.java(ListView的活动)

@Override
public void onItemClick(AdapterView<?> parent, View view,
    int position, long id) {
    // Récupère les valeurs depuis ListItem
    udl = ((TextView) view.findViewById(R.id.udl)).getText().toString();
    // This is the spinning wheel
    loader = ((ProgressBar) view.findViewById(R.id.spinWheel2));

    filepath = dirpath + udl + ".pdf";
    File file = new File(filepath);
    if (file.exists()) {

        // If the file exists, I open it

    }else{ // Else I download it
        // Setting the spinning wheel to VISIBLE
        loader.setVisibility(View.VISIBLE);

        SharedPreferences codeSaveUrl = getSharedPreferences(PREFS_TEXT,Context.MODE_PRIVATE);
        url2 = codeSaveUrl.getString("defaut", ""); // Code Organisation
        // Constructing the uriString
        uri = url10 + url2 + "&file=" + udl ;

        Uri myuri = Uri.parse(uri);
        DownloadManager mgr=(DownloadManager)getSystemService(Context.DOWNLOAD_SERVICE);
        mgr.enqueue(new DownloadManager.Request(myuri)
        .setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI |DownloadManager.Request.NETWORK_MOBILE)
        .setAllowedOverRoaming(false)
        .setTitle(udl + ".pdf")
        .setDescription("Téléchargement en cours")
        .setDestinationInExternalPublicDir("/Protocols/", (udl+".pdf"))
        .setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE));                    

        // Hiding the spinning wheel
        loader.setVisibility(View.GONE);

    }
}

请注意,如果我不使纺车轮消失,点击该项目后它将始终可见.使用隐藏它的行,它甚至不会出现.

---

编辑:
我添加了一个BroadcastReceiver.

将这两行放在onCreate()中:

final DownloadManager mgr=(DownloadManager)getSystemService(Context.DOWNLOAD_SERVICE);
registerReceiver(onComplete, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));

并补充说:

BroadcastReceiver onComplete = new BroadcastReceiver() {
        public void onReceive(Context context, Intent intent) {
            loader.setVisibility(View.GONE);
        }
    };

    @Override
    public void onDestroy(){
        super.onDestroy();
        unregisterReceiver(onComplete);
    }

---

编辑2: 好的,这是我做的一些改变:

我将下载的ID保存在变量中:

lastDownload = mgr.enqueue(new DownloadManager.Request(myuri)
                .setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI |DownloadManager.Request.NETWORK_MOBILE)
                .setAllowedOverRoaming(false)
                .setTitle(udl + ".pdf")
                .setDescription("Téléchargement en cours")
                .setDestinationInExternalPublicDir("/Protocols/", (udl+".pdf"))
                .setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED));

根据下载的状态,我想做不同的事情:

BroadcastReceiver onComplete = new BroadcastReceiver() {
        public void onReceive(Context context, Intent intent) {
            Cursor c = mgr.query(new DownloadManager.Query().setFilterById(lastDownload));
            if(c.moveToFirst()){
                int x = c.getInt(c.getColumnIndex(DownloadManager.COLUMN_STATUS));
                switch(x){
                case DownloadManager.STATUS_PAUSED:
                case DownloadManager.STATUS_PENDING:
                case DownloadManager.STATUS_RUNNING:
                    break;
                case DownloadManager.STATUS_SUCCESSFUL:
                    loader.setVisibility(View.GONE);
                    break;
                case DownloadManager.STATUS_FAILED:
                    //TODO: retry download
                    break;
                }
            }

        }
    };

问题是,旋转轮只隐藏在listView中单击的最后一个项目.我尝试使用调试模式,但该程序具有正确的行为(loader.setVisibility(View.GONE)每次下载都会调用该含义).我不知道为什么除了点击的最后一项外,纺车不会隐藏.

---

编辑:3 我知道为什么除了点击的最后一项外,纺车不会隐藏.

当我点击多个项目时,lastDownload会获取最后一个项目的ID.因此,在广播接收器中,它点击最后一个项目的情况下点击了项目的数量.
我尝试将lastDownload更改为longs数组/表,并将其与referenceId进行比较,我相信它是intent中包含的id.
这是新代码(y = 0,ld是单击的项目数):

BroadcastReceiver onComplete = new BroadcastReceiver() {
        public void onReceive(Context context, Intent intent) { 
            long referenceId = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1);
            if(y <ld){
                if(lastDownload[y] == referenceId){

            Cursor c = mgr.query(new DownloadManager.Query().setFilterById(lastDownload[y]));
            if(c.moveToFirst()){
                int x = c.getInt(c.getColumnIndex(DownloadManager.COLUMN_STATUS));
                switch(x){
                case DownloadManager.STATUS_PAUSED:
                case DownloadManager.STATUS_PENDING:
                case DownloadManager.STATUS_RUNNING:
                    break;
                case DownloadManager.STATUS_SUCCESSFUL:
                    loader.setVisibility(View.GONE); // This loader is the one of the last item clicked
                    break;
                case DownloadManager.STATUS_FAILED:
                    //TODO: retry download
                    break;
                }

            }

                       y=y+1;

                   }
            }   
        }
    };

我没有编写将变量放回0的部分,但是现在代码几乎按预期工作.剩下的唯一问题是我制造的纺车消失了最后一个项目的纺车轮点击.而且我知道为什么.因为这一行: loader = ((ProgressBar) view.findViewById(R.id.spinWheel2));位于onItemClicked方法中.我不认为我可以把它放在其他地方,因为它所在的视图不是活动的视图.

简而言之:我必须找到一种方法来访问我点击的项目/视图的进度条,知道我可以在第一个到达广播接收器之前点击多个项目.

---

编辑:4好的所以我这样做了:

y,z和ld被设置为0在开始时.

单击某个项目时:

// Loader of the clicked item is made visible
loader[z].setVisibility(View.VISIBLE);

// Construction of the URL
SharedPreferences codeSaveUrl = getSharedPreferences(PREFS_TEXT,Context.MODE_PRIVATE);
url2 = codeSaveUrl.getString("defaut", ""); // Organization code
uri = url10 + url2 + "&file=" + udl ;

// URL parse to URI
Uri myuri = Uri.parse(uri);

// Enqueue file to downloads, with notification. Storage of download id in a table
lastDownload[ld] = mgr.enqueue(new DownloadManager.Request(myuri)
.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI |DownloadManager.Request.NETWORK_MOBILE)
.setAllowedOverRoaming(false)
.setTitle(udl + ".pdf")
.setDescription("Téléchargement en cours")
.setDestinationInExternalPublicDir("/Protocols/", (udl+".pdf"))
.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE));

// Increment variables for next downloads
ld=ld+1;
z=z+1;

广播接收器:

// Broadcast Receiver called when a download is finished
BroadcastReceiver onComplete = new BroadcastReceiver() {
    public void onReceive(Context context, Intent intent) {
        // referenceId is the download's id for which the method is called
        long referenceId = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1);
        // If y (=0 at the beginning) is inferior to the number of downloads
        if(y <ld){
            // If the id of the download corresponds to the one for which the method is called
            if(lastDownload[y] == referenceId){
                // We define a cursor depending on the id
                Cursor c = mgr.query(new DownloadManager.Query().setFilterById(lastDownload[y]));
                if(c.moveToFirst()){
                    // Download status recovery
                    int x = c.getInt(c.getColumnIndex(DownloadManager.COLUMN_STATUS));
                    switch(x){
                    // If download is paused, pending or running, we do nothing
                    case DownloadManager.STATUS_PAUSED:
                    case DownloadManager.STATUS_PENDING:
                    case DownloadManager.STATUS_RUNNING:
                        break;
                    // If file has successfully been downloaded, loader is hidden
                    case DownloadManager.STATUS_SUCCESSFUL:
                        loader[y].setVisibility(View.GONE); 
                        // Increment y to go to next download
                        y=y+1;
                        break;
                    // If download failed, it is retried
                    case DownloadManager.STATUS_FAILED:
                        //TODO: retry download
                        break;
                    }
                }
            }
        }
    }
};

工作正常,除非在下载大文件时单击一个小文件的项目.小文件优先,下载管理器不再遵循表的顺序,导致加载轮不会消失.

---

编辑:5

我找到了一种方法来做我想做的事,看看我的回答.

谢谢你的帮助.

Answer 1

好吧，我设法用 HashTable 做我想做的事情：

\n\n

// HashTable to store download id\'s and loaders\nHashtable<Long, SyncedProgressBar> storeTable = new Hashtable<Long, SyncedProgressBar>();\n

\n\n

在我的 onClickListener 方法中，在loader[z]和之后lastDownload[ld]获取它们的值之后，我将它们放入 HashTable 中：（下载 id 将是键，加载器将是值）

\n\n

// Storing download id and loader in HashTable\nstoreTable.put(lastDownload[ld], loader[z]);\n

\n\n

在我的广播接收器的 onReceive 方法中，而不是这样做：

\n\n

if(lastDownload[y] == referenceId)\n

\n\n

我查看 HashTable 是否包含意图的下载 id：

\n\n

if(storeTable.containsKey(referenceId))\n

\n\n

我将正确的值放入加载程序中：

\n\n

loader[y] = storeTable.get(referenceId);\n

\n\n

然后我只需要把加载器的可见性设置为GONE我想要的位置即可。这个解决方案对我有用，但如果我发现新的东西，我会更新它。

\n\n

这是我的新代码：

\n\n

在onClickListener方法中：（这里不完整）

\n\n

// Loader of the clicked item is made visible\nloader[z].setVisibility(View.VISIBLE);\n\n// Construction of the URL\nSharedPreferences codeSaveUrl = getSharedPreferences(PREFS_TEXT,Context.MODE_PRIVATE);\nurl2 = codeSaveUrl.getString("defaut", ""); // Organization code\nuri = url10 + url2 + "&file=" + udl ;\n\n// URL parse to URI\nUri myuri = Uri.parse(uri);\n\n// Enqueue file to downloads, with notification. Storage of download id in a table\nlastDownload[ld] = mgr.enqueue(new DownloadManager.Request(myuri)\n.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI |DownloadManager.Request.NETWORK_MOBILE)\n.setAllowedOverRoaming(false)\n.setTitle(udl + ".pdf")\n.setDescription("T\xc3\xa9l\xc3\xa9chargement en cours")\n.setDestinationInExternalPublicDir("/Protocols/", (udl+".pdf"))\n.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE));\n\n// Storing download id and loader in HashTable\nstoreTable.put(lastDownload[ld], loader[z]);\n\n// Increment variables for next downloads\nld=ld+1;\nz=z+1;\n

\n\n

广播接收器：

\n\n

// Broadcast Receiver called when a download is finished\nBroadcastReceiver onComplete = new BroadcastReceiver() {\n    public void onReceive(Context context, Intent intent) {\n        // referenceId is the download\'s id for which the method is called\n        long referenceId = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1);\n        // If y (=0 at the beginning) is inferior to the number of downloads\n        if(y <ld){\n            // If the HashTable contains the Key-download-id for which the method is called\n            if(storeTable.containsKey(referenceId)){\n                // Loader takes the value for the key\n                loader[y] = storeTable.get(referenceId);\n                // We define a cursor depending on the id\n                Cursor c = mgr.query(new DownloadManager.Query().setFilterById(referenceId));\n                if(c.moveToFirst()){\n                    // Download status recovery\n                    int x = c.getInt(c.getColumnIndex(DownloadManager.COLUMN_STATUS));\n                    switch(x){\n                    // If download is paused, pending or running, we do nothing\n                    case DownloadManager.STATUS_PAUSED:\n                    case DownloadManager.STATUS_PENDING:\n                    case DownloadManager.STATUS_RUNNING:\n                        break;\n                    // If file has successfully been downloaded, loader is hidden\n                    case DownloadManager.STATUS_SUCCESSFUL:\n                        loader[y].setVisibility(View.GONE); \n                        // Increment y to go to next download\n                        y=y+1;\n                        break;\n                    // If download failed, it is retried\n                    case DownloadManager.STATUS_FAILED:\n                        //TODO: retry download\n                        break;\n                    }\n                }\n            }\n        }\n    }\n};\n

\n