android - 如何使用 android 中的下载管理器将下载的图像存储在内部存储中

Question

如何使用下载管理器将图像或 mp3 文件保存在内部存储中

代码:

   public void StartDownload(String path)
   {
   ContextWrapper cw = new ContextWrapper(context);
        File directory = cw.getDir("channel" + cId, Context.MODE_PRIVATE);
        if (!directory.exists()) {
            directory.mkdir();
        }
        DownloadManager mgr = (DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE);

        Uri downloadUri = Uri.parse(path);
        DownloadManager.Request request = new DownloadManager.Request(
                downloadUri);
        String imgnm = path.substring(path.lastIndexOf("/") + 1);
        startdownloadurl = directory.getAbsolutePath()+"/";
        System.out.println(" directory " + startdownloadurl);
        request.setAllowedNetworkTypes(
                DownloadManager.Request.NETWORK_WIFI | DownloadManager.Request.NETWORK_MOBILE)
                .setAllowedOverRoaming(false).setTitle(imgnm)
                .setDescription("Downloading...")
                .setVisibleInDownloadsUi(true)
                .setDestinationInExternalPublicDir(startdownloadurl, imgnm);


        mgr.enqueue(request);
    }

我正在尝试将下载的图像或 mp3 文件存储在我的内部存储器中
但效果不好
所需路径为“data/data/packagename/app_channel1/image1.jpg”

Answer 1

只有您自己的应用程序可以Access应用程序 internal storage默认的 android 内置下载管理器无法访问您的应用程序内部存储，因此您无法在内部存储中下载。

解决方案:

在 sd card 中下载文件临时文件和下载完成时register a receive然后从 external 复制文件至internal storage.
完整代码:

public class MainActivity extends Activity {
    private long enqueue;
    private DownloadManager dm;

    /**
     * Called when the activity is first created.
     */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        BroadcastReceiver receiver = 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);
                    DownloadManager.Query query = new DownloadManager.Query();
                    query.setFilterById(enqueue);
                    Cursor c = dm.query(query);
                    if (c.moveToFirst()) {
                        int columnIndex = c
                                .getColumnIndex(DownloadManager.COLUMN_STATUS);
                        if (DownloadManager.STATUS_SUCCESSFUL == c
                                .getInt(columnIndex)) {

                            ImageView view = (ImageView) findViewById(R.id.imageView1);
                            String uriString = c
                                    .getString(c
                                            .getColumnIndex(DownloadManager.COLUMN_LOCAL_URI));

                            Uri a = Uri.parse(uriString);
                            File d = new File(a.getPath());
                           // copy file from external to internal will esaily avalible on net use google.
                            view.setImageURI(a);
                        }
                    }
                }
            }
        };

        registerReceiver(receiver, new IntentFilter(
                DownloadManager.ACTION_DOWNLOAD_COMPLETE));
    }

    public void onClick(View view) {
        dm = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
        DownloadManager.Request request = new DownloadManager.Request(
                Uri.parse("http://www.vogella.de/img/lars/LarsVogelArticle7.png")).setDestinationInExternalPublicDir("/Sohail_Temp", "test.jpg");
        enqueue = dm.enqueue(request);
    }

    public void showDownload(View view) {
        Intent i = new Intent();
        i.setAction(DownloadManager.ACTION_VIEW_DOWNLOADS);
        startActivity(i);
    }
}

版面:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical">

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="onClick"
        android:text="Start Download"></Button>

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="showDownload"
        android:text="View Downloads"></Button>

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/image_1"></ImageView>
</LinearLayout>

权限:

 <uses-permission android:name="android.permission.INTERNET" />
 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />