Question

我看过很多关于android下载管理器的教程，每个教程都是相同的。但是问题是我在使用后在应用中使用了此代码，但是每当我单击此按钮时，我的应用就会崩溃。我的版本是android棉花糖，我的代码在这里。我也想问一下，我在互联网清单和外部存储清单中具有三个权限。我还想知道，“可以，可以将下载文件保存在我的应用程序文件夹中”

public class Dashboard extends AppCompatActivity {
    Button btn;

Context context;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.dashboard);

    Button btn = (Button) findViewById(R.id.btn);

    btn.setOnClickListener(new View.OnClickListener()

{
    @Override
    public void onClick (View view){
        String url = "http://www.myweb.com/abc.png";
        DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));

// only download via WIFI
            request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI);
            request.setTitle("Example");
            request.setDescription("Downloading a very large zip");

// we just want to download silently
            request.setVisibleInDownloadsUi(false);
            request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_HIDDEN);
            request.setDestinationInExternalFilesDir(context, null, "large.zip");

// enqueue this request
            DownloadManager downloadManager = (DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE);
            long downloadID = downloadManager.enqueue(request);
    }
    });
}

}

Answer 1

我在您的代码中发现了两个错误。第一个是显示404的网址。另一个是您未提供下载目录。

请尝试以下代码片段-希望它能解决您的问题。

public class Dashboard extends AppCompatActivity {
        Button btn;

    Context context;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.dashboard);

        Button btn = (Button) findViewById(R.id.btn);

        btn.setOnClickListener(new View.OnClickListener()

    {
        @Override
        public void onClick (View view){
            String url = "http://www.myweb.com/abc.png"; // Please use a valid url. This url is says 404 not found.
        DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));

// only download via WIFI
        request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI);
        request.setTitle("Example");
        request.setDescription("Downloading a very large zip");

// we just want to download silently
        request.setVisibleInDownloadsUi(false);
        request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_HIDDEN);
        request.setDestinationInExternalFilesDir(context, Environment.getExternalStorageDirectory().getAbsolutePath(), "2.gif");

// enqueue this request
        DownloadManager downloadManager = (DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE);
        long downloadID = downloadManager.enqueue(request);
        }
        });
    }

    }

下载mananger调试但崩溃

1 个答案: