Android：不是文件 URI：在下载 .apk 文件时

Question

我想下载 .apk 文件并安装它。 当我不使用 FileProvider 时，一切都很顺利，但是当我使用 FileProvider 从文件创建 uri 时，我得到了 IllegalArgumentException: Not a file URI: content://pl.rasztabiga.klasa1a.provider/external_storage_root/klasa1a。 apk上线

final long downloadId = manager.enqueue(request);

我尝试了 stackoverflow 中的所有内容，但没有任何帮助。 这是我的代码：

File file = new File(Environment.getExternalStorageDirectory(), "klasa1a.apk");
final Uri uri = FileProvider.getUriForFile(MainActivity.this, getApplicationContext().getPackageName() + ".provider", file);

        //Delete update file if exists
        //File file = new File(destination);
        if (file.exists())
            file.delete();

        //get url of app on server
        String url = "http://rasztabiga.ct8.pl/klasa1a.apk";

        //set downloadmanager
        DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
        request.setDescription("Downloading new version");
        request.setTitle(MainActivity.this.getString(R.string.app_name));

        //set destination
        request.setDestinationUri(uri);

        // get download service and enqueue file
        final DownloadManager manager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
        final long downloadId = manager.enqueue(request);

        //set BroadcastReceiver to install app when .apk is downloaded
        BroadcastReceiver onComplete = new BroadcastReceiver() {
            public void onReceive(Context ctxt, Intent intent) {
                Intent install = new Intent(Intent.ACTION_VIEW);
                install.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                install.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
                install.setDataAndType(uri,
                        manager.getMimeTypeForDownloadedFile(downloadId));
                startActivity(install);

                unregisterReceiver(this);
                finish();
            }
        };
        //register receiver for when .apk download is compete
        registerReceiver(onComplete, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));

Answer 1

ACTION_VIEW和ACTION_INSTALL_PACKAGE仅支持 Android 7.0 以后的content方案。 在此之前，您别无选择，只能使用file 。 所以，改变：

final Uri uri = FileProvider.getUriForFile(MainActivity.this, getApplicationContext().getPackageName() + ".provider", file);

到：

final Uri uri = (Build.VERSION.SDK_INT>=Build.VERSION_CODES.N) ?
    FileProvider.getUriForFile(MainActivity.this, BuildConfig.APPLICATION_ID + ".provider", file) :
    Uri.fromFile(file);

Answer 2

问题出在下载管理器中。 它无法将 uri 解析为“content://”，只能解析为“file://”，因此从 sdk24 开始，我们无法使用它。 使用常见的 IOStreams 和 HttpURLConnection 一切正常。 感谢@CommonsWare 向我展示了他的项目。 这就是现在的样子：

        File file = new File(Environment.getExternalStorageDirectory(), "klasa1a.apk");
        final Uri uri = (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) ?
                FileProvider.getUriForFile(MainActivity.this, BuildConfig.APPLICATION_ID + ".provider", file) :
                Uri.fromFile(file);

        //Delete update file if exists
        //File file = new File(destination);
        if (file.exists())
            //file.delete() - test this, I think sometimes it doesnt work
            file.delete();

        //get url of app on server
        String url = "http://rasztabiga.ct8.pl/klasa1a.apk";

        InputStream input = null;
        OutputStream output = null;
        HttpURLConnection connection = null;
        try {
            URL sUrl = new URL(url);
            connection = (HttpURLConnection) sUrl.openConnection();
            connection.connect();

            // download the file
            input = connection.getInputStream();
            output = new FileOutputStream(file);

            byte data[] = new byte[4096];
            int count;
            while ((count = input.read(data)) != -1) {
                // allow canceling with back button
                if (isCancelled()) {
                    input.close();
                    return null;
                }

                output.write(data, 0, count);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (output != null)
                    output.close();
                if (input != null)
                    input.close();
            } catch (IOException ignored) {
            }

            if (connection != null)
                connection.disconnect();
        }

        Intent install = new Intent(Intent.ACTION_INSTALL_PACKAGE)
                .setData(uri)
                .addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
        startActivity(install);

        return null;
    }

Answer 3

对于那些仍然想使用DownloadManager并发现CommonsWare的答案没有解决问题的人，您需要为APK文件包含一个例外

final Uri uri = (!file.getAbsolutePath().endsWith(".apk") && Build.VERSION.SDK_INT>=Build.VERSION_CODES.N) ?
    FileProvider.getUriForFile(MainActivity.this, BuildConfig.APPLICATION_ID + ".provider", file) :
    Uri.fromFile(file);
request.setDestinationUri(uri);

哪个是更短的版本

if (!file.getAbsolutePath().endsWith(".apk") && Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
    request.setDestinationUri(FileProvider.getUriForFile(MainActivity.this,  BuildConfig.APPLICATION_ID + ".provider", download));
} else {
    request.setDestinationUri(Uri.fromFile(file));
}

这可能更容易遵循。

简短的回答是 apk 文件应该用Uri.fromFile处理，但这不必以改变整个过程为代价。

但是，如果您想要彻底，您还可以捕获IllegalArgumentException for Not a file URI并使用它来尝试Uri.fromFile