java - FileUriExposed 异常错误

Question

我在 logcat 中收到以下错误。

: android.os.FileUriExposedException: file:///storage/emulated/0/download/AllCast.apk exposed beyond app through Intent.getData()

它仅发生在某些设备上，即 Marsh Mellow 和 Nougat。

这是发生错误的地方

intent.setDataAndType(Uri.fromFile(new File(Environment.getExternalStorageDirectory() + "/download/" + newnamestring)), "application/vnd.android.package-archive");
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

        startActivity(intent);

我尝试添加这行代码

 intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);

也在我的应用程序类中尝试过这个

 StrictMode.VmPolicy.Builder builder = new StrictMode.VmPolicy.Builder();
    StrictMode.setVmPolicy(builder.build());
    builder.detectFileUriExposure(); 

谁能告诉我我做错了什么。谢谢

编辑****

好的，我正在尝试让@CommonsWare 得到工作答案，我可以获取文件以将 fin 下载到提供程序文件夹。但当我的应用程序尝试处理 Intent 时，它崩溃了。这是我的新日志猫

05-07 16:25:35.784 8715-8715/com.example.harrops.h20droidapp2 E/AndroidRuntime: FATAL EXCEPTION: main
                                                                            Process: mypackagename, PID: 8715
                                                                            java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.io.File.getName()' on a null object reference
                                                                                at my package name.Casting_Apps$DownloadFileFromURL.onPostExecute(Casting_Apps.java:273)

这引导我到代码部分

File newFile = null;

        MimeTypeMap mime = MimeTypeMap.getSingleton();
        String ext = newFile.getName().substring(newFile.getName().lastIndexOf(".") + 1);
        String type = mime.getMimeTypeFromExtension(ext);
        try {
            Intent intent = new Intent();
            intent.setAction(Intent.ACTION_VIEW);
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
                intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
                Uri contentUri = FileProvider.getUriForFile(getBaseContext(), "my package name", newFile);
                intent.setDataAndType(contentUri, type);
            } else {
                intent.setDataAndType(Uri.fromFile(newFile), type);
            }
            startActivityForResult(intent, ACTIVITY_VIEW_ATTACHMENT);
        } catch (ActivityNotFoundException anfe) {
            Toast.makeText(getBaseContext(), "No activity found to open this attachment.", Toast.LENGTH_LONG).show();
        }

Answer 1

这就是我想要的答案..感谢@CommonsWare 的帮助

File toInstall = new File(appDirectory, appName + ".apk");
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
Uri apkUri = FileProvider.getUriForFile(activity, BuildConfig.APPLICATION_ID + ".provider", toInstall);
Intent intent = new Intent(Intent.ACTION_INSTALL_PACKAGE);
intent.setData(apkUri);
intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
activity.startActivity(intent)
} else {
Uri apkUri = Uri.fromFile(toInstall);
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(apkUri, "application/vnd.android.package-archive");
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
activity.startActivity(intent);

}