java - 我收到文件未找到异常，我不知道为什么路径是正确的

Question

我正在编写一个应用程序，当使用 ShareActionProvider 点击工具栏上的共享选项时，它将允许用户通过电子邮件向其发送歌曲。但我不断收到 FileNotFoundException 异常，这是代码，异常是这样的

java.io.FileNotFoundException:song.mp3:打开失败:ENOENT(没有这样的文件或目录)

        @Override
public boolean onCreateOptionsMenu(Menu menu)
{
    // TODO: Implement this method
    menu.clear();
    MenuInflater inflator = getMenuInflater();
    inflator.inflate(R.menu.sidebar_menu, menu);
    SubMenu subMenu = menu.addSubMenu("Themes");
    subMenu.add(0 , blue , 0 , "Blue");
    subMenu.add(0, pink , 1, "Pink");
    items = subMenu.getItem().getItemId();

    // tool bar menu
    ArrayList<Uri> al = new ArrayList<Uri>();
    ArrayList<Uri> emailAl = new ArrayList<Uri>();
    ListView lv = (ListView)findViewById(R.id.downloads);
    MenuItem mi = menu.findItem(R.id.searchable);
    MenuItem share = menu.findItem(R.id.share);
    mi.setIcon(android.R.drawable.ic_search_category_default);
    SearchView searchView = (SearchView) menu.findItem(R.id.searchable).getActionView();
    SearchManager searchManager = (SearchManager) getSystemService(Context.SEARCH_SERVICE);
    searchView.setSearchableInfo(searchManager.getSearchableInfo(getComponentName()));
    ShareActionProvider sap =(ShareActionProvider) MenuItemCompat.getActionProvider(share);
    Intent intentShare = new Intent(Intent.ACTION_SEND_MULTIPLE);
    Intent intentEmail = new Intent(Intent.ACTION_SEND_MULTIPLE);
    intentShare.setType("audio/mp3");
    intentEmail.setType("audio/mp3");
    Uri uri = null;
    Uri uriEmail = null;
        try{

            for(String file : mp3Files ){
                File filein = new File(file);
                uri = Uri.fromFile(filein);
                FileInputStream in = new FileInputStream(filein.getName());
                File outFile = new File(filein.getPath(), filein.getName()); // IMPORTANT! You need to create your file object separately, so you can then pass it to intent as well.. 
                OutputStream out = new FileOutputStream(outFile);
                byte[] buf = new byte[1024]; 
                int len; while ( (len = in.read(buf, 0, buf.length)) != -1){
                    out.write(buf, 0, len);
                    } 

                    in.close(); 
                    out.close();

                    uriEmail = Uri.fromFile(outFile); // Here you passed the parent directory file.. Pass newly created file object .. 
                    al.add(uri); 
                    emailAl.add(uriEmail);
            }

            } catch(IOException e){
                e.printStackTrace();
            }
            String text = "";
    intentShare.putParcelableArrayListExtra(Intent.EXTRA_STREAM,al );
    intentEmail.putParcelableArrayListExtra(Intent.EXTRA_STREAM,emailAl);
    intentEmail.putExtra(Intent.EXTRA_SUBJECT , "Subject");
    intentEmail.putExtra(Intent.EXTRA_TEXT , text);

    sap.setShareIntent(intentShare);
    sap.setShareIntent(intentEmail);
    MenuItemCompat.OnActionExpandListener el = new MenuItemCompat.OnActionExpandListener(){
        @Override
   public boolean onMenuItemActionCollapse(MenuItem item) {
        // Do something when action item collapses
        return true; // Return true to collapse action view
    }

这是全局声明 mp3files 的 mp3files 部分

    private void ShowLists(){
    files = new File(Environment.getExternalStoragePublicDirectory( Environment.DIRECTORY_DOWNLOADS).toString());

    downloads = files.listFiles(new FileFilter(){
        @Override
        public boolean accept(File file){
            String ext = file.getName();
            if(ext.endsWith(".mp3")){
                return true;
            }
            return false;
        }
    });
    mp3Files = new String[downloads.length];
    for(int i = 0; i < mp3Files.length; i++){
        mp3Files[i] = downloads[i].getName();
    }
    adapter = new ArrayAdapter<String>(this,R.layout.downloads, R.id.textviewone , mp3Files);
    ListView downloadsList = (ListView) findViewById(R.id.downloads);
    downloadsList.setAdapter(adapter);
    if(adapter.isEmpty()){
        downloadsList.setAdapter(null);
    } else {
        downloadsList.setAdapter(adapter);
    }
}

我还尝试使用几种不同的方式来获取下载目录，包括环境方式，但它仍然不起作用，请帮助

已编辑已更新

所以我将代码更改为这个，但仍然无法工作

    try{
            for(File file : mp3Files){
                File filein = new File(file.toString());
                uri = Uri.fromFile(filein);
                FileInputStream in = new FileInputStream(filein);
                File outFile = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS), filein.getName()); // IMPORTANT! You need to create your file object separately, so you can then pass it to intent as well.. 
                OutputStream out = new FileOutputStream(outFile);
                byte[] buf = new byte[1024]; 
                int len; while ( (len = in.read(buf, 0, buf.length)) != -1){
                    out.write(buf, 0, len);
                    } 

                    in.close(); 
                    out.close();

                    uriEmail = Uri.fromFile(outFile); // Here you passed the parent directory file.. Pass newly created file object .. 
                    al.add(uri); 
                    emailAl.add(uriEmail);
            }
            } catch(IOException e){
                e.printStackTrace();
            }

Answer 1

mp3Files 只是文件名，而不是磁盘上文件的完整路径。

mp3Files[i] = downloads[i].getName();

您收到 FileNotFound 是因为您无法仅使用名称 new File() 并期望它知道在哪里查找该文件。

需要是这个，但正如你所看到的，mp3Files 不是必须使用的。

mp3Files[i] = downloads[i];

换句话说，mp3Files = files.listFiles(...)

然后，这个循环可能只是for (File file : mp3Files)

for(String file : mp3Files ){
    File filein = new File(file);
    uri = Uri.fromFile(filein);

如果您确实希望适配器仅显示文件的名称，那么您可以实现自己的 ArrayAdapter 类来接受 File[]，然后仅显示 getName() getView() 方法中该 File 的 。

此外，检查 adapter.isEmpty() 并设置空适配器并不是真正必要的。如果适配器为空，则不显示任何数据。如果你想显示一个空 View ，那么ListView类有一个setEmptyView方法。