我收到“找不到文件”異常，而且我不知道為什么路徑正確

Question

我正在編寫一個應用程序，通過ShareActionProvider在工具欄上點擊共享選項，它將允許用戶通過電子郵件向其發送歌曲。 但我不斷收到FileNotFoundException的異常，這里是代碼，異常是

java.io.FileNotFoundException：song.mp3：打開失敗：ENOENT（無此文件或目錄）

        @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
    }

這是mp3files全局聲明的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);
    }
}

我也嘗試過使用幾種不同的方式來獲取下載目錄，包括環境方式，但仍然無法正常工作，請幫助

編輯更新

所以我將代碼更改為此並且仍然無法正常工作

    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，而不是磁盤上文件的完整路徑。

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

之所以得到FileNotFound，是因為您不能僅使用名稱來new File()並希望它知道在哪里查找該文件。

需要這樣，但是如您所見，不需要使用mp3Files 。

mp3Files[i] = downloads[i];

換句話說， mp3Files = files.listFiles(...)

然后，此循環可能僅for (File file : mp3Files)

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

如果確實希望適配器僅顯示文件名，則可以實現自己的ArrayAdapter類以接受File[] ，然后在getView()方法中僅顯示該File的getName() 。

另外， adapter.isEmpty()沒有必要檢查adapter.isEmpty()並設置空適配器。 如果適配器為空，則不會顯示任何數據。 如果要顯示一個空視圖，則ListView類具有setEmptyView方法。