如何分享一个文件

public class FileProviderExample extends Activity {
    private static final String AUTHORITY = "com.example.android.supportv4.my_files";


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


    public void onShareFileClick(View view) {
        // Save a thumbnail to file
        final File thumbsDir = new File(getFilesDir(), "thumbs");
        thumbsDir.mkdirs();
        final File file = new File(thumbsDir, "private.png");
        android.util.Log.i("FileProviderExample", "onShareFileClick--->file:"+file);
        saveThumbnail(view, file);


        // Now share that private file using FileProvider
        final Uri uri = FileProvider.getUriForFile(this, AUTHORITY, file);
        final Intent intent = new Intent(Intent.ACTION_SEND);
        intent.setType("image/png");
        intent.putExtra(Intent.EXTRA_STREAM, uri);
        startActivity(intent);
    }


    /**
     * Save thumbnail of given {@link View} to {@link File}.
     */
    private void saveThumbnail(View view, File file) {
        final Bitmap bitmap = Bitmap.createBitmap(
                view.getWidth(), view.getHeight(), Bitmap.Config.ARGB_8888);
        android.util.Log.i("FileProviderExample", "saveThumbnail--->width:"+view.getWidth());
        android.util.Log.i("FileProviderExample", "saveThumbnail--->height:"+view.getHeight());
        final Canvas canvas = new Canvas(bitmap);
        view.draw(canvas);


        try {
            final OutputStream os = new FileOutputStream(file);
            android.util.Log.i("FileProviderExample", "saveThumbnail--->os:"+os);
            try {
                bitmap.compress(Bitmap.CompressFormat.PNG, 100, os);
            } finally {
                os.close();
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

}

mainifest.xml

<provider
            android:name="android.support.v4.content.FileProvider"
            android:authorities="com.example.android.supportv4.my_files"
            android:grantUriPermissions="true"
            android:exported="false">
            <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/my_paths" />
        </provider>

/res/xml/my_paths.xml

<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- Offer access to files under Context.getFilesDir() + "thumbs/"
         through alias "my_thumbs" -->
    <files-path name="my_thumbs" path="thumbs/" />


    <!-- Offer access to files under Environment.getExternalStorageDirectory()
         through alias "my_external" -->
    <external-path name="my_external" />


    <!-- Offer access to files under Context.getCacheDir() -->
    <cache-path name="my_cache" />
</paths>