Question

我正在尝试在gridview中显示缩略图，但我无法弄清楚如何让我的光标访问一个名为＆＃34; FoMOvideos＆＃34;的特定文件夹。我该怎么用 .getColumnIndex（MediaStore.Files.FileColumns.DATA 只访问外部存储空间中的一个文件夹？

private Uri getUriFromMediaStore(int position) {
        //int dataIndex = mMediaStoreCursor.getColumnIndex(MediaStore.Files.FileColumns.DATA);
        int dataIndex = mMediaStoreCursor.getColumnIndex(MediaStore.Files.FileColumns.DATA + "FoMOvideos");

        mMediaStoreCursor.moveToPosition(position);

        String dataString = mMediaStoreCursor.getString(dataIndex);
        Uri mediaUri = Uri.parse("file://" + dataString);
        //TODO: Figure out how to direct only to FoMO videos.
        //Uri mediaUri = Uri.parse("file:///storage/emulated/0/Movies/AppVideos" + dataString);
        return mediaUri;
    }

    private void getOnClickUri(int position) {
        int mediaTypeIndex = mMediaStoreCursor.getColumnIndex(MediaStore.Files.FileColumns.MEDIA_TYPE);
        int dataIndex = mMediaStoreCursor.getColumnIndex(MediaStore.Files.FileColumns.DATA + "FoMOvideos");

        mMediaStoreCursor.moveToPosition(position);
        String dataString = mMediaStoreCursor.getString(dataIndex);
        Uri mediaUri = Uri.parse("file://" + dataString);
        //TODO: Figure out how to direct only to FoMO videos.
        //Uri mediaUri = Uri.parse("file:///storage/emulated/0/Movies/AppVideos" + dataString);

我尝试添加＆＃34; FoMOvideos＆＃34;我的dataindex变量的文件夹名称，但这会导致以下错误：

03-26 19：28：43.949 16399-16399 /？ E / AndroidRuntime：致命异常：主要处理：example.fadysi.fomoapp，PID：16399 java.lang.IllegalStateException：无法从中读取第0行，第1行 CursorWindow。确保之前正确初始化了Cursor 从中访问数据。在android.database.CursorWindow.nativeGetString（本机方法）在android.database.CursorWindow.getString（CursorWindow.java:438）在android.database.AbstractWindowedCursor.getString（AbstractWindowedCursor.java:51）在android.database.CursorWrapper.getString（CursorWrapper.java:137） at example.fadysi.fomoapp.ThumbnailVideoPlay.MediaStoreAdapter.getUriFromMediaStore（MediaStoreAdapter.java:104） at example.fadysi.fomoapp.ThumbnailVideoPlay.MediaStoreAdapter.onBindViewHolder（MediaStoreAdapter.java:46） at example.fadysi.fomoapp.ThumbnailVideoPlay.MediaStoreAdapter.onBindViewHolder（MediaStoreAdapter.java:18）在android.support.v7.widget.RecyclerView $ Adapter.onBindViewHolder（RecyclerView.java:6067）在android.support.v7.widget.RecyclerView $ Adapter.bindViewHolder（RecyclerView.java:6100）在android.support.v7.widget.RecyclerView $ Recycler.getViewForPosition（RecyclerView.java:5282）在android.support.v7.widget.RecyclerView $ Recycler.getViewForPosition（RecyclerView.java:5158）在android.support.v7.widget.LinearLayoutManager $ LayoutState.next（LinearLayoutManager.java:2061）在android.support.v7.widget.GridLayoutManager.layoutChunk（GridLayoutManager.java:562）在android.support.v7.widget.LinearLayoutManager.fill（LinearLayoutManager.java:1408）在android.support.v7.widget.LinearLayoutManager.onLayoutChildren（LinearLayoutManager.java:580）在android.support.v7.widget.GridLayoutManager.onLayoutChildren（GridLayoutManager.java:170）在android.support.v7.widget.RecyclerView.dispatchLayoutStep2（RecyclerView.java:3379）在android.support.v7.widget.RecyclerView.dispatchLayout（RecyclerView.java:3188）在android.support.v7.widget.RecyclerView.onLayout（RecyclerView.java:3632）在android.view.View.layout（View.java:16636）在android.view.ViewGroup.layout（ViewGroup.java:5437）在android.widget.FrameLayout.layoutChildren（FrameLayout.java:336）在android.widget.FrameLayout.onLayout（FrameLayout.java:273）在android.view.View.layout（View.java:16636）在android.view.ViewGroup.layout（ViewGroup.java:5437）在android.support.v4.view.ViewPager.onLayout（ViewPager.java:1799）在android.view.View.layout（View.java:16636）在android.view.ViewGroup.layout（ViewGroup.java:5437）在android.support.design.widget.HeaderScrollingViewBehavior.layoutChild（HeaderScrollingViewBehavior.java:131）在android.support.design.widget.ViewOffsetBehavior.onLayoutChild（ViewOffsetBehavior.java:42）在android.support.design.widget.AppBarLayout $ ScrollingViewBehavior.onLayoutChild（AppBarLayout.java:1367）在android.support.design.widget.CoordinatorLayout.onLayout（CoordinatorLayout.java:849）在android.view.View.layout（View.java:16636）在android.view.ViewGroup.layout（ViewGroup.java:5437）在android.widget.FrameLayout.layoutChildren（FrameLayout.java:336）在android.widget.FrameLayout.onLayout（FrameLayout.java:273）在android.view.View.layout（View.java:16636）在android.view.ViewGroup.layout（ViewGroup.java:5437）在android.widget.LinearLayout.setChildFrame（LinearLayout.java:1743）在android.widget.LinearLayout.layoutVertical（LinearLayout.java:1586）在android.widget.LinearLayout.onLayout（LinearLayout.java:1495）在android.view.View.layout（View.java:16636）在android.view.ViewGroup.layout（ViewGroup.java:5437）在android.widget.FrameLayout.layoutChildren（FrameLayout.java:336）在android.widget.FrameLayout.onLayout（FrameLayout.java:273）在android.view.View.layout（View.java:16636）在android.view.ViewGroup.layout（ViewGroup.java:5437）在android.widget.LinearLayout.setChildFrame（LinearLayout.java:1743）在android.widget.LinearLayout.layoutVertical（LinearLayout.java:1586）在android.widget.LinearLayout.onLayout（LinearLayout.java:1495）在android.view.View.layout（View.java:16636）在android.view.ViewGroup.layout（ViewGroup.java:5437）在android.widget.FrameLayout.layoutChildren（FrameLayout.j

getColumnIndex访问外部存储器中的特定文件夹

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