java - java.lang.IndexOutOfBoundsException:索引:0，大小:0？

因此，我正在创建一个网格视图。

本活动的想法是使用网格视图进入将要显示的目录，该视图将显示照片中的照片。假设正确显示了我将从网格视图中选择的图像

但是当我进入“活动”时，它崩溃了，并重新启动了应用程序

Logcat

java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
                                                                                      at java.util.ArrayList.get(ArrayList.java:411)
                                                                                      at com.example.dmckoy.myapplication.Search.GalleryFragment.setupGridView(GalleryFragment.java:133)
                                                                                      at com.example.dmckoy.myapplication.Search.GalleryFragment.access$100(GalleryFragment.java:34)
                                                                                      at com.example.dmckoy.myapplication.Search.GalleryFragment$3.onItemSelected(GalleryFragment.java:108)

这是错误3的来源：

第一个代码：

setImage(imgURLs.get(0), galleryImage, mAppend);

第二：

public class GalleryFragment extends Fragment {
    private static final String TAG = "GalleryFragment";

第三：

    setupGridView(directories.get(position));

这是整个代码：

public class GalleryFragment extends Fragment {
    private static final String TAG = "GalleryFragment";

    //constants
    private static final int NUM_GRID_COLUMNS = 3;

    //widgets
    private GridView gridView;
    private ImageView galleryImage;
    private ProgressBar mProgressBar;
    private Spinner directorySpinner;



    //var
    private ArrayList<String> directories;
    private String mAppend = "file:/";

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view  = inflater.inflate(R.layout.fragment_gallery, container, false);
        galleryImage = (ImageView) view.findViewById(R.id.galleryImageView);
        gridView = (GridView) view.findViewById(R.id.gridView);
        directorySpinner = (Spinner) view.findViewById(R.id.spinnerDirectory);
        mProgressBar = (ProgressBar) view.findViewById(R.id.progressBar);
        mProgressBar.setVisibility(View.GONE);
        directories = new ArrayList<>();
        Log.d(TAG, "onCreateView: started. ");

        ImageView shareClose = (ImageView) view.findViewById(R.id.ivCloseShare);
        shareClose.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.d(TAG, "onClick: closing the gallery fragment. ");
                getActivity().finish();
            }
        });

        TextView nextScreen = (TextView) view.findViewById(R.id.tvNext);
        nextScreen.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.d(TAG, "onClick: navigating to the final share screen. ");


            }
        });
        init();

        return view;
    }

    private void init() {
        FilePath filePath = new FilePath();

        //check for other folder inside "/storage/emulated/0/pictures
        if (FileSearch.getDirectoryPaths(filePath.Picture) != null) {
            directories = FileSearch.getDirectoryPaths(filePath.Picture);
        }

        directories.add(filePath.CAMERA);

        ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(),
                android.R.layout.simple_spinner_item, directories);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        directorySpinner.setAdapter(adapter);

        directorySpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                Log.d(TAG, "onItemClick: selected. " + directories.get(position));

                //setup our image grid for the directory chosen
                setupGridView(directories.get(position));
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {

            }
        });
    }


    private void setupGridView(String selectedDirectory) {
        Log.d(TAG, "setupGridView: directory chosen: " + selectedDirectory);
        final ArrayList<String> imgURLs = FileSearch.getFilePaths(selectedDirectory);

        //set the grid column width
        int gridWidth = getResources().getDisplayMetrics().widthPixels;
        int imageWidth = gridWidth/NUM_GRID_COLUMNS;
        gridView.setColumnWidth(imageWidth);

        //use the grid adapter to adapter the image to gridview file://
        GridImageAdapter adapter = new GridImageAdapter(getActivity(), R.layout.layout_grid_imageview, mAppend, imgURLs);
        gridView.setAdapter(adapter);

        //set the first image to be displayed whent the activity fragment view is inflated
        setImage(imgURLs.get(0), galleryImage, mAppend);

       gridView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
           @Override
           public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
               Log.d(TAG, "onItemClick: selected an image: " + imgURLs.get(position));

               setImage(imgURLs.get(position), galleryImage, mAppend);
           }
       });
    }

    private void setImage(String imgURL, ImageView image, String append){
        Log.d(TAG, "setImage: setting image");

        ImageLoader imageLoader = ImageLoader.getInstance();

        imageLoader.displayImage(append + imgURL, image, new ImageLoadingListener() {
            @Override
            public void onLoadingStarted(String imageUri, View view) {
                mProgressBar.setVisibility(View.VISIBLE);
            }

            @Override
            public void onLoadingFailed(String imageUri, View view, FailReason failReason) {
                mProgressBar.setVisibility(View.INVISIBLE);
            }

            @Override
            public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
                mProgressBar.setVisibility(View.INVISIBLE);
            }

            @Override
            public void onLoadingCancelled(String imageUri, View view) {
                mProgressBar.setVisibility(View.INVISIBLE);
            }
        });
    }
}

最佳答案

java.lang.IndexOutOfBoundsException：索引：0，大小：0


您是using:

setImage(imgURLs.get(0), galleryImage, mAppend);

这意味着imgURLs具有0个元素。
在使用imgURLs.get(0)之前，只需检查它是否具有第一个元素，例如：

if (imgURLs != null && imgURLs.size()>=1) { ... }