java - 从 SD 卡和 gridview 中删除选定的视频

Question

我创建了一个图像查看器应用程序。它工作正常，但是当我选择一个 gridview 项目来删除它时，它停止工作。选择项目后，会出现删除按钮。单击删除按钮后，会出现一个警告对话框，要求确认。我希望在单击"is"按钮后删除该文件。但这并没有发生。相反，它会抛出一个 indexoutofbounds 异常。如何成功删除选定的文件？

PhotosActivity.java

import static com.example.dell_1.myapp3.ImageViewer.ImageGallery.al_images;

public class PhotosActivity extends AppCompatActivity {
    int int_position;
    private GridView gridView;
    GridViewAdapter adapter;
    ArrayList<Model_images> al_menu = new ArrayList<>();

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

        final ImageButton button1 = (ImageButton) findViewById(R.id.button1);
        final ImageButton button2 = (ImageButton) findViewById(R.id.button2);
        final ImageButton button3 = (ImageButton) findViewById(R.id.button3);
        final ImageButton button4 = (ImageButton) findViewById(R.id.button4);
        final ImageButton button5 = (ImageButton) findViewById(R.id.button5);
        button1.setVisibility(View.GONE);
        button2.setVisibility(View.GONE);
        button3.setVisibility(View.GONE);
        button4.setVisibility(View.GONE);
        button5.setVisibility(View.GONE);

        gridView = (GridView) findViewById(android.R.id.list);
        int_position = getIntent().getIntExtra("value", 0);
        adapter = new GridViewAdapter(this, al_images, int_position);
        gridView.setAdapter(adapter);

        gridView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                String abc = "file://" + al_images.get(int_position).getAl_imagepath().get(position);

                Intent i = new Intent(getApplicationContext(), FullImageActivity.class);
                i.putExtra("id", position);
                i.putExtra("folderPosition", int_position);
                i.putExtra("abc", abc);
                startActivity(i);
            }
        });

        gridView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view, final int position, long id) {
                for (int j = 0; j < parent.getChildCount(); j++)
                    parent.getChildAt(j).setBackgroundColor(Color.TRANSPARENT);

                // change the background color of the selected element
                view.setBackgroundColor(Color.LTGRAY);
                button1.setVisibility(View.VISIBLE);
                button2.setVisibility(View.VISIBLE);
                button3.setVisibility(View.VISIBLE);
                button4.setVisibility(View.VISIBLE);
                button5.setVisibility(View.VISIBLE);
                button3.setOnClickListener(
                        new View.OnClickListener() {
                            public void onClick(View view) {
                                AlertDialog.Builder builder1 = new AlertDialog.Builder(PhotosActivity.this);
                                builder1.setMessage("Are you sure you want to delete it ?");
                                builder1.setCancelable(true);

                                builder1.setPositiveButton(
                                        "Yes",
                                        new DialogInterface.OnClickListener() {
                                            public void onClick(DialogInterface dialog, int id) {
                                                File file = new File( al_menu.get(int_position).getAl_imagepath().get(position));
                                                file.delete();
                                               al_menu.remove(position);
                                                adapter.notifyDataSetChanged();
                                            }
                                        });

                                builder1.setNegativeButton(
                                        "No",
                                        new DialogInterface.OnClickListener() {
                                            public void onClick(DialogInterface dialog, int id) {
                                                dialog.cancel();
                                            }
                                        });

                                AlertDialog alert11 = builder1.create();
                                alert11.show();
                            }
                        });
                return true;
            }
        });


    }
}

GridViewAdapter.java:

public class GridViewAdapter extends ArrayAdapter<Model_images> {

    Context context;
    ViewHolder viewHolder;
    ArrayList<Model_images> al_menu = new ArrayList<>();
    int int_position;


    public GridViewAdapter(Context context, ArrayList<Model_images> al_menu,int int_position) {
        super(context, R.layout.activity_adapter__photos_folder, al_menu);
        this.al_menu = al_menu;
        this.context = context;
        this.int_position = int_position;
    }

    @Override
    public int getCount() {

        Log.e("ADAPTER LIST SIZE", al_menu.get(int_position).getAl_imagepath().size() + "");
        return al_menu.get(int_position).getAl_imagepath().size();
    }

    @Override
    public int getItemViewType(int position) {
        return position;
    }

    @Override
    public int getViewTypeCount() {
        if (al_menu.get(int_position).getAl_imagepath().size() > 0) {
            return al_menu.get(int_position).getAl_imagepath().size();
        } else {
            return 1;
        }
    }

    @Override
    public long getItemId(int position) {
        return position;
    }


    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {

        if (convertView == null) {

            viewHolder = new ViewHolder();
            convertView = LayoutInflater.from(getContext()).inflate(R.layout.activity_adapter__photos_folder, parent, false);
            viewHolder.tv_foldern = (TextView) convertView.findViewById(R.id.tv_folder);
            viewHolder.tv_foldersize = (TextView) convertView.findViewById(R.id.tv_folder2);
            viewHolder.iv_image = (ImageView) convertView.findViewById(R.id.iv_image);


            convertView.setTag(viewHolder);
        } else {
            viewHolder = (ViewHolder) convertView.getTag();
        }

        viewHolder.tv_foldern.setVisibility(View.GONE);
        viewHolder.tv_foldersize.setVisibility(View.GONE);



        Glide.with(context).load("file://" + al_menu.get(int_position).getAl_imagepath().get(position))
                .diskCacheStrategy(DiskCacheStrategy.NONE)
                .skipMemoryCache(true)
                .into(viewHolder.iv_image);


        return convertView;

    }

    private static class ViewHolder {
        TextView tv_foldern, tv_foldersize;
        ImageView iv_image;

    }
}

LOGCAT:

10-15 11:38:03.449 31844-31844/com.example.dell_1.Myapp3 E/AndroidRuntime: FATAL EXCEPTION: main
                                                                           Process: com.example.dell_1.Myapp3, PID: 31844
                                                                           java.lang.IndexOutOfBoundsException: Index: 1, Size: 0
                                                                               at java.util.ArrayList.get(ArrayList.java:411)
                                                                               at com.example.dell_1.myapp3.ImageViewer.PhotosActivity$2$1$1.onClick(PhotosActivity.java:87)
                                                                               at android.support.v7.app.AlertController$ButtonHandler.handleMessage(AlertController.java:161)
                                                                               at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                               at android.os.Looper.loop(Looper.java:154)
                                                                               at android.app.ActivityThread.main(ActivityThread.java:6077)
                                                                               at java.lang.reflect.Method.invoke(Native Method)
                                                                               at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
                                                                               at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)

Answer 1

什么是al_images？？

您尚未初始化al_images