SD卡上的图像的ViewPager无法正常工作

Question

我是android应用程序开发的新手，我正在按照本教程创建图片库。 https://deepshikhapuri.wordpress.com/2017/03/20/get-all-images-from-gallery-in-android-programmatically/ 。
它工作正常，但是现在我想在ViewPager显示图像，以便能够通过向左/向右滑动来显示图像。我正在使用适配器来做到这一点。 我尝试这样做，但无法正常工作，我不知道为什么。我无法刷卡图像。 有人可以帮我吗？ 我是否使用正确的图像路径？

这个项目可以在github上找到：
https://github.com/avi003/MyApp0-master-master

ImageGallery.java ：

public class ImageGallery extends AppCompatActivity {
    public static ArrayList<Model_images> al_images = new ArrayList<>();
    boolean boolean_folder;
    Adapter_PhotosFolder obj_adapter;
    GridView gv_folder;
    private static final int REQUEST_PERMISSIONS = 100;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_image_gallery);
        gv_folder = (GridView)findViewById(R.id.gv_folder);

        gv_folder.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                Intent intent = new Intent(getApplicationContext(), PhotosActivity.class);
                intent.putExtra("value",i);
                startActivity(intent);
            }
        });

        if ((ContextCompat.checkSelfPermission(getApplicationContext(),
                Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) && (ContextCompat.checkSelfPermission(getApplicationContext(),
                Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED)) {
            if ((ActivityCompat.shouldShowRequestPermissionRationale(ImageGallery.this,
                    Manifest.permission.WRITE_EXTERNAL_STORAGE)) && (ActivityCompat.shouldShowRequestPermissionRationale( ImageGallery.this,
                    Manifest.permission.READ_EXTERNAL_STORAGE))) {

            } else {
                ActivityCompat.requestPermissions( ImageGallery.this,
                        new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.READ_EXTERNAL_STORAGE},
                        REQUEST_PERMISSIONS);
            }
        }else {
            Log.e("Else","Else");
            fn_imagespath();
        }
    }

    public ArrayList<Model_images> fn_imagespath() {
        al_images.clear();

        int int_position = 0;
        Uri uri;
        Cursor cursor;
        int column_index_data, column_index_folder_name;

        String absolutePathOfImage;
        uri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;

        String[] projection = {MediaStore.MediaColumns.DATA, MediaStore.Images.Media.BUCKET_DISPLAY_NAME};

        final String orderBy = MediaStore.Images.Media.DATE_TAKEN;
        cursor = getApplicationContext().getContentResolver().query(uri, projection, null, null, orderBy + " DESC");

        column_index_data = cursor.getColumnIndexOrThrow(MediaStore.MediaColumns.DATA);
        column_index_folder_name = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.BUCKET_DISPLAY_NAME);
        while (cursor.moveToNext()) {
            absolutePathOfImage = cursor.getString(column_index_data);
            Log.e("Column", absolutePathOfImage);
            Log.e("Folder", cursor.getString(column_index_folder_name));

            for (int i = 0; i < al_images.size(); i++) {
                if (al_images.get(i).getStr_folder().equals(cursor.getString(column_index_folder_name))) {
                    boolean_folder = true;
                    int_position = i;
                    break;
                } else {
                    boolean_folder = false;
                }
            }


            if (boolean_folder) {

                ArrayList<String> al_path = new ArrayList<>();
                al_path.addAll(al_images.get(int_position).getAl_imagepath());
                al_path.add(absolutePathOfImage);
                al_images.get(int_position).setAl_imagepath(al_path);

            } else {
                ArrayList<String> al_path = new ArrayList<>();
                al_path.add(absolutePathOfImage);
                Model_images obj_model = new Model_images();
                obj_model.setStr_folder(cursor.getString(column_index_folder_name));
                obj_model.setAl_imagepath(al_path);

                al_images.add(obj_model);


            }


        }


        for (int i = 0; i < al_images.size(); i++) {
            Log.e("FOLDER", al_images.get(i).getStr_folder());
            for (int j = 0; j < al_images.get(i).getAl_imagepath().size(); j++) {
                Log.e("FILE", al_images.get(i).getAl_imagepath().get(j));
            }
        }
        obj_adapter = new Adapter_PhotosFolder(getApplicationContext(),al_images);
        gv_folder.setAdapter(obj_adapter);
        return al_images;
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        switch (requestCode) {
            case REQUEST_PERMISSIONS: {
                for (int i = 0; i < grantResults.length; i++) {
                    if (grantResults.length > 0 && grantResults[i] == PackageManager.PERMISSION_GRANTED) {
                        fn_imagespath();
                    } else {
                        Toast.makeText(ImageGallery.this, "The app was not allowed to read or write to your storage. Hence, it cannot function properly. Please consider granting it this permission", Toast.LENGTH_LONG).show();
                    }
                }
            }
        }
    }

}

PhotosActivity.java ：

public class PhotosActivity extends AppCompatActivity {
    int int_position;
    private GridView gridView;
    GridViewAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_image_gallery);
        gridView = (GridView)findViewById(R.id.gv_folder);
        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("abc",abc);
                startActivity(i);
            }
        });
    }
}

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;

    }
}

Adapter_PhotosFolder.java ：

public class Adapter_PhotosFolder extends ArrayAdapter<Model_images> {

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


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

    @Override
    public int getCount() {

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

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

    @Override
    public int getViewTypeCount() {
        if (al_menu.size() > 0) {
            return al_menu.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.setText(al_menu.get(position).getStr_folder());
        viewHolder.tv_foldersize.setText(al_menu.get(position).getAl_imagepath().size()+"");



        Glide.with(context).load("file://" + al_menu.get(position).getAl_imagepath().get(0))
                .diskCacheStrategy(DiskCacheStrategy.NONE)
                .skipMemoryCache(true)
                .into(viewHolder.iv_image);


        return convertView;

    }

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


    }
}

Model_images.java：

public class Model_images {
    String str_folder;
    ArrayList<String> al_imagepath;

    public String getStr_folder() {
        return str_folder;
    }

    public void setStr_folder(String str_folder) {
        this.str_folder = str_folder;
    }

    public ArrayList<String> getAl_imagepath() {
        return al_imagepath;
    }

    public void setAl_imagepath(ArrayList<String> al_imagepath) {
        this.al_imagepath = al_imagepath;
    }
}

FullImageActivity.java：

public class FullImageActivity extends AppCompatActivity {
    ImageView images;
    int position;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_full_image);
        Intent i = getIntent();
        images = (ImageView) findViewById(R.id.fullImage);

        // Selected image id
        position = i.getExtras().getInt("id");
        Bundle extras = getIntent().getExtras();
        String value = extras.getString("abc");

        Glide.with(FullImageActivity.this)
                .load(value)
                .skipMemoryCache(false)
                .into(images);

        ViewPager mViewPager = (ViewPager) findViewById(R.id.viewpager);
        mViewPager.setAdapter(new TouchImageAdapter(this,al_images));
    }
}

activity_full_image.xml ：

<?xml version="1.0" encoding="utf-8"?>

     <LinearLayout
         xmlns:android="http://schemas.android.com/apk/res/android"
         android:id="@+id/jazzy_pager"
         android:layout_width="match_parent"
         android:layout_height="match_parent">

     <ImageView
            android:id="@+id/fullImage"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_gravity="center"
            android:scaleType="centerCrop"
         />

     <android.support.v4.view.ViewPager
         android:id="@+id/viewpager"
         android:layout_width="match_parent"
         android:layout_height="match_parent" />

</LinearLayout>

TouchImageAdapter.java：

class TouchImageAdapter extends PagerAdapter {
    Context context;
    String filename;
    ArrayList<Model_images> al_menu = new ArrayList<>();
    int position,int_position;

    public TouchImageAdapter(Context context,ArrayList<Model_images> al_menu){
        this.al_menu = al_menu;
        this.context = context;
    }

    @Override
    public int getCount() {
        return al_menu.size();
    }

    @Override
    public View instantiateItem(ViewGroup container, int position) {
        ImageView img = new ImageView(container.getContext());
        img.setImageDrawable(getImageFromSdCard(filename,position));
        container.addView(img, LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT);
        return img;
    }

    public int getItemPosition(Object object) {
        return POSITION_NONE;
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        container.removeView((View) object);
    }

    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view == object;
    }


    public Drawable getImageFromSdCard(String imageName,int position) {
        Drawable d = null;
        try {
            String path = al_menu.get(int_position).getAl_imagepath().get(position)
                    + "/";
            Bitmap bitmap = BitmapFactory.decodeFile(path + "/" + imageName
                    + ".jpeg");
            d = new BitmapDrawable(context.getResources(),bitmap);
        } catch (IllegalArgumentException e) {
            // TODO: handle exception
        }
        return d;

    }
}

Answer 1

在这里，您没有传递该文件夹内的图像计数，因此在TouchImageAdapter中，您传递的文件夹计数如下：

 al_menu.size() // it always give you size of folder, 

al_menu.get(int_position).getAl_imagepath().size(); 

// passing the folder position so that correct folder images are to be shown.
public TouchImageAdapter(Context context,ArrayList<Model_images> al_menu, int position){
        this.al_menu = al_menu;
        this.context = context;
        this.int_position = position;
    }

    @Override
    public int getCount() {
        return al_menu.get(int_position).getAl_imagepath().size();
    }

这是我在https://github.com/redviper00/game上推送的更新代码

Answer 2

尝试这个

String[] filenames = new String[0];
        File path = new File(Environment.getExternalStorageDirectory() + "/your folder");
        if (path.exists()) {
            filenames = path.list();
        }
        for (int i = 0; i < filenames.length; i++) {
            imagesPathArrayList.add(path.getPath() + "/" + filenames[i]);
            Log.e("FAV_Images", imagesPathArrayList.get(i));
            adapter = new ImageAdapter(FavActivity.this, imagesPathArrayList);
            myviewpager.setAdapter(adapter);

        }

创建这样的适配器类

public class ImageAdapter extends PagerAdapter {

        Context context;
        ArrayList<String> arrayList;

        ImageAdapter(Context context, ArrayList<String> arrayList) {
            this.context = context;
            this.arrayList = arrayList;
        }

        @Override
        public int getCount() {
            return arrayList.size();
        }

        @Override
        public boolean isViewFromObject(View view, Object object) {
            return view == ((ImageView) object);
        }

        @Override
        public Object instantiateItem(ViewGroup container, int position) {
            viewPagerImageView = new ImageView(context);



            viewPagerImageView.setScaleType(ImageView.ScaleType.CENTER_CROP);

            Bitmap bitmap = BitmapFactory.decodeFile(arrayList.get(position));
            viewPagerImageView.setImageBitmap(bitmap);


            ((ViewPager) container).addView(viewPagerImageView, 0);

            return viewPagerImageView;

        }

        @Override
        public void destroyItem(ViewGroup container, int position, Object object) {
            ((ViewPager) container).removeView((ImageView) object);
        }
    }

Answer 3

看来您正在显示Viewview页面上方的Imageview

images = (ImageView) findViewById(R.id.fullImage);

这就是为什么当您尝试滑动imageview时，应执行tocuh操作而不是view pager的原因。 去掉它。