Android 筆記 - ViewPager2 滑動換頁

ViewPager2 是左右滑動（或上下滑動）換頁的方法

在 new 出 Adapter 物件後呼叫 setAdapter，設定後即可使用

ViewPager2 vp = findViewById(R.id.你的ViewPager2的ID);
vp.setAdapter(new ViewPager2Adapter(this));

 Adapter 用法 - Fragment

各頁面的程式碼，如下範例

    public static class ViewPager2Fragment extends Fragment {
        int pos;
        public ViewPager2Fragment(int position) {
            pos = position;
        }
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            return inflater.inflate(R.layout.你的layoutXML, container, false);
        }
        @Override
        public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
            super.onViewCreated(view, savedInstanceState);
            TextView tv = view.findViewById(R.id.你的LayoutXML裡的物件ID);
            tv.setText("pos = " + pos); //可在這修改頁面細節
        }
    }
    private class ViewPager2Adapter extends FragmentStateAdapter {
        public ViewPager2Adapter(FragmentActivity fa) {
            super(fa);
        }
        @Override
        public Fragment createFragment(int position) {
            return new ViewPager2Fragment(position);
        }
        @Override
        public int getItemCount() {
            return 頁數數值;
        }
    }

Adapter 用法 - RecyclerView

各頁面的程式碼，如下範例

    class ViewPager2Adapter extends RecyclerView.Adapter<ViewPager2Adapter.ViewHolder> {
        public class ViewHolder extends RecyclerView.ViewHolder {
            ImageView images;
            public ViewHolder(@NonNull View itemView) {
                super(itemView);
                images = itemView.findViewById(R.id.images);
            }
        }

        private int[] images = { R.drawable.image1, R.drawable.image2, R.drawable.image3 };
        @NonNull
        @Override
        public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
            View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.你的layoutXML, parent, false);
            return new ViewHolder(view);
        }
        @Override
        public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
            holder.images.setImageResource(images[position]);
        }

        @Override
        public int getItemCount() {
            return images.length;
        }
    }