Android新手必读的RecyclerView使用总结

RecyclerView比ListView要复杂一些，如果总结起来，使用方法也很清晰。希望我的总结能帮助到更多的Andoid爱好者。

1.依赖库

使用RecylerView需要Google支持库recyclerview-v7

2.RecylerView

作用：回收和定位屏幕上的View，列表项显示数据还是需要另外两个子类的支持：ViewHolder子类和Adapter子类。

• setLayoutManager方法，需要LayoutManager的支持，LinearLayoutManger数值列表，GridLayoutManager网格列表。
• setAdapter方法，设置RecylerView.Adapter

    FragmentBeatBoxBinding binding = DataBindingUtil
            .inflate(inflater, R.layout.fragment_beat_box, container, false);
    binding.recyclerView.setLayoutManager(new GridLayoutManager(getActivity(), 3));
    binding.recyclerView.setAdapter(new SoundAdapter(mBeatBox.getmSounds()));

3.RecylerView.ViewHolder

作用：容纳子项的View视图

• 构造方法：调用super()传入总的布局视图，实例化视图组件
• bind方法：传入数据模型，将模型的值传给组件

private class SoundHolder extends RecyclerView.ViewHolder{
    private ListItemSoundBinding mBinding;

    public SoundHolder(ListItemSoundBinding binding) {
        super(binding.getRoot());
        mBinding = binding;
        mBinding.setViewModel(new SoundViewModel(mBeatBox));
    }

    public void bind(Sound sound){
        mBinding.getViewModel().setSound(sound);
        mBinding.executePendingBindings();
    }
}

4.RecylerView.Adapter

作用：管理子项

• 创建必要的ViewHolder
• 绑定ViewHodler到模型层数据

RecylerView和Adapter会话：

1. getItemCount()，询问数组列表包含对象个数
2. onCreateViewHolder(ViewGoup, int)创建ViewHolder和要显示的视图
3. 传入ViewHolder及其位置，调用onBindViewHolder(ViewHolder, int)，找到目标位置的数据并绑定到ViewHolder视图上。

使用：

private class SoundAdapter extends RecyclerView.Adapter<SoundHolder>{

    private List<Sound> mSounds;

    public SoundAdapter(List<Sound> sounds) {
        this.mSounds = sounds;
    }

    @Override
    public SoundHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        LayoutInflater inflater = LayoutInflater.from(getActivity());
        ListItemSoundBinding binding = DataBindingUtil
                .inflate(inflater, R.layout.list_item_sound, parent, false);
        return new SoundHolder(binding);
    }

    @Override
    public void onBindViewHolder(SoundHolder holder, int position) {
        Sound sound = mSounds.get(position);
        holder.bind(sound);
    }

    @Override
    public int getItemCount() {
        return mSounds.size();
    }
}

项目的关键源码我上传到了github上。