RecyclerView加载不同类型的布局

最新推荐文章于 2024-07-18 11:35:02 发布

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#android #RecyclerView

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本文介绍了RecyclerView在Android开发中的优势，并详细讲解了如何通过设置type字段实现不同item的布局效果。通过在数据中添加type属性，根据type值动态判断getItemViewType方法返回的布局类型，进而调用onCreateViewHolder加载相应的视图。

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RecyclerView有什么优点以及和ListView有什么区别就不多说了，今天来实现RecyclerView的不同item布局效果，直接上图：

实现的思路是为数据添加一个type，根据type的值来判定getItemViewType返回的类型。getItemViewType(int position)返回的值就是onCreateViewHolder(ViewGroup parent, int viewType)的参数viewType，所以根据不同的值加载不同的布局。代码如下：

public class MyAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>{

    public static enum ITEM_TYPE{
        ITEM_TYPE_LEFT,
        ITEM_TYPE_RIGHT;
    }

    private LayoutInflater layoutInflater;
    private Context context;
    private List<Content> contents;

    public MyAdapter(Context c, List<Content> strs){
        layoutInflater = LayoutInflater.from(c);
        context = c;
        contents = strs;
    }

    @Override
    public int getItemCount() {
        return contents != null ? contents.size() : 0;
    }

    @Override
    public int getItemViewType(int position) {
        return contents.get(position).getType() == 0 ? ITEM_TYPE.ITEM_TYPE_LEFT.ordinal() : ITEM_TYPE.ITEM_TYPE_RIGHT.ordinal() ;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        if(viewType == ITEM_TYPE.ITEM_TYPE_LEFT.ordinal()){
            return new LeftViewHolder(layoutInflater.inflate(R.layout.item_text_left,parent,false));
        }else{
            return new RightViewHolder(layoutInflater.inflate(R.layout.item_text_right,parent,false));
        }
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {

        if(holder instanceof LeftViewHolder){
            ((LeftViewHolder) holder).tv_left.setText(contents.get(position).getMessage());
        }else if(holder instanceof  RightViewHolder){
            ((RightViewHolder) holder).tv_right.setText(contents.get(position).getMessage());
        }
    }

    public static class LeftViewHolder extends RecyclerView.ViewHolder{

        public TextView tv_left;
        public LeftViewHolder(View v){
            super(v);
            tv_left = (TextView)v.findViewById(R.id.tv_left);
        }
    }

    public static class RightViewHolder extends RecyclerView.ViewHolder{

        public TextView tv_right;
        public RightViewHolder(View v){
            super(v);
            tv_right = (TextView)v.findViewById(R.id.tv_right);
        }
    }
}