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Android - 关于Adapter的使用

2018-01-03  本文已影响85人  Allens_Jiang
老婆保佑,代码无BUG

前言

首先说一下,为什么我想写这个文章,实际项目中,一般我都会使用自己封装的BaseAdater,或者鸿洋大神的万能适配器,这就导致了,很多基础的用法,知道是那么回事,但是每次写,总感觉很手生,所以,这里坐下记录,也方便小伙伴们查阅


目录


一:ArrayAdapter

public class MainActivity extends Activity {
    private ListView lv;//控件引用声明
    private List<String> list;//数据源集合引用声明
    private ArrayAdapter<String> adapter;//适配器声明
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        lv = (ListView) findViewById(R.id.listView1);//找出ListView对象
        list = new ArrayList<String>();//数据源集合创建
        for(int i=1;i<=50;i++){
            list.add(Integer.toString(i));//往数据源集合中添加50个字符串
        }
        //创建适配器,第一个参数上下文,第二个是单项的布局,第三个是数据源,这里已经将数据源整合到适配器
        adapter = new ArrayAdapter<String>(this, R.layout.my_item, list);//用自己定义的单项布局
//        adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, list);
        lv.setAdapter(adapter);//再将适配器组装到ListView控件上
    }
}

二: SimpleAdapter

 //创建简单适配器对象,第一个参数上下文,第二个数据源,第三个单项布局
//第四个表示要展现在ListView单项视图中的数据的键,是一个字符串数组
//第五个表示展示上述数据的控件的id,是一个int数组
SimpleAdapter adapter = new SimpleAdapter(this, list, R.layout.item, 
        new String[]{"name","age"}, new int[]{R.id.textView1,R.id.textView2});
//位于第一个的name的值放到同样第一个的textView1中,位于第二个的age的值放到同样第二个的textView2中

三:BaseAdapter

public class MyAdapter extends BaseAdapter  
{  
    private LayoutInflater mInflater;  
    private Context mContext;  
    private List<String> mDatas;  
  
    public MyAdapter(Context context, List<String> mDatas)  
    {  
        mInflater = LayoutInflater.from(context);  
        this.mContext = context;  
        this.mDatas = mDatas;  
    }  
  
    @Override  
    public int getCount()  
    {  
        return mDatas.size();  
    }  
  
    @Override  
    public Object getItem(int position)  
    {  
        return mDatas.get(position);  
    }  
  
    @Override  
    public long getItemId(int position)  
    {  
        return position;  
    }  
  
    @Override  
    public View getView(int position, View convertView, ViewGroup parent)  
    {  
        ViewHolder viewHolder = null;  
        if (convertView == null)  
        {  
            convertView = mInflater.inflate(R.layout.item_single_str, parent,  
                    false);  
            viewHolder = new ViewHolder();  
            viewHolder.mTextView = (TextView) convertView  
                    .findViewById(R.id.id_tv_title);  
            convertView.setTag(viewHolder);  
        } else  
        {  
            viewHolder = (ViewHolder) convertView.getTag();  
        }  
        viewHolder.mTextView.setText(mDatas.get(position));  
        return convertView;  
    }  
  
    private final class ViewHolder  
    {  
        TextView mTextView;  
    }  
} 

四:RecyclerAdapter

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

    /**
     * 展示数据
     */
    private ArrayList<String> mData;

    /**
     * 事件回调监听
     */
    private MyAdapter.OnItemClickListener onItemClickListener;

    public MyAdapter(ArrayList<String> data) {
        this.mData = data;
    }

    public void updateData(ArrayList<String> data) {
        this.mData = data;
        notifyDataSetChanged();
    }

    /**
     * 添加新的Item
     */
    public void addNewItem() {
        if(mData == null) {
            mData = new ArrayList<>();
        }
        mData.add(0, "new Item");
        notifyItemInserted(0);
    }

    /**
     * 删除Item
     */
    public void deleteItem() {
        if(mData == null || mData.isEmpty()) {
            return;
        }
        mData.remove(0);
        notifyItemRemoved(0);
    }

    /**
     * 设置回调监听
     * 
     * @param listener
     */
    public void setOnItemClickListener(MyAdapter.OnItemClickListener listener) {
        this.onItemClickListener = listener;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        // 实例化展示的view
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.view_rv_item, parent, false);
        // 实例化viewholder
        ViewHolder viewHolder = new ViewHolder(v);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(final ViewHolder holder, int position) {
        // 绑定数据
        holder.mTv.setText(mData.get(position));

        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(final View v) {
                if(onItemClickListener != null) {
                    int pos = holder.getLayoutPosition();
                    onItemClickListener.onItemClick(holder.itemView, pos);
                }
            }
        });

        holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View v) {
                if(onItemClickListener != null) {
                    int pos = holder.getLayoutPosition();
                    onItemClickListener.onItemLongClick(holder.itemView, pos);
                }
                //表示此事件已经消费,不会触发单击事件
                return true;
            }
        });
    }

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

    public static class ViewHolder extends RecyclerView.ViewHolder {

        TextView mTv;

        public ViewHolder(View itemView) {
            super(itemView);
            mTv = (TextView) itemView.findViewById(R.id.item_tv);
        }
    }

    public interface OnItemClickListener {
        void onItemClick(View view, int position);
        void onItemLongClick(View view, int position);
    }
}

五: 张鸿洋 万能适配器

base-adapter

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