Android简单开发之 通用Adapter ViewHolder

Posted 2020-09-27 blfbuaa

我们寻常使用Adapter的方式

public class BusbaseSearchApadter extends SimpleBaseApadter {

	private List<Busbase> busbases = new ArrayList<Busbase>();
	public Context context;
	public void setList(List<Busbase> busbases) {
		this.busbases = busbases;
	}
	
	public BusbaseSearchApadter(Context context) {
		super(context);
		this.context = context;
	}

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

	@Override
	public Object getItem(int position) {
		return busbases.get(position);
	}

	@Override
	public long getItemId(int position) {
		return position;
	}

	@Override
	public View getView(int position, View convertView, ViewGroup parent) {
		Busbase busbase = busbases.get(position);
		ViewHolder holder = null;
		if(convertView == null){
			holder = new ViewHolder();
			convertView = LayoutInflater.from(context).inflate(R.layout.hx_item_search_bus, parent, false);
			holder.hx_item_bus_search_image = (ImageView)convertView.findViewById(R.id.hx_item_bus_search_image);
			holder.hx_item_bus_search_name = (TextView)convertView.findViewById(R.id.hx_item_bus_search_name);
			holder.hx_item_bus_search_mobile = (TextView)convertView.findViewById(R.id.hx_item_bus_search_mobile);
			convertView.setTag(holder);
		}else{
			holder = (ViewHolder)convertView .getTag();
		}
		bitmapUtils.display(holder.hx_item_bus_search_image, busbase.getShopLogo());
		holder.hx_item_bus_search_name.setText(busbase.name);
		holder.hx_item_bus_search_mobile.setText(busbase.mobile);
		return convertView;
	}


	class ViewHolder{
		ImageView hx_item_bus_search_image;
		TextView hx_item_bus_search_name;
		TextView hx_item_bus_search_mobile;
	}

能够看出当中  实用的代码仅仅有仅仅有getView  和ViewHolder  可是其它的代码又不得不写，太痛苦 了不得不反复的写无数adapter 和ViewHoder.

我们能够写一个通用的ViewHolder

public class ViewHolder {
	private final SparseArray<View> mViews;  
    private int mPosition;  
    private View mConvertView;  
    protected BitmapUtils bitmapUtils;
  
    private ViewHolder(Context context, ViewGroup parent, int layoutId,  
            int position)  
    {  
    	bitmapUtils = new BitmapUtils(context);
		bitmapUtils.configDefaultLoadingImage(R.drawable.hx_loodding);
		bitmapUtils.configDefaultLoadFailedImage(R.drawable.hx_loodding);
		bitmapUtils.configDefaultBitmapConfig(Bitmap.Config.RGB_565);
        this.mPosition = position;  
        this.mViews = new SparseArray<View>();  
        mConvertView = LayoutInflater.from(context).inflate(layoutId, parent,  
                false);  
        // setTag  
        mConvertView.setTag(this);  
    }  
  
    /** 
     * 拿到一个ViewHolder对象 
     *  
     * @param context 
     * @param convertView 
     * @param parent 
     * @param layoutId 
     * @param position 
     * @return 
     */  
    public static ViewHolder get(Context context, View convertView,  
            ViewGroup parent, int layoutId, int position)  
    {  
        if (convertView == null)  
        {  
            return new ViewHolder(context, parent, layoutId, position);  
        }  
        return (ViewHolder) convertView.getTag();  
    }  
  
    public View getConvertView()  
    {  
        return mConvertView;  
    }  
  
    /** 
     * 通过控件的Id获取对于的控件，假设没有则增加views 
     *  
     * @param viewId 
     * @return 
     */  
    public <T extends View> T getView(int viewId)  
    {  
        View view = mViews.get(viewId);  
        if (view == null)  
        {  
            view = mConvertView.findViewById(viewId);  
            mViews.put(viewId, view);  
        }  
        return (T) view;  
    }  
  
    /** 
     * 为TextView设置字符串 
     *  
     * @param viewId 
     * @param text 
     * @return 
     */  
    public ViewHolder setText(int viewId, String text)  
    {  
        TextView view = getView(viewId);  
        view.setText(text);  
        return this;  
    }  
  
    /** 
     * 为ImageView设置图片 
     *  
     * @param viewId 
     * @param drawableId 
     * @return 
     */  
    public ViewHolder setImageResource(int viewId, int drawableId)  
    {  
        ImageView view = getView(viewId);  
        view.setImageResource(drawableId);  
  
        return this;  
    }  
  
    /** 
     * 为ImageView设置图片 
     *  
     * @param viewId 
     * @param drawableId 
     * @return 
     */  
    public ViewHolder setImageBitmap(int viewId, Bitmap bm)  
    {  
        ImageView view = getView(viewId);  
        view.setImageBitmap(bm);  
        return this;  
    }  
  
    /** 
     * 为ImageView设置图片 
     *  
     * @param viewId 
     * @param drawableId 
     * @return 
     */  
    public ViewHolder setImageByUrl(int viewId, String url)  
    {  
    	bitmapUtils.display((ImageView) getView(viewId), url);
        return this;  
    }  
  
    public int getPosition()  
    {  
        return mPosition;  
    }

使用一个SparseArray将View存起来

如今Adapter这样写

public abstract class AbstuctBaseApadter<T> extends SimpleBaseApadter {

	protected LayoutInflater mInflater;  
	protected Context mContext;  
	protected List<T> mDatas;  
	protected int mItemLayoutId;  
	public AbstuctBaseApadter(Context context) {
		super(context);
	}
  
    public AbstuctBaseApadter(Context context, List<T> mDatas, int itemLayoutId)  
    {  
    	this(context);
        this.mContext = context;  
        this.mInflater = LayoutInflater.from(mContext);  
        this.mDatas = mDatas;  
        this.mItemLayoutId = itemLayoutId;  
    }  
    
    public void setList(List<T> mDatas){
    	 this.mDatas = mDatas;  
    }
  
    @Override  
    public int getCount()  
    {  
        return mDatas.size();  
    }  
  
    @Override  
    public T 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)  
    {  
        final ViewHolder viewHolder = getViewHolder(position, convertView,  
                parent);  
        convert(viewHolder, getItem(position));  
        return viewHolder.getConvertView();  
  
    }  
  
    public abstract void convert(ViewHolder helper, T item);  
  
    private ViewHolder getViewHolder(int position, View convertView,  
            ViewGroup parent)  
    {  
        return ViewHolder.get(mContext, convertView, parent, mItemLayoutId,  
                position);  
    }

如今我们仅仅须要重写 convert方法  看activity里面怎么使用

		AbstuctBaseApadter abstuctBaseApadter = new AbstuctBaseApadter<Map<String,Object>>(activity,list_map,R.layout.hx_money_item) {
			public void convert(ViewHolder helper, Map<String, Object> item) {
				helper.setText(R.id.id_item_1, item.get("time").toString());
				helper.setText(R.id.id_item_3, item.get("sourcename").toString());
			}
		};

直接在activity里面写匿名内部类就能够了

哈哈  打工改成