Android之Adapter的封裝與抽象

在開發的過程中，常常會用到ViewPager、ListView、GridView等、這些帶有Item的視圖控件，而這些控件有個共同點就是都要用到它們的適配器，我們在實現視圖展示時，一般都會去寫個自定義的適配器去繼承PagerAdapter或Adapter或Adapter的子類，因為Android源碼自帶的這些適配器都比較抽象，往往在我們開發時，寫的一些自定義適配器都需要重寫Adapter父類的一些方法，在重寫時，有很多較通用性的代碼，比較耦合，下面將PagerAdapter和Adapter的子類BaseAdapter進行了封裝與抽象，免去了每次都去重寫這些通用的代碼，代碼如下：

1.ViewPagerAdapter

/**
 * 通用ViewPagerAdapter
 * @author Jenly
 *
 */
public class ViewPagerAdapter extends PagerAdapter {

	private List listViews = null;

	public ViewPagerAdapter(List listViews) {
		this.listViews = listViews;
	}
	
	@Override
	public void destroyItem(View container, int position, Object object) {
		((ViewPager)container).removeView(listViews.get(position));
	}
	
	@Override
	public int getCount() {
		return listViews.size();
	}
	
	@Override
	public Object instantiateItem(View container, int position) {
		((ViewPager)container).addView(listViews.get(position),0);
		return listViews.get(position);
	}

	@Override
	public boolean isViewFromObject(View paramView, Object paramObject) {
		return paramView == paramObject;
	}

	public List getListViews() {
		return listViews;
	}

	public void setListViews(List listViews) {
		this.listViews = listViews;
	}
	
	
}

2.AbstractAdapter

/**
 * 抽象適配器（免去一些有共性的代碼）
 * @author Jenly
 *
 * @param 
 */
public abstract class AbstractAdapter extends BaseAdapter {
	
	protected Context context;
	
	protected List listData;
	
	protected LayoutInflater layoutInflater;
	
	public AbstractAdapter(Context context,List listData){
		this.context = context;
		this.listData = listData;
		layoutInflater = LayoutInflater.from(context);
	}

	@Override
	public int getCount() {
		if(listData!=null){
			return listData.size();
		}
		return 0;
	}

	@Override
	public Object getItem(int position) {
		if(listData!=null){
			return listData.get(position);
		}
		return null;
	}

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

	public void setListData(List listData) {
		this.listData = listData;
	}
	

}

/**
 * 通用適配器（適合一些常規的適配器）
 * @author Jenly
 *
 * @param 
 */
public abstract class HolderAdapter extends AbstractAdapter{

	public HolderAdapter(Context context, List listData) {
		super(context, listData);
	}

	@Override
	public View getView(int position, View convertView, ViewGroup parent) {
		Object holder = null;
		if(convertView==null){
			convertView = buildConvertView(layoutInflater);
			holder = buildHolder(convertView);
			
			convertView.setTag(holder);
		}else{
			holder = convertView.getTag();
		}
		bindViewData(holder,listData.get(position),position);
		
		return convertView;
	}
	
	/**
	 * 建立convertView
	 * @param layoutInflater
	 * @return
	 */
	public abstract View buildConvertView(LayoutInflater layoutInflater);
	
	/**
	 * 建立視圖Holder
	 * @param convertView
	 * @return
	 */
	public abstract Object buildHolder(View convertView);
	
	/**
	 * 綁定數據
	 * @param holder
	 * @param t
	 * @param position
	 */
	public abstract void bindViewDatas(Object holder,T t,int position);
	

}

public class TestHolderAdapter extends HolderAdapter{

	public TestHolderAdapter(Context context, List listData) {
		super(context, listData);
	}

	@Override
	public View buildConvertView(LayoutInflater layoutInflater) {
		return layoutInflater.inflate(R.layout.activity_list_item, null);
	}

	@Override
	public Object buildHolder(View convertView) {
		ViewHolder holder = new ViewHolder();
		holder.tv = (TextView)convertView.findViewById(R.id.tv);
		return holder;
	}

	@Override
	public void bindViewDatas(Object holder, String t, int position) {
		((ViewHolder)holder).tv.setText(t);
	}
	
	private static class ViewHolder{
		TextView tv;
	}

}