• 使适配器更加简单


       传统写法

       

    public class CustomerAdapter extends BaseAdapter {
    
    	 private List<CustomerInfo> mCustomerList;
    	 private LayoutInflater mInflater;
    	 private Context context;
    	 public CustomerAdapter(Context context, List<CustomerInfo> customerList)
    	 {
    		 mCustomerList = customerList;
    		 mInflater = LayoutInflater.from(context);
    		 this.context = context;
    	 }
    	@Override
    	public int getCount() {
    		// TODO Auto-generated method stub
    		if(mCustomerList == null){
    			return 0;
    		}
    		
    		return mCustomerList.size();
    	}
    
    	@Override
    	public Object getItem(int position) {
    		// TODO Auto-generated method stub
    		return null;
    	}
    
    	@Override
    	public long getItemId(int position) {
    		// TODO Auto-generated method stub
    		return position;
    	}
    
    	@Override
    	public View getView(int position, View convertView, ViewGroup parent) {
    		// TODO Auto-generated method stub
             ViewHolder holder=null;
    		if(convertView == null)
    		{
    			convertView =mInflater.inflate(R.layout.customer_item, null);
    			holder = new ViewHolder();
    			holder.tele=(TextView) convertView.findViewById(R.id.tv_tel);
    			holder.details=(TextView) convertView.findViewById(R.id.tv_write);
    			holder.time=(TextView) convertView.findViewById(R.id.tv_time);
    			convertView.setTag(holder);
    		}
    		else
    		{
    			holder = (ViewHolder) convertView.getTag();
    		}
    		holder.tele.setText(mCustomerList.get(position).getCustomerTel());
    		holder.details.setText(mCustomerList.get(position).getCustomerDetails());
    		holder.time.setText(mCustomerList.get(position).getCustomerTime());
    		return convertView;
    	}
    
    
    	public class ViewHolder
    	{	
    		
    	    public TextView tele;
    	    public TextView details;
    	    public TextView time;
    	   
    	}
    }

      改进版本一

      将ViewHolder作为一个通用的类

       SparseArray   //比传统Hashmap更加有效率  map<int,object>这种情况下


      

    public View getView(int position, View convertView, ViewGroup parent) {
    	
    		ViewHolder holder = ViewHolder.get(mContext,convertView,parent,R.layout.item,position);
    		CustomInfo a=mCustomerList.get(position);
    		((TextView)holder.getView(R.id.tele)).setText(a.getTele());
    		((TextView)holder.getView(R.id.details)).setText(a.getDetails());
    		((TextView)holder.getView(R.id.time)).setText(a.getTime());
    		return holder.getConvertView();
    	}

    public class ViewHolder {
        private SparseArray<View> mViews;
        private int mPosition;
        private View mConvertView;
        
        public ViewHolder(Context context,ViewGroup parent,int layoutId,int position)
        {
        	this.mPosition=position;
        	this.mViews = new SparseArray<View>();
        	mConvertView=LayoutInflater.from(context).inflate(layoutId, parent,false);
        	mConvertView.setTag(this);
        	
        }
        /**
         * 入口方法
         */
        public static ViewHolder get(Context context,View convertView,ViewGroup parent,int layoutId,int position)
        {
        	if(convertView == null)
        	{
        		return new ViewHolder(context, parent, layoutId, position);
        	}
        	else
        	{
        	    ViewHolder holder = (ViewHolder) convertView.getTag();//convertView复用
        	    holder.mPosition = position;   //position需要不断变化
        	    return holder;
        	}
        }
        /**
        *返回ConvertView
        */
        public View getConvertView()
        {
        	return mConvertView;
        }
        /**
         * 通过viewId获取控件
         */
        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; 
        }    
    }

    改进版本2

    封装adapter

    public abstract class CommonAdapter<T> extends BaseAdapter {
    
    	public Context mContext;
    	public List<T> mDatas;
    	public LayoutInflater mInflater;
    	
    	public CommonAdapter(Context context , List<T> datas)
    	{
    		this.mContext = context;
    		mInflater = LayoutInflater.from(context);
    		this.mDatas = datas;
    	}
    	@Override
    	public int getCount() {
    		// TODO Auto-generated method stub
    		return mDatas.size();
    	}
    
    	@Override
    	public Object getItem(int position) {
    		// TODO Auto-generated method stub
    		return mDatas.get(location);
    	}
    
    	@Override
    	public long getItemId(int position) {
    		// TODO Auto-generated method stub
    		return position;
    	}
    
    	@Override
    	public abstract View getView(int position, View convertView, ViewGroup parent);
    }

    public class Myadapter extends CommonAdapter<CustomInfo> {
    
    	 public CustomerAdapter(Context context, List<CustomerInfo> customerList)
    	 {
    		super(context,customerList);
    	 }
    	@Override
    	public View getView(int position, View convertView, ViewGroup parent) {
    	
    		ViewHolder holder = ViewHolder.get(mContext,convertView,parent,R.layout.item,position);
    		CustomInfo a=mCustomerList.get(position);
    		((TextView)holder.getView(R.id.tele)).setText(a.getTele());
    		((TextView)holder.getView(R.id.details)).setText(a.getDetails());
    		((TextView)holder.getView(R.id.time)).setText(a.getTime());
    		return holder.getConvertView();
    	}
    }
    再改进


    public abstract class CommonAdapter<T> extends BaseAdapter {
    
    	public Context mContext;
    	public List<T> mDatas;
    	public LayoutInflater mInflater;
    	
    	public CommonAdapter(Context context , List<T> datas)
    	{
    		this.mContext = context;
    		mInflater = LayoutInflater.from(context);
    		this.mDatas = datas;
    	}
    	@Override
    	public int getCount() {
    		// TODO Auto-generated method stub
    		return mDatas.size();
    	}
    
    	@Override
    	public T getItem(int position) {
    		// TODO Auto-generated method stub
    		return mDatas.get(location);
    	}
    
    	@Override
    	public long getItemId(int position) {
    		// TODO Auto-generated method stub
    		return position;
    	}
    
    	@Override
    	public View getView(int position, View convertView, ViewGroup parent)
    	{
    		ViewHolder holder = ViewHolder.get(mContext,convertView,parent,R.layout.item,position);
            
    		convert(holder,getItem(position));
    		
    		return holder.getConvertView();
    	}
    	private abstract void convert(ViewHolder holder, T t);
    }



    public class Myadapter extends CommonAdapter<CustomInfo> {
    
    	 public CustomerAdapter(Context context, List<CustomerInfo> customerList)
    	 {
    		super(context,customerList);
    	 }
    	 public void convert(ViewHolder holder,CustomInfo t)
    	 {
    		 ((TextView)holder.getView(R.id.tele)).setText(a.getTele());
    		 ((TextView)holder.getView(R.id.details)).setText(a.getDetails());
    		 ((TextView)holder.getView(R.id.time)).setText(a.getTime());
    	 }
    }
    

    再次小改进

    ViewHolder类中

    添加设置TextView的方法

    public ViewHolder setText(int viewId,String text)

    {

         TextView tv=getView(viewId);

         tv.setText(text);

         return this;

    }

    Adapter中使用链式进一步简化代码量

      holder.setText(,).setText.(,).setText(,);

    MyaAdapter可以直接声明为内部类,减少代码量

    mListView.setAdapter(new CommonAdapter<CustomInfo>(MainActivity.this,mDatas)

    {

        public void convert(ViewHolder holder,CustomInfo t)

        {

              public class Myadapter extends CommonAdapter<CustomInfo> {


    public CustomerAdapter(Context context, List<CustomerInfo> customerList)
    {
    super(context,customerList);
    }
    public void convert(ViewHolder holder,CustomInfo t)
    {
    ((TextView)holder.getView(R.id.tele)).setText(a.getTele());
    ((TextView)holder.getView(R.id.details)).setText(a.getDetails());
    ((TextView)holder.getView(R.id.time)).setText(a.getTime());
    }
    }

        }

    });

    点击item没反应解决方法

    1.focusable = false;//防止焦点被抢

    2.descendantFocusablility="blockDescendants"//禁止焦点往下传递

    conVertView复用出现的问题解决

     private boolean ischecked;

    private List<Integer> mPos = new ArrayList<Integer>();去记录点击的状态

    final CheckBox cb = holder.getView(R.id......);

    cb.setChecked(false);

    if(mPos.contains(holder.getPosition()))

    {

          cb.setChecked(true);

    }

    cb.setOnClickListener(new OnClickListener()

          public void onClick(View v)

          {

                mPos.add(holder.getPositon());

          }else

         {

               mPos.remove((Integer)holder.getPosition());

         }

    );


      

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  • 原文地址:https://www.cnblogs.com/peterleee/p/9373780.html
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