MU Class Network Universal Adapter Learning Notes

First of all, thank you again for the technology of the network, Daniel shared the course.

A. Traditional mode of the ListView adapter: 1. Create a ListView and create the item layout for the ListView 2. Encapsulating Data 3. Create a specific adapter for the item layout for data presentation. (In this process, if there are too many controls in a ListView item, the life and invocation of the control will cause the code to rise, and if there are many places in an app that need to be used in a ListView, writing multiple adapters separately can lead to many repetitive operations, In order to avoid this situation, make coding easier, you can refer to Mu-class network Android Universal adapter writing. ）。

The traditional adapter coding style is as follows:

Package com.imooc.imooc_adapter;import java.util.list;import android.content.context;import  android.view.layoutinflater;import android.view.view;import android.view.viewgroup;import  android.widget.BaseAdapter;import android.widget.TextView;public class MyAdapter  extends baseadapter {    private context context;     private list<bean> mlist;    public myadapter (Context  context, list<bean> mlist)  {        super ();         this.context = context;         this.mlist = mlist;    }         public list<bean> getmlist ()  {         return mlist;  &nbsP; }    public void setmlist (list<bean> mlist)  {         this.mlist = mlist;    }      @Override     public int getcount ()  {         return mlist.size ();    }     @Override     public object getitem (int arg0)  {         return mlist.get (arg0);    }     @Override      public long getitemid (int arg0)  {         return arg0;    }     @Override      public view getview (int position, view convertview, viewgroup parent)  {        viewholer holder =null;        if  (convertview ==null)  {            holder  = new viewholer ();             convertview =  (Layoutinflater)  context                     .getsystemservice (Context.LAYOUT_INFLATER_ SERVICE))                      .inflate (R.layout.item, parent,false);             holder.name=  (TextView)  convertview.findviewbyid (r.id.name);             holder.phone =  (TextView)   Convertview.findviewbyid (R.ID.PHone);             convertview.settag (holder);         }else{             convertview.settag (Holder);        }         final bean bean = mlist.get (position);         holder.name.settext (Bean.getusername ());         holder.phone.settext (Bean.getphone ());         return  convertView;    }    class ViewHoler{         textview name;        textview  phone;    }    }

The universal adapter code is as follows:

Package com.imooc.imooc_adapter; Import java.util.List; Import Android.content.Context; Import Com.imooc.util.commonadapter;import Com.imooc.util.ViewHolder; public class Newadapter extends commonadapter<bean>{public newadapter (context context, list<bean> Mdatas,    int layoutid) {Super (context, mdatas,layoutid); } @Override public void convert (Viewholder holder, bean Bean) {holder.settext (R.id.phone, Bean.getphone ()). s    Ettext (R.id.name, Bean.getusername ()); } }

This shows that the universal adapter can be reduced the amount of code.

The universal adapter encapsulates user-defined Viewholder and Baseadapter declarations, and calls Commonadapter and Viewholer two classes.

Universal Adapter Authoring Logic:

1. Package Viewholder, free the view Convertview, implement a code to complete the instantiation of the Convertview:

Viewholder holder = Viewholder.get (Mcontext, Convertview, parent, postion, LayoutID);

Implementation method:

public class viewholder {    private sparsearray<view>  Mviews;    private context mcontext;    private view  mConvertView;    private int mposition;      Public view getmconvertview ()  {        return  Mconvertview;    }         public int  getmposition ()  {        return mposition;     }     public viewholder (context context, viewgroup  Parent, int layoutid,            int  position)  {        this.mposition = position;       &nbsP; this.mviews = new sparsearray<view> ();         mconvertview = layoutinflater.from (context). Inflate (layoutid, parent,                 false);         mconvertview.settag (This);    }      Public static viewholder get (context context, view convertview,             viewgroup parent, int position,  int layoutid)  {        if  (convertview ==  null)  {            return new  viewholder (context, parent, layoutid, position);         } else {            viewholder holder =  (ViewHolder)  convertview.gettag ();             holder.mposition = position;             return holder;        }    }          public <t extends view> t getview (int &NBSP;VIEWID)  {        view view = mviews.get ( Viewid);        if  (view == null)  {             view = mconvertview.findviewbyid (Viewid) ;             mviews.put (Viewid, view);         }        return  (T)  view;    } 

The use of Sparearray here is similar to the:list<int,object> form of storage, to compare hashmap<int,object> to save time and improve efficiency.

To create an abstract class Commonadapter:

public abstract class commonadapter<t> extends baseadapter {     protected Context mcontext;    protected List<T>  Mdatas;    protected layoutinflater minlater;    private  int layoutid;    public commonadapter (context context ,list<t > datas,int layoutid)  {        this.mcontext =  context;        this.mDatas= datas;         this.layoutId = layoutId;         Minlater = layoutinflater.from (context);    }               public context getmcontext ()  {       &nbSp; return mcontext;    }      public void  setmcontext (Context mcontext)  {        this.mcontext  = mcontext;    }      public List<T>  getmdatas ()  {        return mDatas;     }      public void setmdatas (List<t> mdatas)  {         this.mDatas = mDatas;    }        @Override     public int getcount ()  {         return mdatas.size ();    }       @Override     public t getitem (int arg0)  {       &nbSp; return mdatas.get (arg0);    }      @Override      public long getitemid (int arg0)  {         return arg0;    }      @Override      public  view getview (Int postion, view convertview, viewgroup  parent) {        viewholder holder =  Viewholder.get (Mcontext, convertview, parent, postion, layoutid);         convert (Holder, getitem (postion));         return holder.getmconvertview ();    };    public  Abstract void convert (viewholder holder,t t);}

Open the Convert method to the developer for a simple assignment operation.

Inherit the Commonadapter in the custom adapter:

public class Newadapter extends commonadapter<bean>{public newadapter (context context, list<bean> Mdatas,    int layoutid) {Super (context, mdatas,layoutid); } @Override public void convert (Viewholder holder, bean Bean) {holder.settext (R.id.phone, Bean.getphone ()). s    Ettext (R.id.name, Bean.getusername ()); }}

When you initialize a custom adapter in mainactivity, you can use:

adapter= New Newadapter (Getapplicationcontext (), Mlist,r.layout.item);

Where you can encapsulate the operation of the control in the Viewholder package class (depending on your individual needs) adapter

Public Viewholder setText (int viewId, String text) {TextView TV = GetView (viewId);        Tv.settext (text);    return this;        }public viewholder setimageresource (int viewid,int resId) {ImageView img= getView (viewId);        Img.setimageresource (RESID);            return this; }

MU Class Network Universal Adapter Learning Notes