Android Baseadapter and Viewholder optimizations

First of all, praise the great God of Hyman

Previously it was simply rewriting a baseadapter to keep the GetView method abstract. and Viewholder not abstract ...

Viewholder (with a collection + generic management access view)

/** * author:stone * Email: [email protected] * time:15/7/24 */public class Stoneviewholder {privat    e int mposition;    Private View Mconvertview;  Private sparsearray<view> mviews;        Manage view public Stoneviewholder in Listview-item (context context, int layoutid, int position, ViewGroup parent) {        This.mposition = position;        This.mconvertview = Layoutinflater.from (context). Inflate (LayoutID, parent, false);        This.mConvertView.setTag (this);    This.mviews = new sparsearray<view> ();    Public View Getconvertview () {return mconvertview; } public static Stoneviewholder getinstance (context context, int layoutid, int position, View Convertview, V Iewgroup parent) {if (Convertview = = null) {return new Stoneviewholder (context, LayoutID, position, PA        Rent);            } else {Stoneviewholder holder = (stoneviewholder) convertview.gettag ();  Holder.mposition = position; MorePosition return holder in the newly reused Convertview;        }} 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;    } public <T> void Settag (int viewId, T tag) {GetView (viewId). Settag (tag);    } public <T> T gettag (int viewId) {return (T) GetView (VIEWID). Gettag (); }/*------------------------Set the View property (extended later)--------------------------------*/public stoneviewholder setText (int v        Iewid, String text) {((TextView) GetView (viewId)). SetText (text);    return this;        } public stoneviewholder SetText (int viewId, int resId) {//r.string.        ((TextView) GetView (viewId)). SetText (ResId);    return this; } public stoneviewholder Setimagebitmap (int viewId, Bitmap Bitmap) {(ImageView) GetView (viewId)). Setimagebitmap   (bitmap);     return this; The public stoneviewholder setimageresource (int viewId, int resId) {(ImageView) GetView (viewId)). Setimageresource        (RESID);    return this; }}

Adapter

/** * author:stone * Email: [email protected] * time:15/7/24 + */public abstract class STONELISTADAPTER&L T    T> extends Baseadapter {private list<t> mdata;    Private Context Mcontext;    private int mlayoutid;        Public Stonelistadapter (context context, int layoutid, list<t> data) {This.mcontext = context;        This.mlayoutid = LayoutID; This.mdata = data = = null?    New Arraylist<t> (): data;    } @Override public int getcount () {return mdata.size ();    } @Override public T getItem (int position) {return mdata.get (position);    } @Override public long getitemid (int position) {return position; } @Override public View getView (int position, view Convertview, ViewGroup parent) {Stoneviewholder Holder =        Stoneviewholder.getinstance (Mcontext, Mlayoutid, Position, Convertview, parent);        GetView (Mcontext, holder, position); Return Holder.getconvertview (); } protected abstract void GetView (context context, stoneviewholder holder, int position);}

Use in Listviewactivity

Stonebaseadapter = new Stonelistadapter<user> (Listviewactivity.this, R.layout.activity_listview_item, MData) {    @Override    protected void GetView (context context, final Stoneviewholder holder, final int position) {        User u Ser = GetItem (position);        Holder.settext (r.id.tv_id, User.getid ()). SetText (R.id.tv_name, User.getname ())                . SetText (R.id.tv_age, User.getage () + "");        Holder.getview (r.id.btn_test). Setonclicklistener (New View.onclicklistener () {            @Override public            Void OnClick (View v) {            }}        );}    ;

about Adapter View grab Focus :

If Listview.setonitemclicklistener (listener); and the Button.setonclicklistener (listener) in item;

No matter how you click, the button will always be triggered ...

Just add a property to the Root-layout of item: android:descendantfocusability= "Blocksdescendants"

About Item-view re-use, show chaos:

Sometimes too many entries, sliding to the next screen of data, some view reuse, the state of the view (such as the selection of the checkbox, ImageView Pictures repeated) will become chaotic.

In general, there needs to be a mechanism to manage a correspondence relationship: What state does the current position correspond to?

For example, CheckBox check state confusion:

Class Myadapter extends Stonelistadapter<user> {private Sparsebooleanarray mcheckstatearray;            Public Myadapter (context context, int layoutid, List data) {Super (context, layoutid, data);        This.mcheckstatearray = new Sparsebooleanarray ();        } public void setchecked (int position, Boolean isChecked) {mcheckstatearray.put (position, isChecked);        } public boolean isChecked (int position) {return mcheckstatearray.get (position);                        } @Override protected void GetView (context context, final Stoneviewholder holder, final int position) {            CheckBox cb = Holder.getview (R.id.cb_check); Cb.setoncheckedchangelistener (New Compoundbutton.oncheckedchangelistener () {@Override publi c void OnCheckedChanged (Compoundbutton buttonview, Boolean isChecked) {setchecked (position, isChecked)        ;//record status, anti-cache display}    });        Cb.setchecked (isChecked (position)); }    }

Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced.

Android Baseadapter and Viewholder optimizations