android studio怎么新建adapter的自定义列表
2015-03-30 · 知道合伙人数码行家
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在例子中我们把原来的AndroidGraphics2DTutorial改名为AndroidGra
phics2DTutorial1,重新创建一个类AndroidGraphics2DTutorial来显示示例列表。打算使用三个View来显示列表中的一项,一个图标(例子中随机使用了一些图
标),一个文本框显示示例Activity名称,另一个文本框显示示例的具体信息。在res\layout目录下创建一个
activitylist.xml。内容如下:
这次我们不从AndroidManifest.xml中读取Activity列表,而是使用String
Array资源。在res\value\string.xml 中添加下列Array资源:
<string-array name=”activity_name”> <item>Bezier</item> <item>Brush</item> <item>Colors</item> <item>Font</item> <item>Image</item> <item>Path</item> <item>Pen</item> <item>Shape</item> <item>Transform</item> </string-array> <string-array name=”activity_info”> <item>Bezier</item> <item>Pattern ,Gradients</item> <item>Colors</item> <item>FontDemo, FontTypes</item> <item>DrawMap, JumbleImage, SeeThroughImage</item> <item>Polys, Paths</item> <item>Lines, Dashes, LineCap,LineJoin</item> <item>Oval ,Pear ,Shape2DDemo</item> <item>Transform</item> </string-array>
定义了这些资源后,可以在程序中使用自定义Adapter来显示列表:
class ActivityInfo{ int iconIndex; String activityName; String activityInfo; } class ActivityInfoAdapter extends ArrayAdapter<ActivityInfo>{ int resource; public ActivityInfoAdapter(Context context, int resourceId, List<ActivityInfo> objects) { super(context, resourceId, objects); resource=resourceId; } @Override public View getView(int position,View ConvertView,ViewGroup parent){ LinearLayout activityInfoView; ActivityInfo activityInfo=getItem(position); String activity_Name=activityInfo.activityName; String activity_Info=activityInfo.activityInfo; int iconIndex=activityInfo.iconIndex; if(ConvertView==null){ activityInfoView=new LinearLayout(getContext()); String inflater=Context.LAYOUT_INFLATER_SERVICE; LayoutInflater vi; vi=(LayoutInflater)getContext().getSystemService(inflater); vi.inflate(resource, activityInfoView,true); }else{ activityInfoView=(LinearLayout)ConvertView; } TextView activity_NameView =(TextView)activityInfoView.findViewById(R.id.activityName); TextView activity_InfoView =(TextView)activityInfoView.findViewById(R.id.activityInfo); ImageView iconView =(ImageView)activityInfoView.findViewById(R.id.iconImage); activity_NameView.setText(activity_Name); activity_InfoView.setText(activity_Info); iconView.setImageResource(iconIndex); return activityInfoView; } } public class AndroidGraphics2DTutorial extends ListActivity { private ArrayList<ActivityInfo> activityInfos =new ArrayList<ActivityInfo>(); private ActivityInfoAdapter aa; private final static String packgeName="com.pstreets.graphics2d"; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); Resources res = getResources(); String[] activity_Names = res.getStringArray(R.array.activity_name); String[] activity_Infos = res.getStringArray(R.array.activity_info); for(int i=0;i<activity_Names.length;i++){ ActivityInfo activityInfo=new ActivityInfo(); activityInfo.activityName=activity_Names[i]; activityInfo.activityInfo=activity_Infos[i]; activityInfo.iconIndex=R.drawable.icon1+i; activityInfos.add(activityInfo); } aa=new ActivityInfoAdapter(this,R.layout.activitylist,activityInfos); setListAdapter(aa); } @Override protected void onListItemClick(ListView l, View v, int position, long id) { ActivityInfo activityInfo = (ActivityInfo) l.getItemAtPosition(position); Intent intent = new Intent(); intent.setClassName(this, packgeName+".example." +activityInfo.activityName); startActivity(intent); } }
类ActivityInfo定义列表每个元素的Data Model,为Activity的Icon资源ID,Activity Name以及Activity
Info.
类ActivityInfoAdapter为自定义Adapter,关键的是public View getView(int position,View
ConvertView,ViewGroup parent)。这个函数返回用来显示没个类别元素的View的示例。
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