我想为列表视图创建一个自定义适配器。有没有任何文章可以告诉我如何创建一个,并解释它是如何工作的?
当前回答
public class CustomAdapter extends BaseAdapter{
ArrayList<BookPojo> data;
Context ctx;
int index=0;
public CustomAdapter(ArrayList<BookPojo> data, Context ctx) {
super();
this.data = data;
this.ctx = ctx;
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return data.size();
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return data.get(position);
}
@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
View v=convertview;
if(v==null){
LayoutInflater vi=LayoutInflater.from(ctx);
v=vi.inflate(R.layout.messgeview,null);
}
RelativeLayout rlmessage=(RelativeLayout)v.findViewById(R.id.rlmessgeview);
TextView tvisdn=(TextView)v.findViewById(R.id.tvisdn);
TextView tvtitle=(TextView)v.findViewById(R.id.tvtitle);
TextView tvauthor=(TextView)v.findViewById(R.id.tvauthor);
TextView tvprice=(TextView)v.findViewById(R.id.tvprice);
BookPojo bpj=data.get(position);
tvisdn.setText(bpj.isdn+"");
tvtitle.setText(bpj.title);
tvauthor.setText(bpj.author);
tvprice.setText(bpj.price+"");
if(index%2==0)
{
rlmessage.setBackgroundColor(Color.BLUE);
}
else
{
rlmessage.setBackgroundColor(Color.YELLOW);
}
index++;
return v;
}
}
其他回答
这段代码很容易理解。
three_horizontal_text_views_layout.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/leftTextView"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/centreTextView"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/rightTextView"/>
</LinearLayout>
ThreeStrings.java
public class ThreeStrings {
private String left;
private String right;
private String centre;
public ThreeStrings(String left, String right, String centre) {
this.left = left;
this.right = right;
this.centre = centre;
}
}
ThreeHorizontalTextViewsAdapter.java
public class ThreeHorizontalTextViewsAdapter extends ArrayAdapter<ThreeStrings> {
private int layoutResource;
public ThreeHorizontalTextViewsAdapter(Context context, int layoutResource, List<ThreeStrings> threeStringsList) {
super(context, layoutResource, threeStringsList);
this.layoutResource = layoutResource;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View view = convertView;
if (view == null) {
LayoutInflater layoutInflater = LayoutInflater.from(getContext());
view = layoutInflater.inflate(layoutResource, null);
}
ThreeStrings threeStrings = getItem(position);
if (threeStrings != null) {
TextView leftTextView = (TextView) view.findViewById(R.id.leftTextView);
TextView rightTextView = (TextView) view.findViewById(R.id.rightTextView);
TextView centreTextView = (TextView) view.findViewById(R.id.centreTextView);
if (leftTextView != null) {
leftTextView.setText(threeStrings.getLeft());
}
if (rightTextView != null) {
rightTextView.setText(threeStrings.getRight());
}
if (centreTextView != null) {
centreTextView.setText(threeStrings.getCentre());
}
}
return view;
}
}
main_layout.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
android:orientation="vertical"
tools:context="com.androidapplication.ListActivity">
<ListView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/listView"></ListView>
</LinearLayout>
MainActivity.java
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
List<ThreeStrings> threeStringsList = new ArrayList<>();
ThreeStrings threeStrings = new ThreeStrings("a", "b", "c");
threeStringsList.add(threeStrings);
ListView listView = (ListView)findViewById(R.id.listView);
ThreeHorizontalTextViewsAdapter threeHorizontalTextViewsAdapter = new ThreeHorizontalTextViewsAdapter(this, R.layout.three_horizontal_text_views_layout, threeStringsList);
listView.setAdapter(threeHorizontalTextViewsAdapter);
}
//......}
谷歌有一个名为EfficientAdapter的示例,在我看来,它是如何实现自定义适配器的最佳简单示例。http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/view/List14.html @CommonsWare很好地解释了上面例子中使用的模式 http://commonsware.com/Android/excerpt.pdf
检查这个链接,在非常简单的通过convertView,我们可以得到一行的布局,这将显示在listview(这是parentView)。
View v = convertView;
if (v == null) {
LayoutInflater vi;
vi = LayoutInflater.from(getContext());
v = vi.inflate(R.layout.itemlistrow, null);
}
使用position,你可以得到List<Item>的对象。
Item p = items.get(position);
在此之后,我们必须将对象的所需细节设置为标识的表单小部件。
if (p != null) {
TextView tt = (TextView) v.findViewById(R.id.id);
TextView tt1 = (TextView) v.findViewById(R.id.categoryId);
TextView tt3 = (TextView) v.findViewById(R.id.description);
if (tt != null) {
tt.setText(p.getId());
}
if (tt1 != null) {
tt1.setText(p.getCategory().getId());
}
if (tt3 != null) {
tt3.setText(p.getDescription());
}
}
然后它将返回构造的视图,该视图将附加到parentView(这是一个ListView/GridView)。
您可以在官方ApiDemos中查看这个示例。它展示了如何扩展BaseAdapter并将其应用到ListView。在此之后,只需查看BaseAdapter的引用,并尝试理解每个方法做什么(包括继承的方法)以及何时/如何使用它。
另外,谷歌是你的朋友:)。
import android.app.Activity;
import android.content.Context;
import android.text.Html;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import org.json.JSONObject;
import java.util.ArrayList;
public class OurteamAdapter extends BaseAdapter {
Context cont;
ArrayList<OurteamModel> llist;
OurteamAdapter madap;
LayoutInflater inflater;
JsonHelper Jobj;
String Id;
JSONObject obj = null;
int position = 0;
public OurteamAdapter(Context c,ArrayList<OurteamModel> Mi)
{
this.cont = c;
this.llist = Mi;
}
@Override
public int getCount()
{
// TODO Auto-generated method stub
return llist.size();
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return llist.get(position);
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
@Override
public View getView(final int position, View convertView, ViewGroup parent)
{
// TODO Auto-generated method stub
if(convertView == null)
{
LayoutInflater in = (LayoutInflater) cont.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
convertView = in.inflate(R.layout.doctorlist, null);
}
TextView category = (TextView) convertView.findViewById(R.id.button1);
TextView title = (TextView) convertView.findViewById(R.id.button2);
ImageView i1=(ImageView) convertView.findViewById(R.id.imageView1);
category.setText(Html.fromHtml(llist.get(position).getGalleryName()));
title.setText(Html.fromHtml(llist.get(position).getGalleryDetail()));
if(llist.get(position).getImagesrc()!=null)
{
i1.setImageBitmap(llist.get(position).getImagesrc());
}
else
{
i1.setImageResource(R.drawable.anandlogo);
}
return convertView;
}
}
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