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
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
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;
}
}
public class ListAdapter extends ArrayAdapter<Item> {
private int resourceLayout;
private Context mContext;
public ListAdapter(Context context, int resource, List<Item> items) {
super(context, resource, items);
this.resourceLayout = resource;
this.mContext = context;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
if (v == null) {
LayoutInflater vi;
vi = LayoutInflater.from(mContext);
v = vi.inflate(resourceLayout, null);
}
Item p = getItem(position);
if (p != null) {
TextView tt1 = (TextView) v.findViewById(R.id.id);
TextView tt2 = (TextView) v.findViewById(R.id.categoryId);
TextView tt3 = (TextView) v.findViewById(R.id.description);
if (tt1 != null) {
tt1.setText(p.getId());
}
if (tt2 != null) {
tt2.setText(p.getCategory().getId());
}
if (tt3 != null) {
tt3.setText(p.getDescription());
}
}
return v;
}
}
这是我在项目中使用的一个类。你需要有一个你想要显示的项目的集合，在我的例子中是<Item>。你需要重写View getView(int position, View convertView, ViewGroup parent)方法。
itemlistrow定义了ListView的行。
<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="wrap_content" android:orientation="vertical"
android:layout_width="fill_parent">
<TableRow android:layout_width="fill_parent"
android:id="@+id/TableRow01"
android:layout_height="wrap_content">
<TextView android:textColor="#FFFFFF"
android:id="@+id/id"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="id" android:textStyle="bold"
android:gravity="left"
android:layout_weight="1"
android:typeface="monospace"
android:height="40sp" />
</TableRow>
<TableRow android:layout_height="wrap_content"
android:layout_width="fill_parent">
<TextView android:textColor="#FFFFFF"
android:id="@+id/categoryId"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="categoryId"
android:layout_weight="1"
android:height="20sp" />
<TextView android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:layout_weight="1"
android:textColor="#FFFFFF"
android:gravity="right"
android:id="@+id/description"
android:text="description"
android:height="20sp" />
</TableRow>
</TableLayout>
在MainActivity中定义listview，
ListView yourListView = (ListView) findViewById(R.id.itemListView);
// get data from the table by the ListAdapter
ListAdapter customAdapter = new ListAdapter(this, R.layout.itemlistrow, List<yourItem>);
yourListView .setAdapter(customAdapter);
数据模型
public class DataModel {
String name;
String type;
String version_number;
String feature;
public DataModel(String name, String type, String version_number, String feature ) {
this.name=name;
this.type=type;
this.version_number=version_number;
this.feature=feature;
}
public String getName() {
return name;
}
public String getType() {
return type;
}
public String getVersion_number() {
return version_number;
}
public String getFeature() {
return feature;
}
}
数组适配器
public class CustomAdapter extends ArrayAdapter<DataModel> implements View.OnClickListener{
private ArrayList<DataModel> dataSet;
Context mContext;
// View lookup cache
private static class ViewHolder {
TextView txtName;
TextView txtType;
TextView txtVersion;
ImageView info;
}
public CustomAdapter(ArrayList<DataModel> data, Context context) {
super(context, R.layout.row_item, data);
this.dataSet = data;
this.mContext=context;
}
@Override
public void onClick(View v) {
int position=(Integer) v.getTag();
Object object= getItem(position);
DataModel dataModel=(DataModel)object;
switch (v.getId())
{
case R.id.item_info:
Snackbar.make(v, "Release date " +dataModel.getFeature(), Snackbar.LENGTH_LONG)
.setAction("No action", null).show();
break;
}
}
private int lastPosition = -1;
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// Get the data item for this position
DataModel dataModel = getItem(position);
// Check if an existing view is being reused, otherwise inflate the view
ViewHolder viewHolder; // view lookup cache stored in tag
final View result;
if (convertView == null) {
viewHolder = new ViewHolder();
LayoutInflater inflater = LayoutInflater.from(getContext());
convertView = inflater.inflate(R.layout.row_item, parent, false);
viewHolder.txtName = (TextView) convertView.findViewById(R.id.name);
viewHolder.txtType = (TextView) convertView.findViewById(R.id.type);
viewHolder.txtVersion = (TextView) convertView.findViewById(R.id.version_number);
viewHolder.info = (ImageView) convertView.findViewById(R.id.item_info);
result=convertView;
convertView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) convertView.getTag();
result=convertView;
}
Animation animation = AnimationUtils.loadAnimation(mContext, (position > lastPosition) ? R.anim.up_from_bottom : R.anim.down_from_top);
result.startAnimation(animation);
lastPosition = position;
viewHolder.txtName.setText(dataModel.getName());
viewHolder.txtType.setText(dataModel.getType());
viewHolder.txtVersion.setText(dataModel.getVersion_number());
viewHolder.info.setOnClickListener(this);
viewHolder.info.setTag(position);
// Return the completed view to render on screen
return convertView;
}
}
主要活动
public class MainActivity extends AppCompatActivity {
ArrayList<DataModel> dataModels;
ListView listView;
private static CustomAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
listView=(ListView)findViewById(R.id.list);
dataModels= new ArrayList<>();
dataModels.add(new DataModel("Apple Pie", "Android 1.0", "1","September 23, 2008"));
dataModels.add(new DataModel("Banana Bread", "Android 1.1", "2","February 9, 2009"));
dataModels.add(new DataModel("Cupcake", "Android 1.5", "3","April 27, 2009"));
dataModels.add(new DataModel("Donut","Android 1.6","4","September 15, 2009"));
dataModels.add(new DataModel("Eclair", "Android 2.0", "5","October 26, 2009"));
dataModels.add(new DataModel("Froyo", "Android 2.2", "8","May 20, 2010"));
dataModels.add(new DataModel("Gingerbread", "Android 2.3", "9","December 6, 2010"));
dataModels.add(new DataModel("Honeycomb","Android 3.0","11","February 22, 2011"));
dataModels.add(new DataModel("Ice Cream Sandwich", "Android 4.0", "14","October 18, 2011"));
dataModels.add(new DataModel("Jelly Bean", "Android 4.2", "16","July 9, 2012"));
dataModels.add(new DataModel("Kitkat", "Android 4.4", "19","October 31, 2013"));
dataModels.add(new DataModel("Lollipop","Android 5.0","21","November 12, 2014"));
dataModels.add(new DataModel("Marshmallow", "Android 6.0", "23","October 5, 2015"));
adapter= new CustomAdapter(dataModels,getApplicationContext());
listView.setAdapter(adapter);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
DataModel dataModel= dataModels.get(position);
Snackbar.make(view, dataModel.getName()+"\n"+dataModel.getType()+" API: "+dataModel.getVersion_number(), Snackbar.LENGTH_LONG)
.setAction("No action", null).show();
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
row_item.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="10dp">
<TextView
android:id="@+id/name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:text="Marshmallow"
android:textAppearance="?android:attr/textAppearanceSmall"
android:textColor="@android:color/black" />
<TextView
android:id="@+id/type"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/name"
android:layout_marginTop="5dp"
android:text="Android 6.0"
android:textColor="@android:color/black" />
<ImageView
android:id="@+id/item_info"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:src="@android:drawable/ic_dialog_info" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true">
<TextView
android:id="@+id/version_heading"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="API: "
android:textColor="@android:color/black"
android:textStyle="bold" />
<TextView
android:id="@+id/version_number"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="23"
android:textAppearance="?android:attr/textAppearanceButton"
android:textColor="@android:color/black"
android:textStyle="bold" />
</LinearLayout>
</RelativeLayout>
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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