ListView 使用BaseAdapter

本文主要是介绍ListView 使用BaseAdapter，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

目的:为了加快UI的响应和使用自定义的ListView
BaseAdapter基本结构
public int getCount();
//返回适配器中数据的条数
public Object getItem(int i);
//获取数据集中与指定索引对应的数据项
public long getItemId(int i);
//获取指定行对应的ID
public View getView(int i,VIew view, ViewGRoup viewGroup);
//获取每一个Item的显示内容
参数１:i,判断显示在界面上的第几个item
参数2:view,显示在界面上的一个item

参数3:viewGroup加载xml视图时使用

1.主界面的xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context="com.xxx.baseadaptertest.MainActivity"><ListViewandroid:id="@+id/listView"android:layout_width="0dp"android:layout_height="0dp"android:layout_marginBottom="8dp"android:layout_marginEnd="8dp"android:layout_marginStart="8dp"android:layout_marginTop="8dp"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>

2.自定义布局的xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:orientation="vertical"android:layout_width="match_parent"android:layout_height="wrap_content"><TextView android:id="@+id/device_name"android:layout_width="match_parent"android:layout_height="wrap_content"android:textSize="24dp"/><TextView android:id="@+id/device_address"android:layout_width="match_parent"android:layout_height="wrap_content"android:textSize="24dp"/>
</LinearLayout>

3.代码

public class MainActivity extends AppCompatActivity {private ListView lv;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);lv = (ListView)findViewById(R.id.listView);MyAdapter adapter = new MyAdapter(this);lv.setAdapter(adapter);}//静态类static class ViewHolder{TextView deviceName;TextView deviceAddress;}private class MyAdapter extends BaseAdapter{private LayoutInflater mInflator;public MyAdapter(Context context){//根据context上下文加载布局this.mInflator = LayoutInflater.from(context);}//显示多少条item的数据@Overridepublic int getCount() {return 3;}@Overridepublic Object getItem(int i) {return i;}@Overridepublic long getItemId(int i) {return i;}@Overridepublic View getView(int i, View view, ViewGroup viewGroup) {ViewHolder viewHolder = null;//如果缓存view为空,则新建　if(view == null){viewHolder = new ViewHolder();//加载自定义的item布局view = mInflator.inflate(R.layout.listitem_device,null);viewHolder.deviceName = (TextView)view.findViewById(R.id.device_name);viewHolder.deviceAddress = (TextView)view.findViewById(R.id.device_address);//将设置好的布局保存到缓存中,设置到tag里方便后面取出view.setTag(viewHolder);}else{viewHolder = (ViewHolder)view.getTag();}//设置数据,以可以根据传入的Data来获取viewHolder.deviceName.setText("vivo");viewHolder.deviceAddress.setText("123456");return view;}}}