android适配器之基于BaseAdapt自定义简单适配器

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代码样例：

一布局文件

<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context="com.example.listview.MainActivity" >    <ListView android:layout_width="match_parent"        android:layout_height="match_parent"        android:id="@+id/lv"></ListView></RelativeLayout>

二自定义ListView布局文件

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical" >        <TextView android:layout_width="wrap_content"        android:layout_height="320px"        android:id="@+id/tv"/></LinearLayout>

三自定义适配器

package com.example.listview;import java.util.List;import android.content.Context;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.TextView;public class MyAdapt extends BaseAdapter {private Context context;private List<Integer> list;int count = 0;public MyAdapt(Context context,List<Integer> list){this.context = context;this.list = list;}@Overridepublic int getCount() {// TODO Auto-generated method stubreturn list.size();}@Overridepublic Object getItem(int position) {// TODO Auto-generated method stubreturn list.get(position);}@Overridepublic long getItemId(int position) {// TODO Auto-generated method stubreturn 0;}@Overridepublic View getView(int position, View convertView, ViewGroup parent) {View view = View.inflate(context, R.layout.mylayout, null);TextView textView = (TextView) view.findViewById(R.id.tv);textView.setText(list.get(position)+"");return view;}}

四 MainActivity

package com.example.listview;import java.util.ArrayList;import java.util.List;import android.app.Activity;import android.os.Bundle;import android.widget.ListView;public class MainActivity extends Activity {private ListView listView;private List<Integer> list;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);listView = (ListView)findViewById(R.id.lv);list = new ArrayList<>();for (int i = 0; i < 100; i++) {list.add(i);}listView.setAdapter(new MyAdapt(this, list));}}

五总结

这种方式在数据量大的时候ListView的效率极低，显示每行数据都要重复执行一遍MyAdapt中的getView方法，其中除了要传递的数据不一样，样式等其他的都一样，所以这样效率非常低下。但是这种方法对于初学者来说比较好理解。到后面也要对这个ListView进行优化。

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