Android入门：ListView

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一、ListView介绍

ListView是类似于将一个界面分为一行一行，如下图：

ListView只是一个视图，而如果要在这个列表视图中显示数据，则必须要通过“Adapter”，我们通常有三种Adapter：

(1)ArrayAdapter：每行只能是一个文本；

(2)SimpleAdapter：此种方式不是很好，经过测试，只能显示一行数据；

(3)继承BaseAdapter：此种方式较灵活，可以自定义将每行对应到不同的布局xml中；

(4)SimpleCursorAdapter：此处传入的数据不是List，而是数据库查询返回的Cursor；

二、ListView实例

这个实例分别实现了三种ListView的使用；

工程的层次结构如下：

ListView的界面如图所示：

ArrayAdapter的显示界面如下：

SimpleAdapter的界面如下：

ExtendBaseAdapter的界面如下：

1.主界面模块：

ListViewActivity.java

package org.xiazdong;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.ArrayAdapter;import android.widget.Button;public class ListViewActivity extends Activity implements OnClickListener{private Button btn1;private Button btn2;private Button btn3;    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);//一定要先setContentView，才findViewById        btn1 = (Button) this.findViewById(R.id.arrayAdapter);        btn2 = (Button) this.findViewById(R.id.simpleAdapter);        btn3 = (Button)this.findViewById(R.id.baseAdapter);        btn1.setOnClickListener(this);        btn2.setOnClickListener(this);        btn3.setOnClickListener(this);    }@Overridepublic void onClick(View v) {if(v==btn1){Intent intent = new Intent(ListViewActivity.this,ArrayAdapterActivity.class);this.startActivity(intent);}else if(v==btn2){Intent intent = new Intent(ListViewActivity.this,SimpleAdapterActivity.class);this.startActivity(intent);}else if(v==btn3){Intent intent = new Intent(ListViewActivity.this,ExtendBaseAdapterActivity.class);this.startActivity(intent);}}}

main.xml

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:orientation="vertical" >    <TextView        android:id="@+id/tv"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:layout_centerHorizontal="true"        android:text="ListView的使用"        android:textSize="50px" />    <Button        android:id="@+id/arrayAdapter"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:layout_below="@id/tv"        android:text="ArrayAdapter" >    </Button>    <Button        android:id="@+id/simpleAdapter"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:layout_below="@id/arrayAdapter"        android:text="SimpleAdapter" >    </Button><Button        android:id="@+id/baseAdapter"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:layout_below="@id/simpleAdapter"        android:text="ExtendBaseAdapter" >    </Button>    <TextView        android:id="@+id/textView1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentBottom="true"        android:layout_alignParentRight="true"        android:layout_marginBottom="142dp"        android:layout_marginRight="16dp"        android:text="by xiazdong"        android:textSize="20px" /></RelativeLayout>

2.ArrayAdapter模块

ArrayAdapterActivity.java

package org.xiazdong;import java.util.ArrayList;import java.util.List;import android.app.Activity;import android.os.Bundle;import android.widget.ArrayAdapter;import android.widget.ListView;/* * 每创建一个Activity就要在AndroidManifest.xml中声明 * ArrayAdapter只能显示基本的字符串 * SimpleAdapter能够显示自定义视图 */public class ArrayAdapterActivity extends Activity {private ListView lv;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);lv = new ListView(this);   //ListView继承ViewList<String> list = new ArrayList<String>();for (int i = 0; i < 10; i++) {list.add("xiazdong-" + i);}ArrayAdapter<String> sa = new ArrayAdapter<String>(this,   //将List赋给ArrayAdapter，采用simple_item_1样式android.R.layout.simple_list_item_1, list);lv.setAdapter(sa);//将ArrayAdapter的值映射到ListView中this.setContentView(lv);}}

3.SimpleAdapter模块

一般ListView都是用来显示列表的，一般列表的数据都是来自数据库的，因此我们这里假设前面已经实现了一个DBService类，里面存在pageQuery(int offset,int length);

比如dbservice.pageQuery(3,5);表示跳过3个记录，插入5条记录；

main.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:orientation="vertical" >    <LinearLayout        android:layout_width="wrap_content"//注意一定要wrap_content        android:layout_height="wrap_content"//注意一定要wrap_content        android:orientation="horizontal" >        <TextView        android:layout_width="100dp"        android:layout_height="wrap_content"        android:text="ID" />        <TextView        android:layout_width="100dp"        android:layout_height="wrap_content"        android:text="NAME" />        <TextView        android:layout_width="100dp"        android:layout_height="wrap_content"        android:text="AGE" />    </LinearLayout>    <ListView        android:id="@+id/listview"        android:layout_width="wrap_content"        android:layout_height="fill_parent" >    </ListView></LinearLayout>

item.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:orientation="horizontal" >    <TextView        android:id="@+id/id1"        android:layout_width="100dp"        android:layout_height="wrap_content"        />    <TextView        android:id="@+id/name"        android:layout_width="100dp"        android:layout_height="wrap_content"        />    <TextView        android:id="@+id/age"        android:layout_width="100dp"        android:layout_height="wrap_content"        /></LinearLayout>

MainActivity.java

package org.xiazdong.db;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import org.xiazdong.db.domain.Person;import org.xiazdong.db.service.DBService;import android.app.Activity;import android.os.Bundle;import android.util.Log;import android.widget.ListView;import android.widget.SimpleAdapter;public class MainActivity extends Activity {private ListView listView;@Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        listView = (ListView)this.findViewById(R.id.listview);        DBService service = new DBService(this);        List<Person> persons = service.pageQuery(0, 10);        List<HashMap<String,Object>> data = new ArrayList<HashMap<String,Object>>();        for(Person person:persons){        HashMap<String,Object>map = new HashMap<String,Object>();        map.put("id", person.getId());        map.put("name", person.getName());        map.put("age", person.getAge());        data.add(map);        }        System.out.println(data);        SimpleAdapter adapter = new SimpleAdapter(this, data, R.layout.item, new String[]{"id","name","age"}, new int[]{R.id.id1,R.id.name,R.id.age});//data表示显示的数据，一个Map为一行，List<Map>表示多行//R.layout.item表示一个item的布局//new String[]{"id","name","age"}表示将key="id"的值映射到R.id.id1上        listView.setAdapter(adapter);}}

总结：SimpleAdapter不需要内部实现Adapter，只能实现每个item布局都一样的列表；

4.继承BaseAdapter类

ExtendBaseAdapterActivity.java

package org.xiazdong;import java.util.ArrayList;import java.util.List;import android.app.Activity;import android.os.Bundle;import android.widget.ArrayAdapter;import android.widget.ListView;public class ExtendBaseAdapterActivity extends Activity {private ListView lv;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);lv = new ListView(this);MyAdapter ma = new MyAdapter(this, new int[] { R.layout.sub1,R.layout.sub2 }); // 分别在每行中显示sub1的布局和sub2的布局lv.setAdapter(ma);this.setContentView(lv);}}

MyAdapter.java

package org.xiazdong;import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.View.OnClickListener;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.Button;import android.widget.CheckBox;import android.widget.CompoundButton;import android.widget.CompoundButton.OnCheckedChangeListener;import android.widget.Toast;public class MyAdapter extends BaseAdapter {private Context context;private int layoutID[];private LayoutInflater inflator;public MyAdapter(Context context, int layoutID[]) {this.context = context;this.layoutID = layoutID;inflator = LayoutInflater.from(context);}@Overridepublic int getCount() { // 一个布局占一行return layoutID.length;}@Overridepublic Object getItem(int position) {return null;}@Overridepublic long getItemId(int position) {return 0;}@Override// position表示要显示第几行，0表示第一行// convertView表示要显示的视图public View getView(int position, View convertView, ViewGroup parent) {convertView = inflator.inflate(layoutID[position], null);//每次将一个布局xml映射到一项中if (convertView.findViewById(R.id.checkBox1) instanceof CheckBox) {CheckBox cb1 = (CheckBox) convertView.findViewById(R.id.checkBox1);cb1.setOnCheckedChangeListener(new OnCheckedChangeListener() {@Overridepublic void onCheckedChanged(CompoundButton buttonView,boolean isChecked) {Toast t = Toast.makeText(context, "点击了复选框", Toast.LENGTH_SHORT);t.show();}});}if (convertView.findViewById(R.id.button1) instanceof Button) {Button b1 = (Button) convertView.findViewById(R.id.button1);b1.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {Toast t = Toast.makeText(context, "点击了按钮", Toast.LENGTH_SHORT);t.show();}});}return convertView;}}

sub1.xml

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent" >       <TextView        android:id="@+id/textView1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignBaseline="@+id/checkBox1"        android:layout_alignBottom="@+id/checkBox1"        android:layout_alignParentLeft="true"        android:text="点击弹出提示" /> <CheckBox        android:id="@+id/checkBox1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentRight="true"        android:layout_alignParentTop="true"        android:text="" /> </RelativeLayout>

sub2.xml

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent" > <TextView     android:id="@+id/textView2"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:layout_alignBaseline="@+id/button1"     android:layout_alignBottom="@+id/button1"     android:layout_alignParentLeft="true"     android:text="TextView" /><Button     android:id="@+id/button1"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:layout_alignParentRight="true"     android:layout_alignParentTop="true"     android:text="Button" /></RelativeLayout>