Android开发笔记3之控件

浏览数：27 / 时间：2015年06月11日

一：编辑框

在res文件夹下的layout的文件夹的xml文件

这样在xml中我们就声明了两个控件，一个EditText和一个TextView

<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=".MainActivity" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <EditText
        android:id="@+id/editText1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_below="@+id/textView1"
        android:layout_marginTop="24dp"
        android:ems="10" >

        <requestFocus />
    </EditText>

</RelativeLayout>

并且我们将为EditText控件添加事件监听setOnKeyListener,并实现了onKey方法--在这个项目中也就是用户在按键是变回触发这个事件，从而可以通过getText()方法来获取用户输入的内容，当然，用户在没有输入的默认情况下，编辑框EditText默认显示“输入账号”，实现这个功能的方法为Edit.SetHint(“请输入账号！”)或者在xml布局上写上“android:hit=”请输入账号！””，

代码为

package com.example.test;

import android.os.Bundle;
import android.app.Activity;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;


public class MainActivity extends Activity {
    private TextView m_texTextView;
    private EditText m_EditText;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        m_texTextView=(TextView)findViewById(R.id.textView1);
        m_EditText=(EditText)findViewById(R.id.editText1);
        m_EditText.setHint("请输入账号:");
        m_EditText.setOnKeyListener(new EditText.OnKeyListener(){
            @Override
            public boolean onKey(View arg0,int arg1,KeyEvent arg2){
                m_texTextView.setText("文本框中的内容是:"+m_EditText.getText().toString());
                return false;
            }
        });
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    
}

二：Spinner控件

1.在Activity中自定数据的绑定方式

private static final String[] m={"A型","B型","O型","AB型","其他"}; 
    private ArrayAdapter<String> adapter;

在Oncrete方法中做各种实例化spinner

     setContentView(R.layout.activity_main);
        Spinner spinner = (Spinner) findViewById(R.id.planets_spinner);        adapter=new ArrayAdapter<String>(this,  android.R.layout.simple_spinner_item, m);
        adapter.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line);  
        spinner.setAdapter(adapter);  
        spinner.setOnItemSelectedListener(new SpinnerSelectedListener());
        spinner.setVisibility(View.VISIBLE);

实现事件的注册

class SpinnerSelectedListener  implements OnItemSelectedListener{
        
        @Override
        public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,
                long arg3) {
            // TODO Auto-generated method stub
              Toast.makeText(MainActivity.this, "你的血型是："+m[arg2], 1).show();
        }
        @Override
        public void onNothingSelected(AdapterView<?> arg0) {
            // TODO Auto-generated method stub
            
        }
    }

2.在vlues文件夹中定义arrays.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string-array name="plantes">
        <item>NOKIA</item>
        <item>MOTO</item>
        <item>HTC</item>
        <item>LG</item>
        <item>其他</item>
    </string-array>
</resources>

private ArrayAdapter adapter2;
rotected void onCreate(Bundle savedInstanceState) {
   adapter2 = ArrayAdapter.createFromResource(this, R.array.plantes, android.R.layout.simple_spinner_item);
        adapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);  
        spinner1.setAdapter(adapter2);  
        spinner1.setOnItemSelectedListener(new SpinnerXMLSelectedListener());  
}
class SpinnerXMLSelectedListener  implements OnItemSelectedListener{
        
        @Override
        public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,
                long arg3) {
            // TODO Auto-generated method stub
             Toast.makeText(MainActivity.this, "你使用什么样的手机："+adapter2.getItem(arg2), 1).show();
        }
        @Override
        public void onNothingSelected(AdapterView<?> arg0) {
            // TODO Auto-generated method stub
            
        }
    }

注意两种方法分别给adater绑定数据的不同，而且simper_spinner_dropdown_item系统默认的layout方式

三：listView控件

1.使用listview对数据进行简单的绑定,这里使用Arrayadater适配器进行简单的数据绑定

public class MainActivity extends Activity {
    private ListView listView;
    private ArrayAdapter<String> adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listView=(ListView)this.findViewById(R.id.listView1);
        adapter=new ArrayAdapter<String>(MainActivity.this, 
                android.R.layout.simple_list_item_1, getDataSourece());
        listView.setAdapter(adapter);
    }

    public List<String> getDataSourece() {
        List<String> list=new ArrayList<String>();
        for(int i =0;i<30;i++){
            
            list.add("bibly"+i);
        }
        return list;
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    
}

2.自定义listview控件

1.使用SimpleAdapter+ListView

SimpleAdapter其中一个构造函数如下：

public SimpleAdapter (Context context, List<? extends Map<String, ?>> data, int resource, String[] from, int[] to)
第一个参数：当前上下文对象。第二个参数：一个List类型的泛型集合，泛型类型必须继承之Map类型。第三个：布局资源的ID，

第四个参数：需要绑定的Key列表。第五个参数：与Key列表项对应的资源文件中的具体组件ID集合。

自定义一个布局文件image.xml

<?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">
  
  
  <ImageView    
     android:layout_width="wrap_content"    
     android:layout_height="wrap_content"   
     android:id="@+id/img">    
  </ImageView>  
  
  
  <TextView
   android:id="@+id/txtName"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
  >
  </TextView>
  
  <TextView
   android:paddingLeft="20sp"
   android:id="@+id/txtLength"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
  >
  </TextView>
  
</LinearLayout>

package com.example.mytestxml;

import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.example.mytestxml.R.id;
import com.example.mytestxml.R.string;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.SimpleAdapter;

public class MainActivity extends Activity {
    private ListView listView;
    private ArrayAdapter<String> adapter;
    private Button button;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listView=(ListView)this.findViewById(R.id.listView1);
        button=(Button)this.findViewById(R.id.button1);
        button.setOnClickListener(new View.OnClickListener() {
            
            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub
                   String []from={"img","name","length"};
                     int[]to={R.id.img,R.id.txtName,R.id.txtLength};
                     SimpleAdapter adapter=new SimpleAdapter(MainActivity.this,getData(),
                             R.layout.image, from, to);
                     listView.setAdapter(adapter);  
            }
        });
        adapter=new ArrayAdapter<String>(MainActivity.this, 
                android.R.layout.simple_list_item_1, getDataSourece());
        listView.setAdapter(adapter);
    }
    public List<Map<String, Object>> getData() {
        List<Map<String,Object>> lists=new ArrayList<Map<String,Object>>();
        for(int i=0;i<4;i++){
            Map<String,Object> map=new HashMap<String,Object>();
            map.put("img", R.drawable.ic_launcher);
            map.put("name", "SimpleAdapter"+i);
            map.put("length", "300");
            lists.add(map);
        }
        return lists;
    }
    public List<String> getDataSourece() {
        List<String> list=new ArrayList<String>();
        for(int i =0;i<30;i++){
            
            list.add("bibly"+i);
        }
        return list;
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    
}

2.使用SimpleAdapter

activity_main.xml下更改代码

<?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">  
  
     <ImageView android:id="@+id/picture"  
        android:layout_width="wrap_content"  
        android:layout_height="wrap_content"  
        android:layout_margin="5dip"/>  
  
    <LinearLayout android:orientation="vertical"  
        android:layout_width="wrap_content"  
        android:layout_height="wrap_content">  
  
        <TextView android:id="@+id/title"  
            android:layout_width="wrap_content"  
            android:layout_height="wrap_content"  
            android:textColor="#16CCDD"  
            android:textSize="22sp" />  
  
        <TextView android:id="@+id/info"  
            android:layout_width="wrap_content"  
            android:layout_height="wrap_content"  
            android:textColor="#666666"  
            android:textSize="16sp" />  
    </LinearLayout>  
   
</LinearLayout>

更改MainActivity.java

public class MainActivity extends ListActivity  {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        SimpleAdapter adapter = new SimpleAdapter(this,getData(),  
                R.layout.activity_main,  
                new String[]{"title","info","picture"},  
                new int[]{R.id.title,R.id.info,R.id.picture});  
       setListAdapter(adapter);
    }
    private List<Map<String, Object>> getData() {  
        List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();  
        Map<String, Object> map = new HashMap<String, Object>();  
        map.put("title", "图片");  
        map.put("info", "美辰良景，给你无限的遐思，让人感觉无限温馨……");  
        map.put("picture", R.drawable.ic_launcher);  
        list.add(map);  
  
        map = new HashMap<String, Object>();  
        map.put("title", "音乐");  
        map.put("info", "轻曼音乐，令人如入仙境，如痴如醉……");  
        map.put("picture", R.drawable.ic_launcher);  
        list.add(map);  
  
        map = new HashMap<String, Object>();  
        map.put("title", "视频");  
        map.put("info", "震撼场景，360度的视觉捕获，一览无遗……");  
        map.put("picture", R.drawable.ic_launcher);  
        list.add(map);  
        return list;  
    }   
}

注意这里的MainActivity extends ListActivity ，ListActivity和普通的Activity没有太大的差别，不同就是对显示ListView做了许多优化，方面显示而已。

3.使用SimpleAdapter+ListView读取xml数据并访问(使用dom解析的方式读取xml数据)

定义的xml数据

<?xml version="1.0" encoding="utf-8"?>
<channel>
<item id="0" url="http://www.baidu.com">百度</item>
<item id="1" url="http://www.qq.com">腾讯</item>
<item id="2" url="http://www.sina.com.cn">新浪</item>
<item id="3" url="http://www.taobao.com">淘宝</item>
</channel>

定义对应的类来读取数据

public class channel {
    
    private String id;
    private String url;
    private String name;
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getUrl() {
        return url;
    }
    public void setUrl(String url) {
        this.url = url;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }

}

定义读取xml读取数据的类(使用Dom方式)

ublic class DomParserHelper {
    
    public static List<channel> getChannelList(InputStream stream)
    {
        List<channel> list=new ArrayList<channel>();
        
        //得到 DocumentBuilderFactory 对象, 由该对象可以得到 DocumentBuilder 对象
        DocumentBuilderFactory factory=DocumentBuilderFactory.newInstance();
        
        try {
            //得到DocumentBuilder对象
            DocumentBuilder builder=factory.newDocumentBuilder();
            //得到代表整个xml的Document对象
            Document document=builder.parse(stream);
            //得到 "根节点" 
            Element root=document.getDocumentElement();
            //获取根节点的所有items的节点
            NodeList items=root.getElementsByTagName("item");  
            //遍历所有节点
            for(int i=0;i<items.getLength();i++)
            {
                channel chann=new channel();
                Element item=(Element)items.item(i);
                chann.setId(item.getAttribute("id"));
                chann.setUrl(item.getAttribute("url"));
                chann.setName(item.getFirstChild().getNodeValue());
                list.add(chann);
            }
            
        } catch (ParserConfigurationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SAXException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
        return list;
    }

}

private List<Map<String, String>> getData2() {
        List<Map<String, String>> list = new ArrayList<Map<String, String>>();
        InputStream stream = getResources().openRawResource(R.raw.channels);
        List<channel> channlist = DomParserHelper.getChannelList(stream);

        for (int i = 0; i < channlist.size(); i++) {
            Map<String, String> map = new HashMap<String, String>();
            channel chann = (channel) channlist.get(i);
            map.put("id", chann.getId());
            map.put("url", chann.getUrl());
            map.put("name", chann.getName());
            list.add(map);
        }

        return list;
    }

button2.setOnClickListener(new View.OnClickListener() {
            
            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub
                 String []from={"id","name","url"};
                 int[]to={R.id.id,R.id.name,R.id.url};
                SimpleAdapter adapter = new SimpleAdapter(MainActivity.this,getData2(),
                         R.layout.myxml, from, to);
                  listView.setAdapter(adapter);  
            }
        });