Android入門ProgressBar和ListView

一、提要

       今天要學習的是兩個稍微復雜一些的控件。

      ProgressBar經常用於文件載入，處理文件，下載等場合。

      ListView用於以列表的形式展示內容。

     最終效果:

二、ListView三個元素：

1．ListVeiw 用來展示列表的View。

2．適配器 用來把數據映射到ListView上的中介。

3．數據    具體的將被映射的字符串，圖片，或者基本組件。

根據列表的適配器類型，列表分為三種，ArrayAdapter，SimpleAdapter和SimpleCursorAdapter

其中以ArrayAdapter最為簡單，只能展示一行字。SimpleAdapter有最好的擴充性，可以自定義出各種效果。SimpleCursorAdapter可以認為是SimpleAdapter對數據庫的簡單結合，可以方面的把數據庫的內容以列表的形式展示出來。

ProgressBar比較簡單，有圓形和長條形。

三、代碼：

這裡把ProgressBar和ListView放在一個Acivity裡了。

MainActivy.java

[java]
<SPAN style="FONT-SIZE: 14px">package com.example.activity_02; 
 
import java.util.ArrayList; 
import java.util.HashMap; 
import java.util.Map; 
 
import android.os.Bundle; 
import android.app.Activity; 
import android.app.AlertDialog; 
 
import android.view.MenuItem; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.AdapterView; 
import android.widget.AdapterView.OnItemClickListener; 
import android.widget.Button; 
import android.widget.ListView; 
import android.widget.ProgressBar; 
import android.widget.SimpleAdapter; 
import android.widget.Toast;  
 
public class MainActivity extends Activity { 
    private ProgressBar myProgressBar1=null; 
    private ProgressBar myProgressBar2=null; 
    private Button myButton=null; 
    private ListView myListView=null;  
    private SimpleAdapter myAdapter=null; 
    private int i=0; 
 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.activity_main); 
 
        myProgressBar1=(ProgressBar)findViewById(R.id.myProgressBar1); 
        myProgressBar2=(ProgressBar)findViewById(R.id.myProgressBar2); 
        myButton=(Button)findViewById(R.id.myButton); 
        myButton.setOnClickListener(new ButtonListener()); 
        myListView = (ListView)findViewById(R.id.myListView);  
 
        //生成動態數組，並且轉載數據    
        ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();   
        for(int i=0;i<10;i++)   
        {   
            HashMap<String, String> map = new HashMap<String, String>();   
            map.put("ItemTitle", "I'm title!");   
            map.put("ItemText", "I'm content!I'm content!I'm content!");   
            mylist.add(map);   
        }   
        //生成適配器，數組===》ListItem    
        myAdapter= new SimpleAdapter(this, //沒什麼解釋    
                mylist,//數據來源     
                R.layout.my_listitem,//ListItem的XML實現    
 
                //動態數組與ListItem對應的子項            
                new String[] {"ItemTitle", "ItemText"},    
 
                //ListItem的XML文件裡面的兩個TextView ID    
                new int[] {R.id.ItemTitle,R.id.ItemText});  
        //添加並且顯示    
        myListView.setAdapter(myAdapter);   
        myListView.setOnItemClickListener(new OnItemClickListenerImpl()); 
    } 
 
    @Override 
    public boolean onMenuItemSelected(int featureId, MenuItem item) { 
        // TODO Auto-generated method stub  
        if(item.getItemId()==1) finish(); 
        if(item.getItemId()==2) new AlertDialog.Builder(this) .setTitle("About") .setMessage("Powerd By Empty.") .show();   
        return super.onMenuItemSelected(featureId, item); 
    } 
 
    class ButtonListener implements OnClickListener{  
        @Override 
        public void onClick(View v) { 
            // TODO Auto-generated method stub  
            if(i==0) 
            { 
                myProgressBar1.setVisibility(View.VISIBLE); 
                myProgressBar2.setVisibility(View.VISIBLE); 
            } 
            else if (i<myProgressBar1.getMax()) 
            { 
                myProgressBar1.setProgress(i); 
                myProgressBar1.setSecondaryProgress(i+10); 
                //默認模式的進度條無法設置狀態  
                //myProgressBar2.setProgress(i);  
            } 
            else 
            { 
                //myProgressBar1.setVisibility(View.GONE);  
                //myProgressBar2.setVisibility(View.GONE);  
                i=0; 
            } 
            i+=10; 
            System.out.println("ClickMe"); 
        } 
    } 
     
    private class OnItemClickListenerImpl implements OnItemClickListener { 
 
 
        @SuppressWarnings("unchecked") 
        @Override 
        public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {  
         
            //獲得選中項的HashMap對象   
            HashMap<String,String> map=(HashMap<String,String>)myListView.getItemAtPosition(arg2);  
            String title=map.get("ItemTitle");  
            String content=map.get("ItemText");  
            Toast.makeText(getApplicationContext(),   
                    "你選擇了第"+arg2+"個Item，itemTitle的值是："+title+"itemContent的值是:"+content,  
                    Toast.LENGTH_SHORT).show();  
        }  
    } 
} 
</SPAN> 

package com.example.activity_02;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

import android.os.Bundle;
import android.app.Activity;
import android.app.AlertDialog;

import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.Button;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.SimpleAdapter;
import android.widget.Toast;

public class MainActivity extends Activity {
 private ProgressBar myProgressBar1=null;
 private ProgressBar myProgressBar2=null;
 private Button myButton=null;
 private ListView myListView=null;
 private SimpleAdapter myAdapter=null;
 private int i=0;

 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);

  myProgressBar1=(ProgressBar)findViewById(R.id.myProgressBar1);
  myProgressBar2=(ProgressBar)findViewById(R.id.myProgressBar2);
  myButton=(Button)findViewById(R.id.myButton);
  myButton.setOnClickListener(new ButtonListener());
  myListView = (ListView)findViewById(R.id.myListView);

  //生成動態數組，並且轉載數據 
  ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>(); 
  for(int i=0;i<10;i++) 
  { 
   HashMap<String, String> map = new HashMap<String, String>(); 
   map.put("ItemTitle", "I'm title!"); 
   map.put("ItemText", "I'm content!I'm content!I'm content!"); 
   mylist.add(map); 
  } 
  //生成適配器，數組===》ListItem 
  myAdapter= new SimpleAdapter(this, //沒什麼解釋 
    mylist,//數據來源  
    R.layout.my_listitem,//ListItem的XML實現 

    //動態數組與ListItem對應的子項         
    new String[] {"ItemTitle", "ItemText"},  

    //ListItem的XML文件裡面的兩個TextView ID 
    new int[] {R.id.ItemTitle,R.id.ItemText});
  //添加並且顯示 
  myListView.setAdapter(myAdapter); 
  myListView.setOnItemClickListener(new OnItemClickListenerImpl());
 }

 @Override
 public boolean onMenuItemSelected(int featureId, MenuItem item) {
  // TODO Auto-generated method stub
  if(item.getItemId()==1) finish();
  if(item.getItemId()==2) new AlertDialog.Builder(this) .setTitle("About") .setMessage("Powerd By Empty.") .show(); 
  return super.onMenuItemSelected(featureId, item);
 }

 class ButtonListener implements OnClickListener{
  @Override
  public void onClick(View v) {
   // TODO Auto-generated method stub
   if(i==0)
   {
    myProgressBar1.setVisibility(View.VISIBLE);
    myProgressBar2.setVisibility(View.VISIBLE);
   }
   else if (i<myProgressBar1.getMax())
   {
    myProgressBar1.setProgress(i);
    myProgressBar1.setSecondaryProgress(i+10);
    //默認模式的進度條無法設置狀態
    //myProgressBar2.setProgress(i);
   }
   else
   {
    //myProgressBar1.setVisibility(View.GONE);
    //myProgressBar2.setVisibility(View.GONE);
    i=0;
   }
   i+=10;
   System.out.println("ClickMe");
  }
 }
 
 private class OnItemClickListenerImpl implements OnItemClickListener {

  @SuppressWarnings("unchecked")
  @Override
  public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
  
            //獲得選中項的HashMap對象
            HashMap<String,String> map=(HashMap<String,String>)myListView.getItemAtPosition(arg2);
            String title=map.get("ItemTitle");
            String content=map.get("ItemText");
            Toast.makeText(getApplicationContext(), 
                    "你選擇了第"+arg2+"個Item，itemTitle的值是："+title+"itemContent的值是:"+content,
                    Toast.LENGTH_SHORT).show();
        }
 }
}

[html]
<SPAN style="FONT-SIZE: 14px"><!--my_listitem.xml--> 
<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:id="@+id/myListItem" 
    android:layout_width="fill_parent" 
    android:layout_height="match_parent" 
    android:orientation="vertical" 
    android:paddingBottom="3dip" 
    android:paddingLeft="10dip" > 
 
    <TextView 
        android:id="@+id/ItemTitle" 
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:textSize="30dip" > 
    </TextView> 
 
    <TextView 
        android:id="@+id/ItemText" 
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" > 
    </TextView> 
 
</LinearLayout></SPAN> 

<!--my_listitem.xml-->
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/myListItem"
    android:layout_width="fill_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingBottom="3dip"
    android:paddingLeft="10dip" >

    <TextView
        android:id="@+id/ItemTitle"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:textSize="30dip" >
    </TextView>

    <TextView
        android:id="@+id/ItemText"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" >
    </TextView>

</LinearLayout>
[html]
<SPAN style="FONT-SIZE: 14px"><!--activity_main.xml--> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    android:orientation="vertical" > 
 
    <TextView 
        android:id="@+id/myTextView" 
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:text="@string/tip1" 
        android:textSize="20dp" /> 
 
    <ProgressBar 
        android:id="@+id/myProgressBar1" 
        style="?android:attr/progressBarStyleHorizontal" 
        android:layout_width="200dp" 
        android:layout_height="wrap_content" 
        android:visibility="gone" /> 
 
    <ProgressBar 
        android:id="@+id/myProgressBar2" 
        style="?android:attr/progressBarStyle" 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        android:visibility="gone" /> 
 
    <Button 
        android:id="@+id/myButton" 
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:text="@string/tip2" /> 
 
    <TextView 
        android:id="@+id/myTextView2" 
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:text="@string/tip3" 
        android:textSize="20dp" /> 
 
    <ListView 
        android:id="@+id/myListView" 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" > 
    </ListView> 
 
</LinearLayout></SPAN> 

<!--activity_main.xml-->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/myTextView"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/tip1"
        android:textSize="20dp" />

    <ProgressBar
        android:id="@+id/myProgressBar1"
        style="?android:attr/progressBarStyleHorizontal"
        android:layout_width="200dp"
        android:layout_height="wrap_content"
        android:visibility="gone" />

    <ProgressBar
        android:id="@+id/myProgressBar2"
        style="?android:attr/progressBarStyle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:visibility="gone" />

    <Button
        android:id="@+id/myButton"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/tip2" />

    <TextView
        android:id="@+id/myTextView2"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/tip3"
        android:textSize="20dp" />

    <ListView
        android:id="@+id/myListView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" >
    </ListView>

</LinearLayout>