更新LisView里面的进度条-优快云博客

本文介绍了一种在Android应用中更新UI的方法，通过处理线程发送包含进度信息的消息给Handler，Handler再更新List的Adapter，从而实现在List视图中动态展示进度。文中提供了一个具体的例子，包括代码实现和布局文件。

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今天看到论坛上有人问这个。估计是要搞一个类似下载软件的东西吧。

所以就有了本篇，原理：

处理线程先给handler发消息，消息中包括进度信息，handler在去更改List的Adapter里面的信息，并通知List更新UI。

原理很简单，就直接上码了：

 
     001package hol.test.listprogress; 

     002  

     003import java.util.ArrayList; 

     004import java.util.HashMap; 

     005import java.util.List; 

     006  

     007import android.app.Activity; 

     008import android.content.Context; 

     009import android.os.Bundle; 

     010import android.os.Handler; 

     011import android.os.Message; 

     012import android.view.LayoutInflater; 

     013import android.view.View; 

     014import android.view.ViewGroup; 

     015import android.widget.BaseAdapter; 

     016import android.widget.Button; 

     017import android.widget.ListView; 

     018import android.widget.ProgressBar; 

     019import android.widget.TextView; 

     020  

     021public class TestListProgress extends Activity { 

     022    private Button testDo = null; 

     023    private ListView progressList = null; 

     024    private List<HashMap<String, Object>> list; 

     025    private MyAdapter myAdapet; 

     026    private MyHandler myHandler; 

     027  

     028    @Override

     029    public void onCreate(Bundle savedInstanceState) { 

     030        super.onCreate(savedInstanceState); 

     031        setContentView(R.layout.main); 

     032  

     033        myHandler = new MyHandler(); 

     034  

     035        findView(); 

     036        addListerner(); 

     037        initList(); 

     038    } 

     039  

     040    private void findView() { 

     041        testDo = (Button) findViewById(R.id.btn_test); 

     042        progressList = (ListView) findViewById(R.id.lst_progress); 

     043    } 

     044  

     045    private void addListerner() { 

     046        testDo.setOnClickListener(new ClickEvent()); 

     047    } 

     048  

     049    private void initList() { 

     050        list = new ArrayList<HashMap<String, Object>>(); 

     051        HashMap<String, Object> dataA = new HashMap<String, Object>(); 

     052        HashMap<String, Object> dataB = new HashMap<String, Object>(); 

     053        dataA.put("title", "dataA"); 

     054        dataA.put("current", 0); 

     055        list.add(dataA); 

     056        dataB.put("title", "dataB"); 

     057        dataB.put("current", 0); 

     058        list.add(dataB); 

     059  

     060        myAdapet = new MyAdapter(TestListProgress.this, list); 

     061        progressList.setAdapter(myAdapet); 

     062  

     063    } 

     064  

     065    // 模拟处理线程 

     066    class UpdateRunnable implements Runnable { 

     067        int id; 

     068        int currentPos = 0; 

     069        int delay; 

     070        MyHandler handler; 

     071  

     072        public UpdateRunnable(int id, int delay, MyHandler handler) { 

     073            this.id = id; 

     074            this.handler = handler; 

     075            this.delay = delay; 

     076        } 

     077  

     078        @Override

     079        public void run() { 

     080            // TODO Auto-generated method stub 

     081            while (currentPos <= 100) { 

     082                Message msg = handler.obtainMessage(); 

     083                msg.what = 1; 

     084                msg.arg1 = id; 

     085                msg.arg2 = currentPos; 

     086                currentPos = currentPos + 5; 

     087                msg.sendToTarget(); 

     088                try { 

     089                    Thread.sleep(delay); 

     090                } catch (InterruptedException e) { 

     091                    // TODO Auto-generated catch block 

     092                    e.printStackTrace(); 

     093                } 

     094            } 

     095        } 

     096  

     097    } 

     098  

     099    // 消息Handler用来更新UI 

     100    class MyHandler extends Handler { 

     101        @Override

     102        public void handleMessage(Message msg) { 

     103            // TODO Auto-generated method stub 

     104            switch (msg.what) { 

     105            case 1: 

     106                int id = msg.arg1; 

     107                int current = msg.arg2; 

     108                updateProgress(id, current); 

     109                break; 

     110            } 

     111            super.handleMessage(msg); 

     112        } 

     113  

     114        private void updateProgress(int id, int currentPos) { 

     115            HashMap<String, Object> dataTemp = list.get(id); 

     116            dataTemp.put("current", currentPos); 

     117            myAdapet.chargeProgress(id, dataTemp); 

     118        } 

     119    } 

     120  

     121    // 按钮事件 

     122    class ClickEvent implements View.OnClickListener { 

     123  

     124        @Override

     125        public void onClick(View v) { 

     126            // TODO Auto-generated method stub 

     127            switch (v.getId()) { 

     128            case (R.id.btn_test): 

     129                new Thread(new UpdateRunnable(0, 400, myHandler)).start(); 

     130                new Thread(new UpdateRunnable(1, 200, myHandler)).start(); 

     131                System.out.println("OnClick"); 

     132                break; 

     133            } 

     134        } 

     135  

     136    } 

     137  

     138    // List的显示 

     139    class MyAdapter extends BaseAdapter { 

     140  

     141        List<HashMap<String, Object>> list; 

     142        LayoutInflater infl = null; 

     143  

     144        public MyAdapter(Context context, List<HashMap<String, Object>> list) { 

     145            this.infl = (LayoutInflater) context 

     146                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE); 

     147            this.list = list; 

     148        } 

     149  

     150        @Override

     151        public int getCount() { 

     152            // TODO Auto-generated method stub 

     153            return list.size(); 

     154        } 

     155  

     156        @Override

     157        public Object getItem(int position) { 

     158            // TODO Auto-generated method stub 

     159            return list.get(position); 

     160        } 

     161  

     162        @Override

     163        public long getItemId(int position) { 

     164            // TODO Auto-generated method stub 

     165            return position; 

     166        } 

     167  

     168        @Override

     169        public View getView(int position, View convertView, ViewGroup parent) { 

     170            // TODO Auto-generated method stub 

     171            convertView = infl.inflate(R.layout.list_layout, null); 

     172            ProgressBar progressBar = (ProgressBar) convertView 

     173                    .findViewById(R.id.progress); 

     174            TextView titleView = (TextView) convertView 

     175                    .findViewById(R.id.title); 

     176  

     177            HashMap<String, Object> detail = list.get(position); 

     178            String t = (String) detail.get("title"); 

     179            titleView.setText(t); 

     180            int progress = (Integer) detail.get("current"); 

     181            progressBar.setProgress(progress); 

     182            return convertView; 

     183        } 

     184  

     185        // 改变进度，postion就是要改的那个进度 

     186        public void chargeProgress(int postion, HashMap<String, Object> detail) { 

     187            this.list.set(postion, detail); 

     188            // System.out.println("charged:" + detail.get("current")); 

     189            notifyDataSetChanged(); 

     190        } 

     191  

     192    } 

     193}

MyAdapet 里面的 chargeProgress是在用来更新List里面的值。

Message里面arg1就是List中的第几个进度条，arg2就是这个进度条里面的当前应该有的进度。what暂时没什么意义，只是为了标识这类消息是用来更新进度条的。本例也只有这一类消息。

这个是List的LayoutXML文件内容：

 
     01<LinearLayout

     02  xmlns:android="http://schemas.android.com/apk/res/android"

     03  android:orientation="horizontal"

     04  android:layout_width="fill_parent"

     05  android:layout_height="fill_parent"> 

     06  <TextView  android:id="@+id/title"

     07    android:layout_width="wrap_content"

     08    android:layout_height="wrap_content"

     09    android:text="In list"

     10    android:layout_marginRight="5dip"

     11    > 

     12  </TextView> 

     13  <ProgressBar android:id="@+id/progress"

     14    android:layout_width="wrap_content"

     15    android:layout_height="wrap_content"

     16    style="?android:attr/progressBarStyleHorizontal"

     17    android:max="100"

     18    android:layout_weight="1.0"

     19    android:visibility="visible"

     20  /> 

     21</LinearLayout>

Acitvity的布局：

 
     01<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

     02    android:orientation="vertical"

     03    android:layout_width="fill_parent"

     04    android:layout_height="fill_parent"

     05    > 

     06<TextView   

     07    android:layout_width="fill_parent" 

     08    android:layout_height="wrap_content" 

     09    android:text="@string/hello"

     10    /> 

     11    <Button android:id="@+id/btn_test"

     12        android:layout_width="fill_parent"

     13        android:layout_height="wrap_content"

     14        android:text="ListProgress"

     15    /> 

     16    <ListView android:id="@+id/lst_progress"

     17        android:layout_width="fill_parent"

     18        android:layout_height="wrap_content"

     19        android:layout_weight="1.0"

     20        > 

     21    </ListView> 

     22</LinearLayout>