工作线程（耗时操作）与UI线程实现异步更新

来源：互联网发布：java如何安装与卸载编辑：程序博客网时间：2024/04/30 01:54

概述：工作线程A（多任务）执行期间，把单一任务的结果返回到UI线程更新。
实现：创建基础流程类（两个handler）

public abstract class BaseQueueThread{    /**     * 设置处理线程、ui处理流程，由子类实现     */    protected abstract Object doInWork(int integer);//耗时操作    protected abstract void doInUi(Object obj);//更新ui    private Handler mWorkHandler,mUiHandler;    private boolean isDestroy;    private PriorityQueue<Message> mQueue;//优先队列    public BaseQueueThread()    {        initProcess();    }    //暴露数据访问接口    public void sendMessage(int priority,Integer obj)    {        Message msg = Message.obtain();        msg.what = priority;        msg.obj = obj;        mWorkHandler.sendMessage(msg);//从工作线程开始    }    private void initProcess()    {        mUiHandler = new Handler(Looper.getMainLooper());        HandlerThread handlerThread = new HandlerThread(getClass().getName());        handlerThread.start();        mWorkHandler = new Handler(handlerThread.getLooper())        {            private boolean isWait;//是否在等待ui更新            @Override            public void handleMessage(Message msg)            {                if(isDestroy)                {                    return;                }                try                {                    if(msg.what == -1)                    {                        if (mQueue == null)                        {                            isWait = false;                            return;                        }                        msg = mQueue.poll();                        if (msg == null)                        {                            isWait = false;                            return;                        }                    }else if(isWait)                    {                        if (mQueue == null)                        {                            mQueue = new PriorityQueue<Message>(11, new Comparator<Message>()                            {                                @Override                                public int compare(Message lhs, Message rhs)                                {                                    return rhs.what - lhs.what;                                }                            });                        }                        Message message = Message.obtain();                        message.copyFrom(msg);                        mQueue.add(message);                        return;                    }else                    {                        isWait = true;                    }                    final Object result = doInWork((Integer) msg.obj);                    mUiHandler.post(new Runnable()                    {                        @Override                        public void run()                        {                            doInUi(result);                            Message msg1 = Message.obtain();                            msg1.what = -1;//通知ui更新成功                            mWorkHandler.sendMessageAtFrontOfQueue(msg1);                        }                    });                } catch (Exception e)                {                    isWait = false;                    e.printStackTrace();                }            }        };    }    public void onDestroy()    {        isDestroy = true;        if(mWorkHandler!=null)        {            mWorkHandler.removeCallbacksAndMessages(null);        }        if (mUiHandler!=null)        {            mUiHandler.removeCallbacksAndMessages(null);        }    }}

具体实现类：

public class EasyQueueThread extends BaseQueueThread{    private TextView mTextView;    public EasyQueueThread(TextView textView)    {        super();        mTextView = textView;    }    @Override    protected Object doInWork(int obj)    {        try        {            Thread.sleep(1000);        } catch (InterruptedException e)        {            e.printStackTrace();        }        return "ok"+obj;    }    @Override    protected void doInUi(Object obj)    {        mTextView.setText((String)obj);    }}

发送工作线程消息，逐步更新UI:

public class MainActivity extends Activity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        final TextView bt = (TextView) findViewById(R.id.button1);        EasyQueueThread easyQueueThread = new EasyQueueThread(bt);        for (int i = 0;i< 10 ;i++)        {            easyQueueThread.sendMessage(i,i);        }    }}

3.总结：耗时操作不要放在UI线程，关键点要处理好什么时候执行工作线程，什么时候执行UI线程。

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