Only the original thread that created a view hierarchy can touch its views_移动开发_编程开发_程序员俱乐部

异常:--------Only the original thread that created a view hierarchy can touch its views

?

cause by :?Can't create handler inside thread?

?

代码如下:

?

?

private OnClickListener btnLisener = new OnClickListener() {

		public void onClick(View arg0) {
			createProgressDialog(MainActivity.this);
			new ExcuteRunnable("today").start();
		}
};

class ExcuteRunnable extends Thread{
		private String method;
		ExcuteRunnable(String method){
			this.method = method;
		}
		@Override
		public void run() {
			try {
				dataProvider = requestData(method);
				setDataProvider(dataProvider);//更新UI的数据源
				progressDialog.dismiss();
			} catch (Exception e) {
				e.printStackTrace();
			}

		}
		
	}

?

　Activity是主线程 ?在一个新的线程里更新另一个线程的UI　报此异常,主要是Android的相关View和控件不是线程安全的

?

?

出现此异常解决方法有二,都是利用Handler类,即使新现成不能操作原始线程那就将更新的操作放到原始线程中

?

在原始线程中创建一个handler对像 ?重写handlMessage方法，在新线程中通过handler.sendMessage　激活刚方法

?

问题得到解决

?

?

	private OnClickListener btnLisener = new OnClickListener() {

		public void onClick(View arg0) {
			createProgressDialog(MainActivity.this);
			new ExcuteRunnable("today").start();
		}
};

?public Handler handler = new Handler(){

		@Override
		public void handleMessage(Message msg) {
			if(progressDialog!=null)progressDialog.dismiss();
			if(msg.what == 0)//成功
				setDataProvider(dataProvider);//将setDataProvider　从 requestData()方法中分离 　在新线程中无法操作主线程的UI
			else
				popMsg("错误", "请求数据出错!", MainActivity.this);
		}
		
	};
	
	/**
	 * 启动一个线程请求数据 
	 * @author liucf
	 */
	class ExcuteRunnable extends Thread{
		private String method;
		ExcuteRunnable(String method){
			this.method = method;
		}
		@Override
		public void run() {
			try {
				dataProvider = requestData(method);
				handler.sendEmptyMessage(0);
			} catch (Exception e) {
				handler.sendEmptyMessage(1);
			}
			
		}
		
	}

??二,原始线程中创建handler对像　将新线程加入到handler消息队列中

?

final Handler handler= new Handler();

   final Runnable runaable = new Runnable() {
        public void run() {
            setDataProvider(requestData("today"));
        }
    };

private OnClickListener btnLisener = new OnClickListener() {

		public void onClick(View arg0) {
			createProgressDialog(MainActivity.this);
			requestData();
		}
};

    protected void requestData() {
        Thread t = new Thread() {
            public void run() {
                handler.post(runnable); //加入到消息队列    　这样没有启动新的线程，虽然没有报异常。但仍然阻塞ProgressDialog的显示
            }
        };
        t.start();
    }

?