从一个线程更新界面 [英] Update UI from a thread

问题描述

我有一些麻烦试图automaticaly更新我的Andr​​oid活动视图。
该应用程序显示一个类似的聊天有些消息。即时通讯使用一个ListView把消息与一个ArrayAdapter。

我用这个梅托德更新的ListView

 公共无效loadMessages（）{
ArrayList的＆LT;串GT;消息= this.dbHelper.getMessages（）;
conversationArrayAdapter.clear（）;
conversationArrayAdapter.addAll（消息）;
conversationArrayAdapter.notifyDataSetChanged（）;
}
 

我的想法是把调用该梅托德一个线程，但是当我尝试这样做，我有以下错误。

  

只有创建视图层次可以触摸它认为原来的线程。

解决方案

您必须使用自己的线程。下面是使用AsyncTask的解决方案....

所有code将在你Activity类。

 公共无效toCallAsynchronous（）{
                最后的处理程序处理程序=新的处理程序（）;
                定时器定时器=新的Timer（）;
                TimerTask的doAsynchronousTask =新的TimerTask（）{
                    @覆盖
                    公共无效的run（）{
                        handler.post（新的Runnable（）{
                            公共无效的run（）{
                                尝试{
    //异步任务对象CALL每2 SECOND
    汽车pretraga zadatak =新的自动pretraga（）;
    zadatak.execute（TXT pretraga.getText（）的toString（））;
                            }
                        }）;
                    }
                };
timer.schedule（doAsynchronousTask，0，2000）; //每2每秒钟内可执行            }
 

的AsyncTask类.....

 私有类汽车pretraga延伸
                AsyncTask的＆LT;弦乐，对象，列出＆LT; Korisnici＆GT;＆GT; {            @覆盖
            保护列表与LT; Korisnici＆GT; doInBackground（字符串... PARAMS）{
   //别碰GUI对象在这个函数!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
   //调用数据库在这个函数
        返回null;            }            @覆盖
            保护无效onPostExecute（列表＆LT; Korisnici＆GT;的结果）{
                super.onPostExecute（rezultat）;
                //在这个函数您已经RESUT从数据库中
                        //，你可以改变GUI            }        }
 

I'm having some trouble trying to update automaticaly a view in my android activity. The application display some message like a chat. Im using a ListView to put the message with a ArrayAdapter.

I use this metod to update the ListView

public void loadMessages() {
ArrayList<String> messages = this.dbHelper.getMessages();
conversationArrayAdapter.clear();
conversationArrayAdapter.addAll(messages);
conversationArrayAdapter.notifyDataSetChanged();
}

My idea is to put a thread that call that metod, but when i try to do this i have the following error.

Only the original thread that created a view hierarchy can touch its view.

解决方案

You must use your own Thread. Here is solution using AsyncTask....

All code put in your Activity class.

    public void toCallAsynchronous() {
                final Handler handler = new Handler();
                Timer timer = new Timer();
                TimerTask doAsynchronousTask = new TimerTask() {
                    @Override
                    public void run() {
                        handler.post(new Runnable() {
                            public void run() {
                                try {


    //ASYNC TASK OBJECT   CALL EVERY 2 SECOND                   
    AutoPretraga zadatak = new AutoPretraga();
    zadatak.execute(txtPretraga.getText().toString());


                            }
                        });
                    }
                };
timer.schedule(doAsynchronousTask, 0, 2000); // execute in every 2 second

            }

AsyncTask class.....

 private class AutoPretraga extends
                AsyncTask<String, Object, List<Korisnici>> {

            @Override
            protected List<Korisnici> doInBackground(String... params) {
   //DONT TOUCH GUI OBJECT IN THIS FUNCTION !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
   //CALL DATABASE IN THIS FUNCTION             


        return null;

            }

            @Override
            protected void onPostExecute(List<Korisnici> result) {


                super.onPostExecute(rezultat);


                //IN THIS FUNCTION YOU HAVE RESUT FROM DATABASE 
                        //AND YOU CAN CHANGE GUI

            }

        }

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