Android 如何使用主线程解决问题

我尝试从php文件中获取JSON数据

public void connect(){
    System.out.println("%%%%%%%%%%%%%%%%%1" );
    Thread t = new Thread(){

        @Override
        public void run() {

    try {

        System.out.println("%%%%%%%%%%%%%%%%%2" );
        HttpParams params = new BasicHttpParams();
        HttpConnectionParams.setSoTimeout(params, 0);
        HttpClient httpClient = new DefaultHttpClient(params);
        String urlString = "http://url";
        //prepare the HTTP GET call 
        HttpGet httpget = new HttpGet(urlString);
        //get the response entity
        HttpEntity entity = httpClient.execute(httpget).getEntity();
        System.out.println("%%%%%%%%%%%%%%%%%3" );
        if (entity != null) {
            //get the response content as a string
            String response = EntityUtils.toString(entity);
            //consume the entity
            entity.consumeContent();

            // When HttpClient instance is no longer needed, shut down the connection manager to ensure immediate deallocation of all system resources
            httpClient.getConnectionManager().shutdown();

            //return the JSON response

            JSONArray jsonarray = new JSONArray(response); 
            JSONObject jb =(JSONObject) jsonarray.getJSONObject(0);
            String name= jb.getString("name");
            String punkt = jb.getString("punktezahl");

             //String name = jsonarray.getString("name");
             System.out.println("HEEEEEEEEEEEEEEEEEEEEEEEEEEEE" + name);
             fuehrender.setText(name);
             punkte.setText(punkt);
               }



    }catch (Exception e) {
        e.printStackTrace();
    }
}

};
t.start();
}

如果我这样做，我得到的信息是，只有创建视图层次结构的原始线程才能接触其视图

因此，由于此错误消息，我尝试如下操作：

public void connect(){
    System.out.println("%%%%%%%%%%%%%%%%%1" );
    runOnUiThread(new Runnable() {

        @Override
        public void run() {

    try {

        System.out.println("%%%%%%%%%%%%%%%%%2" );
        HttpParams params = new BasicHttpParams();
        HttpConnectionParams.setSoTimeout(params, 0);
        HttpClient httpClient = new DefaultHttpClient(params);
        String urlString = "http://url";
        //prepare the HTTP GET call 
        HttpGet httpget = new HttpGet(urlString);
        //get the response entity
        HttpEntity entity = httpClient.execute(httpget).getEntity();
        System.out.println("%%%%%%%%%%%%%%%%%3" );
        if (entity != null) {
            //get the response content as a string
            String response = EntityUtils.toString(entity);
            //consume the entity
            entity.consumeContent();

            // When HttpClient instance is no longer needed, shut down the connection manager to ensure immediate deallocation of all system resources
            httpClient.getConnectionManager().shutdown();

            //return the JSON response

            JSONArray jsonarray = new JSONArray(response); 
            JSONObject jb =(JSONObject) jsonarray.getJSONObject(0);
            String name= jb.getString("name");
            String punkt = jb.getString("punktezahl");

             //String name = jsonarray.getString("name");
             System.out.println("HEEEEEEEEEEEEEEEEEEEEEEEEEEEE" + name);
             fuehrender.setText(name);
             punkte.setText(punkt);
               }



    }catch (Exception e) {
        e.printStackTrace();
    }
}

});

}
}

---

现在，我得到了

NetworkOnMainThread

错误消息。。如何打破这一厄运循环？

您有一个

runOnUiThread

。移除它。它应该只用于更新ui，而不用于http get请求

使用

AsyncTask

是一个更好的选择。在

doInBackground

中发出http get请求，并解析响应。您可以在

doInbackground

中返回结果，这是

onPostExecute

的一个参数

因此，您可以在ui线程上调用的

onPostExecute

中更新ui

例如：

援引

new TheTask().execute(); // in ui thread

使

AsyncTask

成为活动的内部类

class TheTask extends AsyncTask<Void,Void,String>
{

    @Override
    protected String doInBackground(Void... params1) {
        String response = null; 
            try {
                HttpParams params = new BasicHttpParams();
                HttpConnectionParams.setSoTimeout(params, 0);
                HttpClient httpClient = new DefaultHttpClient(params);
                String urlString = "http://url";
                HttpGet httpget = new HttpGet(urlString);
                HttpEntity entity = httpClient.execute(httpget).getEntity();
                response = EntityUtils.toString(entity);
                httpClient.getConnectionManager().shutdown();
                }
                catch(Exception e)
                {
                    e.printStackTrace();
                }
        return response;
    }

    @Override
    protected void onPostExecute(String result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);
         JSONArray jsonarray = new JSONArray(result; 
         JSONObject jb =(JSONObject) jsonarray.getJSONObject(0);
         String name= jb.getString("name");
         String punkt = jb.getString("punktezahl");
         fuehrender.setText(name);
         punkte.setText(punkt);
    }

}

class任务扩展异步任务
{
@凌驾
受保护字符串doInBackground（无效…参数1）{
字符串响应=null；
试一试{
HttpParams params=新的BasicHttpParams（）；
HttpConnectionParams.setSoTimeout（参数，0）；
HttpClient HttpClient=新的默认HttpClient（参数）；
字符串URL字符串=”http://url";
HttpGet HttpGet=新的HttpGet（urlString）；
HttpEntity entity=httpClient.execute（httpget.getEntity（）；
response=EntityUtils.toString（实体）；
httpClient.getConnectionManager（）.shutdown（）；
}
捕获（例外e）
{
e、 printStackTrace（）；
}
返回响应；
}
@凌驾
受保护的void onPostExecute（字符串结果）{
//TODO自动生成的方法存根
super.onPostExecute（结果）；
JSONArray JSONArray=新JSONArray（结果；
JSONObject jb=（JSONObject）jsonarray.getJSONObject（0）；
字符串名称=jb.getString（“名称”）；
字符串punkt=jb.getString（“punktezahl”）；
fuehrender.setText（名称）；
punkte.setText（punkt）；
}
}

将try-catch块放在AsyncTask中。简短的回答是：不能在同一个线程上进行网络和ui。@user896692您需要使用thread或AsyncTask。AsyncTask更简单。可能是因为您正在调用

connect（）

来自

UI

。从后台

线程调用它

。但是我同意，这非常简单谢谢，这非常有用！但是我如何从onPostExecute访问我的TextView呢？@user896692将TextView声明为实例变量，并在onCreate中初始化它。将AsyncTask作为活动的内部类。如果AsyncTask是内部类，则ss，您可以在onPostExecute（）方法中引用TextView。