Android线程更新UI报错:Can'tcreatehandlerinsidethreadthathasnotcalledLooper.prepare()

String title = titleText.getText().toString();
String timelength = lengthText.getText().toString();
ExecutorService exec = Executors.newCachedThreadPool();
exec.execute(new NewsService(getApplicationContext(),title,timelength));
}

NewsService代码：

@Override
public void run() {
String path = "http://192.168.0.102:8080/videonews/ManageServlet";
Map String,String params = new HashMap String,String
params.put("title",title);
params.put("timelength",timelength);
boolean result=false;
try {
result = sendGETRequest(path,params);
} catch (Exception e) {
e.printStackTrace();
if(result) {
Toast.makeText(context, R.string.success, Toast.LENGTH_LONG).show();
} else {
Toast.makeText(context,R.string.error,Toast.LENGTH_LONG).show();
}

报错：

04-18 13:06:36.191 2284-2305/test.example.com.newsmanage E/AndroidRuntime﹕ FATAL EXCEPTION: pool-1-thread-1
Process: test.example.com.newsmanage, PID: 2284
java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
at android.os.Handler. init (Handler.java:200)
at android.os.Handler. init (Handler.java:114)
at android.widget.Toast$TN. init (Toast.java:336)
at android.widget.Toast. init (Toast.java:100)
at android.widget.Toast.makeText(Toast.java:250)
at android.widget.Toast.makeText(Toast.java:277)
at test.example.com.service.NewsService.run(NewsService.java:86)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)

查了资料，说是Android中不能在子线程中来刷新UI。如果要实现你这功能的话。建议是在你的子线程中添加hander来发送消息更新线程。

下面这样做就OK了

1.在Activity中增加如下代码

private Handler myHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case 0x00 :
Toast.makeText(getApplicationContext(),"save success",Toast.LENGTH_SHORT).show();
break;
default:
Toast.makeText(getApplicationContext(),"save fail",Toast.LENGTH_SHORT).show();
};

2.启动线程时，将handler传入:

exec.execute(new NewsService(getApplicationContext(),myHandler,title,timelength));

3.在线程中，发送消息给handler:

@Override
public void run() {
String path = "http://192.168.0.102:8080/videonews/ManageServlet";
Map String,String params = new HashMap String,String
params.put("title",title);
params.put("timelength",timelength);
boolean result=false;
try {
result = sendGETRequest(path,params);
} catch (Exception e) {
e.printStackTrace();
Message msg = new Message();
if(result)
msg.what = 0x00;
else
msg.what = 0x01;
handler.sendMessage(msg);
}

完成。