我正在尝试发出简单的POST请求，并从网址获取回复。我使用异步任务来完成此操作，但我收到以下错误：
04-20 16:00:11.043 17340-17393/com.me.teli.c4k E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #5
Process: com.me.teli.c4k, PID: 17340
java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:300)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
Caused by: 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$TN.<init>(Toast.java:336)
at android.widget.Toast.<init>(Toast.java:100)
at android.widget.Toast.makeText(Toast.java:250)
at com.me.teli.c4k.models.activity_model.CreateNewAccountWithoutFacebook$CallAsyncTask.doInBackground(CreateNewAccountWithoutFacebook.java:102)
at com.me.teli.c4k.models.activity_model.CreateNewAccountWithoutFacebook$CallAsyncTask.doInBackground(CreateNewAccountWithoutFacebook.java:84)
at android.os.AsyncTask$2.call(AsyncTask.java:288)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)...
更奇怪的是，我在另一个项目中使用相同的代码并且它可以工作，但由于某些原因，在这个项目中它不起作用。我假设错误与在非ui线程上运行进程有关。但为什么我会收到此错误？我正在使用异步任务作为后台线程。
当我调试时，应用程序崩溃在我的Async Task：
HttpResponse response = httpclient.execute(httppost);
请帮忙。
这是我的代码：
public class CreateNewAccountWithoutFacebook extends ActionBarActivity {
...
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
ImageView saveme=(ImageView)findViewById(R.id.login_button);
saveme.setOnClickListener(new ImageView.OnClickListener(){
public void onClick(View v)
{
try{
new CallAsyncTask().execute();
}
catch(Exception ex)
{
}
}
});
}
public class CallAsyncTask extends AsyncTask<String,String,String>
{
@Override
protected String doInBackground(String... arg0)
{
// code for checking user name and password
try
{
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://xxxx.xxxx.xxxx.xxxx/login.php");
// Build The parameter
nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("username","jjj"));
nameValuePairs.add(new BasicNameValuePair("password",password.getText().toString()));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
// ERROR AT THIS LINE
HttpResponse response = httpclient.execute(httppost);
entity = response.getEntity();
}
catch(Exception e1)
{
Toast.makeText(getBaseContext(), "Error" + e1.toString(), Toast.LENGTH_LONG).show();
}
//read the responce into string
try
{
is = entity.getContent();
BufferedReader reader=new BufferedReader(new InputStreamReader(is));
StringBuilder builder=new StringBuilder();
String line=null;
while((line=reader.readLine())!=null)
{
builder.append(line+"\n");
}
Json=builder.toString();
is.close();
reader.close();
}
catch(Exception e2 )
{
Log.d("Buffer", "failed" + e2.toString());
}
// create the json object
try
{
jsonobject = new JSONObject(Json);
Iterator<String> iter = jsonobject.keys();
while (iter.hasNext()) {
String key = iter.next();
try {
int i=0;
Object value = jsonobject.get(key);
values.add(i, value);
i++;
} catch (JSONException e) {
Log.d("JsonException","error"+e.toString());
}
}
}
catch(Exception e3)
{
Log.d("InJson","error"+e3.toString());
}
return null;
}
@Override
protected void onPostExecute(String result)
{
super.onPostExecute(result);
new AlertDialog.Builder(CreateNewAccountWithoutFacebook.this)
.setTitle("Login Details")
.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
if(values.get(0).equals("Success")){
Intent intent = new Intent(CreateNewAccountWithoutFacebook.this, MainActivity.class);
startActivity(intent);
}else{
password.setText("");
}
}
})
.setIcon(android.R.drawable.ic_dialog_alert)
.show();
progressdialog.dismiss();
}
@Override
protected void onPreExecute()
{
super.onPreExecute();
progressdialog=new ProgressDialog(CreateNewAccountWithoutFacebook.this);
progressdialog.setMessage("Checking username and password please wait");
progressdialog.show();
}
}
}