Java Android:AsyncTask onPostExecute获得空回复
我正在开发一个Android应用程序,在该应用程序中,我在与活动相同的类中使用AsyncTask。在我有一个线程模型之前,我会加入线程并等待得到回复。但由于它锁定了UI,我正在将代码迁移到异步任务。其他方法进展顺利,但我遇到了一个错误,没有收到任何信息 由于服务器位于localhost中,因此我将记录我发送的回复。而且,它与线程配合得很好。我做错了什么 错误日志:Java Android:AsyncTask onPostExecute获得空回复,java,android,multithreading,android-asynctask,Java,Android,Multithreading,Android Asynctask,我正在开发一个Android应用程序,在该应用程序中,我在与活动相同的类中使用AsyncTask。在我有一个线程模型之前,我会加入线程并等待得到回复。但由于它锁定了UI,我正在将代码迁移到异步任务。其他方法进展顺利,但我遇到了一个错误,没有收到任何信息 由于服务器位于localhost中,因此我将记录我发送的回复。而且,它与线程配合得很好。我做错了什么 错误日志: 10-14 13:47:00.917 31746-31746/internetlegion.twentynotes E/Androi
10-14 13:47:00.917 31746-31746/internetlegion.twentynotes E/AndroidRuntime: FATAL EXCEPTION: main
10-14 13:47:00.917 31746-31746/internetlegion.twentynotes E/AndroidRuntime: Process: internetlegion.twentynotes, PID: 31746
10-14 13:47:00.917 31746-31746/internetlegion.twentynotes E/AndroidRuntime: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object org.springframework.http.ResponseEntity.getBody()' on a null object reference
10-14 13:47:00.917 31746-31746/internetlegion.twentynotes E/AndroidRuntime: at internetlegion.twentynotes.Activity.GroupAccountActivity$getGroupAccountsForLoggedInUser.onPostExecute(GroupAccountActivity.java:125)
10-14 13:47:00.917 31746-31746/internetlegion.twentynotes E/AndroidRuntime: at internetlegion.twentynotes.Activity.GroupAccountActivity$getGroupAccountsForLoggedInUser.onPostExecute(GroupAccountActivity.java:108)
10-14 13:47:00.917 31746-31746/internetlegion.twentynotes E/AndroidRuntime: at android.os.AsyncTask.finish(AsyncTask.java:632)
10-14 13:47:00.917 31746-31746/internetlegion.twentynotes E/AndroidRuntime: at android.os.AsyncTask.access$600(AsyncTask.java:177)
10-14 13:47:00.917 31746-31746/internetlegion.twentynotes E/AndroidRuntime: at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645)
10-14 13:47:00.917 31746-31746/internetlegion.twentynotes E/AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:102)
10-14 13:47:00.917 31746-31746/internetlegion.twentynotes E/AndroidRuntime: at android.os.Looper.loop(Looper.java:155)
10-14 13:47:00.917 31746-31746/internetlegion.twentynotes E/AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:5696)
10-14 13:47:00.917 31746-31746/internetlegion.twentynotes E/AndroidRuntime: at java.lang.reflect.Method.invoke(Native Method)
10-14 13:47:00.917 31746-31746/internetlegion.twentynotes E/AndroidRuntime: at java.lang.reflect.Method.invoke(Method.java:372)
10-14 13:47:00.917 31746-31746/internetlegion.twentynotes E/AndroidRuntime: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1028)
10-14 13:47:00.917 31746-31746/internetlegion.twentynotes E/AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:823)
GroupAccountActivity:
public class GroupAccountActivity extends Activity {
private ResponseEntity<RestGroupAccount[]> responseEntity;
GroupAccountAdapter groupAccountAdapter;
final String groupAccountRetrieveURL = StaticRestTemplate.baseURL+"getgroupsforuser/";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_group_account);
if(isOnline()) {
new getGroupAccountsForLoggedInUser().execute();
}else {
Toast.makeText(getApplicationContext(),"No Internet connection",Toast.LENGTH_LONG).show();
}
}
public class getGroupAccountsForLoggedInUser extends AsyncTask<Void,Void,ResponseEntity<RestGroupAccount[]>>{
@Override
protected ResponseEntity<RestGroupAccount[]> doInBackground(Void... params) {
RestTemplate restTemplate = StaticRestTemplate.getRest();
HttpHeaders requestHeaders = new HttpHeaders();
requestHeaders.add("Cookie", "JSESSIONID=" + StaticRestTemplate.jsessionid);
requestHeaders.setAccept(Collections.singletonList(new MediaType("application", "json")));
HttpEntity<?> requestEntity = new HttpEntity<Object>(requestHeaders);
restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
return restTemplate.exchange(groupAccountRetrieveURL, HttpMethod.GET, requestEntity, RestGroupAccount[].class);
}
@Override
protected void onPostExecute(ResponseEntity<RestGroupAccount[]> entity) {
super.onPostExecute(entity);
// Line below is throwing error.
RestGroupAccount[] restGroupAccounts = responseEntity.getBody();
Collections.addAll(restGroupAccountList, restGroupAccounts);
ArrayList<HashMap<String, String>> groupList = new ArrayList<HashMap<String, String>>();
}
}
公共类GroupAccountActivity扩展活动{
私人责任;
GroupAccountAdapter GroupAccountAdapter;
最后一个字符串groupAccountRetrieveURL=StaticRestTemplate.baseURL+“getgroupsforuser/”;
@凌驾
创建时的公共void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity\u group\u account);
if(isOnline()){
新建getGroupAccountsForLoggedInUser().execute();
}否则{
Toast.makeText(getApplicationContext(),“无Internet连接”,Toast.LENGTH_LONG.show();
}
}
公共类getGroupAccountsForLoggedInUser扩展异步任务{
@凌驾
受保护的响应性doInBackground(无效…参数){
RestTemplate RestTemplate=StaticRestTemplate.getRest();
HttpHeaders requestHeaders=新的HttpHeaders();
添加(“Cookie”、“JSSessionId=“+StaticRestTemplate.jsSessionId”);
setAccept(Collections.singletonList(新媒体类型(“应用程序”、“json”));
HttpEntity requestEntity=新的HttpEntity(requestHeaders);
restemplate.getMessageConverters().add(新映射Jackson2HttpMessageConverter());
返回restTemplate.exchange(groupAccountRetrieveURL、HttpMethod.GET、requestEntity、RestGroupAccount[].class);
}
@凌驾
PostExecute上受保护的void(响应实体){
super.onPostExecute(实体);
//下面一行是抛出错误。
RestGroupAccount[]restGroupAccounts=responseEntity.getBody();
Collections.addAll(restGroupAccountList、restGroupAccounts);
ArrayList groupList=新建ArrayList();
}
}
请让我知道。非常感谢。:-您在onPostExecute中引用了错误的对象。您应该引用结果对象/参数 将代码更改为:
RestGroupAccount[] restGroupAccounts = entity.getBody();
您在onPostExecute中引用了错误的对象。您应该引用结果对象/参数 将代码更改为:
RestGroupAccount[] restGroupAccounts = entity.getBody();
responseEntity
从不初始化
我想你是想这么做的
RestGroupAccount[] restGroupAccounts = entity.getBody();
responseEntity
从不初始化
我想你是想这么做的
RestGroupAccount[] restGroupAccounts = entity.getBody();
我想我发现了错误。你所做的是
RestGroupAccount[]restGroupAccounts=responseEntity.getBody();
但是在onPostExecute中,响应被称为实体
您在上面声明了响应,如:
private ResponseEntity ResponseEntity;
但这一条没有包含回应
试着改变
RestGroupAccount[]restGroupAccounts=responseEntity.getBody();
到
RestGroupAccount[]restGroupAccounts=entity.getBody();
我想我找到了错误。您要做的是
RestGroupAccount[]restGroupAccounts=responseEntity.getBody();
但是在onPostExecute中,响应被称为实体
您在上面声明了响应,如:
private ResponseEntity ResponseEntity;
但这一条没有包含回应
试着改变
RestGroupAccount[]restGroupAccounts=responseEntity.getBody();
到
RestGroupAccount[]restGroupAccounts=entity.getBody();
我太天真了。非常感谢。:-)我会在11分钟内接受你的答案,就像我现在说的那样。我太天真了。非常感谢。:-)我会在11分钟内接受你的答案,就像我现在说的那样。