在android java中运行AsyncTask的问题
抱歉,这是一篇重复的文章,因为我之前上传了一个版本,但那个版本没有这个版本的答案 我在android编程中遇到asyncTask问题。我正在尝试在后台线程中加载一个文本文件,该线程是异步任务。首先,在我的应用程序中,我将一个变量从一个由数组列表控制的类发送到asyncTask类,该数组列表随后由xml文件中的按钮控制,因为它通过微调器选择索引。当涉及到后台线程类时,它失败了,因为我不太了解那个部分。如果有什么不清楚的地方,请询问,因为我是android编程的初学者。感谢您的帮助 以下是发送变量的代码:在android java中运行AsyncTask的问题,java,android,multithreading,android-asynctask,Java,Android,Multithreading,Android Asynctask,抱歉,这是一篇重复的文章,因为我之前上传了一个版本,但那个版本没有这个版本的答案 我在android编程中遇到asyncTask问题。我正在尝试在后台线程中加载一个文本文件,该线程是异步任务。首先,在我的应用程序中,我将一个变量从一个由数组列表控制的类发送到asyncTask类,该数组列表随后由xml文件中的按钮控制,因为它通过微调器选择索引。当涉及到后台线程类时,它失败了,因为我不太了解那个部分。如果有什么不清楚的地方,请询问,因为我是android编程的初学者。感谢您的帮助 以下是发送变量的
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_game_action);
Intent callingIntent = getIntent();
int index = callingIntent.getIntExtra("INDEX",0);
if(index==0){
fileReader_async=new FileReader_async(getApplicationContext(), this);
fileReader_async.execute("hogskoleprovet.txt");
}
else {
if (index == 1) {
fileReader_async = new FileReader_async(getApplicationContext(), this);
fileReader_async.execute("hogskoleprovet.txt");
} else if (index == 1) {
fileReader_async = new FileReader_async(getApplicationContext(), this);
fileReader_async.execute("hogskoleprovet.txt");
}
}
setNewQuestion();
}
以下是异步类:
package com.example.arnpet.ultimatehogskoleprovet;
import android.content.Context;
import android.os.AsyncTask;
import com.example.arnpet.ultimatehogskoleprovet.Question;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.security.auth.callback.Callback;
public class FileReader_async extends AsyncTask {
private Context context;
private Callback callback;
private List<Question> mQuestions;
public FileReader_async(Context context,Callback callback)
{
this.callback=callback;
}
@Override
protected Object doInBackground(Object... params) {
InputStream iS = null;
try {
iS = context.getAssets().open("hogskoleprovet");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
BufferedReader reader = new BufferedReader(new InputStreamReader(iS));
mQuestions = new ArrayList<Question>();
String question, answer, answerOne, answerTwo, answerThree, answerFour;
try {
while (reader.readLine() != null) {
//reading some lines from resource file
question = reader.readLine();
answer = reader.readLine();
answerOne = reader.readLine();
answerTwo = reader.readLine();
answerThree = reader.readLine();
answerFour = reader.readLine();
Question q = new Question(question, answer, answerOne, answerTwo, answerThree, answerFour);
mQuestions.add(q);
break;
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
reader.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return 0;
}
@Override
protected void onPostExecute(Object result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
callback.notify_result(mQuestions);
}
public interface Callback {
public void notify_result(List<Question> question_list);
}
public int getQuestionsLeft() {
return mQuestions.size();
}
public Question getRandomQuestion() {
Random random = new Random();
int index = random.nextInt(mQuestions.size());
Question newQuestion = mQuestions.get(index);
mQuestions.remove(index);
return newQuestion;
}
package com.example.arnpet.ultimatehogskoleprovet;
导入android.content.Context;
导入android.os.AsyncTask;
导入com.example.arnpet.ultimatehogskoleprovet.Question;
导入java.io.BufferedReader;
导入java.io.IOException;
导入java.io.InputStream;
导入java.io.InputStreamReader;
导入java.util.ArrayList;
导入java.util.List;
导入java.util.Random;
导入javax.security.auth.callback.callback;
公共类FileReader\u async扩展了AsyncTask{
私人语境;
私有回调;
私有列表mQuestions;
公共文件读取器异步(上下文上下文,回调)
{
this.callback=callback;
}
@凌驾
受保护对象doInBackground(对象…参数){
InputStream=null;
试一试{
iS=context.getAssets().open(“hogskoleprovet”);
}捕获(IOE异常){
//TODO自动生成的捕捉块
e、 printStackTrace();
}
BufferedReader reader=新的BufferedReader(新的InputStreamReader(iS));
mQuestions=newarraylist();
串问题,回答,回答一,回答二,回答三,回答四;
试一试{
while(reader.readLine()!=null){
//从资源文件中读取一些行
问题=reader.readLine();
答案=reader.readLine();
answerOne=reader.readLine();
answerTwo=reader.readLine();
answerThree=reader.readLine();
answerFour=reader.readLine();
问题q=新问题(问题、答案、答案一、答案二、答案三、答案四);
mQuestions.add(q);
打破
}
}捕获(IOE异常){
//TODO自动生成的捕捉块
e、 printStackTrace();
}
试一试{
reader.close();
}捕获(IOE异常){
//TODO自动生成的捕捉块
e、 printStackTrace();
}
返回0;
}
@凌驾
受保护的void onPostExecute(对象结果){
//TODO自动生成的方法存根
super.onPostExecute(结果);
回调。通知_结果(mQuestions);
}
公共接口回调{
公共无效通知结果(列表问题列表);
}
public int getQuestionsLeft(){
返回mQuestions.size();
}
公共问题{
随机=新随机();
int index=random.nextInt(mQuestions.size());
Question newQuestion=mQuestions.get(索引);
mQuestions.remove(索引);
返回新问题;
}
}
有人要求参加另一个可能是问题所在的课程:
public class pagebeforeAction extends Activity {
private Spinner spinnerOne;
private Button btnSubmit;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_pagebefore_action);
spinnerOne = (Spinner) findViewById(R.id.spinnerOne);
List<String> list = new ArrayList<String>();
list.add("Nivå 1");
list.add("Nivå 2");
list.add("Nivå 3");
list.add("Nivå 4");
list.add("Nivå 5");
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>
(this, android.R.layout.simple_spinner_item,list);
dataAdapter.setDropDownViewResource
(android.R.layout.simple_spinner_dropdown_item);
spinnerOne.setAdapter(dataAdapter);
// Spinner item selection Listener
addListenerOnSpinnerItemSelection();
}
public void returnOne(View v){
Intent intent = new Intent(this, MainActivity.class);
Button button = (Button) findViewById(R.id.buttonTwo);
startActivity(intent);
}
// Add spinner data
public void addListenerOnSpinnerItemSelection(){
spinnerOne.setOnItemSelectedListener(new CustomOnItemSelectedListener());
}
//get the selected dropdown list value
public void submit(View v)
{
Button btnSubmit = (Button) findViewById(R.id.submit);
Intent intent = new Intent (this, gameAction.class);
Toast.makeText(pagebeforeAction.this,
"On Button Click : " +
"\n" + String.valueOf(spinnerOne.getSelectedItem()) ,
Toast.LENGTH_LONG).show();
int index = Integer.parseInt(btnSubmit.getTag().toString());
intent.putExtra("INDEX",index);
startActivity(intent);
}
05-02 09:04:28.823 29549-29549/com.example.arnpet.ultimatehogskoleprovet E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.arnpet.ultimatehogskoleprovet, PID: 29549
java.lang.IllegalStateException: Could not execute method of the activity
at android.view.View$1.onClick(View.java:3969)
at android.view.View.performClick(View.java:4637)
at android.view.View$PerformClick.run(View.java:19422)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5479)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at
public class pagebeforeAction扩展活动{
私人纺纱机;
私人按钮btnSubmit;
@凌驾
创建时的公共void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity\u pagebefore\u action);
喷丝头=(喷丝头)findViewById(R.id.喷丝头);
列表=新的ArrayList();
列表。添加(“Nivå1”);
添加(“Nivå2”);
添加(“Nivå3”);
添加(“Nivå4”);
列表。添加(“Nivå5”);
ArrayAdapter dataAdapter=新的ArrayAdapter
(这是android.R.layout.simple\u微调器\u项,列表);
dataAdapter.setDropDownViewResource
(android.R.layout.simple\u微调器\u下拉菜单\u项);
喷丝头1.setAdapter(数据适配器);
//微调器项选择侦听器
addListenerOnSpinnerItemSelection();
}
公共空间一(视图五){
意向意向=新意向(此,MainActivity.class);
Button Button=(Button)findViewById(R.id.buttonTwo);
星触觉(意向);
}
//添加微调器数据
public void addListenerOnSpinnerItemSelection(){
spinnerOne.setOnItemSelectedListener(新的CustomOnItemSelectedListener());
}
//获取选定的下拉列表值
公开作废提交(视图五)
{
按钮btnSubmit=(按钮)findViewById(R.id.submit);
意向意向=新意向(这个,gameAction.class);
Toast.makeText(pagebeforeAction.this,
“单击按钮时:”+
“\n”+String.valueOf(spinnerOne.getSelectedItem()),
Toast.LENGTH_LONG).show();
int index=Integer.parseInt(btnSubmit.getTag().toString());
意向。额外(“索引”,索引);
星触觉(意向);
}
05-02 09:04:28.823 29549-29549/com.example.arnpet.ultimatehogskoleprovet E/AndroidRuntime﹕ 致命异常:主
流程:com.example.arnpet.ultimatehogskoleprovet,PID:29549
java.lang.IllegalStateException:无法执行活动的方法
在android.view.view$1.onClick上(view.java:3969)
在android.view.view.performClick上(view.java:4637)
在android.view.view$PerformClick.run(view.java:19422)
位于android.os.Handler.handleCallback(Handler.java:733)
位于android.os.Handler.dispatchMessage(Handler.java:95)
位于android.os.Looper.loop(Looper.java:136)
位于android.app.ActivityThread.main(ActivityThread.java:5479)
位于java.lang.reflect.Method.Invokenactive(本机方法)
位于java.lang.reflect.Method.invoke(Method.java:515)
在
我通过在您的活动中创建一个公共方法而不是回调来解决此问题。通知结果(mQuestions)
yo将执行以下操作:
activity.notify_结果(mQuestions);
i
((ActivityName) context).notify_result(mQuestions);