您好我有一个Android应用程序，基本上有一个EditText来获取用户输入，TextView输出处理过的数据和一个按钮来执行所有操作。一旦用户单击一个按钮并创建了新线程，并且以下两个循环正在运行，并且每次都将新输出附加到TextView。然而，当循环结束时，TextView输出实时没有进入TextView的问题，它会立即显示所有输出的数据，请帮忙。
package com.example.assignment2_android;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Calendar;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Random;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.app.Activity;
import android.content.Intent;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class station extends Activity
{
Button run, clear, home;
EditText userinput;
TextView useroutput;
//LinkedList Customer Queue created here.
public static Queue<String> line = new LinkedList<String> ();
private static String time; //time variable.
private static DateFormat dateFormat = new SimpleDateFormat("HH:mm:ss"); //DateFormat variable.
private int intervals;
private int cashiers;
private int processing_time;
Thread arrival;
Handler handler, handlerr, handlerrr;
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.station);
userinput = (EditText)findViewById(R.id.s_userinput);
useroutput = (TextView)findViewById(R.id.s_useroutput);
clear = (Button)findViewById(R.id.button_clear);
clear.setOnClickListener(new View.OnClickListener()
{
public void onClick(View view)
{
line.clear();
userinput.setText("Line Cleared");
useroutput.setText("");
System.out.println("cleared");
}
});
home = (Button)findViewById(R.id.button_home);
home.setOnClickListener(new View.OnClickListener()
{
public void onClick(View view)
{
Intent a = new Intent(station.this, MainActivity.class);
startActivity(a);
}
});
}
public void startProgress(View view)
{
handler = new Handler();
Thread arrival = new Thread();
{
useroutput.append("CUSTOMERS ARE COMING !!!! !!!!" + "\n" + "\n");;
//Array of all the customer that will enter the queue.
String list[] = {"Naqi", "Monty", "Mohin", "Yasmin", "Maighjoo", "Ashish", "Paal", "Kevin", "Ruhail", "Tony"};
//2nd ArrayList which customer are added to and removed later on so no duplicates arise.
ArrayList<String> customer = new ArrayList<String>(Arrays.asList(list));
int array_customer_list = list.length; //Recording the number of customers in the array.
//While statement containing for loop add customers to the empty LinkedList object.
while (line.isEmpty())
{
for (int x = 0; x < array_customer_list; x++ )
{
try
{
Thread.sleep(ran_interval() * 1000); //Sleep method to hold the arrival time by 1-2 seconds.
int cus = (int) (Math.random() * customer.size()); //Random customer is picked here.
String new_cus = customer.get(cus); //New customer object is created ere.
line.add(new_cus); //Customer objects are added to the empty LinkedList queue.
customer.remove(cus);
//For loop statement to outputting the queue.
for (String s : line)
{
useroutput.append("[" + s.toString() + " " + "]" + "\n");; //Outputting each customer and using the ".name" method so customers are readable.
}
//Outputting the whole queue and stating who has joined the queue.
useroutput.append("\n" + "The queue has " + line.size() + " customers so far" + "\n" +
new_cus.toString() + " Has Joined the Queue " + " <=== WAITING" + "\n" + "\n");
}
catch(Exception a) //ERROR handler for sleep method.
{
System.out.println("Intervals error: " + a); //Outputting the ERROR message.
System.exit(0); //If ERROR found exit system.
}
}
}
userinput.append("\n");
useroutput.append("CUSTOMERS ARE WAITING !!!! !!!!" + "\n" + "\n");
useroutput.append("Processing START !!!!" + "\n" + "\n");
while (!line.isEmpty()) //While statement with for loop to remove each customer from LinkedList queue.
{
try
{
String cus = line.remove(); //Method to remove customer from LinkedList queue.
String time = getTime();
Thread.sleep((processing_time() * 1000) / cashiers); //Sleep method to hold the processing by 1-3 seconds.
for (String s : line)
{
useroutput.append("[" + s.toString() + " " + "]" + "\n"); //Outputting each customer and using the ".name" method so customers are readable.
}
//Outputting the whole queue and stating who has joined the queue.
useroutput.append("\n" + "The queue has " + line.size() + " customers left" + "\n" +
cus.toString()+ " waited for " + time + " <=== SERVED" + "\n" + "\n");
}
catch(Exception a) //ERROR handler for sleep method.
{
System.out.println("Cashiers_wait error: " + a); //Outputting the ERROR message.
System.exit(0); //If ERROR found exit system.
}
}
useroutput.append("Processing FINISHED !!!!" + "\n");
System.out.println("working" + "\n" + "random arrival time is :" + intervals + "\n" +
"random processing time is :" + processing_time);
}; arrival.start();
};
public void append_output(final String text)
{
runOnUiThread(new Runnable()
{
@Override
public void run()
{
useroutput.append(text);
}
});
}
static String getTime() //Time Constructor
{
Calendar cal = Calendar.getInstance();
time = dateFormat.format(cal.getTime()); //Getting the current system time.
return time; //Return time.
}
public int ran_interval()
{
Random rand = new Random(); //Random object created here.
int interval = this.intervals = rand.nextInt(2) + 1; //Random number between 1-2 is generated for customer arrival here.
return interval;
}
public int processing_time()
{
Random ran = new Random(); //Random object created here.
int time = this.processing_time = ran.nextInt(4) + 1; //Random number between 1-3 is generated for customer arrival here.
return time;
}
}
答案 0 :(得分：0)
看起来您的问题是您尝试从不打算这样做的线程更新UI。为此目的，你似乎已经创建了函数append_output，但从未使用它。由于您的arrival线程未在UI上运行，因此无法实时更新文本框。所以基本上，不是在你的到达线程中有一堆useroutput.append，而是将它们全部更改为append_output(text)，并且应该解决你的问题。
答案 1 :(得分：0)
首先组织你的导入并尊重android编码风格。我纠正了你的代码的开始。
private static Button mRun, mClear, mHome;
private static EditText mUserInput;
private static TextView mUserOutput;
//LinkedList Customer Queue created here.
public static Queue<String> line = new LinkedList<String> ();
private static String time; //time variable.
private static DateFormat dateFormat = new SimpleDateFormat("HH:mm:ss"); //DateFormat variable.
private int intervals;
private int cashiers;
private int processing_time;
Thread arrival;
Handler handler, handlerr, handlerrr;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.station);
mClear = (Button)findViewById(R.id.button_clear);
mHome = (Button) findViewById(R.id.button_home);
mUserInput = (EditText) findViewById(R.id.s_userinput);
mUserOutput = (TextView) findViewById(R.id.s_useroutput);
if (mClear != null) {
mClear.setOnClickListener(this);
}
if (mHome != null) {
mHome.setOnClickListener(this);
}
}
public void onClick(View view) {
if (view == mClear) {
line.clear();
mUserInput.setText(getString(R.string.line_cleared)); //Use string ressource !
mUserOutput.setText("");
System.out.println("cleared"); // Use string ressource
} else if (view == mHome) {
Intent a = new Intent(this, MainActivity.class);
startActivity(a);
}
}
你必须使用线程来做一些复杂的计算，获取你的数据。但是无法在工作线程中完成用户界面的初始化。你必须在主线程上。像往常一样，一切都在这里：http://developer.android.com/guide/components/processes-and-threads.html
答案 2 :(得分：0)
但实际上，您应该使用AsyncTask来处理UI更新。做类似的事情：
private class updateTextView extends AsyncTask<String, String, Void> {
protected void doInBackground(String text) {
publishProgress(text)
}
protected void onProgressUpdate(String text)
{
useroutput.append(text)
}
}
在您的班级声明之上。
然后，每次要更新文本视图时，只需执行
new updateTextView().execute(text)
我不确定这些的确切语法，因为我不是安装了Android SDK的计算机，但这至少应该让你足够远，你的IDE应该能够处理休息。虽然这可能是草率或“糟糕的形式”，但它应该让事情适合你。