什么是android中的无效索引90大小是90

Question

我得到一个错误“无效的索引90大小是90”如何解决这个问题？

package com.example.micro;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileWriter; 
import java.io.InputStreamReader;    
import java.util.ArrayList;
import java.util.StringTokenizer;    
import android.app.Activity;    
import android.os.Bundle;
import android.os.Environment;    
import android.view.View;    
import android.view.View.OnClickListener;    
import android.widget.Button;    
import android.widget.Toast;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        task_final();

    }
    //  Button btn;
        //btn = (Button) findViewById(R.id.button1);
        //btn.setOnClickListener(new OnClickListener() {
            //public void onClick(View v) {
                // write on SD card file data in the text box
        public void task_final()
        {
            ArrayList<String> al = new ArrayList<String>();
            ArrayList<String> s1 = new ArrayList<String>();
            String aDataRow = "";
            StringTokenizer st = null;
            String start=null;
            String mid=null;
            String end=null;
            String sm_time,sn_time,mm_time,mn_time,em_time,en_time;
            try {
                File dir = Environment.getExternalStorageDirectory();
                File file = new File(dir, "/Notes/task_name5.csv");
                FileInputStream fIn = new FileInputStream(file);
                BufferedReader myReader = new BufferedReader(new InputStreamReader(fIn));
                FileWriter outFile = new FileWriter("/sdcard/Notes/delay.csv");  
                BufferedWriter outStream = new BufferedWriter(outFile);


                //ArrayList<String> e1 = new ArrayList<String>();
                while ((aDataRow = myReader.readLine()) != null) {
                    //aBuffer += aDataRow + "\n";
                    st = new StringTokenizer(aDataRow,",");
                    while (st.hasMoreTokens()) {
                    al.add(st.nextToken());
                      }//while
                }//while
                int i=0,j;

                do
                {
                    start=al.get(i);
                    sm_time=al.get(i+1);
                    sn_time=al.get(i+2);
                    mid=al.get(i+3);
                    mm_time=al.get(i+4);
                    mn_time=al.get(i+5);
                    j=i+3;

                    while((start.equals(mid)))
                    {
                           j+=3;
                           mid=al.get(j);

                    }
                    end=al.get(j-3);
                    em_time=al.get(j-2);
                    en_time=al.get(j-1);
                  /*  if(i!=(j-3)){
                    System.out.print(start);
                    System.out.print(" ");
                    System.out.print(sm_time);
                    System.out.print(" ");
                    System.out.print(sn_time);
                    System.out.print("\n");
                    System.out.print(end);
                    System.out.print(" ");
                    System.out.print(em_time);
                    System.out.print(" ");
                    System.out.print(en_time);
                    System.out.print("\n");
                    }*/
                       if(i!=(j-3))
                       {
                           s1.add(start);
                           s1.add(sm_time);
                           s1.add(sn_time);
                           s1.add(end);
                           s1.add(em_time);
                           s1.add(en_time);
                       }
                    i=j;
                }while(i<al.size());

                for (int k = 0; k < s1.size(); k+=3)  
                {
                outStream.write(s1.get(k));
                outStream.write(",");    
                outStream.write(s1.get(k+1));
                outStream.write(",");
                outStream.write(s1.get(k+2));
                outStream.write("\n");

                }
                outStream.close(); 
            }
            catch (Exception e)
            {
                Toast.makeText(getBaseContext(), e.getMessage(),
                        Toast.LENGTH_SHORT).show();
            }
    }
    }

Answer 1

我认为您需要更改for循环

for (int k = 0; k < s1.size(); k+=3) 

转到

for (int k = 0; k < s1.size()-1; k+=3) 

你也需要把注意力集中在这几行上

          do
            {
                start=al.get(i);
                sm_time=al.get(i+1);
                sn_time=al.get(i+2);
                mid=al.get(i+3);
                mm_time=al.get(i+4);
                mn_time=al.get(i+5);
                j=i+3;

                while((start.equals(mid)))
                {
                       j+=3;
                       mid=al.get(j);

                }
                end=al.get(j-3);
                em_time=al.get(j-2);
                en_time=al.get(j-1);

Answer 2

Java中的索引从0开始，包含90个元素的数组列表的索引从0到89。尝试索引元素90会导致此错误。

你没有具体说明你是从哪里得到它的，但我假设它是这个循环：

for (int k = 0; k < s1.size(); k+=3)

其中，您可以访问元素k、k+1和k+2，但for循环条件仅检查到k。将条件更改为

for (int k = 0; k + 2 < s1.size(); k+=3)

以确保所有索引在每次迭代中都有效。

另一个循环也有未检查的数组元素访问。这当然也是一个bug，尽管像这样的bug可能不会导致所有输入的异常。

Answer 3

试试这条路

更改此行

for (int k = 0; k < s1.size(); k+=3) 

使用

for (int k = 0; k < s1.size()-3; k+=3)