我得到索引0大小0异常如何解决这个问题？

Question

我是Android新手。

我在代码中使用了2个数组列表al和oh。

我假设循环条件为k+2 < al.size()，但我仍然遇到异常＆＃34;索引0大小为0＆＃34;。我该如何解决这个问题？

公共类延迟扩展了活动{

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.delay);
    //final EditText text;
    Button btnReadSDFile;
    //String line="" ;
    //String file_name;
    btnReadSDFile = (Button) findViewById(R.id.button12);
    //text = (EditText) findViewById(R.id.text);
    //text.setHint("Enter some lines of data here...");
    btnReadSDFile.setOnClickListener(new OnClickListener() {
    public void onClick(View v) {
        // write on SD card file data in the text box
    try {
        File dir = Environment.getExternalStorageDirectory();
        File file = new File(dir, "/Notes/delay.csv");
        FileInputStream fIn = new FileInputStream(file);
        BufferedReader myReader = new BufferedReader(
                new InputStreamReader(fIn));

        FileWriter outFile = new FileWriter("/sdcard/Notes/duration.csv");  
        BufferedWriter outStream = new BufferedWriter(outFile); 


        String aDataRow = "";

        StringTokenizer st = null;
        String start=null;

        String end=null;
        String sm_time,sn_time,em_time,en_time;
        long dm_time1,sn_time1,em_time1,en_time1;
        ArrayList<String> al = new ArrayList<String>();

        ArrayList<String> oh = new ArrayList<String>();
                    while ((aDataRow = myReader.readLine()) != null) {

             st = new StringTokenizer(aDataRow, ",");
              while (st.hasMoreTokens()) {
                  al.add(st.nextToken());
              }//while
        }
                    int i=0;

        do{
            start=al.get(i);
            end=al.get(i+3);
            if(start.equals(end))
            {
                sm_time=al.get(i+1);
                em_time=al.get(i+4);
                dm_time1=Long.parseLong(em_time)-Long.parseLong(sm_time);
                oh.add(start);
                oh.add(String.valueOf(dm_time1));
                sn_time=al.get(i+2);
                en_time=al.get(i+5);
                sn_time1=Long.parseLong(en_time)-Long.parseLong(sn_time);
                oh.add(String.valueOf(sn_time1));
                i+=2;

            }
            else{
                dm_time1=1;
                oh.add(start);
                oh.add(String.valueOf(dm_time1));
                sn_time1=1;
                oh.add(String.valueOf(sn_time1));
                i++;
            }

        }while((i+5)<al.size());

        outStream.write("AppName");
        outStream.write(",");
        outStream.write("duration(ms)");
        outStream.write(",");
        outStream.write("duration(ns)");
        outStream.write("\n");

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

        }
        outStream.close(); 
           // System.out.println("Data saved."); 
         }//try
    catch (Exception e) {
        Toast.makeText(getBaseContext(), e.getMessage(),
                Toast.LENGTH_SHORT).show();
    }
    }// onClick
    }); // btnReadSDFile
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

}

Answer 1

if(al.size()>0){
//loop here
}else{
//do something
}