问题描述

程序运行时强制关闭，可能为空指针

日志：java.lang.RuntimeException: Unable to start activity ComponentInfo{pcAlarm.pack/pcAlarm.pack.PCAlarmActivity}: java.lang.NumberFormatException: 空指针错误，可能在
private void readSaveAlarm(){
SharedPreferences sp =getContext().getSharedPreferences(PCAlarmActivity.class.getName() Context.MODE_PRIVATE);
String content=sp.getString(KEY_ALARM_LIST null);

if (content!=null) {String[] timeString=content.split("");for (String string : timeString) {

adapter.add(new AlarmData(Long.parseLong(string)));
}
}
}方法里
package pcAlarm.pack;

import java.util.ArrayList;
import java.util.Calendar;
import java.util.Currency;
import java.util.List;

import pcAlarm.pack.PCAlarmActivity;

import android.app.Activity;
import android.app.AlertDialog;
import android.app.PendingIntent.OnFinished;
import android.app.TimePickerDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.os.Bundle;
import android.provider.Contacts;
import android.view.View;
import android.widget.ArrayAdapter;
import pcAlarm.pack.AlarmView;
import pcAlarm.pack.AlarmView.AlarmData;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TabHost;
import android.widget.TimePicker;

public class PCAlarmActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
tabHost = (TabHost)findViewById(android.R.id.tabhost);
tabHost.setup();

    tabHost.addTab(tabHost.newTabSpec(""tabAlarm"").setIndicator(""闹钟"").setContent(R.id.tabAlarm));    btnAddAlarm=(Button)findViewById(R.id.btnAddAlarm);    lvListView=(ListView)findViewById(R.id.lvListView);    adapter=new ArrayAdapter<PCAlarmActivity.AlarmData>(getContext() android.R.layout.simple_list_item_1);    lvListView.setAdapter(adapter);    adapter.add(new AlarmData(System.currentTimeMillis()));    readSaveAlarm();    btnAddAlarm.setOnClickListener(new OnClickListener() {        private Calendar mcalender;        @Override        public void onClick(View v) {            Calendar.getInstance().setTimeInMillis(System.currentTimeMillis());            mcalender = Calendar.getInstance();            int mHour = Calendar.getInstance().get(Calendar.HOUR_OF_DAY);            int mMinute = Calendar.getInstance().get(Calendar.MINUTE);            new TimePickerDialog(PCAlarmActivity.this new TimePickerDialog.OnTimeSetListener() {                @Override                public void onTimeSet(TimePicker view int hourOfDay int minute) {                    // TODO Auto-generated method stub                    Calendar.getInstance().setTimeInMillis(System.currentTimeMillis());                    Calendar.getInstance().set(Calendar.HOUR_OF_DAY hourOfDay);                    Calendar.getInstance().set(Calendar.MINUTE minute);                    Calendar.getInstance().set(Calendar.SECOND 0);                    Calendar.getInstance().set(Calendar.MILLISECOND 0);                    AlarmData add = new AlarmData(Calendar.getInstance().getTimeInMillis());                    saveAlarmList();                }            } mHour mMinute true).show();        }    });    lvListView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {        @Override        public boolean onItemLongClick(AdapterView<?> parent View arg1                final int position long id) {            new AlertDialog.Builder(getContext()).setTitle(""操作选项"").setItems(new CharSequence[]{""删除""} new DialogInterface.OnClickListener() {                @Override                public void onClick(DialogInterface dialog int which) {                    switch (which) {                    case 0:                        deleteAlarm(position);                        break;                    default:                        break;                    }                }            }).setNegativeButton(""取消"" null).show();            return true;        }    });}private void deleteAlarm(int position){    adapter.remove(adapter.getItem(position));}private void saveAlarmList(){    Editor editor=getContext().getSharedPreferences(PCAlarmActivity.class.getCanonicalName() Context.MODE_PRIVATE).edit();    StringBuffer sb=new StringBuffer();    for (int i = 0; i < adapter.getCount(); i  ) {        sb.append(adapter.getItem(i).getTime()).append("");    }    String content = sb.toString().substring(0 sb.length()-1);    editor.putString(KEY_ALARM_LIST sb.toString().substring(0 sb.length()));    System.out.println();    editor.commit();}

解决方案

String content=sp.getString(KEY_ALARM_LIST null);

if (content!=null) { String[] timeString=content.split("");
你的代码首先不是空指针异常，而是值类型异常。那么比较可能是，首先share里没有值，可是你默认取出的是null还不是""""，所以你的content值可能是null，接下来content来跟空比较，首次肯定是要出错的。

解决方案二：

 if (content!=null) {String[] timeString=content.split("");for (String string : timeString) {//看看timeString是什么adapter.add(new AlarmData(Long.parseLong(string)));}可以加个判断for (String string : timeString) {//看看timeString是什么  if(string!=null&&string.trim().length>0){//看看是不是有空串，另外看看string是否有非数字的存在    adapter.add(new AlarmData(Long.parseLong(string)));}}

解决方案三：
java.lang.NumberFormatException 数字格式化异常，很有可能是这句adapter.add(new AlarmData(Long.parseLong(string))); 抛出的异常，
仔细检查一下你的String数组里面的内容

解决方案四：
最好搞一个txt发过来 这有点多

解决方案五：
打一下断点，运行确定每一项传回来的参数，确定谁是空值

解决方案六：
java.lang.NumberFormatException