当我使用警报管理器使用接收器发出通知时，显示此错误java.lang.NullPointerException。
我从listView中选择一个项目然后调用setNotification方法，然后设置重复闹钟以触发通知。
这是代码：
public class TimesActivity extends OptionsMenu {
ArrayList<String> getTiName = new ArrayList<String>();
ArrayList<String> getTiTime = new ArrayList<String>();
ArrayList<String> getTiBroad = new ArrayList<String>();
ArrayList<String> getTiImg = new ArrayList<String>();
public DAOTimes timeDatabase = null;
int minutes;
String prNameSelected;
String prTimeSelected;
Long now, start;
int period;
AlarmManager am;
// =============================================================================
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.listvideo);
timeDatabase = new DAOTimes(this);
getTimes();
showTimes();
}
// =============================================================================
@Override
protected Dialog onCreateDialog(int id) {
switch (id) {
case 0:
// Create out AlterDialog
final CharSequence[] array = { "5 min", "10 min", "15 min",
"45 min", "60 min" };
Builder builder = new AlertDialog.Builder(this);
builder.setCancelable(true);
builder.setNegativeButton("Cancel",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int whichButton) {
}
});
builder.setSingleChoiceItems(array, -1,
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
if (array[which] == "1 min") {
minutes = 1;
} else if (array[which] == "10 min") {
minutes = 10;
} else if (array[which] == "15 min") {
minutes = 15;
} else if (array[which] == "45 min") {
minutes = 45;
} else if (array[which] == "60 min") {
minutes = 60;
}
dialog.dismiss();
}
});
AlertDialog dialog = builder.create();
dialog.show();
}
return super.onCreateDialog(id);
}
// =============================================================================
public void setNotification() {
Toast.makeText(TimesActivity.this, "result : ",
Toast.LENGTH_LONG).show();
Calendar calendar = Calendar.getInstance();
calendar.setTimeInMillis(System.currentTimeMillis());
calendar.add(Calendar.MILLISECOND, period);
Intent intent = new Intent(this, NotAlarm.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0,
intent, PendingIntent.FLAG_CANCEL_CURRENT);
am.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(),
30000, pendingIntent);
}
// =============================================================================
public void showTimes() {
final ListView listview = (ListView) findViewById(R.id.listView1);
listview.setOnItemClickListener(new ListView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View v,
int position, long id) {
prNameSelected = getTiName.get(position);
prTimeSelected = getTiTime.get(position);
String date = getIntent().getStringExtra("DAY_DATE");
SimpleDateFormat format = new SimpleDateFormat(
"yyyy-MM-dd, HH:mm:ss.SS");
format.setLenient(false);
Calendar calendar = Calendar.getInstance();
int year = calendar.get(Calendar.YEAR);
int month = calendar.get(Calendar.MONTH);
int day = calendar.get(Calendar.DAY_OF_MONTH);
int hour = calendar.get(Calendar.HOUR_OF_DAY);
int minute = calendar.get(Calendar.MINUTE);
int second = calendar.get(Calendar.SECOND);
int millisecond = calendar.get(Calendar.MILLISECOND);
String time1 = year + "-" + (month + 1) + "-" + day + ", "
+ hour + ":" + minute + ":" + second + "."
+ millisecond;
Date date1;
try {
date1 = format.parse(time1);
now = date1.getTime();
} catch (ParseException e) {
e.printStackTrace();
}
String time2 = date + ", " + prTimeSelected + ":00.00";
Date date2;
try {
date2 = format.parse(time2);
start = date2.getTime();
} catch (ParseException e) {
e.printStackTrace();
}
int result = (int) (start - now);
if (start > now) {
period = result;
} else {
// period = start + (7 * 24 * 60 * 60 * 1000);
}
Toast.makeText(TimesActivity.this, "result : " + period,
Toast.LENGTH_LONG).show();
setNotification();
// showDialog(0);
}
});
listview.setAdapter(new TimesAdapter(TimesActivity.this, getTiName
.toArray(new String[getTiName.size()]), getTiTime
.toArray(new String[getTiTime.size()]), getTiBroad
.toArray(new String[getTiBroad.size()]), getTiImg
.toArray(new String[getTiImg.size()])));
}
}
接收者活动：
package com.shadatv.shada;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
public class NotAlarm extends BroadcastReceiver {
NotificationManager nm;
@Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub
NotificationManager nm = (NotificationManager) context
.getSystemService(Context.NOTIFICATION_SERVICE);
Notification.Builder builder = new Notification.Builder(context);
builder.setSmallIcon(android.R.drawable.btn_star);
builder.setTicker("notification");
Notification notify = builder.getNotification();
CharSequence title = "you have been notified";
CharSequence details = "bvcburhvurh uhuh hghu hu";
PendingIntent pending = PendingIntent
.getActivity(context, 0, new Intent(), 0);
notify.setLatestEventInfo(context, title, details, pending);
nm.notify(0, notify);
}
}
logcat的：
03-27 10:39:33.550: E/AndroidRuntime(3890): FATAL EXCEPTION: main
03-27 10:39:33.550: E/AndroidRuntime(3890): java.lang.NullPointerException
03-27 10:39:33.550: E/AndroidRuntime(3890): at com.shadatv.shada.TimesActivity.setNotification(TimesActivity.java:161)
03-27 10:39:33.550: E/AndroidRuntime(3890): at com.shadatv.shada.TimesActivity$3.onItemClick(TimesActivity.java:228)
03-27 10:39:33.550: E/AndroidRuntime(3890): at android.widget.AdapterView.performItemClick(AdapterView.java:292)
03-27 10:39:33.550: E/AndroidRuntime(3890): at android.widget.AbsListView.performItemClick(AbsListView.java:1179)
03-27 10:39:33.550: E/AndroidRuntime(3890): at android.widget.AbsListView$PerformClick.run(AbsListView.java:2707)
03-27 10:39:33.550: E/AndroidRuntime(3890): at android.widget.AbsListView$1.run(AbsListView.java:3462)
03-27 10:39:33.550: E/AndroidRuntime(3890): at android.os.Handler.handleCallback(Handler.java:605)
03-27 10:39:33.550: E/AndroidRuntime(3890): at android.os.Handler.dispatchMessage(Handler.java:92)
03-27 10:39:33.550: E/AndroidRuntime(3890): at android.os.Looper.loop(Looper.java:137)
03-27 10:39:33.550: E/AndroidRuntime(3890): at android.app.ActivityThread.main(ActivityThread.java:4507)
03-27 10:39:33.550: E/AndroidRuntime(3890): at java.lang.reflect.Method.invokeNative(Native Method)
03-27 10:39:33.550: E/AndroidRuntime(3890): at java.lang.reflect.Method.invoke(Method.java:511)
03-27 10:39:33.550: E/AndroidRuntime(3890): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
03-27 10:39:33.550: E/AndroidRuntime(3890): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
03-27 10:39:33.550: E/AndroidRuntime(3890): at dalvik.system.NativeStart.main(Native Method)
答案 0 :(得分：2)
您忘记初始化am闹钟管理器。
像这样初始化它。
AlarmManager am = (AlarmManager)context.getSystemService(Context.ALARM_SERVICE);