Android 制作闹钟,为什么我的日历是空的?
今年夏天,为了学习应用程序开发,我决定在没有Java或OOP知识的情况下在Android Studio中制作闹钟 我试图使用TimePickerDiaglog获取用户对报警的输入,然后将该时间存储在日历实用程序中,这样我就可以使用报警管理器设置一个挂起的意图Android 制作闹钟,为什么我的日历是空的?,android,android-studio,alarm,android-calendar,android-timepicker,Android,Android Studio,Alarm,Android Calendar,Android Timepicker,今年夏天,为了学习应用程序开发,我决定在没有Java或OOP知识的情况下在Android Studio中制作闹钟 我试图使用TimePickerDiaglog获取用户对报警的输入,然后将该时间存储在日历实用程序中,这样我就可以使用报警管理器设置一个挂起的意图 public class AlarmParameters extends AppCompatActivity { EditText time; Button btn_set_alarm; TimePickerDial
public class AlarmParameters extends AppCompatActivity {
EditText time;
Button btn_set_alarm;
TimePickerDialog mTimePicker;
Calendar mcurrentTime;
AlarmManager alarmManager;
private PendingIntent pending_intent;
private AlarmReceiver alarm;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_alarm_parameters);
//match ids
btn_set_alarm = (Button) findViewById(R.id.parameters_btn_set_alarm);
time = (EditText) findViewById(R.id.time_box_text);
//remove pesky keyboard
time.setInputType(InputType.TYPE_NULL);
// perform click event listener on edit text
time.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//retrieve current time
final Calendar mcurrentTime = Calendar.getInstance();
int hour = mcurrentTime.get(Calendar.HOUR_OF_DAY);
int minute = mcurrentTime.get(Calendar.MINUTE);
mTimePicker = new TimePickerDialog(AlarmParameters.this, new TimePickerDialog.OnTimeSetListener() {
@Override
public void onTimeSet(TimePicker timePicker, int selectedHour, int selectedMinute) {
//adds the 0, like : 10:6 AM --> 10:06 AM
if(selectedMinute<10){
time.setText(selectedHour + ":0" + selectedMinute);
}
else {
time.setText(selectedHour + ":" + selectedMinute);
}
//store time picked in the calendar
mcurrentTime.set(Calendar.HOUR_OF_DAY, selectedHour);
mcurrentTime.set(Calendar.MINUTE, selectedMinute);
// no seconds in the calendar
mcurrentTime.add(Calendar.SECOND, 0);
}
}, hour, minute, true);//Yes 24 hour time
//more settings for dialog window
mTimePicker.setTitle("Select Time");
mTimePicker.show();
}
});
//actions when you hit the set alarm text
btn_set_alarm.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//get the time of the alarm set from text box
String alarm_set_string = String.valueOf(time.getText());
//add that alarm to list of alarms on first page
MainActivity.ALARMARRAY.add(alarm_set_string);
//create intent to send to alarmReceiver
final Intent myIntent = new Intent(AlarmParameters.this, AlarmReceiver.class);
//set up alarm manager
alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
//make the myIntent a pending intent?
pending_intent = PendingIntent.getBroadcast(AlarmParameters.this, 0, myIntent, PendingIntent.FLAG_UPDATE_CURRENT);
//tell alarmManager to send the pending intent at the time selected by the timepicker (in calendar now)
alarmManager.set(AlarmManager.RTC_WAKEUP, mcurrentTime.getTimeInMillis(), pending_intent);//error here
Log.e("BUTTON", "alarm set");
finish();
}
});
}}
所以我想问题就归结到我在时间选择器对话框中说这些的地方
//store time picked in the calendar
mcurrentTime.set(Calendar.HOUR_OF_DAY, selectedHour);
mcurrentTime.set(Calendar.MINUTE, selectedMinute);
我试着这样做,设置日历,在btn_set_alarm.setOnclickListener中。。。但是我不知道在TimePickerDialog之外如何使用int-selectedHour/Minute(onTimeSet()的参数)。当我尝试在onTimeSet()中设置一个公共变量selectedHour/Minute时,它说这是不允许的
最后,我有3个问题:
1。为什么在onTimeSet()中设置选定的小时/分钟值时,我的日历没有收到这些值?
2。为什么我“不允许”在onTimeSet()中设置公共变量?
3。如何在onTimeSet()之外使用selectedHour/Minute变量?
谢谢你抽出时间
--还有,如果你看到我做错了什么,或者我可以做得更好,请告诉我!我是来学习的(•◡•) / 您重新声明了mCurrentTime。只需删除第
行的最终日历mCurrentTime=Calendar.getInstance();
您重新声明了mCurrentTime。只需删除第行的最终日历mCurrentTime=Calendar.getInstance()
谢谢您的回复!很遗憾,现在我遇到了另一个错误:java.lang.NullPointerException:尝试调用虚拟方法'int java.util.Calendar.get(int)'在空对象引用上
由于某种原因,它认为日历仍然为空,即使它刚刚得到实例?请在帖子中编辑您的代码,并告诉我哪一行与此错误相关。别担心!我在编辑代码时出错了。它现在可以工作了!非常感谢!感谢您的回复!很遗憾,现在我又收到了另一行错误错误:java.lang.NullPointerException:尝试调用虚拟方法'int java.util.Calendar.get(int)'在空对象引用上
出于某种原因,它认为日历仍然为空,即使它刚刚得到实例?请在帖子中编辑您的代码,并告诉我哪一行与此错误相关。别担心!我在编辑代码时出错了。现在可以了!非常感谢!
//store time picked in the calendar
mcurrentTime.set(Calendar.HOUR_OF_DAY, selectedHour);
mcurrentTime.set(Calendar.MINUTE, selectedMinute);