你好，stackoverflow的人，
我想编写一个带有部分的应用程序，以便在特定时间和日期发出警报。理想情况下，它会触发通知，但如果警报能够正常工作，我几乎会感到高兴。我尝试了一些教程和示例，但没有一个彻底解释（如果你知道一个网站请发送链接）。我想现在我有各种各样的尝试。 这是应该收集关于警报何时起飞并触发它的信息的活动：
public class Activity_new_termin extends Activity {
Button btnSelectDate,btnSelectTime, submit;
EditText mTitle, mDescr;
DatePicker pickerDate;
TimePicker pickerTime;
static final int DATE_DIALOG_ID = 0;
static final int TIME_DIALOG_ID = 1;
final static int RQS_1 = 1;
public int year,month,day,hour,minute;
private int mYear, mMonth, mDay,mHour,mMinute;
private string date_name;
private string descr;
TextView info;
public Activity_new_termin()
{
final Calendar c = Calendar.getInstance();
mYear = c.get(Calendar.YEAR);
mMonth = c.get(Calendar.MONTH);
mDay = c.get(Calendar.DAY_OF_MONTH);
mHour = c.get(Calendar.HOUR_OF_DAY);
mMinute = c.get(Calendar.MINUTE);
}
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_new_termin);
btnSelectDate=(Button)findViewById(R.id.buttonSelectDate);
btnSelectTime=(Button)findViewById(R.id.buttonSelectTime);
submit=(Button)findViewById(R.id.butt_submit_newdate);
mTitle=(EditText)findViewById(R.id.editText_datename_newdate);
mDescr=(EditText)findViewById(R.id.editText_datedescr_newdate);
btnSelectDate.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
showDialog(DATE_DIALOG_ID);
}
});
btnSelectTime.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
showDialog(TIME_DIALOG_ID);
}
});
submit.setOnClickListener(
new View.OnClickListener()
{
public void onClick(View view)
{
Log.v("editText_datename_newdate", mTitle.getText().toString());
Log.v("editText_datedescr_newdate", mDescr.getText().toString());
Calendar current = Calendar.getInstance();
Calendar cal = Calendar.getInstance();
cal.set(Calendar.YEAR, year);
cal.set(Calendar.MONTH, month);
cal.set(Calendar.DAY_OF_MONTH, day);
cal.set(Calendar.HOUR_OF_DAY, hour);
cal.set(Calendar.MINUTE, minute);
cal.set(Calendar.SECOND, 0);
cal.set(Calendar.MILLISECOND, 0);
if(cal.compareTo(current) <= 0){
Toast.makeText(getApplicationContext(),
"Invalid Date/Time",
Toast.LENGTH_LONG).show();
}else{
setAlarm(cal);
}
}
});
}
private DatePickerDialog.OnDateSetListener mDateSetListener =
new DatePickerDialog.OnDateSetListener() {
public void onDateSet(DatePicker view, int yearSelected,
int monthOfYear, int dayOfMonth) {
year = yearSelected;
month = monthOfYear;
day = dayOfMonth;
btnSelectDate.setText("Date selected : "+day+"-"+month+"-"+year);
}
};
private TimePickerDialog.OnTimeSetListener mTimeSetListener =
new TimePickerDialog.OnTimeSetListener() {
public void onTimeSet(TimePicker view, int hourOfDay, int min) {
hour = hourOfDay;
minute = min;
btnSelectTime.setText("Time selected :"+hour+"-"+minute);
}
};
@Override
protected Dialog onCreateDialog(int id) {
switch (id) {
case DATE_DIALOG_ID:
return new DatePickerDialog(this,
mDateSetListener,
mYear, mMonth, mDay);
case TIME_DIALOG_ID:
return new TimePickerDialog(this,
mTimeSetListener, mHour, mMinute, false);
}
return null;
}
private void setAlarm(Calendar targetCal){
info.setText("\n\n***\n"
+ "Alarm is set@ " + targetCal.getTime() + "\n"
+ "***\n");
Intent intent = new Intent(getBaseContext(), AlarmReceiver.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(getBaseContext(), RQS_1, intent, 0);
AlarmManager alarmManager = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
alarmManager.set(AlarmManager.RTC_WAKEUP, targetCal.getTimeInMillis(), pendingIntent);
}
}
及其xml：
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="470dp"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin" >
<TextView
android:id="@+id/textview_title_newdate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="10dp"
android:text="@string/title_new_termin" />
<EditText
android:id="@+id/editText_datename_newdate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/textview_title_newdate"
android:layout_centerHorizontal="true"
android:layout_marginTop="36dp"
android:ems="10"
android:inputType="textMultiLine" />
<EditText
android:id="@+id/editText_datedescr_newdate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/buttonSelectDate"
android:layout_below="@+id/buttonSelectTime"
android:layout_marginTop="27dp"
android:ems="10" >
<requestFocus />
</EditText>
<Button
android:id="@+id/butt_submit_newdate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textview_title_newdate"
android:layout_below="@+id/editText_datedescr_newdate"
android:layout_marginTop="38dp"
android:text="@string/butt_newdate_submit" />
<Button
android:id="@+id/buttonSelectDate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/editText_datename_newdate"
android:layout_centerHorizontal="true"
android:layout_marginTop="20dp"
android:text="Select Date" />
<Button
android:id="@+id/buttonSelectTime"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/editText_datedescr_newdate"
android:layout_below="@+id/buttonSelectDate"
android:layout_marginTop="14dp"
android:text="Select Time" />
</RelativeLayout>
</ScrollView>
最后是闹剧接收者：
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.widget.Toast;
public class AlarmReceiver extends BroadcastReceiver
{
@Override
public void onReceive(Context context, Intent intent)
{
// Show the toast like in above screen shot
Toast.makeText(context, "Alarm ausgelöst", Toast.LENGTH_LONG).show();
}
}
提前非常感谢你！
答案 0 :(得分：1)
我测试了你的代码。您在NullPointerException
TextView info;
您已声明TextView info，但您从未指定过它，例如
info = (TextView) findViewById(R.id.what_ever);
之后，您可以像使用
一样使用它info.setText("\n\n***\n"+ "Alarm is set@ " + targetCal.getTime() + "\n" + "***\n");