我在尝试在 Android 中执行重复任务时遇到一些问题。以下是我填充 ListView 的方法:
public View getView(int position, View convertView, ViewGroup parent) {
String recurID;
if (convertView == null) {
convertView = inflater.inflate(R.layout.recur_listview_row, null);
viewHolder = new ViewHolder();
viewHolder.txt_ddate = (TextView) convertView.findViewById(R.id.txtDisplayRecurDate);
viewHolder.txt_damount = (TextView) convertView.findViewById(R.id.txtDisplayRecurAmount);
viewHolder.txt_dfrequency = (TextView) convertView.findViewById(R.id.txtDisplayFrequency);
convertView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) convertView.getTag();
}
recurID = _recurlist.get(position).getRecurringID();
// Format and calculate the next payment date based on frequency
try {
String dateStr = _recurlist.get(position).getRecurringStartDate();
String frequencyStr = _recurlist.get(position).getFrequency();
Calendar cal = Calendar.getInstance();
cal.setTime(dateFormat.parse(dateStr));
if (frequencyStr.equals("Daily")) {
cal.add(Calendar.DAY_OF_MONTH, 1);
viewHolder.txt_ddate.setText("Next Payment On: " + dateFormat.format(cal.getTimeInMillis()));
cal.add(Calendar.DAY_OF_MONTH, -1);
} else if (frequencyStr.equals("Weekly")) {
cal.add(Calendar.WEEK_OF_YEAR, 1);
viewHolder.txt_ddate.setText("Next Payment On: " + dateFormat.format(cal.getTimeInMillis()));
cal.add(Calendar.WEEK_OF_YEAR, -1);
}
} catch (ParseException e) {
e.printStackTrace();
}
viewHolder.txt_dfrequency.setText(_recurlist.get(position).getFrequency().trim());
if (_recurlist.get(position).getRecurringType().equals("W")) {
viewHolder.txt_damount.setTextColor(Color.rgb(180, 4, 4));
viewHolder.txt_damount.setText("Credit $ " + amount);
} else if (_recurlist.get(position).getRecurringType().equals("D")) {
viewHolder.txt_damount.setTextColor(Color.rgb(8, 138, 8));
viewHolder.txt_damount.setText("Debit $ " + amount);
}
// Get current date
String currentDate = "Next Payment On: " + dateFormat.format(new Date());
// If current date matches with the next payment date, insert new
// transaction record
if (currentDate.equals(viewHolder.txt_ddate.getText())) {
DatabaseAdapter mDbHelper = new DatabaseAdapter(Recurring.this);
mDbHelper.createDatabase();
mDbHelper.open();
TransactionRecModel trm = new TransactionRecModel();
CategoryController cc = new CategoryController(mDbHelper.open());
trm.setDate(dateFormat.format(new Date()));
if (_recurlist.get(position).getRecurringType().equals("W")) {
trm.setType("W");
} else if (_recurlist.get(position).getRecurringType().equals("D")) {
trm.setType("D");
}
trm.setAmount(Float.parseFloat(formatAmount));
TransactionRecController trc = new TransactionRecController(mDbHelper.open());
if (trc.addTransactionRec(trm)) {
// After successfully insert transaction record, update the
// recurring start date
rm = new RecurringModel();
rm.setRecurringID(recurID);
rm.setRecurringStartDate(dateFormat.format(new Date()));
RecurringController rc = new RecurringController(mDbHelper.open());
if (rc.updateRecurringDate(rm)) {
mDbHelper.close();
}
}
}
return convertView;
}
从代码中,我尝试获取当前日期并与根据频率计算的下一个付款日期进行比较。但是,使用这些代码,它不会在后台运行。
假设我设置了一个重复事件,该事件将在昨天每天重复。但我今天没有运行该应用程序。正确地说,循环应该在后台运行并执行循环。但不知何故,事实并非如此。
我想知道我是否需要像 AlarmManager 这样的服务来做到这一点?
提前致谢。
编辑
所以我改变的是当我尝试比较日期时的部分,如果日期匹配,它将调用alarmManager并一路解析一些值:
if (currentDate.equals(viewHolder.txt_ddate.getText())) {
long when = new Date().getTime();
notificationCount = notificationCount + 1;
AlarmManager mgr = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
Intent notificationIntent = new Intent(context, ReminderAlarm.class);
notificationIntent.putExtra("RecurID", recurID);
notificationIntent.putExtra("Date", dateFormat.format(new Date()));
notificationIntent.putExtra("Description", viewHolder.txt_ddesc.getText().toString());
notificationIntent.putExtra("Type", _recurlist.get(position).getRecurringType());
notificationIntent.putExtra("Amount", Float.parseFloat(formatAmount));
notificationIntent.putExtra("CategoryID", viewHolder.txt_dcat.getText().toString());
notificationIntent.putExtra("NotifyCount", notificationCount);
PendingIntent pi = PendingIntent.getBroadcast(context, notificationCount, notificationIntent, PendingIntent.FLAG_UPDATE_CURRENT);
mgr.set(AlarmManager.RTC_WAKEUP, when, pi);
}
在我的 ReminderAlarm 类中,我正在执行插入和更新 SQL 语句:
public class ReminderAlarm extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
String recurID = intent.getStringExtra("RecurID");
String date = intent.getStringExtra("Date");
String description = intent.getStringExtra("Description");
String type = intent.getStringExtra("Type");
Float amount = Float.parseFloat(intent.getStringExtra("Amount"));
String categoryID = intent.getStringExtra("CategoryID");
DatabaseAdapter mDbHelper = new DatabaseAdapter(ReminderAlarm.this);
mDbHelper.createDatabase();
mDbHelper.open();
TransactionRecModel trm = new TransactionRecModel();
CategoryController cc = new CategoryController(mDbHelper.open());
trm.setDate(date);
trm.setTransDescription(description);
if (type.equals("W")) {
trm.setType("W");
} else if (type.equals("D")) {
trm.setType("D");
}
trm.setAmount(amount);
// Get the categoryID based on categoryName
String catID = cc.getCatIDByName(categoryID);
trm.setCategory(catID);
TransactionRecController trc = new TransactionRecController(mDbHelper.open());
if (trc.addTransactionRec(trm)) {
// After successfully insert transaction record, update the
// recurring start date
RecurringModel rm = new RecurringModel();
rm.setRecurringID(recurID);
rm.setRecurringStartDate(date);
RecurringController rc = new RecurringController(mDbHelper.open());
if (rc.updateRecurringDate(rm)) {
mDbHelper.close();
}
}
}
}
最佳答案
您的适配器
应该接收准备显示的数据。每次 ListView
项目出现在屏幕上时都会调用 getView
,因此如果您希望保持 60fps 滚动,则希望将此处的工作时间保持在 16 毫秒以下。因此,您应该在它到达适配器之前完成所有繁重的工作。
由于数据库数据通常无法显示,因此您通常会使用Loader
来获取数据,并将其转换为适配器就绪的“项目”列表。这应该发生在您的 Activity
或 Fragment
中,并且您在 onLoadFinished
中填充 Adapter
。这通常意味着创建一个新的 POJO 来表示显示数据。
最好的起点是 Loader tutorial .
如果您想设置重复任务,您应该使用AlarmManager
,正如您所怀疑的那样。 AlarmManager
通常会触发 BroadcastManager
,后者又会生成一个 Service
来完成工作。
关注AlarmManager tutorial了解更多详情。
关于java - Android 循环任务在后台运行,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/25934628/