在 Android 中通过 ArrayAdapter 在 ListView 中单击它后如何更改单个 ImageView 背景？

Question

我的 Fragment activity 中有一个 ListView，它获取存储在内部存储器中的文件的名称。 ListView 还有一个 ImageView，当点击它时，它会设置一个显示通知的警报。我希望在单击时更改特定 ImageView 的背景。我的问题是关闭应用程序后，ImageView 的背景变回正常。那么，我应该如何改变每个被点击的ImageView的背景呢？

这是我的片段class代码：

ListView listView;
CustomArrayAdapter arrayAdapter;
ArrayList<String> FilesInFolder;

FilesInFolder = GetFiles(getActivity().getFilesDir());

arrayAdapter = new CustomArrayAdapter(FilesInFolder, getContext());

Collections.sort(FilesInFolder);

listView.setAdapter(arrayAdapter);

这是我的 CustomArrayAdapter class:

public class CustomArrayAdapter extends ArrayAdapter<String> {

    private ArrayList<String> list;
    Context mContext;

    TimePickerDialog timePickerDialog;
    DatePickerDialog datePickerDialog;
    int currentHour, currentMinute, currentYear, currentMonth, currentDay, currentDate;
    int setHour, setMinute, setYear, setMonth, setDay;
    Calendar calendar;

    AlarmManager alarmManager;
    PendingIntent pendingIntent;
    public static final String NOTIFICATION_CHANNEL_ID = "10001";

    public static class ViewHolder {
        TextView titleTextView;
        ImageView imageView;
    }

    public CustomArrayAdapter(ArrayList<String> list, Context context) {
        super(context, R.layout.custom_listview, list);
        this.list = list;
        this.mContext = context;

        calendar = Calendar.getInstance();
        currentHour = calendar.get(Calendar.HOUR_OF_DAY);
        currentMinute = calendar.get(Calendar.MINUTE);

        currentYear = calendar.get(Calendar.YEAR);
        currentMonth = calendar.get(Calendar.MONTH);
        currentDay = calendar.get(Calendar.DAY_OF_MONTH);
        currentDate = calendar.get(Calendar.DATE);
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        String string = getItem(position);
        ViewHolder viewHolder;

        if (convertView == null) {
            viewHolder = new ViewHolder();
            LayoutInflater inflater = LayoutInflater.from(getContext());
            convertView = inflater.inflate(R.layout.custom_listview, parent, false);
            viewHolder.imageView = convertView.findViewById(R.id.bellIcon);
            viewHolder.titleTextView = convertView.findViewById(R.id.textView);
            convertView.setTag(viewHolder);
            viewHolder = (ViewHolder) convertView.getTag();
        }
        else {
            viewHolder = (ViewHolder) convertView.getTag();
        }

        ViewHolder finalViewHolder = viewHolder;
        viewHolder.imageView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (finalViewHolder.imageView.getTag() == "done") {
                    Snackbar.make(v, setHour + " " + setMinute + ", on" + " " + setDay + " " + setMonth + " " + setYear, Snackbar.LENGTH_LONG).show();
                } else {
                    timePickerDialog = new TimePickerDialog(getContext(), new TimePickerDialog.OnTimeSetListener() {
                        @Override
                        public void onTimeSet(TimePicker timePicker, final int hourOfDay, int minute) {
                            setHour = hourOfDay;
                            setMinute = minute;

                            datePickerDialog = new DatePickerDialog(getContext(), new DatePickerDialog.OnDateSetListener() {
                                @Override
                                public void onDateSet(DatePicker view, int year, int month, int dayOfMonth) {
                                    setYear = year;
                                    setMonth = month;
                                    setDay = dayOfMonth;

                                    Calendar setTime = Calendar.getInstance();
                                    setTime.set(setYear, setMonth, setDay, setHour, setMinute, 0);

                                    Date date = setTime.getTime();

                                    scheduleNotification(string, date.getTime());

                                    finalViewHolder.imageView.setImageResource(R.drawable.ic_baseline_notifications_active_24);
                                    finalViewHolder.imageView.setTag("done");

                                    Snackbar.make(v, "Reminder set for: " + string + "!", Snackbar.LENGTH_LONG)
                                            .setAnimationMode(BaseTransientBottomBar.ANIMATION_MODE_SLIDE)
                                            .show();
                                }
                            }, currentYear, currentMonth, currentDay);

                            datePickerDialog.show();
                        }
                    }, currentHour, currentMinute, false);

                    timePickerDialog.show();
                }
            }
        });

        viewHolder.titleTextView.setText(string);
        return convertView;
    }

    public void scheduleNotification (String fileName, long delay) {
        Intent notificationIntent = new Intent(this.mContext, MyBroadCastReceiver.class);
        notificationIntent.putExtra(MyBroadCastReceiver.NOTIFICATION_ID, (int)System.currentTimeMillis());
        notificationIntent.putExtra("title", fileName);

        pendingIntent = PendingIntent.getBroadcast(getContext(), (int)System.currentTimeMillis(), notificationIntent, PendingIntent.FLAG_UPDATE_CURRENT);
        alarmManager = (AlarmManager) getContext().getSystemService(Context.ALARM_SERVICE);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            alarmManager.setAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, delay, pendingIntent);
        } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            alarmManager.setExact(AlarmManager.RTC_WAKEUP, delay, pendingIntent);
        } else {
            alarmManager.set(AlarmManager.RTC_WAKEUP, delay, pendingIntent);
        }
    }
}

Answer 1

这是预期的行为，因为您没有保存数据的状态。我建议创建一个反映真实状态的模型。也许是这样的：

class File {
    String filepath;
    boolean reminderSet;
}

现在您有了一个模型 class，您可以使用 Room 以持久的方式保存数据。当执行点击时，只需去更新数据库中的相应对象（将 reminderSet 设置为 true）。这样，当您在应用程序启动后加载数据时，它仍会保留其先前的状态。

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