如何在没有意图的情况下将数据从适配器传递到活动

Question

我尝试在不使用意图的情况下将值从适配器传递到活动。 当我单击RecyclerView时，数据应存储到活动中。 下面是我的代码

活动.java

public class BookingCalender extends AppCompatActivity implements ItemClickListener, TimeAdapter.AdapterCallback {
TextView userphone,username,txt_from_date,txt_end_date;
RecyclerView recyclerView;
RecyclerView.LayoutManager timeLayoutManager;
private RecyclerView.Adapter adapter;
String time,date="";
ArrayList<String> times;
private MaterialCalendarView calendarView;
private TextView selectedDateTv;
private String start_time="";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_booking_calender);
//Init
recyclerView = (RecyclerView) findViewById(R.id.recyclerView_timeSlots);
recyclerView.setHasFixedSize(true);
timeLayoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(timeLayoutManager);

txt_from_date=(TextView)findViewById(R.id.txt_from_date);
txt_end_date=(TextView)findViewById(R.id.txt_to_date);
//Initialize CustomCalendarView from layout
calendarView = (MaterialCalendarView) findViewById(R.id.calendarView);
calendarView.setSelectionColor(Color.parseColor("#7EA2FA"));
try {
getCurrentDateandTime();
getCurrentTime();
} catch (ParseException e) {
e.printStackTrace();
}

times = new ArrayList<String>();
Calendar calender = Calendar.getInstance();
calender.setTimeZone(TimeZone.getTimeZone("Asia/Calcutta"));
int ti = calender.get(Calendar.HOUR_OF_DAY);
int minutes = calender.get(Calendar.MINUTE);
System.out.println(minutes);
//int hourInTime=String.valueOf(ti);
String[] quarterHours = {
"00",
"15",
"30",
"45"
};
boolean isflag = false;
ti=9;
times = new ArrayList < > ();
for (int i = ti; i < 22; i++) {
if(ti==9) {
for (int j = 0; j < 4; j++) {
if ((i == ti && minutes < Integer.parseInt(quarterHours[j])) || ( i!=ti)|| isflag == true) {
isflag = true;
String time = i + ":" + quarterHours[j];
if (i < 10) {
time = "0" + time;
}
times.add("Today " + time);
}
}
}
}
VehicleViewHolder vehicleViewHolder = null;

String one="";
adapter = new TimeAdapter(times, getApplicationContext(),one);
//    Toast.makeText(BookingCalender.this,"Selected Time is :"+one,Toast.LENGTH_LONG).show();
recyclerView.setAdapter(adapter);

calendarView.addDecorator(new PrimeBeforeDayDisableDecorator());
calendarView.addDecorator(new PrimeAfterDayDisableDecorator());

MaterialCalendarView materialCalView = findViewById(R.id.calendarView);
materialCalView.setDateSelected(CalendarDay.today(), true);
// Toast.makeText(BookingCalender.this,"Clicked"+one,Toast.LENGTH_LONG).show();
}
private void getCurrentTime() {
DateFormat df = new SimpleDateFormat("HH:mm a");
time = df.format(Calendar.getInstance().getTime());
//    Toast.makeText(BookingCalender.this,""+date,Toast.LENGTH_LONG).show();
}

private void getCurrentDateandTime() throws ParseException {
date = new SimpleDateFormat("dd MMM").format(new Date());

}

@Override
public void onClick(View view, int position, boolean isLongClick) {
Toast.makeText(BookingCalender.this,"Hi",Toast.LENGTH_LONG).show();
}
@Override
public void onClick(int position) {
Toast.makeText(BookingCalender.this,"Hi",Toast.LENGTH_LONG).show();
}
@Override
public void onClick(View.OnClickListener onClickListener) {
Toast.makeText(BookingCalender.this,"Hi",Toast.LENGTH_LONG).show();
}
@Override
public void onMethodCallback() {
Toast.makeText(BookingCalender.this,"Hi",Toast.LENGTH_LONG).show();
}

private static class PrimeBeforeDayDisableDecorator implements DayViewDecorator {
@Override
public boolean shouldDecorate(final CalendarDay day) {
CalendarDay date = CalendarDay.today();
return (day.isBefore(date)) ? true : false;
}
@Override
public void decorate(final DayViewFacade view) {
view.setDaysDisabled(true);
}

}
private static class PrimeAfterDayDisableDecorator implements DayViewDecorator {
@Override
public boolean shouldDecorate(final CalendarDay day) {
CalendarDay date = CalendarDay.today();
return (day.isAfter(date)) ? true : false;
}

@Override
public void decorate(final DayViewFacade view) {
view.setDaysDisabled(true);
//  view.setBackgroundDrawable(ContextCompat.getDrawable(PrimeAfterDayDisableDecorator.this,R.co));
//  view.addSpan(new BackgroundColorSpan(Color.rgb(0,0,255)));
}
}
}

适配器.java

public class TimeAdapter extends RecyclerView.Adapter<TimeAdapter.TimeViewHolder> {
private AdapterCallback mAdapterCallback;
ArrayList<String> times;
private  Context context;
String start_time="";
public String getStart_time() {
return start_time;
}
public void setStart_time(String start_time) {
this.start_time = start_time;
}
public TimeAdapter(ArrayList<String> times, Context context, String start_time) {
this.times = times;
this.context = context;
this.start_time = start_time;
try {
this.mAdapterCallback = ((AdapterCallback) context);
} catch (ClassCastException e) {
throw new ClassCastException("Activity must implement AdapterCallback.");
}
}
@Override
public TimeAdapter.TimeViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.time_slot_layout, parent, false);
TimeViewHolder viewHolder = new TimeViewHolder(v);
return viewHolder;
}
@Override
public void onBindViewHolder(final TimeAdapter.TimeViewHolder holder, final int position) {
holder.text_time.setText(times.get(position).toString());

holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
start_time=times.get(position).toString();
mAdapterCallback.onMethodCallback();
//itemClickListener.onItemClick(position);

//   holder.itemClickListener.onClick(position);

//   Toast.makeText(v.getContext(),"Selected Time is :"+times.get(position).toString(),Toast.LENGTH_LONG).show();
}
});

}
@Override
public int getItemCount() {
return times.size();
}
public static class TimeViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
private ItemClickListener itemClickListener;
protected TextView text_time;

//  private ItemClickListener itemClickListener;
public TimeViewHolder(View itemView) {
super(itemView);

text_time = (TextView) itemView.findViewById(R.id.time_slot);

itemView.setOnClickListener(this);
}
public void setItemClickListener(ItemClickListener itemClickListener) {
this.itemClickListener = itemClickListener;
}
@Override
public void onClick(View v) {
itemClickListener.onClick(v, getAdapterPosition(), false);
}
}
public static interface AdapterCallback {
void onMethodCallback();
}
}

Answer 1

看起来您正在传递应用程序上下文而不是在上述代码中实现TimeAdapter.AdapterCallback的活动，您只需要执行以下更改。

adapter = new TimeAdapter(times, this ,one);

Answer 2

您可以将回调更改为：

public static interface AdapterCallback {
void onMethodCallback(String data);
}

并像下面这样称呼它：

mAdapterCallback.onMethodCallback(times.get(position).toString());

Answer 3

在活动类中定义一个带参数的方法，并通过传递值作为参数从适配器类调用此方法。