单击 Cardview 时如何在另一个活动中显示详细信息

Question

I am having a problem, how can I display the value of the cardView based on its position? I feel like I am kinda missing something.

here is my code

    @Override
    public void onBindViewHolder(AnnouncementViewHolder holder, int position) {
        AnnouncementModel announcement = announcementList.get(position);

        if (announcement.getImage()!=null && !announcement.getImage().isEmpty()){
            Picasso.get()
                    .load(announcement.getImage())
                    // To fit image into imageView
                    .fit()
                    // To prevent fade animation
                    .noFade()
                    .into(holder.imageView);
        }else{
            //Do nothing
        }

        holder.textViewDate.setText(announcement.getDate());
        holder.textViewTitle.setText(announcement.getTitle());
        holder.textViewExcerpt.setText(announcement.getExcerpt());

    }

    @Override
    public int getItemCount() {
        return announcementList.size();
    }

    class AnnouncementViewHolder extends RecyclerView.ViewHolder {

        TextView textViewTitle, textViewExcerpt,textViewDate;
        ImageView imageView;

        public AnnouncementViewHolder(View itemView) {
            super(itemView);

            textViewDate = itemView.findViewById(R.id.textAnnouncementDate);
            textViewTitle = itemView.findViewById(R.id.textAnnouncementDesc);
            textViewExcerpt = itemView.findViewById(R.id.textAnnouncementDesc);
            imageView = itemView.findViewById(R.id.AnnouncementImageView);

            itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Context context = v.getContext();
                    Intent intent = new Intent(context, DetailActivityAnnouncement.class);
                    intent.putExtra(DetailActivity.EXTRA_POSITION, getAdapterPosition());
                    context.startActivity(intent);
                }
            });

        }
    }

I want to display the textViewDate and textViewTitle to my other activity when click.

Here is my detailActvity

public class DetailActivity extends AppCompatActivity {


    public static final String EXTRA_POSITION = "position";
    AnnouncementModel model;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_detail_announcement);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);


        int postion = getIntent().getIntExtra(EXTRA_POSITION, 0);

        TextView announcementContent = (TextView) findViewById(R.id.textAnnouncementContext);
        TextView announcementDate = (TextView) findViewById(R.id.textAnnouncementDate);
        ImageView announcementImage = (ImageView) findViewById(R.id.AnnouncementImageView);
        TextView announcementOtherDetails = (TextView) findViewById(R.id.textAnnouncementOtherDetails);


    }

}

I feel like I am already close to my answer but I am still stuck. Any help would be really appreciated.

Answer 1

You can use intent to send data from one activity to another.

In your itemView.setOnClickListener() you already defined the Intent to open your DetailActivity .

Now all you need to do is add data with intent like

Context context = v.getContext();
Intent intent = new Intent(context, DetailActivityAnnouncement.class);
intent.putExtra(DetailActivity.EXTRA_POSITION, getAdapterPosition());

// putExtra can be used to send data with intent, here "date"
// and "title" is key that we will need later to access these values 
intent.putExtra("date",announcementList.get(getAdapterPosition()).getDate());
intent.putExtra("title", announcementList.get(getAdapterPosition()).getTitle());

context.startActivity(intent);

In your DetailActivity you can retrieve this information in your onCreate method

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_detail_announcement);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);


        int postion = getIntent().getIntExtra(EXTRA_POSITION, 0);

        //you can retrieve data from intent like
        String textViewDate = getIntent().getStringExtra("date");
        String textViewTitle = getIntent().getStringExtra("title");

        TextView announcementContent = (TextView) findViewById(R.id.textAnnouncementContext);
        TextView announcementDate = (TextView) findViewById(R.id.textAnnouncementDate);
        ImageView announcementImage = (ImageView) findViewById(R.id.AnnouncementImageView);
        TextView announcementOtherDetails = (TextView) findViewById(R.id.textAnnouncementOtherDetails);


    }

Extra:- you should always check that you have received data from intent and make sure textViewDate, textViewTitle is not null.

you can also check before retrieving data in activity like if(getIntent().hasExtra("date")) if you have data then it will be true.

Answer 2

I think instead of passing just the position to the detail activity you should try passing date and title in the intent(instead of just position) and then get both of them in detail activity to display it OR you can make your announcement object parcelable and then pass it in the intent itself that way you can get all details. you can set a tag to the itemView using itemView.setTag() and then get the object using itemView.getTag()

Answer 3

I suggest you make an interface

public interface DeviceClickedInterface {
void DeviceSelectedInterface(int position);
}

and in your Adapter pass it to the Class

private DeviceClickedInterface deviceClickedInterface;

public DevicesAdapter( DeviceClickedInterface deviceClickedInterface, ... the rest of params.) {
    //other params. init.
    this.deviceClickedInterface = deviceClickedInterface;
}

make the AnnouncementViewHolder contains the itemView as child too, and inside the onBindViewHolder add ClickListener on the itemView

        holder.itemView.setOnClickListener(v -> deviceClickedInterface.DeviceSelectedInterface(position));

at last make the DetailActivity implements your own DeviceClickedInterface and it will Override DeviceSelectedInterface method in your Activity which will return the position each time you click on a CardView