根據int參數對RecyclerView數組中的項目進行排序

Question

我有一個包含5個項目的Arraylist。每個項目都有優先權。我想要做的是根據該優先級對這些項目進行排序。假設項目3的優先級爲100，那麼該項目應該先列在列表中。項目0的優先級爲-10，那麼該項目必須在列表中最後一個。我如何實現類似的東西？ Adapterclass：

public class CardAdapter extends RecyclerView.Adapter<CardAdapter.cardViewHolder> { 
private ArrayList<Card> item; 
public CardAdapter(ArrayList<Card> item){ 
    this.item = item; 
} 

@Override 
public cardViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { 
    View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.card_layout,parent,false); 
    cardViewHolder card = new cardViewHolder(v); 

    return card; 
} 

@Override 
public void onBindViewHolder(cardViewHolder holder, int position) { 
    holder.titel.setText(item.get(position).getTitel()); 
    holder.card_icon.setImageResource(item.get(position).getIcon()); 
    holder.load_more.setText("Load more"); 

} 

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

public static class cardViewHolder extends RecyclerView.ViewHolder{ 
    TextView titel; 
    ImageView card_icon; 
    TextView load_more; 
    public cardViewHolder(View itemView){ 
     super(itemView); 
     titel = (TextView)itemView.findViewById(R.id.titel); 
     card_icon = (ImageView)itemView.findViewById(R.id.card_icon); 
     load_more = (TextView)itemView.findViewById(R.id.loadmore); 
    } 

}} 

主要類

public class MainActivity extends ActionBarActivity { 
private RecyclerView recycler; 
private RecyclerView.LayoutManager lmanager; 
private RecyclerView.Adapter adapter; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    ArrayList<Card> data = new ArrayList<Card>(); 
    data.add(new Card(R.drawable.mensa, "Mensa", "mensa")); 
    data.add(new Card(R.drawable.book, "Bibliothek", "bibliothek")); 
    data.add(new Card(R.drawable.timetable, "Stundenplan", "timetable")); 
    data.add(new Card(R.drawable.message, "Mitteilungen", "mitteilungen")); 
    data.add(new Card(R.drawable.noten, "Noten", "noten")); 


    recycler = (RecyclerView)findViewById(R.id.recycler); 
    lmanager = new LinearLayoutManager(this); 
    recycler.setLayoutManager(lmanager); 
    adapter = new CardAdapter(data); 
    recycler.setAdapter(adapter); 



}} 

卡類

public class Card { 
private String titel; 
private int card_icon; 
private String id; 
private int priority; 


public Card(int icon, String titel, String id) { 
    this.card_icon = icon; 
    this.titel = titel; 
    this.id = id; 
    priority=0; 
} 

public String getTitel() { 
    return titel; 
} 

public int getIcon() { 
    return card_icon; 
} 

public String getId() { 
    return id; 
} 
public void setPriority(int priority){ 
    this.priority = priority; 
}} 

Answer 1

優先加入卡對象。例如。

data.add(new Card(id, name, description, priority); 

使用自定義對arraylist排序Comparator例如，

public class CustomComparator implements Comparator<Card> { 
     @Override 
     public int compare(Card card1, Card card2) { 
      Integer priority1 = card1.getPriority(); 
      Integer priority2 = card2.getPriority(); 
      return priority2.compareTo(priority1); 
     } 
    } 

Collections.sort(data, new CustomComparator());