RecyclerView中的捆绑问题

Question

在RecolyerViewCustomViewWholder内的OnClickListener()中尝试将我的包放入我的意图时出错。

java.lang.NullPointerException：尝试对空对象引用调用虚拟方法“void android.os.bundle.putString（java.lang.String,java.lang.String）”

我也尝试创建一个新的捆绑包，而不是使用额外的，但得到了与上面相同的错误。奇怪的是，putExtras()方法可以很好地处理一个变量，并且可以正确地传递，但是，唉，我有大约8个不同的变量要插入辅助页面。

代码如下：

    public void onClick(View view) {
    intent = new Intent(itemView.getContext(), CardActivity.class);
    extras = intent.getExtras();
        extras.putString(CARD_IMG, cardList.Basic.get(getAdapterPosition()).getImg());
        extras.putString(CARD_FLAVOR, cardList.Basic.get(getAdapterPosition()).getFlavor());
        extras.putString(CARD_TEXT, cardList.Basic.get(getAdapterPosition()).getText());
        extras.putString(CARD_TYPE, cardList.Basic.get(getAdapterPosition()).getType());
        extras.putString(CARD_ARTIST, cardList.Basic.get(getAdapterPosition()).getArtist());
        extras.putString(CARD_SET, cardList.Basic.get(getAdapterPosition()).getCardSet());
        extras.putString(CARD_RARITY, cardList.Basic.get(getAdapterPosition()).getRarity());
        extras.putString(CARD_NAME, cardList.Basic.get(getAdapterPosition()).getName());
    intent.putExtras(extras);
    itemView.getContext().startActivity(intent);
}

我们将非常感谢在正确的方向上提供任何帮助或推动。

    public class RecyclerAdaptor extends RecyclerView.Adapter<RecyclerAdaptor.CustomViewHolder> {
//for bundle keys
private static final String CARD_FLAVOR = "CARD_FLAVOR";
private static final String CARD_TYPE = "CARD_TYPE";
private static final String CARD_ARTIST = "CARD_ARTIST";
private static final String CARD_SET = "CARD_SET";
private static final String CARD_RARITY = "CARD_RARITY";
private static final String CARD_NAME = "CARD_NAME";
private static final String CARD_IMG = "CARD_IMG";
private static final String CARD_TEXT = "CARD_TEXT";

private static Intent intent;
public static Bundle extras;
public static CardList cardList;

public RecyclerAdaptor(CardList cardList) {
    this.cardList = cardList;
}

@Override
//Number of Items
public int getItemCount() {
    return cardList.Basic.size();
}


@Override
public RecyclerAdaptor.CustomViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View v = LayoutInflater.from(parent.getContext())
            .inflate(R.layout.card_row, parent, false);
    CustomViewHolder holder = new CustomViewHolder(v);
    return holder;
}

@Override
public void onBindViewHolder(RecyclerAdaptor.CustomViewHolder holder, int position) {

    final Card card = cardList.Basic.get(position);
    String cost = "0";
    // Could have made values protected in class, but meh
    holder.cardName.setText(card.getName());
    holder.cardText.setText(card.getText());
    holder.cardFlavor.setText(card.getFlavor());

    // Handles dust value of card
    if (card.getRarity() != null) {
        switch (card.getRarity()) {
            case "Common": cost = "40";
                break;
            case "Rare": cost = "100";
                break;
            case "Epic": cost = "400";
                break;
            case "Legendary": cost = "1600";
                break;
        }
    }

    holder.cardCost.setText(cost);
    Picasso.with(holder.cardImg.getContext()).load(card.getImg()).into(holder.cardImg);

}

public static class CustomViewHolder extends RecyclerView.ViewHolder {

    private TextView cardName;
    private TextView cardText;
    private TextView cardFlavor;
    private TextView cardCost;
    private GifImageView cardImg;
    private Button moreButton;

    public CustomViewHolder(final View itemView) {
        super(itemView);

        cardName = itemView.findViewById(R.id.cardTitle);
        cardText = itemView.findViewById(R.id.cardText);
        cardFlavor = itemView.findViewById(R.id.cardFlavor);
        cardCost = itemView.findViewById(R.id.dustTextView);
        cardImg = itemView.findViewById(R.id.cardImgView);
        moreButton = itemView.findViewById(R.id.moreButton);

        moreButton.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {
                Toast.makeText(itemView.getContext(), "Clicked:" + getAdapterPosition(), Toast.LENGTH_SHORT).show();
                intent = new Intent(itemView.getContext(), CardActivity.class);
                extras = intent.getExtras();
                if(extras == null){
                    extras = new Bundle();
                }
                    extras.putString(CARD_IMG, cardList.Basic.get(getAdapterPosition()).getImg());
                    extras.putString(CARD_FLAVOR, cardList.Basic.get(getAdapterPosition()).getFlavor());
                    extras.putString(CARD_TEXT, cardList.Basic.get(getAdapterPosition()).getText());
                    extras.putString(CARD_TYPE, cardList.Basic.get(getAdapterPosition()).getType());
                    extras.putString(CARD_ARTIST, cardList.Basic.get(getAdapterPosition()).getArtist());
                    extras.putString(CARD_SET, cardList.Basic.get(getAdapterPosition()).getCardSet());
                    extras.putString(CARD_RARITY, cardList.Basic.get(getAdapterPosition()).getRarity());
                    extras.putString(CARD_NAME, cardList.Basic.get(getAdapterPosition()).getName());
                intent.putExtras(extras);
                itemView.getContext().startActivity(intent);
            }
        });

    }
}
}

此外，如果我保持一切原样，去掉原意.putextras的话，它就不会崩溃。

Answer 1

这是因为您的意图为空，请替换为下面的代码

public void onClick(View view) {
    intent = new Intent(itemView.getContext(), CardActivity.class);
    extras = new Bundle(); //<-- so that bundle wont be null anymore
        extras.putString(CARD_IMG, cardList.Basic.get(getAdapterPosition()).getImg());
        extras.putString(CARD_FLAVOR, cardList.Basic.get(getAdapterPosition()).getFlavor());
        extras.putString(CARD_TEXT, cardList.Basic.get(getAdapterPosition()).getText());
        extras.putString(CARD_TYPE, cardList.Basic.get(getAdapterPosition()).getType());
        extras.putString(CARD_ARTIST, cardList.Basic.get(getAdapterPosition()).getArtist());
        extras.putString(CARD_SET, cardList.Basic.get(getAdapterPosition()).getCardSet());
        extras.putString(CARD_RARITY, cardList.Basic.get(getAdapterPosition()).getRarity());
        extras.putString(CARD_NAME, cardList.Basic.get(getAdapterPosition()).getName());
    intent.putExtras(extras);
    itemView.getContext().startActivity(intent);
}