Question

我有一个只有ImageView和TextView的自定义适配器。滚动时，它非常慢，如果你滚动足够多次，应用程序最终会停止。我在想我接近这个方法的效率不高？

public class CustomAdapter extends ArrayAdapter<String> {

CustomAdapter(Context context, String[] breakfast) {
    super(context, R.layout.custom_row, breakfast);
}

@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
    if (convertView == null) {
        convertView = LayoutInflater.from(getContext()).inflate(R.layout.custom_row, parent, false);
    }
    String breakfastElement = getItem(position);
    TextView customListTextView = (TextView) convertView.findViewById(R.id.customListTextView);
    ImageView imageView = (ImageView) convertView.findViewById(R.id.imageView);

    customListTextView.setText(breakfastElement);

    switch(breakfastElement) {
        case "Bacon":
            imageView.setImageResource(R.drawable.bacon);
            break;
        case "Eggs":
            imageView.setImageResource(R.drawable.eggs);
            break;
        case "Toast":
            imageView.setImageResource(R.drawable.toast);
            break;
        case "Ham":
            imageView.setImageResource(R.drawable.ham);
            break;
        case "Hashbrown":
            imageView.setImageResource(R.drawable.hashbrowns);
            break;
        case "Biscuits":
            imageView.setImageResource(R.drawable.biscuit);
            break;
        case "Burrito":
            imageView.setImageResource(R.drawable.burrito);
            break;
        case "Cereal":
            imageView.setImageResource(R.drawable.cereal);
            break;
        case "Oatmeal":
            imageView.setImageResource(R.drawable.oatmeal);
            break;
        case "Sausage":
            imageView.setImageResource(R.drawable.sausage);
            break;
        case "Bagel":
            imageView.setImageResource(R.drawable.bagel);
            break;
        case "Croissant":
            imageView.setImageResource(R.drawable.croissant);
            break;
        case "Orange Juice":
            imageView.setImageResource(R.drawable.orangejuice);
            break;
        case "Milk":
            imageView.setImageResource(R.drawable.milk);
            break;
    }
    return convertView;
  }
}

如果我只为每个列表元素使用相同的图像，我不会慢速滚动。任何帮助表示赞赏

编辑：

  CustomAdapter(Context context, ArrayList<Breakfast> breakfastArrayList) {
    super(context, R.layout.custom_row, breakfastArrayList);
    breakfastArray = breakfastArrayList;
}

它不允许我传递breakfastArrayList作为第三个参数

Answer 1

有这样的早餐数据类

public class Breakfast {

  private String name;
  private Drawable drawable;

  public Breakfast(String name, Drawable drawable) {
    this.name = name;
    this.drawable = drawable;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }

  public Drawable getDrawable() {
    return drawable;
  }

  public void setDrawable(Drawable drawable) {
    this.drawable = drawable;
  }
}

创建像这样的早餐对象的arraylist

ArrayList<Breakfast> breakfastList = new ArrayList<>();
breakfastList.add(new Breakfast("Bacon",R.drawable.bacon);
...
..
.

将此arraylist传递给您的customadapter

public class CustomAdapter extends ArrayAdapter<Breakfast> {

    public CustomAdapter(Context context, int textViewResourceId) {
        super(context, textViewResourceId);
    }

    public CustomAdapter(Context context, int resource, List<Breakfast> items) {
        super(context, resource, items);
    }
   ...
   ...
   ...


    customListTextView.setText(breakfastList.get(position).getName());
imageView.setImageDrawable(breakfastList.get(position).getDrawable());

}

PS：鉴于你开始学习Android，建议你调查RecyclerView而不是ListView

Answer 2

我不确定你的错误是什么，但是通过查看你的代码我不知道为什么你使用了ArrayAdapter。如果你想根据文字显示图像，我会创建一个含有早餐项目的'BreakfastItem'类;谷物，流行挞，烤面包，并将图像与早餐项目配对。然后，您可以将其显示为列表项。

Android Studio自定义列表视图滚动缓慢并导致应用停止

2 个答案: