如何为 Category 和 CategoryItem 制作 android xml 布局

Question

我是使用 java 和 android studio 的新手，我想知道如何在 1 个活动中制作这样的布局。 myImage

Answer 1

您正在寻找的是一个 Listview 适配器

public class ExampleAdapter extends BaseAdapter {
    List<Product> products;
    private Activity context;

    @Override
    public int getCount() {
        return products.size();
    }

    public ExampleAdapter(List<Product> products, Activity context) {
        this.products = products;
        this.context = context;
    }

    @Override
    public Object getItem(int position) {
        return products.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        final Product product = products.get(position);

        ViewHolder holder;

        if (convertView == null) {
            LayoutInflater inflater = context.getLayoutInflater();
            convertView = inflater.inflate(R.layout.row_shopping_item, null);
            holder = new ViewHolder(convertView);
            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }
        holder.getProductTextView().setText(product.getName());
        holder.getProductImageView(). setImageResource(product.getPicture());

        return convertView;
    }

    private class ViewHolder {
        private final TextView productTextView;
        private final ImageView productImageView;

        private ViewHolder(View wrapperView) {
            productTextView = (TextView) wrapperView.findViewById(R.id.tvName);
            productImageView = (TextView) wrapperView.findViewById(R.id.ivPicture);

        }

        public TextView getProductTextView() {
            return productTextView;
        }

        public ImageView getProductImageView() {
            return productImageView;
        }

    }
}

此适配器需要一个布局来定义行的外观。这将是这样的

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal">

    <ImageView
        android:layout_gravity="center_vertical"
        android:layout_width="50dp"
        android:id="@+id/ivPicture"
        android:layout_height="50dp" />

    <TextView
        android:id="@+id/tvName"
        android:text="Product 1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
</LinearLayout>

最后，在您想要显示概览的活动中，您需要使用列表视图并设置适配器

final ExampleAdapter adapter = new ExampleAdapter(list, this);
listview.setAdapter(adapter);