Android~Adapter（BaseAdapter+ListView）demo

一、BaseAdapter+ListView
1、思维导图

2、详细代码
（1）listview_item.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal">

    <ImageView
        android:id="@+id/fruitImg"
        android:layout_width="60dp"
        android:layout_height="60dp"
        android:src="@drawable/strawberry" />

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="60dp"
        android:gravity="center_vertical"
        android:orientation="vertical">

        <TextView
            android:id="@+id/fruitName"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="草莓"
            android:textSize="18sp" />

        <TextView
            android:id="@+id/fruitPrice"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="15元/KG"
            android:textSize="15sp" />
    </LinearLayout>
</LinearLayout>

（2）ListViewAdapter

public class ListViewAdapter extends BaseAdapter {
    
    
    private List<Fruit> mList;
    private Context mContext;
    private ViewHolder viewHolder;

    public ListViewAdapter(List<Fruit> mList, Context mContext) {
    
    
        this.mList = mList;
        this.mContext = mContext;
    }

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

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

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
    
    
        viewHolder = new ViewHolder();
        if (convertView == null) {
    
    
            convertView = LayoutInflater.from(mContext).inflate(R.layout.listview_item, parent, false);
            viewHolder.imageView = convertView.findViewById(R.id.fruitImg);
            viewHolder.textName = convertView.findViewById(R.id.fruitName);
            viewHolder.textPrice = convertView.findViewById(R.id.fruitPrice);
            // 缓存各个控件的实例
            convertView.setTag(viewHolder);
        } else {
    
    
            //  取出缓存
            viewHolder = (ViewHolder) convertView.getTag();
        }
        viewHolder.imageView.setImageResource(mList.get(position).getImage());
        viewHolder.textName.setText(mList.get(position).getName());
        viewHolder.textPrice.setText(mList.get(position).getPrice());
        return convertView;
    }

    //  内部类
    static class ViewHolder {
    
    
        ImageView imageView;
        TextView textName;
        TextView textPrice;
    }
}

（3）fragment_home.xml

<ListView
      android:id="@+id/listView"
      android:layout_width="match_parent"
      android:layout_height="match_parent" />

（4）HomeFragment 类

public class HomeFragment extends Fragment {
    
    
    private ListView listView;
    private ListViewAdapter adapter;
    private List<Fruit> mList;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
    
    
        View view = inflater.inflate(R.layout.fragment_home, container, false);
        listView = view.findViewById(R.id.listView);
        initFruit();
        adapter = new ListViewAdapter(mList, getContext());
        listView.setAdapter(adapter);
        return view;
    }

    private void initFruit() {
    
    
        mList = new ArrayList<Fruit>();
        mList.add(new Fruit(R.drawable.strawberry, "草莓", "15元/KG"));
        mList.add(new Fruit(R.drawable.cherry, "樱桃", "18元/KG"));
        mList.add(new Fruit(R.drawable.watermelon, "西瓜", "6元/KG"));
        mList.add(new Fruit(R.drawable.apple, "苹果", "10元/KG"));
        mList.add(new Fruit(R.drawable.litchi, "荔枝", "9.9元/KG"));
        mList.add(new Fruit(R.drawable.strawberry, "草莓", "15元/KG"));
        mList.add(new Fruit(R.drawable.cherry, "樱桃", "18元/KG"));
        mList.add(new Fruit(R.drawable.watermelon, "西瓜", "6元/KG"));
        mList.add(new Fruit(R.drawable.apple, "苹果", "10元/KG"));
        mList.add(new Fruit(R.drawable.litchi, "荔枝", "9.9元/KG"));
        mList.add(new Fruit(R.drawable.strawberry, "草莓", "15元/KG"));
        mList.add(new Fruit(R.drawable.cherry, "樱桃", "18元/KG"));
        mList.add(new Fruit(R.drawable.watermelon, "西瓜", "6元/KG"));
        mList.add(new Fruit(R.drawable.apple, "苹果", "10元/KG"));
        mList.add(new Fruit(R.drawable.litchi, "荔枝", "9.9元/KG"));
    }
}

运行效果，如下图所示：

二、ListView加载不同布局
通过getItemViewType()方法，根据不同类型，加载不同的布局，不同布局的加载顺序由具体业务逻辑决定，结合上面1。
1、思维导图

2、详细代码
（1）ListViewAdapter

public class ListViewAdapter extends BaseAdapter {
    
    
    private List<Fruit> mList;
    private Context mContext;
    private ViewHolder viewHolder;
    private ViewHolderSe viewHolderSe;
    private LayoutInflater inflater;
    private static final int type_1 = 0;
    private static final int type_2 = 1;

    public ListViewAdapter(List<Fruit> mList, Context mContext) {
    
    
        this.mList = mList;
        this.mContext = mContext;
    }

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

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

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

    @Override
    public int getViewTypeCount() {
    
    
        return 2;
    }

    @Override
    public int getItemViewType(int position) {
    
    
        int type = position % 5;
        if (type < 4) {
    
    
            return type_1;
        } else {
    
    
            return type_2;
        }
//        return position % 2;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
    
    
        int type = getItemViewType(position);
        viewHolder = new ViewHolder();
        viewHolderSe = new ViewHolderSe();
        inflater = LayoutInflater.from(mContext);
        if (convertView == null) {
    
    
            switch (type) {
    
    
                case type_1:
                    convertView = inflater.inflate(R.layout.listview_item, parent, false);
                    viewHolder.imageView = convertView.findViewById(R.id.fruitImg);
                    viewHolder.textName = convertView.findViewById(R.id.fruitName);
                    viewHolder.textPrice = convertView.findViewById(R.id.fruitPrice);
                    // 缓存各个控件的实例
                    convertView.setTag(viewHolder);
                    break;
                case type_2:
                    convertView = inflater.inflate(R.layout.other_listview_item, parent, false);
                    viewHolderSe.imageViewSe = convertView.findViewById(R.id.oFruitImg);
                    viewHolderSe.textDetails = convertView.findViewById(R.id.oFruitDetails);
                    // 缓存各个控件的实例
                    convertView.setTag(viewHolderSe);
                    break;
                default:
                    break;
            }
        } else {
    
    
            //  取出缓存
            switch (type) {
    
    
                case type_1:
                    viewHolder = (ViewHolder) convertView.getTag();
                    break;
                case type_2:
                    viewHolderSe = (ViewHolderSe) convertView.getTag();
                    break;
                default:
                    break;
            }
        }
        switch (type) {
    
    
            case type_1:
                viewHolder.imageView.setImageResource(mList.get(position).getImage());
                viewHolder.textName.setText(mList.get(position).getName());
                viewHolder.textPrice.setText(mList.get(position).getPrice());
                break;
            case type_2:
                viewHolderSe.imageViewSe.setImageResource(mList.get(position).getImage());
                viewHolderSe.textDetails.setText("\t\t\t\t" + mList.get(position).getDetails());
                break;
            default:
                break;
        }
        return convertView;
    }

    //  内部类
    static class ViewHolder {
    
    
        ImageView imageView;
        TextView textName;
        TextView textPrice;
    }

    static class ViewHolderSe {
    
    
        ImageView imageViewSe;
        TextView textDetails;
    }
}

运行效果，如下图所示：