完善代码import android.content.Context; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.Button; import android.widget.ImageView; import android.widget.TextView; import java.util.HashMap; import java.util.List; public class FBaseAdapter extends BaseAdapter { private LayoutInflater layoutInflater ; private List<HashMap<String, Object> > list ; public FBaseAdapter (Context context , List<HashMap<String, Object>> list){ this.layoutInflater = LayoutInflater .from(context ) ; this.list = list ; } @Override public int getCount() { return list.size(); } @Override public Object getItem(int i) { return null; } @Override public long getItemId(int i) { return i; } @Override public View getView(final int i, View view, ViewGroup viewGroup) { // LayoutInflater layoutInflater = getLayoutInflater(); View v = layoutInflater.inflate(R.layout.item, null); View l = layoutInflater.inflate(R.layout.listlayout, null); TextView tv_title = v.findViewById(R.id.itemtitle); TextView tv_content = v.findViewById(R.id.itemdetail ); TextView tv_price = v.findViewById(R.id.price); TextView tv_num = v.findViewById(R.id.num); ImageView imageView = v.findViewById(R.id.itemimage); Button btnadd = v.findViewById(R.id.addnum); Button btnsub = v.findViewById(R.id.subnum); TextView txtsum = l.findViewById(R.id.txtsum) ; HashMap hashMap = list.get(i); imageView.setImageResource((Integer) hashMap.get("image")); tv_title.setText(hashMap.get("title").toString()); tv_content.setText(hashMap.get("content").toString()); tv_num.setText(hashMap.get("num").toString()); tv_price.setText(hashMap.get("price").toString()); btnadd.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { int num = (int) list.get(i).get("num"); num++; list.get(i).put("num", num); int totalsum = num * (int) list.get(i).get("price"); notifyDataSetChanged(); txtsum.setText(String.valueOf(totalsum)); } }); btnsub.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { int num = (int) list.get(i).get("num"); if (num > 0) num--; else num = 0; list.get(i).put("num", num); int totalsum = num * (int) list.get(i).get("price"); notifyDataSetChanged(); txtsum.setText(String.valueOf(totalsum)); } }); return v; } }
时间: 2024-03-11 09:46:21 浏览: 16
这段代码是一个自定义的 BaseAdapter,用于在 ListView 中显示商品列表。其中,构造方法传入了一个上下文和一个包含了商品信息的列表,通过 getCount、getItem 和 getItemId 方法确定了列表的大小和元素,通过 getView 方法实现了每个商品项的布局和交互。其中,通过 findViewById 方法获取了布局中的各个控件,并通过 HashMap 获取了商品的图片、标题、内容、数量和单价等信息,通过对加减按钮的监听实现了商品数量的增减,并通过 notifyDataSetChanged 方法通知 ListView 更新列表项,同时更新总价文本框。需要注意的是,该 Adapter 没有使用 ViewHolder,因此在滑动列表时可能会出现卡顿和重复加载的问题,建议使用 ViewHolder 优化。
相关问题
我要用Intent实现跳转,应该把代码加在哪?package com.example.afinal import android.content.Intent import android.view.View import android.view.ViewGroup import android.widget.ImageView import android.widget.TextView import androidx.recyclerview.widget.RecyclerView import android.view.LayoutInflater import android.widget.Toast class ContextAdapter(val contextList: List<ContextModel>) : RecyclerView.Adapter<ContextAdapter.ViewHolder>() { inner class ViewHolder(view: View) : RecyclerView.ViewHolder(view) { val contextCover: ImageView = view.findViewById(R.id.contextCover) val contextTitle: TextView = view.findViewById(R.id.contextTitle) } override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder { val view = LayoutInflater.from(parent.context).inflate(R.layout.home_context, parent, false) val viewHolder = ViewHolder(view) viewHolder.itemView.setOnClickListener { val position = viewHolder.adapterPosition val conetext = contextList[position] Toast.makeText(parent.context, "you clicked view ${conetext.title}", Toast.LENGTH_SHORT).show() } viewHolder.contextCover.setOnClickListener { val position = viewHolder.adapterPosition val context = contextList[position] Toast.makeText(parent.context, "you clicked image ${context.title}", Toast.LENGTH_SHORT).show() } return viewHolder } override fun onBindViewHolder(holder: ViewHolder, position: Int) { val context = contextList[position] holder.contextCover.setImageResource(context.coverUrl) holder.contextTitle.text = context.title holder.itemView.setOnClickListener { intent=Intent(this,DetailsActivity::class.java) } } override fun getItemCount() = contextList.size }
将跳转代码加在 onBindViewHolder 方法中。具体地,在 holder.itemView.setOnClickListener {} 中添加跳转代码,如下所示:
holder.itemView.setOnClickListener {
val intent = Intent(holder.itemView.context, DetailsActivity::class.java)
holder.itemView.context.startActivity(intent)
}
这样当用户点击某个列表项时,就会启动名为 "DetailsActivity" 的 Activity。记得事先在 AndroidManifest.xml 文件中声明这个 Activity。
你能在这段代码里面添加删除存储的数据功能package com.example.reciteword; import android.content.Context; import android.content.SharedPreferences; import android.os.Bundle; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.Button; import android.widget.ImageButton; import android.widget.ListView; import android.widget.TextView; import androidx.fragment.app.Fragment; import java.util.ArrayList; import java.util.List; import java.util.Random; public class wrongFragment extends Fragment { private List<Word> wordList = new ArrayList<>(); @Override public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) { return inflater.inflate(R.layout.fragment_wrong, container, false); } @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); final SharedPreferences sharedPre = getActivity().getSharedPreferences("t",Context.MODE_PRIVATE); final int[] wrongNum = {sharedPre.getInt("wrongNum", 0)}; System.out.println(wrongNum[0]); wordList.clear(); for(int i = 1;i<=wrongNum[0];i++){ int temp = sharedPre.getInt("wrong"+i, 0); Word word = new Word(Data.getWord(temp),Data.getPron(temp),Data.getwordDefine(temp),sharedPre.getInt("word"+temp,1),0); System.out.println(Data.getRandNum()+":"+sharedPre.getInt("word"+temp,9)); wordList.add(word); } WordAdapter adapter = new WordAdapter(getActivity(),R.layout.word_item,wordList); ListView listView = (ListView) getActivity().findViewById(R.id.wrong_list_view); listView.setAdapter(adapter); } }
可以添加删除存储的数据功能,具体的实现方法如下:
1. 添加删除按钮
在布局文件fragment_wrong.xml中添加一个ImageButton按钮,用于删除存储的数据。代码如下:
```
<ImageButton
android:id="@+id/delete_btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="right"
android:src="@drawable/ic_delete" />
```
2. 实现删除功能
在onActivityCreated方法中获取删除按钮,并添加点击事件。当点击删除按钮时,遍历wordList中的所有单词,将其在SharedPreferences中存储的数据删除。具体代码如下:
```
ImageButton deleteBtn = getActivity().findViewById(R.id.delete_btn);
deleteBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
SharedPreferences.Editor editor = sharedPre.edit();
for (Word word : wordList) {
editor.remove("wrong" + word.getWordId());
editor.remove("word" + word.getWordId());
}
editor.putInt("wrongNum", 0);
editor.apply();
wordList.clear();
adapter.notifyDataSetChanged();
}
});
```
在删除单词时,需要将SharedPreferences中存储的单词总数wrongNum也同时清零,并且清空wordList中的所有单词。最后调用adapter的notifyDataSetChanged()方法,更新ListView的显示。