import android.content.Context; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.TextView; import java.util.List; public class ChatAdapter extends BaseAdapter { private List<ChatBean> chatBeanList; private LayoutInflater layoutInflater; public ChatAdapter(List<ChatBean> chatBeanList, Context context){ this.chatBeanList=chatBeanList; layoutInflater=LayoutInflater.from(context); } @Override public int getCount() { return chatBeanList.size(); } @Override public Object getItem(int position) { return chatBeanList.get(position); } @Override public long getItemId(int position) { return position; } @Override public View getView(int position, View conventView, ViewGroup parent) { Holder holder=new Holder(); if (chatBeanList.get(position).getState()==ChatBean.RECEIVE){ conventView=layoutInflater.inflate(R.layout.chatting_left_item,null); }else { conventView=layoutInflater.inflate(R.layout.chatting_right_item,null); } holder.tv_chat_content=(TextView) conventView.findViewById(R.id.tv_chat_content); holder.tv_chat_content.setText(chatBeanList.get(position).getMessage()); return conventView; } class Holder{ public TextView tv_chat_content; } }有什么作用
时间: 2024-03-30 07:37:52 浏览: 74
这是一个适配器(Adapter)类,用于将数据源(chatBeanList)中的数据适配到ListView或GridView等控件上显示。具体来说,它会根据数据源中每个ChatBean对象的状态(是接收还是发送)来决定使用哪个布局(chatting_left_item或chatting_right_item),然后将对应的聊天内容显示在布局中的TextView上。通过getView()方法返回的View对象,最终会被显示在ListView或GridView的每一行上。
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。
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); } }这段代码有什么用
这段代码是一个 Android 应用程序中的一个 Fragment,用于显示用户所答错的单词列表。在该 Fragment 中,通过 SharedPreferences 来获取用户答错的单词列表,然后将这些单词显示在一个 ListView 中,以便用户进行复习。具体而言,该代码负责以下几个功能:
1. 从布局文件 R.layout.fragment_wrong 中获取界面布局,即 onCreateView 方法。
2. 从 SharedPreferences 中获取用户答错的单词列表,然后将这些单词封装成 Word 对象并添加到 wordList 中,即 onActivityCreated 方法。
3. 创建 WordAdapter 对象,将 wordList 中的单词显示在 ListView 中,即 onActivityCreated 方法。
需要注意的是,该代码片段并不完整,可能还有其他代码片段与之配合使用,才能实现完整的功能。
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