Android ListView万能适配器实例代码

2022-06-06 07:34

短信预约 -IT技能 免费直播动态提醒

ListView是开发中最常用的控件了，但是总是会写重复的代码，浪费时间又没有意义。

最近参考一些资料，发现一个万能ListView适配器，代码量少，节省时间，总结一下分享给大家。

首先有一个自定义的Adapter继承于BaseAdapter，下面是自定义的Adapter，精华在getView()方法中


package com.example.mylistview.util;
import java.util.List;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
public abstract class CommonAdapter<T> extends BaseAdapter {
 
 private Context mContext;
 
 private List<T> mDatas;
 private LayoutInflater mInflater;
 
 private int mlayoutId;
 public CommonAdapter(Context context, List<T> datas, int layoutId) {
  this.mContext = context;
  this.mDatas = datas;
  this.mlayoutId = layoutId;
  mInflater = LayoutInflater.from(context);
 }
 @Override
 public int getCount() {
  // TODO Auto-generated method stub
  return mDatas.size();
 }
 @Override
 public T getItem(int arg0) {
  // TODO Auto-generated method stub
  return mDatas.get(arg0);
 }
 @Override
 public long getItemId(int arg0) {
  // TODO Auto-generated method stub
  return arg0;
 }
 @Override
 public View getView(int arg0, View arg1, ViewGroup arg2) {
  // TODO Auto-generated method stub
  ViewHolder holder = ViewHolder.get(mContext, arg1, arg2, mlayoutId,
    arg0);
  convert(holder, getItem(arg0));
  return holder.getConvertView();
 }
 public abstract void convert(ViewHolder holder, T t);
}

以上的抽象方法convert(ViewHolder holder, T t)；就相当于以前通用代码中的

viewHolder.mTextView = (TextView) convertView .findViewById(R.id.id_tv_title);

viewHolder.mTextView.setText(Bean.getName());

找到控件的id再去设施setText等重复的代码方法中的参数ViewHolder holder, T t holder就相当于以前通用代码中的viewHolder，t就相当于一个自己定义的实体类Bean。

以上代码中getView()方法中有一个ViewHolder是需要自己声明的，以下是代码以及详细注释：


package com.example.mylistview.util;
import android.content.Context;
import android.graphics.Bitmap;
import android.renderscript.Type;
import android.util.SparseArray;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
public class ViewHolder {
 
 private SparseArray<View> mViews;
 
 private int mPosition;
 
 private View mConvertView;
 public View getConvertView() {
  return mConvertView;
 }
 public ViewHolder(Context context, ViewGroup parent, int layoutId,
   int position) {
  this.mViews = new SparseArray<View>();
  this.mPosition = position;
  this.mConvertView = LayoutInflater.from(context).inflate(layoutId,
    parent, false);
  this.mConvertView.setTag(this);
 }
 
 public static ViewHolder get(Context context, View convertView,
   ViewGroup parent, int layoutId, int position) {
  if (null == convertView) {
   return new ViewHolder(context, parent, layoutId, position);
  } else {
   ViewHolder holder = (ViewHolder) convertView.getTag();
   holder.mPosition = position;
   return holder;
  }
 }
 
 public <T extends View> T getView(int viewId) {
  View view = mViews.get(viewId);
  if (null == view) {
   view = mConvertView.findViewById(viewId);
   mViews.put(viewId, view);
  }
  return (T) view;
 }
 
 public ViewHolder setText(int viewId, String text) {
  TextView tv = getView(viewId);
  tv.setText(text);
  return this;
 }
  
 public ViewHolder setImageResource(int viewId, int drawableId) 
 { 
  ImageView view = getView(viewId); 
  view.setImageResource(drawableId); 
  return this; 
 } 
 public int getPosition() 
 { 
  return mPosition; 
 } 
}

再写一个Adapter继承于万能适配器CommonAdapter，还是要写一个自己的Adapter,因为一个项目可能会有多个ListView，但是每个的item元素，布局都会有所不同的，这个泪用来区分不同的ListView与自己所对应的item.这个代码量较少完全可以写成内部类在Activity.java中.


package com.example.mylistview.adapter;
import java.util.List;
import android.content.Context;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.CheckBox;
import com.example.mylistview.R;
import com.example.mylistview.domain.Bean;
import com.example.mylistview.util.CommonAdapter;
import com.example.mylistview.util.ViewHolder;
public class MyAdapter extends CommonAdapter<Bean> {
 public MyAdapter(Context context, List<Bean> datas, int layoutId) {
  super(context, datas, layoutId);
  // TODO Auto-generated constructor stub
 }
 @Override
 public void convert(ViewHolder holder, final Bean bean) {
  // TODO Auto-generated method stub
  holder.setText(R.id.tv_title, bean.getTitle())
    .setText(R.id.tv_desc, bean.getDesc())
    .setText(R.id.tv_time, bean.getTime())
    .setText(R.id.tv_phone, bean.getPhone());
  
  final CheckBox cBox = (CheckBox)(holder.getView(R.id.cb));
  if (cBox != null)
  {
   cBox.setChecked(bean.isChecked());
   cBox.setOnClickListener(new OnClickListener()
   {
    @Override
    public void onClick(View v)
    {
     bean.setChecked(cBox.isChecked());
    }
   });
  }
 }
}

优化之后用适配器的时候就简单多了下面是实体类,item和MainActivity.java中的代码：

实体类：


package com.example.mylistview.domain;
public class Bean {
 private String title;
 private String desc;
 private String time;
 private String phone;
 private boolean isChecked;
 public boolean isChecked() {
  return isChecked;
 }
 public void setChecked(boolean isChecked) {
  this.isChecked = isChecked;
 }
 
 public Bean(String title, String desc, String time, String phone) {
  this.title = title;
  this.desc = desc;
  this.time = time;
  this.phone = phone;
 }
 public String getTitle() {
  return title;
 }
 public void setTitle(String title) {
  this.title = title;
 }
 public String getDesc() {
  return desc;
 }
 public void setDesc(String desc) {
  this.desc = desc;
 }
 public String getTime() {
  return time;
 }
 public void setTime(String time) {
  this.time = time;
 }
 public String getPhone() {
  return phone;
 }
 public void setPhone(String phone) {
  this.phone = phone;
 }
}

MainActivity.java：

重点代码：

参数有上下文，集合，和自己对应的item就可以了
adapter = new MyAdapter(this, mDatas, R.layout.item);


package com.example.mylistview.ui;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
import com.example.mylistview.R;
import com.example.mylistview.adapter.MyAdapter;
import com.example.mylistview.domain.Bean;
public class MainActivity extends Activity {
 private ListView listView;
 private List<Bean> mDatas;
 
 private MyAdapter adapter;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  initView();
  initData();
  listener();
 }
 private void listener() {
  // TODO Auto-generated method stub
  listView.setOnItemClickListener(new OnItemClickListener() {
   @Override
   public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
     long arg3) {
    // TODO Auto-generated method stub
    startActivity(new Intent(MainActivity.this, SecondActivity.class));
   }
  });
 }
 private void initData() {
  // TODO Auto-generated method stub
  mDatas = new ArrayList<Bean>();
  Bean bean = new Bean("Android新技能 Get",
    "Android-打造万能的ListView和GridView适配器", "2015-08-05", "10086");
  mDatas.add(bean);
  bean = new Bean("捡到权志龙一个",
    "在星巴克捡到权志龙一个", "2015-08-06", "10086");
  mDatas.add(bean);
  bean = new Bean("GetTOP一个",
    "在韩国首尔捡到TOP一个", "2015-08-07", "10086");
  mDatas.add(bean);
  adapter = new MyAdapter(this, mDatas, R.layout.item);
  listView.setAdapter(adapter);
 }
 private void initView() {
  // TODO Auto-generated method stub
  listView = (ListView) findViewById(R.id.listView);
 }
}

item布局：


<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:padding="10dp" >
 <CheckBox
  android:focusable="false"
  android:id="@+id/cb"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_alignParentRight="true"
  android:layout_centerInParent="true" />
 <TextView
  android:id="@+id/tv_title"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_marginTop="10dp"
  android:singleLine="true"
  android:text="Android新技能 Get" />
 <TextView
  android:id="@+id/tv_desc"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:layout_below="@id/tv_title"
  android:layout_marginTop="10dp"
  android:layout_toLeftOf="@id/cb"
  android:maxLines="2"
  android:text="Android-打造万能的ListView和GridView适配器"
  android:textColor="#898989" />
 <TextView
  android:id="@+id/tv_time"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_below="@id/tv_desc"
  android:layout_marginTop="10dp"
  android:text="2015-08-05"
  android:textColor="#898989"
  android:textSize="12sp" />
 <TextView
  android:id="@+id/tv_phone"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_alignParentRight="true"
  android:layout_below="@id/tv_desc"
  android:layout_marginTop="10dp"
  android:background="#20793D"
  android:maxLines="1"
  android:text="10086"
  android:padding="4dp"
  android:textColor="#FFF" />
</RelativeLayout>

效果图：

用这个去适配另一个不同的布局：

新布局的Adapter一样继承自己的万能adapter:CommonAdapter


package com.example.mylistview.adapter;
import java.util.List;
import java.util.Map;
import android.content.Context;
import com.example.mylistview.R;
import com.example.mylistview.util.CommonAdapter;
import com.example.mylistview.util.ViewHolder;
public class SecondAdapter extends CommonAdapter<Map<String, String>> {
 public SecondAdapter(Context context, List<Map<String, String>> datas,
   int layoutId) {
  super(context, datas, layoutId);
  // TODO Auto-generated constructor stub
 }
 @Override
 public void convert(ViewHolder holder, Map<String, String> t) {
  // TODO Auto-generated method stub
  holder.setText(R.id.tv_item2values, t.get("values"));
 }
}

Activity.java代码：


package com.example.mylistview.ui;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.app.Activity;
import android.os.Bundle;
import android.widget.ListView;
import com.example.mylistview.R;
import com.example.mylistview.adapter.MyAdapter;
import com.example.mylistview.adapter.SecondAdapter;
public class SecondActivity extends Activity {
 private ListView listView_second;
 private SecondAdapter secondAdapter;
 private List<Map<String, String>> lists = new ArrayList<Map<String, String>>();
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_second);
  initView();
  initData();
 }
 private void initData() {
  // TODO Auto-generated method stub
  for (int i = 0; i < 4; i++) {
   Map map = new HashMap<String, String>();
   map.put("values", "条目" + i);
   lists.add(map);
  }
  secondAdapter = new SecondAdapter(this, lists, R.layout.item2);
  listView_second.setAdapter(secondAdapter);
 }
 private void initView() {
  // TODO Auto-generated method stub
  listView_second = (ListView) findViewById(R.id.listView_second);
 }
}

item：


<?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="match_parent"
 android:orientation="horizontal" >
 <TextView
  android:id="@+id/tv_item2values"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_gravity="center"
  android:text="ffffff"
  android:layout_margin="16dp"
  android:gravity="center" />
</LinearLayout>

效果图：

以上就是对Android ListView 的资料整理，希望能给大家带来帮助！

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