Android ListView萬能適配器實例代碼

2019-12-12 05:20:06

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ListView是開發中最常用的控件了，但是總是會寫重復的代碼，浪費時間又沒有意義。

最近參考一些資料，發現一個萬能ListView適配器，代碼量少，節省時間，總結一下分享給大家。

首先有一個自定義的Adapter繼承于BaseAdapter，下面是自定義的Adapter，精華在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 { /**  * 上下文  */ private Context mContext; /**  * 實體類集合  */ private List<T> mDatas; private LayoutInflater mInflater; /**  * 控件id  */ 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)；就相當于以前通用代碼中的

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

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

找到控件的id再去設施setText等重復的代碼方法中的參數ViewHolder holder, T t holder就相當于以前通用代碼中的viewHolder，t就相當于一個自己定義的實體類Bean。

以上代碼中getView()方法中有一個ViewHolder是需要自己聲明的，以下是代碼以及詳細注釋：

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 { /**  * SparseArray類存放View集合  */ private SparseArray<View> mViews; /**  *   */ private int mPosition; /**  * 布局文件  */ 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); } /**  * 拿到一個ViewHolder對象  * @param context  * @param convertView  * @param parent  * @param layoutId  * @param position  * @return  */ 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;  } } /**  * 通過控件的id獲取對應的控件，如果沒有則加入views  * @param viewId  * @return  */ 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; } /**  * 為TextView設置字符串   * @param viewId  * @param text  * @return  */ public ViewHolder setText(int viewId, String text) {  TextView tv = getView(viewId);  tv.setText(text);  return this; } /**   * 為ImageView設置圖片   *   * @param viewId   * @param drawableId   * @return   */  public ViewHolder setImageResource(int viewId, int drawableId)  {   ImageView view = getView(viewId);   view.setImageResource(drawableId);   return this;  }    public int getPosition()  {   return mPosition;  } }

再寫一個Adapter繼承于萬能適配器CommonAdapter，還是要寫一個自己的Adapter,因為一個項目可能會有多個ListView，但是每個的item元素，布局都會有所不同的，這個淚用來區分不同的ListView與自己所對應的item.這個代碼量較少完全可以寫成內部類在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());  /**   * 防止CheckBox混亂   */  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());    }   });  } }}

優化之后用適配器的時候就簡單多了下面是實體類,item和MainActivity.java中的代碼：

實體類：

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; } /**  * @param title  * @param desc  * @param time  * @param phone  */ 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：

重點代碼：

參數有上下文，集合，和自己對應的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; /**  * 適配器  */ 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-打造萬能的ListView和GridView適配器", "2015-08-05", "10086");  mDatas.add(bean);  bean = new Bean("撿到權志龍一個",    "在星巴克撿到權志龍一個", "2015-08-06", "10086");  mDatas.add(bean);  bean = new Bean("GetTOP一個",    "在韓國首爾撿到TOP一個", "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-打造萬能的ListView和GridView適配器"  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>

效果圖：

用這個去適配另一個不同的布局：

新布局的Adapter一樣繼承自己的萬能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代碼：

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", "條目" + 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>

效果圖：