万能ListView适配器

普通的ListView适配器仅仅适应一个listview，然而一个项目中可能不止一个listview，那么，对于每一个listview都要重写一个Adapter，如果需要的listview有很多，代码量是很大的。同时，每新增一个，都要重写一个适配器，很不方便。那可不可以极大地减少代码量呢，答案当然是可以的，下面就来讲解一下：
首先，需要一个listview，代码如下：

<RelativeLayout xmlns:android="http://
4000
schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >

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

</RelativeLayout>

接着是每一项的布局文件，效果图如下：



xml文件如下，由于checkbox会抢占焦点，所以，需要对此做出处理，一种方法是在RelativeLayout中设置android:descendantFocusability="blocksDescendants"，或者在CheckBox中设置android:focusable="false"，android:drawableLeft="@drawable/phone"是为文字左侧添加图标。

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="10dip"
android:descendantFocusability="blocksDescendants"
tools:context=".MainActivity" >

<TextView
android:id="@+id/id_title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:singleLine="true"
android:text="万能Adapter"
android:textColor="#444"
android:textSize="16sp" />

<CheckBox
android:id="@+id/id_cb"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"/>

<TextView
android:id="@+id/id_desc"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/id_title"
android:layout_marginTop="10dip"
android:layout_toLeftOf="@id/id_cb"
android:minLines="1"
android:maxLines="2"
android:text="利用抽象和封装构造万能Adapter，适配各种listview"
android:textColor="#444"
android:textSize="16sp" />

<TextView
android:id="@+id/id_time"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/id_desc"
android:layout_marginTop="6dip"
android:text="2015-8-7"
android:textColor="#444"
android:textSize="16sp" />

<TextView
android:id="@+id/id_phone"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_below="@id/id_desc"
android:layout_marginTop="6dip"
android:background="#00aa00"
android:drawableLeft="@drawable/phone"
android:text="10086"
android:textColor="#fff"
android:textSize="16sp" />

</RelativeLayout>

接着实体类的创建，从listview的item中可以看出需要的元素，如下：

package com.commonadapter.bean;

public class DataBean {
private String title;
private String desc;
private String time;
private String phone;
private boolean isCheacked;

public DataBean(String title, String desc, String time, String phone) {
//	super();
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;
}

public boolean getIsCheacked() {
return isCheacked;
}

public void setIsCheacked(boolean isCheacked) {
this.isCheacked = isCheacked;
}

}

接着是ViewHolder的抽象，包括ViewHolder的初始化，通过泛型获取获取控件，ConvertView、position的获取，最后还有普通控件通过id和需要资源设置，比如TextView、ImageView等

package com.common.adapter.utils;

import android.content.Context;
import android.util.SparseArray;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

/**
* ViewHolder类
* @author pmx
*
*/
public class ViewHolder {
private SparseArray<View> mViews;
private int mPosition;

private View mConvertView;

public ViewHolder(Context context, ViewGroup parent, int layoutId,
int position) {
this.mPosition = position;
this.mViews = new SparseArray<View>();
mConvertView = LayoutInflater.from(context).inflate(layoutId, parent,
false);
mConvertView.setTag(this);

}

/**
* 初始化ViewHolder
* @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 (convertView == null) {
return new ViewHolder(context, parent, layoutId, position);
} else {
ViewHolder holder = (ViewHolder) convertView.getTag();
holder.mPosition = position;
return holder;
}

}

/**
* 通过viewId获取控件
*
* @param viewId
* @return
*/
@SuppressWarnings("unchecked")
public <T extends View> T getView(int viewId) {
View view = mViews.get(viewId);

if (view == null) {
view = mConvertView.findViewById(viewId);
mViews.put(viewId, view);
}
return (T) view;
}

public View getmConvertView() {
return mConvertView;
}

public int getPosition() {
return mPosition;
}

public ViewHolder setText(int viewId,String text){
TextView tv = getView(viewId);
tv.setText(text);
return this;

}

public ViewHolder setImageURI(int viewId,String url){
ImageView view = getView(viewId);
//Imageloader.getInstance().loadImage(view,url);
return null;

}

}

然后是抽象成CommonAdaoter，CommonAdapter继承了BaseAdapter，其中，可以看出getView相对于传统的getView减少了很多代码，而且，相应的方法都封装在ViewHolder，而convert在MainActivity中重写：

package com.commonadapter.main;

import java.util.List;

import com.common.adapter.utils.ViewHolder;
import com.commonadapter.bean.DataBean;

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 {

protected Context mContext;
protected List<T> mDatas;
protected LayoutInflater mInflater;
private int layoutId;

public CommonAdapter(Context context, List<T> datas,int layoutId) {
this.mContext = context;
this.mInflater = LayoutInflater.from(context);
this.mDatas = datas;
this.layoutId = layoutId;
}

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

@Override
public T getItem(int position) {
return mDatas.get(position);
}

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

@Override
public View getView(int position, View convertView, ViewGroup parent){
ViewHolder holder = ViewHolder.get(mContext, convertView, parent,
layoutId, position);

convert(holder,getItem(position));

return holder.getmConvertView();
}

public abstract void convert(ViewHolder holder,T t);

}

最后，MainActivity实现如下，实现以数据初始化和View的初始化，其中View初始化通过重写CommonAdapter的convert方法实现，可以看出，listview中有差别的项均通过Adapter构造方法和重写传入，而cb.setChecked(bean.getIsCheacked());和bean.setIsCheacked(cb.isChecked());是为了避免listview的复用。

package com.commonadapter.main;

import java.util.ArrayList;
import java.util.List;

import com.common.adapter.utils.ViewHolder;
import com.commonadapter.bean.DataBean;

import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.CheckBox;
import android.widget.ListView;
import android.app.Activity;

public class MainActivity extends Activity {
private ListView mListView;
private List<DataBean> beans;

// private MyAdapter mAdapter;
// private MyAdapterWithCommonViewHolder myAdapterWithCommonViewHolder;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

initDatas();

initView();
}

private void initView() {
mListView = (ListView) findViewById(R.id.id_listview);

// mListView.setAdapter(mAdapter);
// mListView.setAdapter(myAdapterWithCommonViewHolder);
mListView.setAdapter(new CommonAdapter<DataBean>(MainActivity.this,
beans,R.layout.item_main_list) {
//	private List<Integer> mPos = new ArrayList<Integer>();

@Override
public void convert(final ViewHolder holder, final DataBean bean) {
holder.setText(R.id.id_title, bean.getTitle())
.setText(R.id.id_desc, bean.getDesc())
.setText(R.id.id_time, bean.getTime())
.setText(R.id.id_phone, bean.getPhone());
final CheckBox cb = holder.getView(R.id.id_cb);
cb.setChecked(bean.getIsCheacked());
// cb.setChecked(false);
// if(mPos.contains(holder.getPosition())){
// cb.setChecked(true);
// }
cb.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View view) {
bean.setIsCheacked(cb.isChecked());
// if (cb.isChecked()) {
// mPos.add(holder.getPosition());
// } else {
// mPos.remove((Integer)holder.getPosition());
// }
}
});

}

});
}

private void initDatas() {
beans = new ArrayList<DataBean>();
DataBean bean = new DataBean("Android新技能Get1",
"Android打造万能ListView和GridView适配器", "2015-8-7", "10086");
beans.add(bean);
bean = new DataBean("Android新技能Get2",
"Android打造万能ListView和GridView适配器", "2015-8-7", "10086");
beans.add(bean);
bean = new DataBean("Android新技能Get3",
"Android打造万能ListView和GridView适配器", "2015-8-7", "10086");
beans.add(bean);
bean = new DataBean("Android新技能Get4",
"Android打造万能ListView和GridView适配器", "2015-8-7", "10086");
beans.add(bean);
bean = new DataBean("Android新技能Get5",
"Android打造万能ListView和GridView适配器", "2015-8-7", "10086");
beans.add(bean);
bean = new DataBean("Android新技能Get6",
"Android打造万能ListView和GridView适配器", "2015-8-7", "10086");
beans.add(bean);
bean = new DataBean("Android新技能Get7",
"Android打造万能ListView和GridView适配器", "2015-8-7", "10086");
beans.add(bean);
bean = new DataBean("Android新技能Get8",
"Android打造万能ListView和GridView适配器", "2015-8-7", "10086");
beans.add(bean);
bean = new DataBean("Android新技能Get9",
"Android打造万能ListView和GridView适配器", "2015-8-7", "10086");
bean = new DataBean("Android新技能Get0",
"Android打造万能ListView和GridView适配器", "2015-8-7", "10086");
beans.add(bean);
bean = new DataBean("Android新技能Get3",
"Android打造万能ListView和GridView适配器", "2015-8-7", "10086");
beans.add(bean);
bean = new DataBean("Android新技能Get4",
"Android打造万能ListView和GridView适配器", "2015-8-7", "10086");
beans.add(bean);
bean = new DataBean("Android新技能Get5",
"Android打造万能ListView和GridView适配器", "2015-8-7", "10086");
beans.add(bean);

// mAdapter = new MyAdapter(this, beans);
// myAdapterWithCommonViewHolder = new
// MyAdapterWithCommonViewHolder(MainActivity.this, beans);
}

}