1.什么是listview adapter
這個(gè)我就不解釋了忙灼，真有不會(huì)的自己在網(wǎng)上查一下（自己不會(huì)寫開場(chǎng)白驻龟，那這個(gè)湊活一下革半，呵呵）
2.直接先看一下效果圖吧
haha.gif
和普通的adapter適配基本一樣医增。在開發(fā)過程中l(wèi)istview以及gridview是經(jīng)常使用到的谆构，如果每次出現(xiàn)一個(gè)listview或者gridview虾攻，那么我們每次都要寫一個(gè)adapter铡买；這樣不僅麻煩而且不便于觀察，更重要的是浪費(fèi)時(shí)間霎箍。
3.不多說了奇钞，看一下這個(gè)工具類是怎么使用的：
Paste_Image.png
這個(gè)是整個(gè)目錄結(jié)構(gòu)
adapter中就是工具類，直接復(fù)制到項(xiàng)目中使用就可以了
一個(gè)實(shí)體類漂坏，一個(gè)activity
4.Activity
public class MainActivity extends AppCompatActivity {
private ListView mList;
private List<TestBean> mStrList = new ArrayList<>();
private CommonAdapter<TestBean> mAdapter = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mList = (ListView) findViewById(R.id.m_list);
initData();
initAdapter();
}
private void initData() {
mStrList.add(new TestBean("張三", "http://p2.so.qhmsg.com/t018b83cc648853f307.jpg"));
mStrList.add(new TestBean("李四", "http://img4.duitang.com/uploads/item/201305/02/20130502185029_EkKYh.jpeg"));
mStrList.add(new TestBean("王五","http://img1.touxiang.cn/uploads/20120509/09-014358_953.jpg"));
mStrList.add(new TestBean("趙六", "http://www.qqw21.com/article/UploadPic/2013-9/2013911764015374.jpg"));
mStrList.add(new TestBean("田七", "http://www.qqbody.com/uploads/allimg/201308/07-151626_52.jpg"));
}
private void initAdapter() {
mAdapter = new CommonAdapter<TestBean>(MainActivity.this, mStrList, R.layout.layout_test) {
@Override
public void convert(ViewHolder helper, final TestBean item, int position) {
helper.setText(R.id.m_name, item.getName());
ImageView imageView = helper.getView(R.id.m_image);
Picasso.with(MainActivity.this).load(item.getIcon()).into(imageView);
imageView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(MainActivity.this, "點(diǎn)擊了"+ item.getName() +"的圖像", Toast.LENGTH_SHORT).show();
}
});
}
};
mList.setAdapter(mAdapter);
}
}
main.xml我就不貼了景埃，簡(jiǎn)直跟平時(shí)寫的一模一樣媒至。主要代碼是在initAdapter中。比較簡(jiǎn)單相信大家能看的懂谷徙，conert這個(gè)重寫方法中和平時(shí)寫的adapter中的getview是一樣的拒啰，而且還有簡(jiǎn)化部分，就不多解釋了完慧。
5.工具類 CommonAdapter
public abstract class CommonAdapter<T> extends BaseAdapter {
protected LayoutInflater mInflater;
protected Context mContext;
protected List<T> mDatas;
protected final int mItemLayoutId;
public void cleanList() {
mDatas.clear();
}
public CommonAdapter(Context context, List<T> mDatas, int itemLayoutId) {
this.mContext = context;
this.mInflater = LayoutInflater.from(mContext);
this.mDatas = mDatas;
this.mItemLayoutId = itemLayoutId;
}
@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) {
final ViewHolder viewHolder = getViewHolder(position, convertView,
parent);
convert(viewHolder, getItem(position), position);
return viewHolder.getConvertView();
}
public void jiaNotif(){
notifyDataSetChanged();
}
public abstract void convert(ViewHolder helper, T item, int position);
private ViewHolder getViewHolder(int position, View convertView,ViewGroup parent) {
return ViewHolder.get(mContext, convertView, parent, mItemLayoutId,position);
}
}
6.工具類ViewHolder
public class ViewHolder {
private final SparseArray<View> mViews;
private int mPosition;
private View mConvertView;
private 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);
// setTag
mConvertView.setTag(this);
}
/**
* 拿到ViewHolder對(duì)象
*/
public static ViewHolder get(Context context, View convertView,
ViewGroup parent, int layoutId, int position) {
if (convertView == null) {
return new ViewHolder(context, parent, layoutId, position);
}
return (ViewHolder) convertView.getTag();
}
public View getConvertView() {
return mConvertView;
}
/**
* 通過控件的Id獲取對(duì)于的控件图呢，如果沒有則加入views
*/
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 ViewHolder setText(int viewId, String text) {
TextView view = getView(viewId);
view.setText(text);
return this;
}
public ViewHolder setTextColor(int viewId, int text) {
TextView view = getView(viewId);
view.setTextColor(text);
return this;
}
public ViewHolder setImageResource(int viewId, int drawableId) {
ImageView view = getView(viewId);
view.setImageResource(drawableId);
return this;
}
public ViewHolder setVisibility(int viewId,int visibility){
View view = getView(viewId);
view.setVisibility(visibility);
return this;
}
public ViewHolder setImageBitmap(int viewId, Bitmap bm) {
ImageView view = getView(viewId);
view.setImageBitmap(bm);
return this;
}
public ViewHolder setBackColor(int viewId, int color, int index) {
TextView view = getView(viewId);
view.setBackgroundColor(color);
return this;
}
}
1.一般我們寫adapter時(shí)，大多傳兩個(gè)參數(shù)第一個(gè)是Context,主要作用在于找到一個(gè)item布局骗随；第二個(gè)是list集合蛤织，主要作用是設(shè)置getcount、getitem等重寫方法鸿染，但最重要的是在getview方法中填充數(shù)據(jù)指蚜。而其他代碼基本是相同的。這樣我們就可以將不同的代碼提出涨椒，相同的代碼封裝成工具類摊鸡。
2.CommonAdapter類：
1.通過泛型將list集合中的實(shí)體類傳過來
2.通過構(gòu)造方法將集合、layout id傳過來
3.通過抽象蚕冬，對(duì)外new當(dāng)前類實(shí)現(xiàn)convert(viewHolder, getItem(position), position)抽象方法
3.ViewHolder類
1.get方法主要是為CommonAdapter的getView提供一個(gè)view視圖
2.getview方法主要判斷views集合里面是否存在當(dāng)前view免猾，如果存在直接用該view，沒有將其存入views
3.set方法主要是對(duì)外提供設(shè)置囤热，可以根據(jù)自己的項(xiàng)目自行添加或者刪除方法
7.使用方式（mainactivity里面）
1.private List<實(shí)體類> mStrList = new ArrayList<>();
2.private CommonAdapter<實(shí)體類> mAdapter = null;
3.mAdapter = new CommonAdapter<實(shí)體類>(上下文對(duì)象, list集合, 要引用的布局) {
@Override
public void convert(ViewHolder helper, final 實(shí)體類 item, int position) {
//該抽象方法是由list集合數(shù)量猎提，而循環(huán)操作的
//helper可以設(shè)置view屬性，或者獲取一個(gè)view
//item是第position個(gè)實(shí)體類
}
};
mList.setAdapter(mAdapter);
