Adapter类型控件之ListView Item多布局的实现

（一）概述
何为ListView Item多布局 ，就像这样：
网络一张图：

看到了吧，如果他是ListView做的，那么一个listview不就有俩种不同风格的Item，这就是ListView Item多布局 的实现；

（二）实现要点：
view返回总共多少个类别！然后在GetView
应的View ！

代码实现：

MyAdapter2.java

public class MyAdapter2 extends BaseAdapter{

//定义两个类别标志
private static final int TYPE_BOOK = 0;
private static final int TYPE_APP = 1;
private Context mContext;
private ArrayList<Object> mData = null;


public MyAdapter2(Context mContext,ArrayList<Object> mData) {
this.mContext = mContext;
this.mData = mData;
    }

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

@Override
public Object getItem(int position) {
return mData.get(position);
    }

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

//多布局的核心，通过这个判断类别
@Override
public int getItemViewType(int position) {
if (mData.get(position) instanceof App) {
return TYPE_APP;
        } else if (mData.get(position) instanceof Book) {
return TYPE_BOOK;
        } else {
return super.getItemViewType(position);
        }
    }

//类别数目
@Override
public int getViewTypeCount() {
return 2;
    }


@Override
public View getView(int position, View convertView, ViewGroup parent) {
int type = getItemViewType(position);
        ViewHolder1 holder1 = null;
        ViewHolder2 holder2 = null;
if(convertView == null){
switch (type){
case TYPE_APP:
                   holder1 = new ViewHolder1();
                   convertView = LayoutInflater.from(mContext).inflate(R.layout.item_one, parent, false);
                   holder1.img_icon = (ImageView) convertView.findViewById(R.id.img_icon);
                   holder1.txt_aname = (TextView) convertView.findViewById(R.id.txt_aname);
                   convertView.setTag(R.id.Tag_APP,holder1);
break;
case TYPE_BOOK:
                   holder2 = new ViewHolder2();
                   convertView = LayoutInflater.from(mContext).inflate(R.layout.item_two, parent, false);
                   holder2.txt_bname = (TextView) convertView.findViewById(R.id.txt_bname);
                   holder2.txt_bauthor = (TextView) convertView.findViewById(R.id.txt_bauthor);
                   convertView.setTag(R.id.Tag_Book,holder2);
break;
           }
        }else{
switch (type){
case TYPE_APP:
                    holder1 = (ViewHolder1) convertView.getTag(R.id.Tag_APP);
break;
case TYPE_BOOK:
                    holder2 = (ViewHolder2) convertView.getTag(R.id.Tag_Book);
break;
            }
        }

        Object obj = mData.get(position);
//设置下控件的值
switch (type){
case TYPE_APP:
                App app = (App) obj;
if(app != null){
                    holder1.img_icon.setImageResource(app.getaIcon());
                    holder1.txt_aname.setText(app.getaName());
                }
break;
case TYPE_BOOK:
                Book book = (Book) obj;
if(book != null){
                    holder2.txt_bname.setText(book.getbName());
                    holder2.txt_bauthor.setText(book.getbAuthor());
                }
break;
        }
return convertView;
    }


//两个不同的ViewHolder
private static class ViewHolder1{
        ImageView img_icon;
        TextView txt_aname;
    }

private static class ViewHolder2{
        TextView txt_bname;
        TextView txt_bauthor;
    }
}

MainActivity.java

public class MainActivity extends AppCompatActivity {

private static final int TYPE_BOOK = 0;
private static final int TYPE_APP = 1;
private ListView list_content;
private ArrayList<Object> mData = null;
private MutiLayoutAdapter myAdapter = null;

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

//数据准备：
        mData = new ArrayList<Object>();
for(int i = 0;i < 20;i++){
switch ((int)(Math.random() * 2)){
case TYPE_BOOK:
                    mData.add(new Book("《第一行代码》","郭霖"));
break;
case TYPE_APP:
                    mData.add(new App(R.mipmap.iv_icon_baidu,"百度"));
break;
            }
        }

        list_content = (ListView) findViewById(R.id.list_content);
        myAdapter = new MutiLayoutAdapter(MainActivity.this,mData);
        list_content.setAdapter(myAdapter);
    }
}

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