2019独角兽企业重金招聘Python工程师标准>>> 
项目开发中经常需要去自定义适配器，若自定义适配器写得好整个界面就会非常的流畅，反之程序就歇菜了。
下面先贴代码，再讲讲自定义适配器的过程中需要注意的细节。
首先是Activity的代码:
package com.example.textviewtest;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;import android.widget.ListView;
public class MainActivity extends Activity{private static final String TAG = "MainActivity"; private String[] data = {"三星","小米","魅族","苹果","华为","一加","荣耀","Mate7","努比亚","OPPO","vivo","大神","乐视","小辣椒","P8","奇酷","锤子","金立"}; private ListView mListView; private Context mContext; @Overrideprotected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);mContext = this;mListView = (ListView) this.findViewById(R.id.mListView);MyAdapter mAdapter = new MyAdapter(mContext,data);mListView.setAdapter(mAdapter);}}自定义适配器的代码：
package com.example.textviewtest;
import android.content.Context;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
public class MyAdapter extends BaseAdapter{private Context mContext; private String[] data; public MyAdapter(Context mContext, String[] data) { this.mContext = mContext; this.data = data;} @Overridepublic int getCount() { // TODO Auto-generated method stubreturn data.length;} @Overridepublic Object getItem(int position) { // TODO Auto-generated method stubreturn null;} @Overridepublic long getItemId(int position) { // TODO Auto-generated method stubreturn 0;} @Overridepublic View getView(final int position, View convertView, ViewGroup viewGroup) {View myView ;ItemViewHolder itemViewHolder; if(view == null) {myView = View.inflate(mContext, R.layout.my_adapter, null);itemViewHolder = new ItemViewHolder();itemViewHolder.mTextView = (TextView) myView.findViewById(R.id.mTextView);itemViewHolder.mButton = (Button) myView.findViewById(R.id.mButton);myView.setTag(itemViewHolder);} else {myView = view;itemViewHolder = (ItemViewHolder) view.getTag();} itemViewHolder.mTextView.setText(data[position]); itemViewHolder.mButton.setOnClickListener(new OnClickListener() { @Overridepublic void onClick(View view) { Toast.makeText(mContext, data[position], Toast.LENGTH_SHORT).show(); } });myView.setTag(itemViewHolder); return myView;} public class ItemViewHolder { public TextView mTextView; public Button mButton; }}1、在适配器的构造函数中，我们将需要的数据源传入
2、利用Android的Recycler机制，利用convertView来重新回收View，避免每次都去创建新的View。
3、使用ViewHolder将需要缓存的view封装好，convertView的setTag就是将这些缓存起来供下次调用。因此，当第二次使用的时候只需要通过getTag()方法就可以获得ViewHolder对象
