Android(安卓)自定义适配器

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;    @Override    protected 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;    }    @Override    public int getCount() {        // TODO Auto-generated method stub        return data.length;    }    @Override    public Object getItem(int position) {        // TODO Auto-generated method stub        return null;    }    @Override    public long getItemId(int position) {        // TODO Auto-generated method stub        return 0;    }    @Override    public 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() {            @Override            public 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

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