安卓自写Adapter

Posted 2020-07-16 微风&细雨

代码：

package com.example.ouradapter;

import android.app.ListActivity;
import android.content.Context;
import android.graphics.Color;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.RelativeLayout;
import android.widget.TableLayout.LayoutParams;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends ListActivity {  
    private String[] mListTitle = { "姓名", "性别", "年龄", "居住地","邮箱"};  
    private String[] mListStr = { "雨松MOMO", "男", "25", "北京",  
        "[e-mail]" };  
    ImageView iamge = null;  
    TextView title = null;  
    TextView text = null;
    ListView mListView = null; 
//    RelativeLayout rl=(RelativeLayout)this.findViewById(R.id.rl);
    MyListAdapter myAdapter = null;  
    @Override  
    protected void onCreate(Bundle savedInstanceState) { 
    mListView = getListView();  
    myAdapter = new MyListAdapter(this);  
    setListAdapter(myAdapter);  
    mListView.setOnItemClickListener(new OnItemClickListener() {  
        @Override  
        public void onItemClick(AdapterView<?> adapterView, View view, int position,  
            long id) {  
        View v=adapterView.getChildAt(position);  
        v.setBackgroundColor(Color.RED);  
        Toast.makeText(MainActivity.this,"您选择了" + mListStr[position], Toast.LENGTH_LONG).show();  
        }  
    });  
   
//    View v=LayoutInflater.from(this).inflate(R.layout.activity_main, null);
//    iamge = (ImageView)v.findViewById(R.id.color_image);  
//    title =(TextView)v.findViewById(R.id.color_title);  
//    text= (TextView)v.findViewById(R.id.color_text);
//    title.setText(mListTitle[1]);  
//    text.setText("123456789");  
//    iamge.setImageResource(R.drawable.ic_launcher); 
//    this.addContentView(v,new LinearLayout.LayoutParams(      
//            LinearLayout.LayoutParams.WRAP_CONTENT,      
//            LinearLayout.LayoutParams.WRAP_CONTENT));
    super.onCreate(savedInstanceState);  
    }  
   
    public class MyListAdapter extends BaseAdapter { 
        private Context mContext;  
        private int[] colors = new int[] {Color.BLUE, Color.GREEN,Color.YELLOW,Color.WHITE };  
        public MyListAdapter(Context context) {  
            mContext = context;  
        }  
       
        public int getCount() {  
            return mListStr.length;  
        }  
       
//        @Override  
//        public boolean areAllItemsEnabled() {  
//            return false;  
//        }  
        @Override 
        public Object getItem(int position) {  
            return position;  
        }  
        @Override 
        public long getItemId(int position) {  
            return position;  
        }  
       @Override
        public View getView(int position, View convertView, ViewGroup parent) {  
             
            if (convertView == null) {  
            convertView = LayoutInflater.from(mContext).inflate(R.layout.activity_main, null);  
            iamge = (ImageView) convertView.findViewById(R.id.color_image);  
            title =(TextView) convertView.findViewById(R.id.color_title);  
            text= (TextView) convertView.findViewById(R.id.color_text);  
            }  
            int colorPos = position % colors.length;  
            convertView.setBackgroundColor(colors[colorPos]);  
            title.setText(mListTitle[position]);  
            text.setText(mListStr[position]);  
             iamge.setImageResource(R.drawable.ic_launcher);  
            return convertView;  
       }

 
   

    }  
}  

listView在一开始绘制的时候首先会调用getCout()方法得到绘制次数 ，然后会实例化自己定义的BaseAdapter通过getView()方法一层一层绘制ListView,所以我们可以在这里面根据position(当前绘制的ID)来任意的修改绘制的内容。结果：

 

ArrayAdapter是BaseAdapter的子类，ArrayAdapter不仅具有BaseAdapter的所有方法还自定义了一些新的方法来处理列表项，所以单纯的从功能能上来讲ArrayAdapter远远强与BaseAdapter，如果是绘制一些数量比较少的列表建议使用BaseAdapter 如果绘制一些比较复杂的列表项 并且列表项很多的 建议使用ArrayAdapter。