android ListView

1 得到选择item的值

        mContactList.setOnItemClickListener(new OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Cursor c = (Cursor) mContactList.getItemAtPosition(position);
                String name = c.getString(c.getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME));
            }
        });
//根据点击位置取得item，转换为Cursor

 

        mContactList.setOnItemClickListener(new OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                cursor.moveToPosition(position);
                String name = cursor.getString(
                        cursor.getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME));
            }
        });

       //cursor为外部查询得到,在内存中保存一个cursor，根据点击位置去cursor取值

 

 2 自定义ListView

　　1)首先需要自定义item的layout

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView android:id="@+id/icon"
        android:layout_width="48dip"
        android:layout_height="48dip"/>

    <TextView android:id="@+id/text"
        android:layout_gravity="center_vertical"
        android:layout_width="0dip"
        android:layout_weight="1.0"
        android:layout_height="wrap_content"/>

</LinearLayout>

　　2) 自定义Adapter，并且在构造函数中传值

package com.example.android.contactmanager;

import android.content.Context;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

public class ContactItemAdapter extends BaseAdapter{

    private LayoutInflater mInflater;
    private Bitmap mIcon1;
    private Bitmap mIcon2;
    
    private Cursor cursor=null;

    public ContactItemAdapter(Context context,Cursor cursor) {
        this.cursor=cursor;
        // Cache the LayoutInflate to avoid asking for a new one each time.
        mInflater = LayoutInflater.from(context);

        // Icons bound to the rows.
        mIcon1 = BitmapFactory.decodeResource(context.getResources(), R.drawable.icon48x48_1);
        mIcon2 = BitmapFactory.decodeResource(context.getResources(), R.drawable.icon48x48_2);
    }

    /**
     * The number of items in the list is determined by the number of speeches
     * in our array.
     *
     * @see android.widget.ListAdapter#getCount()
     */
    public int getCount() {
        return cursor.getCount();
    }

    /**
     * Since the data comes from an array, just returning the index is
     * sufficent to get at the data. If we were using a more complex data
     * structure, we would return whatever object represents one row in the
     * list.
     *
     * @see android.widget.ListAdapter#getItem(int)
     */
    public Object getItem(int position) {
        return position;
    }

    /**
     * Use the array index as a unique id.
     *
     * @see android.widget.ListAdapter#getItemId(int)
     */
    public long getItemId(int position) {
        return position;
    }

    /**
     * Make a view to hold each row.
     *
     * @see android.widget.ListAdapter#getView(int, android.view.View,
     *      android.view.ViewGroup)
     */
    public View getView(int position, View convertView, ViewGroup parent) {
        // A ViewHolder keeps references to children views to avoid unneccessary calls
        // to findViewById() on each row.
        ViewHolder holder;

        // When convertView is not null, we can reuse it directly, there is no need
        // to reinflate it. We only inflate a new View when the convertView supplied
        // by ListView is null.
        if (convertView == null) {
            convertView = mInflater.inflate(R.layout.test_list_item_icon_text, null);

            // Creates a ViewHolder and store references to the two children views
            // we want to bind data to.
            holder = new ViewHolder();
            holder.text = (TextView) convertView.findViewById(R.id.text);
            holder.icon = (ImageView) convertView.findViewById(R.id.icon);

            convertView.setTag(holder);
        } else {
            // Get the ViewHolder back to get fast access to the TextView
            // and the ImageView.
            holder = (ViewHolder) convertView.getTag();
        }
        
        cursor.moveToPosition(position);
        
        // Bind the data efficiently with the holder.
        holder.text.setText(cursor.getString(1));
        holder.icon.setImageBitmap((position & 1) == 1 ? mIcon1 : mIcon2);

        return convertView;
    }

    static class ViewHolder {
        TextView text;
        ImageView icon;
    }
    
}

　　3)在Activity中调用

　　

   public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Cursor cursor=getContacts();
        setListAdapter(new ContactItemAdapter(this,cursor));
    }

 

 

 

资料：

       ListView使用初步

       ListView添加事件并获取选中项的值