Android之ListView使用总结

小白一枚，有些地方也是知其然不知其所以然，不当之处还望大神指正！

在自己做个android小程序时发现对数据的查询是必不可少的，而数据的显示用的最普遍的就是listview，看了看市面上大部分app实现起来都差不多，我也打算按这个套路来，但是仅仅实现了其基本功能，界面还是很丑很丑~

                

        

首先先贴上ListViewItem的xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >                                                                                         

    <CheckBox
        android:id="@+id/item_cb"
        android:layout_width="wrap_content"
        android:layout_height="40dp"
        android:clickable="false"
        android:focusable="false"
        android:focusableInTouchMode="false"
        android:gravity="center_vertical"/>

    <TextView
        android:id="@+id/item_tv"
        android:layout_width="0dp"
        android:layout_height="40dp"
        android:layout_weight="1"
        android:gravity="center_vertical" />

</LinearLayout>

我对TextView固定高度，不然CheckBox隐藏时大小会不一致；

对CheckBox设置了没有焦点，这样无法单独点击CheckBox，而是在编辑状态下点击Item的时候会对其响应；

接下来自定义一个适配器设置listview的每个条目内容

import java.util.List;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.CheckBox;
import android.widget.TextView;

public class MyAdapter extends BaseAdapter {
    private Context context;
    private List<Data> ls;             //这是一个自定义数据的链表，从Sqlite获取;
    private LayoutInflater inflater = null;
    public MyAdapter(Context c,List<Data> ls){
    	context=c;
    	this.ls=ls;
    	inflater = LayoutInflater.from(context);
    }
	@Override
	public int getCount() {
		// TODO Auto-generated method stub
		return ls.size();
	}

	@Override
	public Object getItem(int position) {
		// TODO Auto-generated method stub
		return ls.get(position);
	}

	@Override
	public long getItemId(int position) {
		// TODO Auto-generated method stub
		return position;
	}

	@Override
	public View getView(int position, View convertView, ViewGroup parent) {
		// TODO Auto-generated method stub
		ViewHolder holder = null;
        if (convertView == null) {
            holder = new ViewHolder();
            convertView=inflater.inflate(R.layout.listviewitem,null);
            holder.tv = (TextView) convertView.findViewById(R.id.item_tv);
            holder.cb = (CheckBox) convertView.findViewById(R.id.item_cb);
            convertView.setTag(holder);
            }
        else{
        	holder = (ViewHolder) convertView.getTag();
        }
        holder.tv.setText(ls.get(position).getWord().toString());
        holder.cb.setChecked(ls.get(position).getFlag());
        if(ls.get(position).getVisibility())            //改变checkbox的隐藏状态
        	holder.cb.setVisibility(View.VISIBLE);
        else
        	holder.cb.setVisibility(View.GONE);
        return convertView;
	}
	public final class ViewHolder{
        TextView tv;
        public CheckBox cb;
    }
}

Activity代码

import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.AlertDialog.Builder;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ListView;

public class Selectword extends Activity {
	private DBmanage helper;
	private ListView lv;
	private Button edit;
	private Button all;
	private Button notall;
	private Button delete;
	private MyAdapter ap;
	private List<Data> ls;
	private int checkNum=0;					//选中计数
	private boolean editsta=false;			//判断是否为编辑状态，默认 全选，全不选，删除 按键隐藏
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		setContentView(R.layout.selectwords);		
		lv=(ListView)findViewById(R.id.selectlv);
		all=(Button)findViewById(R.id.select_all);
		notall=(Button)findViewById(R.id.select_notall);
		edit=(Button)findViewById(R.id.select_edit);
		delete=(Button)findViewById(R.id.select_delete);
		helper=new DBmanage(this);
		ls=helper.selectview();				//由自定义函数从SQLITE获取数据链表
		ap=new MyAdapter(this,ls);
		lv.setAdapter(ap);
		edit.setText("编辑");
		edit.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				editsta=!editsta;				//改变编辑状态
				for (int i = 0; i < ls.size(); i++) {
                    ls.get(i).putVisibility(editsta);
                    ls.get(i).putFlag(false);
                }
				checkNum = 0;
				ap.notifyDataSetChanged();		//更新显示
				if(editsta){					//改变按钮的隐藏状态
					all.setVisibility(View.VISIBLE);
					notall.setVisibility(View.VISIBLE);
					delete.setVisibility(View.VISIBLE);
				}
				else{
					all.setVisibility(View.GONE);
					notall.setVisibility(View.GONE);
					delete.setVisibility(View.GONE);
				}
			}
		});
		all.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				for (int i = 0; i < ls.size(); i++) {
                    ls.get(i).putFlag(true);
                }
                checkNum = ls.size();
                ap.notifyDataSetChanged();        
			}
		});
		notall.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				for (int i = 0; i < ls.size(); i++) {
                    ls.get(i).putFlag(false);
                }
                checkNum = 0;
                ap.notifyDataSetChanged();        
			}
		});
		delete.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				Dialog();                    //确定删除对话框
			}
		});
		lv.setOnItemClickListener(new OnItemClickListener() {
			@Override
			public void onItemClick(AdapterView<?> parent, View view,
					int position, long id) {
				// TODO Auto-generated method stub
				if(editsta){				//单击Item时判断当前编辑状态
					ViewHolder hoder=(ViewHolder) view.getTag();
					hoder.cb.toggle();
					if(hoder.cb.isChecked()){
						ls.get(position).putFlag(true);
						checkNum++;
					}
					else{
						ls.get(position).putFlag(false);
						checkNum--;
					}
				}
				else{
					//单击Item转到其他界面....
				}			
			}
		});
	}
	private void Dialog(){
		AlertDialog.Builder builder=new Builder(Selectword.this);
		builder.setMessage("已选择"+checkNum+"项\n确定删除?");		
		builder.setPositiveButton("Yes",new DialogInterface.OnClickListener() {
			
			@Override
			public void onClick(DialogInterface dialog, int which) {
				// TODO Auto-generated method stub
				dialog.dismiss();
				List<String> list=new ArrayList<String>();
				for (int i = 0; i < ls.size(); i++) {
                    if(ls.get(i).getFlag()){
                    	list.add(ls.get(i).getNo());
                    	ls.remove(i);
                    	i--;
                    }
                }
				if(list.size()>0){
					helper.delete(list);  //由自定义函数对sqlite执行删除操作
					checkNum = 0;
	                ap.notifyDataSetChanged(); 
				}
			}
		});
		builder.setNegativeButton("No", new DialogInterface.OnClickListener() {		
			@Override
			public void onClick(DialogInterface dialog, int which) {
				// TODO Auto-generated method stub
				dialog.dismiss();
			}
		});
		builder.create().show();
	}
}

总结：layout感觉还是不会写，一开始排的很乱，现在也很难看；适配器的部分第一次接触目前也是比着葫芦画瓢以后还得深入学习；目前只想做出对数据的增删改查，但是若有别的需求在这个基础上怎么改我觉得也得挺麻烦；总之，目前只是将就着能用，代码只是让我能想起来写的时候是怎么想的，随着不断的改进代码应该也会不断优化。