ListView 显示数据库条目lv.setAdapter();

最新推荐文章于 2021-03-07 16:42:28 发布

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最新推荐文章于 2021-03-07 16:42:28 发布

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分类专栏： Android

本文链接：https://blog.youkuaiyun.com/u013636377/article/details/38556877

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默认实现类: simpleXXX defaultXXX baseXXX
MVC:
mode 模型， List<SQliteDomain>
view 试图， ListView

controller 控制器 adapter

DB_MainActivity.java

package com.example.android_4_4;

import java.util.List;
import com.example.SQLiteDB.SQliteDomain;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.LinearLayout;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.TextView;

public class DB_MainActivity extends Activity {
	ListView lv;
	List<SQliteDomain> listDB;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_db_main);
		
		lv= (ListView) findViewById(R.id.lv);
		SQliteDao  dao = new SQliteDao(this, "Persons.db", null, 5);
		listDB = dao.showDB();
		for(SQliteDomain list : listDB){
			String info = list.toString();
			
			lv.setAdapter( new MyAdapters());
		}	
	}
	/*
	默认实现类 simpleXXX defaultXXX baseXXX
	MVC:
	mode 模型 ， 	List<SQliteDomain>
	view 试图， 	ListView
	controller 控制器  		adapter
	1.首先调用getCount()确定集合中的条目
	2.调用getView把每个条目创建出来 ，显示在界面布局中，
	       界面布局满了不在创建，当拖动屏幕时，在创建新的条目
	*/
	class MyAdapters extends BaseAdapter{
		private static final String TAG = "MyAdapter";
		@Override
		//控制listview 共有多少条目，listDB集合size
		public int getCount() {
			return listDB.size();
		}
		@Override
		public Object getItem(int position) {
			
			return null;
		}
		@Override
		public long getItemId(int position) {
			
			return 0;
		}
		@Override
		public View getView(int position, View convertView, ViewGroup parent) {
			Log.i(TAG, "return view object , position index :"+position);
			TextView tv = new TextView(getApplicationContext());
			Log.i(TAG, "create textview !!!");
			//获取position 指向位置的单条对象 list
			SQliteDomain list = listDB.get(position);
			Log.i(TAG, "listDB get list !!!");
			tv.setText(list.toString());
			Log.i(TAG, "set test list !!!");
			return tv;
		}	
	}
}

activity_db_main.xml

<LinearLayout  
      			  	xmlns:android="http://schemas.android.com/apk/res/android"
   	 				xmlns:tools="http://schemas.android.com/tools"
        			android:layout_width="match_parent"
    				android:layout_height="match_parent"
   				 	android:orientation="vertical"
    				tools:context="android_4_4.DB_MainActivity" 
    				android:id="@+id/db_root">
    <ListView
    		android:layout_width="match_parent"
    		android:layout_height="match_parent"
    		android:id="@+id/lv"/>
    						    
</LinearLayout>

SQliteDao.java

package com.example.android_4_4;

import java.util.ArrayList;
import java.util.List;
import com.example.SQLiteDB.SQliteDomain;
import com.example.SQLiteDB.sqliteDB;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;

public class SQliteDao {  
    private sqliteDB  helper;  
    //构造方法里面初始化helper  
    public SQliteDao(Context context, String name, CursorFactory factory,int version) {  
        helper = new sqliteDB(context, name, factory,version);  
    }  
    /** 
     * helper.getWritableDatabase(); 获取可写的数据库对象 
     * db.execSQL();  values (?,?) 对应数组 Object[] 
     * @param name  名称 
     * @param number  电话号码 
     * @param money   金额
     */  
    public void add(String name,String number,int money){  
        SQLiteDatabase db = helper.getWritableDatabase();  
      //  db.execSQL("insert into Person (name,number) values (?,?,?)",new Object[]{name,number});  
        ContentValues values = new ContentValues();
        values.put("name", name);
        values.put("number", number);
        values.put("account", money);

        long id = db.insert("Person", null, values);
          
        db.close();  
    }  
    /** 
     * helper.getReadableDatabase(); 只读的数据库对象 
     * Cursor cursor 查询返回结果集对象 
     * @param name 
     * @return true 查询存在 ，false 查询不存在 
     */  
    public boolean find (String name){  
        SQLiteDatabase db = helper.getReadableDatabase();  
      //返回Cursor结构结果集  
//        Cursor cursor = db.rawQuery("select * from Person where name=?", new String[]{name});  
        Cursor cursor = db.query("Person",null, "name=?", new String[]{name}, null, null, null);
        
        boolean result = cursor.moveToNext();  
        cursor.close();  
        db.close();  
        return result;  
    }  
    /** 
     * 根据 name 修改 number 
     * @param name    
     * @param newNumber 
     */  
    public int update(String name,String newNumber){  
        SQLiteDatabase db = helper.getReadableDatabase();  
//        db.execSQL("update Person set number=? where name = ?", new Object[]{newNumber,name});  
        ContentValues values = new ContentValues();
        values.put("number", newNumber);
        int number = db.update("Person", values, "name=?", new String[]{newNumber});
        
        db.close();  
        return number;
    }  
    /** 
     * delete DB name 
     * @param name 
     */  
    public int delete(String name){  
        SQLiteDatabase db = helper.getReadableDatabase();  
//        db.execSQL("delete from Person where name = ?", new String[]{name});  
        int number = db.delete("Person", "name=?", new String[]{name});
        
        db.close();  
        return number;
    }  
    /** 
     * 查询返回cursor 数据库指针 
     * 通过cursor.moveToNext()遍历数据库 
     * 每次结果存到 SQliteDomain listDB 
     * 遍历结果存到 List<SQliteDomain> listArrayDB 
     * @return listArrayDB 数据集合 
     */  
    public List<SQliteDomain> showDB(){  
        SQLiteDatabase db = helper.getReadableDatabase();  
        List<SQliteDomain> listArrayDB = new ArrayList<SQliteDomain>();  
//        Cursor cursor = db.rawQuery("select id,name,number from Person", null);  
        Cursor cursor = db.query("Person", new String[]{"name","id","number"}, null, null, null, null, null);
        while (cursor.moveToNext()) {  
            int id = cursor.getInt(cursor.getColumnIndex("id"));  
            String name = cursor.getString(cursor.getColumnIndex("name"));  
            String number = cursor.getString(cursor.getColumnIndex("number"));  
            SQliteDomain listDB = new SQliteDomain(name, id, number);  
            listArrayDB.add(listDB);  
        }  
        cursor.close();  
        db.close();  
        return listArrayDB;  
    }  
    
}

sqliteDB.java

package com.example.SQLiteDB;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

public class sqliteDB extends SQLiteOpenHelper {
	

	private String TAG="sqliteDB";
	/**
	 * 数据库构造方法， 
	 * @param context  上下文
	 * @param name		数据库 name
	 * @param factory	游标对象。null为默认
	 * @param version	数据库版本
	 */
	public sqliteDB(Context context, String name, CursorFactory factory,int version) {
		super(context, name, factory, version);
	}
	/**
	 * 数据库第一次创建时调用
	 */
	@Override
	public void onCreate(SQLiteDatabase db) {
		//执行sql 语句  
        db.execSQL("create table Person (id integer primary key autoincrement,name varchar(20),number varchar(20)) "); 
	}
	/**
	 * 当数据库版本变化时(修改了数据库表结构)调用
	 */
	@Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
		Log.i(TAG, "数据库版本变化了");
		//添加一个 account 表结构
		db.execSQL("alter table Person add account varchar(20)");
	}

}

SQliteDomain.java

package com.example.SQLiteDB;

public class SQliteDomain {
		private String name;  
	    private int id;  
	    private String number;  
	      
	    public String getName() {  
	        return name;  
	    }  
	    public void setName(String name) {  
	        this.name = name;  
	    }  
	    public int getId() {  
	        return id;  
	    }  
	    public void setId(int id) {  
	        this.id = id;  
	    }  
	    public String getNumber() {  
	        return number;  
	    }  
	    public void setNumber(String number) {  
	        this.number = number;  
	    }  
	      
	    public SQliteDomain(String name, int id, String number) {  
	        this.name = name;  
	        this.id = id;  
	        this.number = number;  
	    }  
	    public SQliteDomain() {  
	    	
	    }
		@Override
		public String toString() {
			return "SQliteDomain [name="+name+",id="+id+",number="+number+"]";
		}  
	    
}