android ListView_顯示數據庫數據

xml

<?xml version="1.0"?>

-<LinearLayout tools:context=".MainActivity" android:orientation="vertical" android:paddingTop="@dimen/activity_vertical_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingBottom="@dimen/activity_vertical_margin" android:layout_height="match_parent" android:layout_width="match_parent" xmlns:tools="http://schemas.android.com/tools" xmlns:android="http://schemas.android.com/apk/res/android">

<Button android:id="@+id/bt_add" android:layout_height="wrap_content" android:layout_width="fill_parent" android:text="@string/add"/>

<Button android:id="@+id/bt_del" android:layout_height="wrap_content" android:layout_width="fill_parent" android:text="@string/del"/>

<Button android:id="@+id/bt_update" android:layout_height="wrap_content" android:layout_width="fill_parent" android:text="@string/update"/>

<Button android:id="@+id/bt_query" android:layout_height="wrap_content" android:layout_width="fill_parent" android:text="@string/query"/>

<ListView android:id="@+id/lv_databases" android:layout_height="match_parent" android:layout_width="fill_parent"/>

</LinearLayout>

 

java

package com.itheima.crud;

import java.util.ArrayList;

import android.app.Activity;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ListView;
import android.widget.Toast;

import com.itheima.crud2_listview.R;
import com.itheima.crud.adapter.QueryAdapter;
import com.itheima.crud.bean.InfoBean;
import com.itheima.crud.dao.InfoDao;

public class MainActivity extends Activity implements OnClickListener {

    private Context mContext;
    private ListView lv_databases;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mContext = this;
        //創建一個幫助類對象
        MySqliteOpenHelper mySqliteOpenHelper = new MySqliteOpenHelper(mContext);
        //調用getReadableDatabase方法,來初始化數據庫的創建
        SQLiteDatabase db = mySqliteOpenHelper.getReadableDatabase();


        //找到相應控件
        findViewById(R.id.bt_add).setOnClickListener(this);

        findViewById(R.id.bt_del).setOnClickListener(this);
        findViewById(R.id.bt_update).setOnClickListener(this);
        findViewById(R.id.bt_query).setOnClickListener(this);
        
        //找到listview
        lv_databases = (ListView) findViewById(R.id.lv_databases);

    }
    @Override
    public void onClick(View v) {
        InfoDao infoDao = new InfoDao(mContext);//創建一個dao對象做增刪改查

        switch (v.getId()) {
        case R.id.bt_add:
            
            InfoBean bean = new InfoBean();
            bean.name = "張三";
            bean.phone ="110";
            boolean result = infoDao.add(bean);
            if(result){
                Toast.makeText(mContext, "添加成功", 0).show();
            }else{
                Toast.makeText(mContext, "添加失敗", 0).show();
            }
            
        
            break;

        case R.id.bt_del:
            
            int del = infoDao.del("張三");
            Toast.makeText(mContext, "成功刪除"+del+"行", 0).show();
            break;

        case R.id.bt_update:
            
            InfoBean bean2 = new InfoBean();
            bean2.name = "張三";
            bean2.phone ="119";
            int update = infoDao.update(bean2);
            Toast.makeText(mContext, "成功修改"+update+"行", 0).show();
            break;


        case R.id.bt_query:
            //獲取查詢的數據
            ArrayList<InfoBean> arrayList = infoDao.query("張三");
            //封裝adapter
            QueryAdapter queryAdapter = new QueryAdapter(mContext,arrayList);
            //將adapter設置給listview
            lv_databases.setAdapter(queryAdapter);
            break;

        default:
            break;
        }

    }




}

 

package com.itheima.crud;

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

public class MySqliteOpenHelper extends SQLiteOpenHelper {

    public MySqliteOpenHelper(Context context) {
        
        //context :上下文   ， name：數據庫文件的名稱    factory：用來創建cursor對象，默認為null 
        //version:數據庫的版本號，從1開始，如果發生改變，onUpgrade方法將會調用,4.0之后只能升不能將
        super(context, "info.db", null,1);
    }

    //oncreate方法是數據庫第一次創建的時候會被調用;  特別適合做表結構的初始化,需要執行sql語句；SQLiteDatabase db可以用來執行sql語句
    @Override
    public void onCreate(SQLiteDatabase db) {
        //通過SQLiteDatabase執行一個創建表的sql語句
        db.execSQL("create table info (_id integer primary key autoincrement,name varchar(20),phone varchar(11))");
    }

    //onUpgrade數據庫版本號發生改變時才會執行； 特別適合做表結構的修改
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        //添加一個phone字段
//        db.execSQL("alter table info add phone varchar(11)");
    }

}

 

package com.itheima.crud.dao;

import java.util.ArrayList;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

import com.itheima.crud.MySqliteOpenHelper;
import com.itheima.crud.bean.InfoBean;

public class InfoDao {


    private MySqliteOpenHelper mySqliteOpenHelper;
    public InfoDao(Context context){
        //創建一個幫助類對象
        mySqliteOpenHelper = new MySqliteOpenHelper(context);

        
    }

    public boolean add(InfoBean bean){

        //執行sql語句需要sqliteDatabase對象
        //調用getReadableDatabase方法,來初始化數據庫的創建
        SQLiteDatabase     db = mySqliteOpenHelper.getReadableDatabase();
        
        
        ContentValues values = new ContentValues();//是用map封裝的對象，用來存放值
        values.put("name", bean.name);
        values.put("phone", bean.phone);
        
        //table: 表名 , nullColumnHack：可以為空，標示添加一個空行, values:數據一行的值 , 返回值：代表添加這個新行的Id ，-1代表添加失敗
        long result = db.insert("info", null, values);//底層是在拼裝sql語句
    
        //關閉數據庫對象
        db.close();
        
        if(result != -1){//-1代表添加失敗
            return true;
        }else{
            return false;
        }
    }

    public int del(String name){

        //執行sql語句需要sqliteDatabase對象
        //調用getReadableDatabase方法,來初始化數據庫的創建
        SQLiteDatabase db = mySqliteOpenHelper.getReadableDatabase();
        
        //table ：表名, whereClause: 刪除條件, whereArgs：條件的占位符的參數 ; 返回值：成功刪除多少行
        int result = db.delete("info", "name = ?", new String[]{name});
        //關閉數據庫對象
        db.close();
        
        return result;

    }
    public int update(InfoBean bean){

        //執行sql語句需要sqliteDatabase對象
        //調用getReadableDatabase方法,來初始化數據庫的創建
        SQLiteDatabase db = mySqliteOpenHelper.getReadableDatabase();
        ContentValues values = new ContentValues();//是用map封裝的對象，用來存放值
        values.put("phone", bean.phone);
        //table:表名, values：更新的值, whereClause:更新的條件, whereArgs：更新條件的占位符的值,返回值：成功修改多少行
        int result = db.update("info", values, "name = ?", new String[]{bean.name});
        //關閉數據庫對象
        db.close();
        return result;

    }
    public ArrayList<InfoBean> query(String name){
        
        ArrayList<InfoBean> list = new ArrayList<InfoBean>();
    
        //執行sql語句需要sqliteDatabase對象
        //調用getReadableDatabase方法,來初始化數據庫的創建
        SQLiteDatabase db = mySqliteOpenHelper.getReadableDatabase();
        
        //table:表名, columns：查詢的列名,如果null代表查詢所有列； selection:查詢條件, selectionArgs：條件占位符的參數值,
        //groupBy:按什么字段分組, having:分組的條件, orderBy:按什么字段排序
        Cursor cursor = db.query("info", new String[]{"_id","name","phone"}, "name = ?", new String[]{name}, null, null, "_id asc");
        //解析Cursor中的數據
        if(cursor != null && cursor.getCount() >0){//判斷cursor中是否存在數據
            
            //循環遍歷結果集，獲取每一行的內容
            while(cursor.moveToNext()){//條件，游標能否定位到下一行
                InfoBean bean = new InfoBean();
                //獲取數據
                bean. id = cursor.getInt(0)+"";
                bean. name = cursor.getString(1);
                bean. phone = cursor.getString(2);
                
                list.add(bean);
                
                
            }
            cursor.close();//關閉結果集
            
        }
        //關閉數據庫對象
        db.close();

        return list;
    }
}

 

package com.itheima.crud.bean;

public class InfoBean {

    public String id;
    public  String name;
    public String phone;
}

 

package com.itheima.crud.adapter;

import java.util.ArrayList;

import com.itheima.crud.bean.InfoBean;
import com.itheima.crud2_listview.R;

import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

public class QueryAdapter  extends BaseAdapter{
    

    private Context mContext;
    private ArrayList<InfoBean> arrayList;

    public QueryAdapter(Context mContext, ArrayList<InfoBean> arrayList) {
        this.mContext = mContext;
        this.arrayList = arrayList;
    }

    @Override
    public int getCount() {
        return arrayList.size();
    }

    @Override
    public Object getItem(int position) {
        return arrayList.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        
        //復用convertView
        View view = null;
        if(convertView != null){
            view = convertView;
        }else {
            view =  View.inflate(mContext, R.layout.item_database_layout, null);
        }
        
        //找到控件
        TextView item_tv_id = (TextView) view.findViewById(R.id.item_tv_id);
        TextView item_tv_name = (TextView) view.findViewById(R.id.item_tv_name);
        TextView item_tv_phone = (TextView) view.findViewById(R.id.item_tv_phone);
        //找到內容
        InfoBean infoBean = arrayList.get(position);
        
        //設置內容
        item_tv_id.setText(infoBean.id);
        item_tv_name.setText(infoBean.name);
        item_tv_phone.setText(infoBean.phone);
        
        return view;
    }

}

 

新聞會了，這個就會了