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数据库SQList 添加查询修改删除

SQListActivity

  1 package com.example.administrator.myapplication.database.Activity;
  2 
  3 import android.content.ContentValues;
  4 import android.database.Cursor;
  5 import android.database.sqlite.SQLiteDatabase;
  6 import android.os.Bundle;
  7 import android.support.v7.app.AppCompatActivity;
  8 import android.view.View;
  9 import android.widget.Button;
 10 import android.widget.EditText;
 11 import android.widget.Toast;
 12 
 13 import com.example.administrator.myapplication.R;
 14 import com.example.administrator.myapplication.database.MySQLiteOpenHelper;
 15 import com.example.administrator.myapplication.util.Common;
 16 
 17 public class SQLiteActivity extends AppCompatActivity {
 18     Button insertBtn;
 19     Button queryBtn;
 20     Button deleteBtn;
 21     Button updateBtn;
 22     EditText titleET;
 23     EditText deleteET;
 24     EditText updateET;
 25     String TitleReceiver;
 26     String deleteReceiver;
 27     String updateReceiver;
 28 
 29     @Override
 30     protected void onCreate(Bundle savedInstanceState) {
 31         super.onCreate(savedInstanceState);
 32         setContentView(R.layout.activity_sqlite);
 33         titleET = (EditText) findViewById(R.id.titleText);
 34         deleteET = (EditText) findViewById(R.id.deleteText);
 35         updateET = (EditText) findViewById(R.id.updateText);
 36         insertBtn = (Button) findViewById(R.id.insertData);
 37         insertBtn.setOnClickListener(new View.OnClickListener() {
 38             @Override
 39             public void onClick(View v) {
 40                 insertData();
 41             }
 42         });
 43         queryBtn = (Button) findViewById(R.id.queryData);
 44         queryBtn.setOnClickListener(new View.OnClickListener() {
 45             @Override
 46             public void onClick(View v) {
 47                 queryData();
 48             }
 49         });
 50         deleteBtn = (Button) findViewById(R.id.deleteData);
 51         deleteBtn.setOnClickListener(new View.OnClickListener() {
 52             @Override
 53             public void onClick(View v) {
 54                 deleteData();
 55             }
 56         });
 57         updateBtn = (Button) findViewById(R.id.updateData);
 58         updateBtn.setOnClickListener(new View.OnClickListener() {
 59             @Override
 60             public void onClick(View v) {
 61                 updateData();
 62             }
 63         });
 64     }
 65 
 66     //插入数据
 67     public void insertData(){
 68         TitleReceiver = titleET.getText().toString();
 69         //调用帮助类的构造函数，创建数据库
 70         MySQLiteOpenHelper mySQLiteOpenHelper = new MySQLiteOpenHelper(this);
 71         //调用帮助类的onCreate方法，创建表
 72         SQLiteDatabase sqLiteDatabase = mySQLiteOpenHelper.getWritableDatabase();
 73         //将保存的数据放入ContentValues中
 74         ContentValues contentValues = new ContentValues();
 75         contentValues.put(Common.NewsTable.TBL_TITLE,TitleReceiver);
 76         contentValues.put(Common.NewsTable.TBL_CONTENT,"内容");
 77         contentValues.put(Common.NewsTable.TBL_SRC,"图片");
 78         contentValues.put(Common.NewsTable.TBL_DATE,"日期");
 79         //调用insert方法，保存数据
 80         sqLiteDatabase.insert(Common.NewsTable.TBL_NAME,null,contentValues);
 81         //!!!数据库操作完成后，一定要关闭数据库
 82         sqLiteDatabase.close();
 83         Toast.makeText(getApplication(),"保存数据成功！",Toast.LENGTH_SHORT).show();
 84     }
 85     //查询数据
 86     public void queryData(){
 87         MySQLiteOpenHelper mySQLiteOpenHelper = new MySQLiteOpenHelper(this);
 88         SQLiteDatabase sqLiteDatabase = mySQLiteOpenHelper.getReadableDatabase();
 89         //调用SQLiteDatabase的Query方法，返回数据库查询的结果集
 90         Cursor cursor = sqLiteDatabase.query(
 91                 Common.NewsTable.TBL_NAME,
 92                 new String[]{Common.NewsTable.TBL_TITLE,Common.NewsTable.TBL_CONTENT,Common.NewsTable.TBL_SRC,Common.NewsTable.TBL_DATE},
 93                 null,null,null,null,null
 94         );
 95         //！！查询对应数据的时候，一定要现获取列的索引值
 96         while (cursor.moveToNext()){
 97             int titleIndex = cursor.getColumnIndex(Common.NewsTable.TBL_TITLE);
 98             String title = cursor.getString(titleIndex);
 99             Toast.makeText(getApplication(),title,Toast.LENGTH_SHORT).show();
100         }
101         //数据查询完毕以后，1:关系结果集 2.关闭SQLiteDataBase
102         cursor.close();
103         sqLiteDatabase.close();
104         Toast.makeText(getApplication(),"查询完毕！",Toast.LENGTH_SHORT).show();
105     }
106     //删除数据
107     private void deleteData() {
108         deleteReceiver = deleteET.getText().toString();
109         MySQLiteOpenHelper mySQLiteOpenHelper = new MySQLiteOpenHelper(this);
110         SQLiteDatabase sqLiteDatabase = mySQLiteOpenHelper.getWritableDatabase();
111         sqLiteDatabase.delete(
112                 Common.NewsTable.TBL_NAME,
113                 // ?：占位符 " = ? "相当于 " = 标题 ", null
114                 Common.NewsTable.TBL_TITLE+ " = ?",
115                 new String[]{deleteReceiver}
116         );
117         sqLiteDatabase.close();
118         Toast.makeText(getApplication(),"删除成功!",Toast.LENGTH_SHORT).show();
119     }
120     //修改数据
121     private void updateData() {
122         updateReceiver = updateET.getText().toString();
123         MySQLiteOpenHelper mySQLiteOpenHelper = new MySQLiteOpenHelper(this);
124         SQLiteDatabase sqLiteDatabase = mySQLiteOpenHelper.getWritableDatabase();
125         ContentValues contentValues = new ContentValues();
126         contentValues.put(Common.NewsTable.TBL_TITLE,"这是修改后的数据");
127         sqLiteDatabase.update(
128                 Common.NewsTable.TBL_NAME,
129                 contentValues,
130                 Common.NewsTable.TBL_TITLE + " = ?",
131                 new String[]{updateReceiver}
132         );
133         sqLiteDatabase.close();
134         Toast.makeText(getApplication(),"修改成功!",Toast.LENGTH_SHORT).show();
135     }
136 }

MySQListOPENHelper   创建数据库 创建表

 1 package com.example.administrator.myapplication.database;
 2 
 3 import android.content.Context;
 4 import android.database.sqlite.SQLiteDatabase;
 5 import android.database.sqlite.SQLiteOpenHelper;
 6 
 7 import com.example.administrator.myapplication.util.Common;
 8 
 9 /**
10  * Created by Administrator on 2016-9-19.
11  */
12 
13 //帮助类继承SQLiteOpenHelper，方法：构造函数，创建数据库，创建表，更新表
14 public class MySQLiteOpenHelper extends SQLiteOpenHelper {
15     private static final String DB_Name = "new.db"; //数据库后缀为db，常量用大写
16     private static final int VERSION = 1; //数据库版本号
17     //上下文，数据库名字，factory默认null,版本号
18     /*public MySQLiteOpenHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
19         super(context, DB_Name, factory, VERSION);
20     }*/
21     //实现了数据库的创建，factory默认null,版本号固定
22     public MySQLiteOpenHelper(Context context) {
23         super(context, DB_Name, null, VERSION);
24     }
25 
26     //在onCreate方法中创建表，只执行一次
27     @Override
28     public void onCreate(SQLiteDatabase db) {
29         String sql = Common.NewsTable.getCreateTableSQL();
30         db.execSQL(sql);
31     }
32     //onUpgrade更新表
33     @Override
34     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
35         //先删除原表，再调用onCreate创建新表
36         db.execSQL("drop table "+ Common.NewsTable.TBL_NAME);
37         onCreate(db);
38     }
39 }

Common 公共类

 1 package com.example.administrator.myapplication.util;
 2 
 3 /**
 4  * Created by Administrator on 2016-9-19.
 5  */
 6 public class Common {
 7     public static class NewsTable{
 8         public static final String TBL_NAME ="News";
 9         public static final String TBL_TITLE = "NewsTitle";
10         public static final String TBL_CONTENT = "NewsContent";
11         public static final String TBL_SRC = "NewsImg";
12         public static final String TBL_DATE = "NewsDate";
13 
14         public static String getCreateTableSQL(){
15             String sql = "create table if not exists "
16                         + TBL_NAME
17                         + "("
18                         + " _id integer primary key autoincrement,"
19                         + TBL_TITLE + " text,"
20                         + TBL_CONTENT + " text,"
21                         + TBL_SRC + " text,"
22                         + TBL_DATE + " varchar(50)"
23                         + ")";
24             return sql;
25         }
26     }
27 }

activity_sqlite

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     xmlns:tools="http://schemas.android.com/tools"
 4     android:layout_width="match_parent"
 5     android:layout_height="match_parent"
 6     android:orientation="vertical"
 7     tools:context=".database.Activity.SQLiteActivity">
 8 
 9     <EditText
10         android:id="@+id/titleText"
11         android:layout_width="match_parent"
12         android:layout_height="wrap_content"
13         android:hint="请输入标题" />
14 
15     <LinearLayout
16         android:layout_width="match_parent"
17         android:layout_height="wrap_content"
18         android:orientation="horizontal">
19 
20         <TextView
21             android:layout_width="wrap_content"
22             android:layout_height="wrap_content"
23             android:text="请输入要删除的数据" />
24 
25         <EditText
26             android:id="@+id/deleteText"
27             android:layout_width="match_parent"
28             android:layout_height="wrap_content" />
29     </LinearLayout>
30 
31     <LinearLayout
32         android:layout_width="match_parent"
33         android:layout_height="wrap_content"
34         android:orientation="horizontal">
35 
36         <TextView
37             android:layout_width="wrap_content"
38             android:layout_height="wrap_content"
39             android:text="请输入要修改的数据" />
40 
41         <EditText
42             android:id="@+id/updateText"
43             android:layout_width="match_parent"
44             android:layout_height="wrap_content" />
45     </LinearLayout>
46 
47     <Button
48         android:id="@+id/insertData"
49         android:layout_width="match_parent"
50         android:layout_height="wrap_content"
51         android:text="添加数据" />
52 
53     <Button
54         android:id="@+id/queryData"
55         android:layout_width="match_parent"
56         android:layout_height="wrap_content"
57         android:text="查找数据  " />
58 
59     <Button
60         android:id="@+id/updateData"
61         android:layout_width="match_parent"
62         android:layout_height="wrap_content"
63         android:text="修改数据" />
64 
65     <Button
66         android:id="@+id/deleteData"
67         android:layout_width="match_parent"
68         android:layout_height="wrap_content"
69         android:text="删除数据" />
70 </LinearLayout>

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原文地址：https://www.cnblogs.com/xiaolei121/p/5885912.html

数据库SQList 添加 查询 修改 删除

数据库SQList 添加查询修改删除