Android-SQLite数据库操作详解
发布时间:2020-05-24 21:03:38 所属栏目:Java 来源:互联网
导读:Android-SQLite数据库操作详解
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下面是脚本之家 jb51.cc 通过网络收集整理的代码片段。 脚本之家小编现在分享给大家,也给大家做个参考。 主要就是创建数据库,添加、查询、更新、删除这几项。package com.wr.sqlite;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.widget.Toast;
public class MyDatebaseHelper extends SQLiteOpenHelper {
public static final String CREATE_BOOK = "create table Book ("
+ "id integer primary key autoincrement," + "author text,"
+ "price real," + "pages integer," + "name text) ";
public static final String CREATE_CATEGORY = "create table Category ("
+ "id integer primary key autoincrement," + "category_name text,"
+ "category_code integer) ";
private Context mContext;
public MyDatebaseHelper(Context context,String name,CursorFactory factory,int version) {
super(context,name,factory,version);
mContext = context;
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL(CREATE_BOOK);
db.execSQL(CREATE_CATEGORY);
Toast.makeText(mContext,"Create succeeded",Toast.LENGTH_SHORT).show();
}
@Override
public void onUpgrade(SQLiteDatabase db,int oldVersion,int newVersion) {
// TODO Auto-generated method stub
switch (oldVersion) {
case 1:
db.execSQL(CREATE_CATEGORY);
case 2:
db.execSQL("alter table Book add column category_id integer");
}
}
}
这里将见表语句定义成了字符串,在哦你Create()方法中建表。 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<Button
android:id="@+id/create_database"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Create database" />
<Button
android:id="@+id/add_data"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Add date" />
<Button
android:id="@+id/update_data"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Update date" />
<Button
android:id="@+id/delete_data"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Delete date" />
<Button
android:id="@+id/query_data"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Query date" />
<Button
android:id="@+id/replace_data"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Replace date" />
</LinearLayout>
最后在MainActiity中,实现一系列的操作。MainActivity.java package com.wr.sqlite;
import android.app.Activity;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class MainActivity extends Activity {
private MyDatebaseHelper dbHelper;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
dbHelper = new MyDatebaseHelper(this,"BookStore.db",null,2);
Button createDatabase = (Button) findViewById(R.id.create_database);
createDatabase.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
dbHelper.getWritableDatabase();
}
});
Button addData = (Button) findViewById(R.id.add_data);
addData.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
SQLiteDatabase db = dbHelper.getWritableDatabase();
ContentValues values = new ContentValues();
values.put("name","The Da Vinci Code");
values.put("author","Dan Brown");
values.put("pages",454);
values.put("price",16.96);
db.insert("Book",values);
values.clear();
values.put("name","The Lost Sysbol");
values.put("author",510);
values.put("price",19.95);
db.insert("Book",values);
}
});
Button updateData = (Button) findViewById(R.id.update_data);
updateData.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
SQLiteDatabase db = dbHelper.getWritableDatabase();
ContentValues values = new ContentValues();
values.put("price",10.99);
db.update("Book",values,"name = ?",new String[] { "The Da Vinci Code" });
}
});
Button deleteData = (Button) findViewById(R.id.delete_data);
deleteData.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
SQLiteDatabase db = dbHelper.getWritableDatabase();
db.delete("Book","pages > ?",new String[] { "500" });
}
});
Button queryData = (Button) findViewById(R.id.query_data);
queryData.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
SQLiteDatabase db = dbHelper.getWritableDatabase();
Cursor cursor = db.query("Book",null);
if (cursor.moveToFirst()) {
do {
String name = cursor.getString(cursor
.getColumnIndex("name"));
String author = cursor.getString(cursor
.getColumnIndex("author"));
int pages = cursor.getInt(cursor
.getColumnIndex("pages"));
double price = cursor.getDouble(cursor
.getColumnIndex("price"));
Log.d("MainActivity","book name is " + name);
Log.d("MainActivity","book author is " + author);
Log.d("MainActivity","book pages is " + pages);
Log.d("MainActivity","book price is " + price);
} while (cursor.moveToNext());
}
cursor.close();
}
});
Button replaceData = (Button) findViewById(R.id.replace_data);
replaceData.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
SQLiteDatabase db = dbHelper.getWritableDatabase();
db.beginTransaction();
try {
db.delete("Book",null);
ContentValues values = new ContentValues();
values.put("name","Game of Thrones");
values.put("author","George Martin");
values.put("pages","720");
values.put("price",20.85);
db.insert("Book",values);
db.setTransactionSuccessful();
} catch (Exception e) {
e.printStackTrace();
} finally {
db.endTransaction();
}
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main,menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button,so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
这其中也包含了事物的使用。比较具体。 以上是脚本之家(jb51.cc)为你收集整理的全部代码内容,希望文章能够帮你解决所遇到的程序开发问题。 如果觉得脚本之家网站内容还不错,欢迎将脚本之家网站推荐给程序员好友。 (编辑:安卓应用网) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |
