【Android】SQLite使用基础

package com.example.databasetest;

import android.os.Bundle;
import android.app.Activity;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {
	
	private MyDatabaseHelper dbHelper;
	Button createDatabase,addData, updateData, deleteButton, queryButton;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		dbHelper = new MyDatabaseHelper(this,"BookStore.db",null,2);
		
		createDatabase = (Button) findViewById(R.id.create_database); 
		addData= (Button)findViewById(R.id.add_data);
		updateData = (Button)findViewById(R.id.update_data);
		deleteButton=(Button)findViewById(R.id.delete_data);
		queryButton = (Button)findViewById(R.id.query_data);
		
		createDatabase.setOnClickListener(new OnClickListener(){

			@Override
			public void onClick(View v) {
				dbHelper.getWritableDatabase(); //创建数据库	
			}
		});
		
		addData.setOnClickListener(new OnClickListener(){

			@Override
			public void onClick(View v) {
				 SQLiteDatabase db = dbHelper.getWritableDatabase(); //获取数据库对象
				 ContentValues cv = new ContentValues(); 
				 cv.put("name", "apple");
				 cv.put("price", 10.99);
				 cv.put("pages", 236);
				 cv.put("author","A");
				 db.insert("Book", null, cv);
				 cv.clear();
				 
				 cv.put("name", "The Lost Symbol");  
	             cv.put("author", "Dan Brown");  
	             cv.put("pages", 510);  
	             cv.put("price", 19.95);  
	             db.insert("Book", null, cv);//插入第二条数据  
			}
		});
		
		  queryButton.setOnClickListener(new OnClickListener() {  
	            @Override  
	            public void onClick(View v) {  
	                SQLiteDatabase db = dbHelper.getWritableDatabase();  
	  
	                //查询Book表中所有的数据，cursor为当前执行对象的游标  
	                Cursor cursor = db.query("Book", null, null, null, null, null,  
	                        null);  
	                //如果数据库中有数据就往下执行  
	                if (cursor.moveToFirst()) {  
	                    do {  
	                        //遍历Cursor对象，去除数据并打印  
	                        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();//关闭cursor  
	            }  
	        });  
		
		
	}

	

}

</pre><pre code_snippet_id="1585783" snippet_file_name="blog_20160223_3_4885881" name="code" class="java"><pre name="code" class="java">package com.example.databasetest;

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

public class MyDatabaseHelper extends SQLiteOpenHelper {
	
	//为要创建的数据库设置列名
	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_CATERGORY = "create table Catergory ("+" id integer primary key autoincrement," 
			+"category_name text,"+" category_code integer)";

	public MyDatabaseHelper(Context context, String name,
			CursorFactory factory, int version) {
		super(context, name, factory, version);
		// TODO Auto-generated constructor stub
	}

	@Override
	public void onCreate(SQLiteDatabase db) {
		db.execSQL(CREATE_BOOK);
		db.execSQL(CREATE_CATERGORY);	
	}

	@Override
	public void onUpgrade(SQLiteDatabase db, int arg1, int arg2) {
		//如果已经存在这两张表，则删除它们，并且用Creat重新创建
		db.execSQL("drop table if exists Book");
		db.execSQL("drop table if exists Catergory");
		onCreate(db);	
	}

}