android 数据库操作初试

昨天进行了GUI界面设计，感受了一下android初次设计的愉悦，今天接着学习其SQLite数据库试用，将昨天的例子中数据存到数库中，并读取查看一下。

   具体看代码（原写的有点问题，再改写如下）：

 

   1)  库操作类：

package com.topsun;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.util.Log;

public class DBHelper {
	private static final String TAG = "UserDB_DBHelper.java";
	private static final String DataBaseName = "UserDB";
	SQLiteDatabase db;
	Context context;

	public DBHelper(Context context) {
		this.open(context);
	}

	private void createTabel() {
		// TODO Auto-generated method stub
		String sql = "";
		try {
			sql = "CREATE TABLE IF NOT EXISTS TestUser    (ID INTEGER PRIMARY KEY autoincrement,  NAME TEXT,  SEX TEXT, AGES INTEGER)";
			this.db.execSQL(sql);
			Log.v(TAG, "Create Table TestUser ok");
		} catch (Exception e) {
			Log.v(TAG, "Create Table TestUser fail");
		} finally {
			//this.db.close();
			Log.v(TAG, "Create Table TestUser ");
		}
	}

	public boolean save(String name, String sex, Integer ages) {
		String sql = "insert into TestUser values(null,'" + name + "','" + sex
				+ "'," + ages + ")";
		try {
			this.db.execSQL(sql);
			Log.v(TAG, "insert  Table TestUser 1 record ok");
			return true;
		} catch (Exception e) {

			Log.v(TAG, "insert  Table TestUser 1 record fail");
			return false;
		} finally {
			//this.db.close();
			Log.v(TAG, "insert  Table TestUser ");
		}
	}

	public Cursor loadAll() {
		Cursor cur = db.query("TestUser", new String[] { "ID", "NAME","SEX","AGES"}, null,
				null, null, null, null);

		return cur;
	}
   public void open(Context context){
	   if (null == db || !this.db.isOpen()){
		   this.context = context;
			this.db = context.openOrCreateDatabase(this.DataBaseName,
					context.MODE_PRIVATE, null);
			createTabel();
			Log.v(this.TAG, "create  or Open DataBase。。。");
		    }
   }
	public void close() {
		db.close();
	}

}

 

 2) 交互代码

     

package com.topsun;

import android.app.Activity;
import android.database.Cursor;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;

public class guiwindows extends Activity implements OnClickListener {

	EditText TEditname;
	EditText TEditsex;
	EditText TEditages;
	EditText TEditmerge;
	Button TSavebutton;
	Button TViewbutton;
	DBHelper db;

	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		this.TEditname = (EditText) this.findViewById(R.id.widgeteditname);
		this.TEditsex = (EditText) this.findViewById(R.id.widgeteditsex);
		this.TEditages = (EditText) this.findViewById(R.id.widgeteditages);
		TEditmerge = (EditText) this.findViewById(R.id.widgeteditmerge);
		this.TSavebutton = (Button) this.findViewById(R.id.widgetSavebutton);
		TViewbutton = (Button) this.findViewById(R.id.widgetViewbutton);
		this.db = new DBHelper(this);
		this.TSavebutton.setOnClickListener(this);
		this.TViewbutton.setOnClickListener(this);
	}

	@Override
	public void onClick(View v) {
		// TODO Auto-generated method stub
		// this.TEditages.setText(this.TEditname.getText().toString()+this.TEditsex.getText().toString());
		if (v.getId() == R.id.widgetSavebutton) {
			try {
				this.db.open(this);
				this.db.save(this.TEditname.getText().toString(), this.TEditsex
						.getText().toString(), Integer.valueOf(this.TEditages
						.getText().toString()));
			} catch (Exception e) {
				Log.v("save data", "save data fail");
			} finally {
				this.db.close();
			}
		} else if (v.getId() == R.id.widgetViewbutton && null != db) {
			this.db.open(this);
			// 浏览所有数据
			Cursor cur = db.loadAll();
			StringBuffer sf = new StringBuffer();
			cur.moveToFirst();
			while (!cur.isAfterLast()) {
				sf.append(cur.getInt(0)).append(" : ").append(cur.getString(1))
						.append(" : ").append(cur.getString(2)).append(" : ")
						.append(cur.getInt(3)).append("\n");
				cur.moveToNext();
			}
			db.close();
			this.TEditmerge.setText(sf.toString());

		}
	}
}

 

 

3）具体效果