Android 数据库操作

1. 数据库DBHelper extends SQLiteOpenHelper

 

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

public class DBHelper extends SQLiteOpenHelper {

	private static final String DB_NAME = "zigbree.db";

	private static final String TBL_NAME = "Zigbree";

	private static final String CREATE_TBL = " create table "
			+ " Zigbree( _id integer primary key autoincrement,room text,light text) ";

//此处必须将id 主键写成 

_id 



//写成_id   SimpleCursorAdapter  报错！ 	
// ERROR/AndroidRuntime(232): java.lang.RuntimeException: Unable to start activity 
//ComponentInfo{com.nec.android.necsthz/com.nec.android.necsthz.QueryActivity}: 
//java.lang.IllegalArgumentException: column '_id' does not exist


private SQLiteDatabase db =null;

	public DBHelper(Context context) {
		super(context, DB_NAME, null, 1);

	}

	@Override
	public void onCreate(SQLiteDatabase db) {
		this.db = db;
		db.execSQL(CREATE_TBL);
	}

	public void insert(ContentValues values) {
		SQLiteDatabase db = getWritableDatabase();
		db.insert(TBL_NAME, null, values);
		db.close();
	}

	public Cursor query() {
		SQLiteDatabase db = getWritableDatabase();
		Cursor c = db.query(TBL_NAME, null, null, null, null, null, null);
		return c;
	}

	@Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

	}

}

 2.Activity 类

 

 

 

 

/**
 * @author 2172980000522
 *
 */
public class RoomLightSet extends Activity {
	
	private EditText et1, et2;  
	
	private Button b1;  
	/* (non-Javadoc)
	 * @see android.app.Activity#onCreate(android.os.Bundle)
	 */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.roomlightset);
		  this.setTitle("哥是一个测试");  
		         et1 = (EditText) findViewById(R.id.room);  
		         et2 = (EditText) findViewById(R.id.light);  
		         b1 = (Button) findViewById(R.id.comfirm);  
		         b1.setOnClickListener(new OnClickListener() {  
		             public void onClick(View v) {  
		                 String name = et1.getText().toString();  
		                 String url = et2.getText().toString();  
		                 ContentValues values = new ContentValues();  
		                 values.put("room", name);  
		                 values.put("light", url);  
		                 DBHelper helper = new DBHelper(getApplicationContext());  
		                 helper.insert(values);  
		                System.out.println("insert  data to database：");
		            
		             }  
		         });
		    }
}

 
 Cursor ca  = contentResolver.query(Browser.BOOKMARKS_URI, null, "1=1", null, null);

public void queryColumnName(Cursor cursor){
for(int i=0;i<cursor.getColumnCount();i++){
String columnName = cursor.getColumnName(i);
Log.d("TAG","column name:"+columnName);
}
}
 

public Cursor select() {
		
		SQLiteDatabase db = this.getReadableDatabase();
//		Cursor cursor =db.rawQuery("select email_acc from email_table" ,);
		Cursor cursor = db.query( TABLE_NAME,null, null, null, null, null, null );
//		db.close(); // 关闭了就查询不到数据
		return cursor;
	}