android SQLiteDatabase之一

最新推荐文章于 2024-08-21 09:37:06 发布

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本文介绍了一个基于Android平台的SQLite数据库操作示例，包括数据库的创建、数据的增删改查等功能，并通过主程序实现了菜单式交互，支持添加、编辑和删除记录。

//创建数据库，增、删、改、查，排序

public class dbHelper extends SQLiteOpenHelper {

	private final static String DATABASE_NAME="dxt_db";
	private final static int DATABASE_VERSION=2;
	private final static String TABLE_NAME="dong_info";
	public final static String FIELD_ID="_id"; 
	public final static String FIELD_NAME="Name";
	public final static String FIELD_TABLE_NUMBER="Table_Number";
	public final static String FIELD_INFO="Info";
	public final static String FIELD_TITLE="gender";
	
	
	public dbHelper(Context context)
	{
		super(context, DATABASE_NAME,null, DATABASE_VERSION);
	}
	
	
	 
	@Override
	public void onCreate(SQLiteDatabase db) {
		// TODO Auto-generated method stub
//		String sql="Create table "+TABLE_NAME+"("+FIELD_ID+" integer primary key autoincrement,"
//		+FIELD_TITLE+" text );";
		String sql="CREAT TABLE IF NOT EXISTS"+TABLE_NAME+"("+FIELD_ID+" integer primary key autoincrement,"
		+FIELD_NAME+" text, "+FIELD_TABLE_NUMBER+" text, "+FIELD_INFO+" text, "
	+FIELD_TITLE+" text );";
		db.execSQL(sql);
		 
	}

	@Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
		// TODO Auto-generated method stub
		String sql=" DROP TABLE IF EXISTS "+TABLE_NAME;
		db.execSQL(sql);
		onCreate(db);
	}

	public Cursor select()
	{
		SQLiteDatabase db=this.getReadableDatabase();
		String[] column = {FIELD_ID,FIELD_NAME,FIELD_TABLE_NUMBER,FIELD_INFO,"sec_Title"};    
//		Cursor cursor=db.query(TABLE_NAME, null, null, null, null, null,  " _id asc");
//		Cursor cursor=db.query(TABLE_NAME, column, null, null, null, null,  " _id desc");
		Cursor cursor=db.query(TABLE_NAME, null, null, null, null, null,  " _id desc");
//		Log.d("tag", "-----"+cursor.getString(0));
		Log.d("tag", "数据库长度--"+cursor.getCount());
		Log.d("tag", "数据库列名称--"+cursor.getColumnName(0));
		Log.d("tag", "数据库列数--"+cursor.getColumnCount());
		Log.d("tag", "数据库名称是第几列--"+cursor.getColumnIndexOrThrow("_id"));
		Log.d("tag", "数据库位置---|"+cursor.getPosition());
		cursor.moveToFirst();   
		 while (cursor.getPosition() != cursor.getCount()) {
			 Log.d("tag", "数据库内容-->"+cursor.getString(1));
					 cursor.moveToNext();
				}
		
		//最后的参数 desc是descend 降序意思 asc 是ascend 升序的意思 
		/**
         *  关于db.query方法的参数，有很多，为了防止大家弄乱，我简单说一下
                        参数1：表名
                        参数2：返回数据包含的列信息，String数组里放的都是列名
                        参数3：相当于sql里的where，sql里where后写的内容放到这就行了，例如：tage>?
                        参数4：如果你在参数3里写了?（知道我为什么写tage>?了吧），
                        那个这里就是代替?的值 接上例：new String[]{"30"}
                        参数5：分组，不解释了，不想分组就传null
                        参数6：having，想不起来的看看SQL
                        参数7：orderBy排序
         */
		return cursor;
	}
	
	public long insert(String Name,String TableNumber,String Info,String Title)
	{
		SQLiteDatabase db=this.getWritableDatabase();
		ContentValues cv=new ContentValues(); 
		
		cv.put(FIELD_NAME, Name);
		cv.put(FIELD_TABLE_NUMBER, TableNumber);
		cv.put(FIELD_INFO, Info);
		cv.put(FIELD_TITLE, Title);
		long row=db.insert(TABLE_NAME, null, cv);
		return row;
	}
	
	public void delete(int id)
	{
		SQLiteDatabase db=this.getWritableDatabase();
		String where=FIELD_ID+"=?";
		String[] whereValue={Integer.toString(id)};
		db.delete(TABLE_NAME, where, whereValue);
	}
	
	public void update(int id,String Name,String TableNumber,String Info,String Title)
	{
		SQLiteDatabase db=this.getWritableDatabase();
		String where=FIELD_ID+"=?";
		String[] whereValue={Integer.toString(id)};
		ContentValues cv=new ContentValues(); 
		cv.put(FIELD_NAME, Name);
		cv.put(FIELD_TABLE_NUMBER, TableNumber);
		cv.put(FIELD_INFO, Info);
		cv.put(FIELD_TITLE, Title);
		db.update(TABLE_NAME, cv, where, whereValue);
	}
	
	
	
	
}

主程序，创建菜单对数据库进行操作，其中用到字符串解析

public class testDbActivity extends Activity {
	
	private dbHelper db;
	private Cursor myCursor;
	private ListView myListView;
	private EditText myEditText;
	private int _id;
	protected final static int MENU_ADD=Menu.FIRST;
	protected final static int MENU_EDIT=Menu.FIRST+1;
	protected final static int MENU_DELETE=Menu.FIRST+2;
	
	   @Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// TODO Auto-generated method stub
		   super.onCreateOptionsMenu(menu);
		menu.add(Menu.NONE, MENU_ADD, 0, R.string.ADD);
		menu.add(Menu.NONE, MENU_EDIT, 0,R.string.EDIT);
		menu.add(Menu.NONE, MENU_DELETE, 0,R.string.DELETE);
		 return true;
	}
	
	   @Override
	public boolean onOptionsItemSelected(MenuItem item) {
		// TODO Auto-generated method stub
		
		super.onOptionsItemSelected(item); 
		switch (item.getItemId()) {
		case MENU_ADD:
			operation("add");
			break;
		case MENU_EDIT:
			operation("edit");
			break;
		case MENU_DELETE:
			operation("delete");
			break;
		default:
			break;
		}
		return true;
	}
	   
	   
	   
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        myEditText=(EditText)findViewById(R.id.EditText1);
        myListView=(ListView)findViewById(R.id.ListView1);
        db=new dbHelper(testDbActivity.this);
        myCursor=db.select();//数据库信息
        SimpleCursorAdapter adpater=new SimpleCursorAdapter(this
        		, R.layout.test, myCursor,
        		new String[]{dbHelper.FIELD_NAME,dbHelper.FIELD_TABLE_NUMBER,dbHelper.FIELD_INFO,dbHelper.FIELD_TITLE},
        		new int[]{R.id.topTextView,R.id.name_view,R.id.tableNumber_view,R.id.info_view});
        /**
         *   参数1:Content
        参数2:布局
        参数3:Cursor游标对象
        参数4:显示的字段，传入String[]
        参数5:显示字段使用的组件，传入int[]，该数组中是TextView组件的id
         */
        myListView.setAdapter(adpater);
        //点击的时候
        myListView.setOnItemClickListener(new OnItemClickListener() {

			@Override
			public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
					long arg3) {
				// TODO Auto-generated method stub
				Log.d("tag", "arg0------>"+arg0);
				Log.d("tag", "arg1------>"+arg1);
				Log.d("tag", "arg2------>"+arg2);//在这个view上的位置
				Log.d("tag", "arg3------>"+arg3);// The row id of the item that was clicked. 一直增加的id号
				myCursor.moveToPosition(arg2);//选择的第几条信息
				_id=myCursor.getInt(0);//此信息的第0项（ID号）
				myEditText.setText(myCursor.getString(1));
			}
		});
        
        //下面这段代码是在获取焦点时 显示焦点的内容
        myListView.setOnItemSelectedListener(new OnItemSelectedListener() {

			@Override
			public void onItemSelected(AdapterView<?> arg0, View arg1,
					int arg2, long arg3) {
				// TODO Auto-generated method stub
				SQLiteCursor sc=(SQLiteCursor)arg0.getSelectedItem();
				_id=sc.getInt(0);
				myEditText.setText(sc.getString(1));
			}

			@Override
			public void onNothingSelected(AdapterView<?> arg0) {
				// TODO Auto-generated method stub
				
			}
		});
    }
    private void operation(String cmd)
    {
    	String et_str = myEditText.getText().toString();
    	if(et_str.equals("")){
    		Toast toast = Toast.makeText(getApplicationContext(), "请输入信息！！！！！！！", 0);
    		toast.setGravity(Gravity.CENTER, 0, 0);
    		toast.show();
    		return;
    	}
    	
    	String et_info[] = et_str.split(",");//解析字符串
    	for (int i = 0; i < et_info.length; i++) {
			Log.d("tag", "-->"+et_info[i]);
		}
    	if(cmd=="add"){
    		db.insert(et_info[0],et_info[1],et_info[2],et_info[3]);
    	}
    	if(cmd=="edit"){
    		db.update(_id,  et_info[0],et_info[1],et_info[2],et_info[3]);
    	}
    	if(cmd=="delete"){
    		db.delete(_id);
    	}
    	myCursor.requery();//重新查询
    	myListView.invalidateViews();//更新listview
    	myEditText.setText("");
    	_id=0;
    	
    }
    
}
//主界面

<?xml version="1.0" encoding="utf-8"?>
<AbsoluteLayout
android:id="@+id/AbsoluteLayout1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
xmlns:android="http://schemas.android.com/apk/res/android"
>
<EditText
android:id="@+id/EditText1"
android:layout_width="292px"
android:layout_height="wrap_content"
android:textSize="18sp"
android:layout_x="11px"
android:layout_y="10px"
android:hint="name,table_number,info,title"
>
</EditText>
<ListView
android:id="@+id/ListView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_x="12px"
android:layout_y="69px"
>
</ListView>
</AbsoluteLayout>


//listview显示的内容及布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
		android:orientation="horizontal"
		android:layout_width="fill_parent"
		android:layout_height="60px">
<TextView 
	android:text="TextView1" android:id="@+id/topTextView"
	android:layout_width="wrap_content" android:textSize="20dip"
	android:layout_height="wrap_content"></TextView>
<TextView 
	android:id="@+id/name_view1"
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
	android:textSize="20dip"
	android:text="->"></TextView>
<TextView 
	android:id="@+id/name_view"
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
	android:textSize="20dip"
	android:text="TextView1"></TextView>
<TextView 
	android:id="@+id/name_view2"
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
	android:textSize="20dip"
	android:text="->"></TextView>
<TextView 
	android:id="@+id/tableNumber_view"
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
	android:textSize="20dip"
	android:text="TextView1"></TextView>
<TextView 
	android:id="@+id/name_view3"
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
	android:textSize="20dip"
	android:text="->"></TextView>
<TextView 
	android:id="@+id/info_view"
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
	android:textSize="20dip"
	android:text="TextView1"></TextView>

</LinearLayout>