sqlite

首先创建一个类继承自SQLiteOpenHelper,然后重写构造方法和onCreate和onUpGrade,在oncreate中创建表

db.execSQL("create table hero(_id integer Primary Key autoincrement,name text(20))");

 方便学习实现了增删改查功能,

添加功能

	//添加
		addButton.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				String name = add.getText().toString();
		    	SQLiteDatabase db = bhelper.getWritableDatabase();
		    	ContentValues values = new ContentValues();
		    	values.put("name", name);
		    	long id = db.insert("hero", "name", values);
		    	if (id != -1) {
					Toast.makeText(MainActivity.this, "插入成功", Toast.LENGTH_SHORT).show();
				}else {
					Toast.makeText(MainActivity.this, "插入失败", Toast.LENGTH_SHORT).show();
				}
		    	db.close();
			}
		});

 

//修改
		alter.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				String name = add.getText().toString();
				SQLiteDatabase db = bhelper.getWritableDatabase();
				ContentValues values = new ContentValues();
				values.put("name", name);
				int cnt = db.update("hero", values, "_id = ?", new String[]{id + ""});
				if(cnt>0){
					Toast.makeText(MainActivity.this, "修改成功", Toast.LENGTH_SHORT).show();
				}else{
					Toast.makeText(MainActivity.this, "修改失败", Toast.LENGTH_SHORT).show();
				}
				db.close();
			}
		});

 

//查看
		look.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				String name = add.getText().toString();
		    	SQLiteDatabase db = bhelper.getReadableDatabase();
		    	String selection = null;
		    	String[] selectionArgs = null;
		    	if (!"".equals(name)) {
		    		selection = " name like ?";//只查询name的模糊查询
		    		selectionArgs = new String[]{name + "%"};
				}
		    	Cursor c = db.query("hero", new String[]{"_id","name"}, selection, selectionArgs, null, null, "name asc");
		    	SimpleCursorAdapter sca = new SimpleCursorAdapter(MainActivity.this, R.layout.person_item, c, new String[]{"name"}, new int[]{R.id.nameTv});
		    	listView.setAdapter(sca);
		    	startManagingCursor(c); 
		    	
		    	db.close();
			}
		});

 

//删除
		delete.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				SQLiteDatabase db = bhelper.getWritableDatabase();
				int cnt = db.delete("hero","_id = ?", new String[]{id +""});
				if(cnt>0){
					Toast.makeText(MainActivity.this, "删除成功", Toast.LENGTH_SHORT).show();
				}else {
					Toast.makeText(MainActivity.this, "修改失败", Toast.LENGTH_SHORT).show();
				}
				db.close();
			}
			
		});