unfortunately的问题

package com.imooc.tao.myapplication;

import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
        private Button insert_btn,delete_btn,update_btn,select_btn;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        setListener();
    }

    private void setListener() {
        ButtonListener b=new ButtonListener();
        insert_btn.setOnClickListener(b);
        delete_btn.setOnClickListener(b);
        update_btn.setOnClickListener(b);
        select_btn.setOnClickListener(b);
    }

    private void initView() {
        insert_btn=(Button)findViewById(R.id.insert_btn);
        delete_btn=(Button)findViewById(R.id.delete_btn);
        update_btn=(Button)findViewById(R.id.update_btn);
        select_btn=(Button)findViewById(R.id.select_btn);
    }

    class ButtonListener implements View.OnClickListener{

        @Override
        public void onClick(View view) {
            switch (view.getId()){
                case R.id.insert_btn:
                    //参数2：数据库名称
                    //如果只有一个数据库名称，那么这个数据库位置将在私有目录中
                    //或给指定路径（sd卡）
                    //游标工厂，null默认
                    String path= Environment.getExternalStorageDirectory()+"/test2.db";
                    SQLiteOpenHelper helper=new SQLiteOpenHelper(MainActivity.this,path,null,2) {
                        @Override
                        public void onCreate(SQLiteDatabase sqLiteDatabase) {
                            //数据库不存在就创建，调用onCreate（），表的创建可以放里面 存在就不创建了 回调方法
                            Toast.makeText(MainActivity.this,"数据库创建",Toast.LENGTH_SHORT).show();
                            String sql="create table test_tb(_id integer primary key autoincrement," +
                                    "name:varchar(20)," +
                                    "age:integer" +
                                    ")";
                            sqLiteDatabase.execSQL(sql);
                        }

                        @Override
                        public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
                            Toast.makeText(MainActivity.this,"数据库升级",Toast.LENGTH_SHORT).show();
                        }
                    };
                    //获取数据库对象
                    //数据库不存在就创建，调用onCreate（），表的创建可以放里面 存在就不创建了
                    //数据库存在，版本号升高，就调用升级方法
                   SQLiteDatabase db= helper.getReadableDatabase();
//                    db.rawQuery() 查询
//                    db.execSQL();添加 删除 修改 创建表
                    break;
                case R.id.delete_btn:

                    break;
                case R.id.update_btn:

                    break;
                case R.id.select_btn:

                    break;
            }
        }
    }
}

运行之后也不报错，点了 添加 就unfortunately。。。闪退问题，看了半天没找到原因，求救！！！