Shulou(Shulou.com)06/01 Report--

Sqlite is different from other common databases, that is, sqlite database is saved as a file, which can be exported directly from the phone, stored as a file, and then put on the computer to view.

The steps for Android to operate the database are as follows:

1. Inherit SQLiteOpenHelper and implement the methods in it.

Public class MyDbHelper extends SQLiteOpenHelper {public MyDbHelper (Context context) {super (context, "db3", null, 1);} @ Override public void onCreate (SQLiteDatabase db) {db.execSQL ("create table db (id int primary key autoincrement,name varchar (10), phone varchar (15);");} @ Override public void onUpgrade (SQLiteDatabase db, int oldVersion, int newVersion) {db.execSQL ("alert table db add column yuan varchar (11);") 2. Create a dao layer, which acts like the dao layer in the ssh framework in java, and is used to manipulate the database public class ContactInfoDao {private final MyDbHelper mMyDbHelper; private final SQLiteDatabase mDb; / / construction method. When generating entity objects of this class, the object public ContactInfoDao (Context context) {mMyDbHelper = new MyDbHelper (context) {mMyDbHelper = mMyDbHelper.getWritableDatabase () is generated directly. } / * add contact information * @ param name * @ param phone * / public void add (String name,String phone) {mDb.execSQL ("insert into db3 (name,phone) values (?)", new Object [] {name,phone}); mDb.close ();}}

3. After writing the corresponding method in the dao layer, call the method in dao in Activity for business logic

Package com.yuanlp.createdb3;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.text.TextUtils;import android.view.View;import android.widget.EditText;import android.widget.Toast;import com.yuanlp.createdb3.dao.ContactInfoDao;public class MainActivity extends AppCompatActivity {private EditText mName; private EditText mPhone; private ContactInfoDao mContactInfoDao; @ Override protected void onCreate (Bundle savedInstanceState) {super.onCreate (savedInstanceState); setContentView (R.layout.layout) MName = (EditText) findViewById (R.id.et_name); mPhone = (EditText) findViewById (R.id.et_phone); mContactInfoDao = new ContactInfoDao (this);} / * * insert database * @ author yuan * @ param view * / public void add (View view) {String name=mName.getText (). ToString (). Trim () String phone=mPhone.getText (). ToString (). Trim (); if (TextUtils.isEmpty (name) | | name==null) {Toast.makeText (this, "name cannot be empty", Toast.LENGTH_SHORT). Show (); return;} else if (TextUtils.isEmpty (phone) | | phone==null) {Toast.makeText (this, "number cannot be empty", Toast.LENGTH_SHORT). Show (); return } mContactInfoDao.add (name,phone); Toast.makeText (this, "insert database successfully", Toast.LENGTH_SHORT). Show ();}}

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.