布局文件
<?xml version="1.0" encoding="utf-8"?> <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity"> <EditText android:id="@+id/editText_name" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_marginStart="8dp" android:layout_marginLeft="8dp" android:layout_marginEnd="8dp" android:layout_marginRight="8dp" android:ems="10" android:hint="Input name?" android:inputType="textPersonName" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" /> <EditText android:id="@+id/editText_age" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_marginStart="8dp" android:layout_marginLeft="8dp" android:layout_marginTop="11dp" android:layout_marginEnd="8dp" android:layout_marginRight="8dp" android:ems="10" android:hint="Input age?" android:inputType="number" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toBottomOf="@+id/editText_name" /> <Button android:id="@+id/button" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="44dp" android:layout_marginEnd="10dp" android:layout_marginRight="10dp" android:onClick="add" android:text="Add" app:layout_constraintEnd_toStartOf="@+id/button2" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="@+id/editText_age" /> <Button android:id="@+id/button2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginEnd="6dp" android:layout_marginRight="6dp" android:onClick="delete" android:text="Delete" app:layout_constraintBottom_toTopOf="@+id/listView" app:layout_constraintEnd_toStartOf="@+id/button3" app:layout_constraintStart_toEndOf="@+id/button" /> <Button android:id="@+id/button3" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginEnd="2dp" android:layout_marginRight="2dp" android:onClick="update" android:text="Update" app:layout_constraintBottom_toTopOf="@+id/listView" app:layout_constraintEnd_toStartOf="@+id/button4" app:layout_constraintStart_toEndOf="@+id/button2" /> <Button android:id="@+id/button4" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginEnd="1dp" android:layout_marginRight="1dp" android:onClick="retrieve" android:text="Retrieve" app:layout_constraintBottom_toTopOf="@+id/listView" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toEndOf="@+id/button3" /> <ListView android:id="@+id/listView" android:layout_width="0dp" android:layout_height="0dp" android:layout_marginStart="8dp" android:layout_marginLeft="8dp" android:layout_marginEnd="8dp" android:layout_marginRight="8dp" android:layout_marginBottom="8dp" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toBottomOf="@+id/button" /> </android.support.constraint.ConstraintLayout>
MySQLHelper
package com.example.sqlitedemo2; import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; public class MySQLHelper extends SQLiteOpenHelper { public static final String PersonTable = "person"; public MySQLHelper(Context context,String name,SQLiteDatabase.CursorFactory factory,int version) { super(context,name,factory,version); } @Override public void onCreate(SQLiteDatabase db) { db.execSQL("create table if not exists person(_id integer primary key autoincrement,name text,age integer)"); } @Override public void onUpgrade(SQLiteDatabase db,int oldVersion,int newVersion) { } }
MainActivity.java
package com.example.sqlitedemo2; import android.content.ContentValues; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.os.AsyncTask; import android.support.annotation.Nullable; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.CursorAdapter; import android.widget.EditText; import android.widget.ListView; import android.widget.SimpleCursorAdapter; public class MainActivity extends AppCompatActivity { MySQLHelper mySQLHelper; SQLiteDatabase db; EditText editText_name,editText_age; ListView listView; SimpleCursorAdapter adapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); editText_name = findViewById(R.id.editText_name); editText_age = findViewById(R.id.editText_age); listView = findViewById(R.id.listView); mySQLHelper = new MySQLHelper(this,"db",null,1); db = mySQLHelper.getWritableDatabase(); Cursor cursor = db.query(MySQLHelper.PersonTable,null); adapter = new SimpleCursorAdapter(this,android.R.layout.simple_list_item_2,cursor,new String[]{"name","age"},new int[]{android.R.id.text1,android.R.id.text2},CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER); listView.setAdapter(adapter); } public void add(View view){ String name = editText_name.getText().toString(); String age = editText_age.getText().toString(); // db.execSQL("insert into person(name,age) values('"+name+"','"+age+"')"); ContentValues contentValues = new ContentValues(); contentValues.put("name",name); contentValues.put("age",age); db.insert(MySQLHelper.PersonTable,contentValues); reload(); } public void delete(View view){ String name = editText_name.getText().toString(); db.delete(MySQLHelper.PersonTable,"name=?",new String[]{name}); reload(); } public void update(View view){ String name = editText_name.getText().toString(); String age = editText_age.getText().toString(); ContentValues contentValues = new ContentValues(); contentValues.put("name",age); db.update(MySQLHelper.PersonTable,contentValues,new String[]{name}); reload(); } public void retrieve(View view){ String name = editText_name.getText().toString(); new MyAsyncTask().execute("%"+name+"%"); // Cursor cursor=db.query(MySQLHelper.PersonTable,"name like *",new String[]{name},null); // adapter.swapCursor(cursor); } private void reload() { Cursor cursor = db.query(MySQLHelper.PersonTable,null); adapter.swapCursor(cursor); } class MyAsyncTask extends AsyncTask<String,Nullable,Cursor>{ @Override protected Cursor doInBackground(String... strings) { Cursor cursor=db.query(MySQLHelper.PersonTable,"name like ?",new String[]{"%"+strings[0]+"%"},null); return cursor; } @Override protected void onPostExecute(Cursor cursor) { super.onPostExecute(cursor); adapter.swapCursor(cursor); } } }