增删改查
作者:互联网
package com.example.myapplication; import android.os.Bundle; import android.app.Activity; import android.content.ContentValues; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.view.Menu; import android.view.View; import android.widget.EditText; import android.widget.TextView; import android.widget.Toast; public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } public void add(View v) { StuOpenHelper helper = new StuOpenHelper(this); SQLiteDatabase db = helper.getWritableDatabase(); String name = ((EditText) findViewById(R.id.et_name)).getText() .toString(); int age = Integer.parseInt(((EditText) findViewById(R.id.et_age)) .getText().toString()); // 原生sql操作, // db.execSQL("insert into stuinfo (name,age) values('lisi',22)"); // db.execSQL("insert into stuinfo (name,age) values(?,?)",new // Object[]{"kitty",30}); db.execSQL("insert into stuinfo (name,age) values(?,?)", new Object[] { name, age }); Toast.makeText(this, "ok", 0).show(); } public void delete(View view) { StuOpenHelper helper = new StuOpenHelper(this); SQLiteDatabase db = helper.getWritableDatabase(); db.execSQL("delete from stuinfo where _id=?", new Object[] { 2 }); Toast.makeText(this, "删除成功", 0).show(); } public void update(View view) { StuOpenHelper helper = new StuOpenHelper(this); SQLiteDatabase db = helper.getWritableDatabase(); db.execSQL("update stuinfo set name=? where _id=?", new Object[] { "micky", 3 }); Toast.makeText(this, "修改成功", 0).show(); } public void search(View view) { StuOpenHelper helper = new StuOpenHelper(this); SQLiteDatabase db = helper.getWritableDatabase(); String s = ""; Cursor cursor = db.rawQuery("select * from stuinfo", null); if (cursor.getCount() != 0) { while (cursor.moveToNext()) { s += cursor.getInt(0) + " " + cursor.getString(1) + " " + cursor.getInt(2) + "\n"; } } // Toast.makeText(this, s, 0).show(); ((TextView) (findViewById(R.id.tv_show))).setText(s); } }
package com.example.myapplication; import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteDatabase.CursorFactory; import android.database.sqlite.SQLiteOpenHelper; public class StuOpenHelper extends SQLiteOpenHelper { public StuOpenHelper(Context context) { super(context, "stu.db", null, 1); // TODO Auto-generated constructor stub } @Override public void onCreate(SQLiteDatabase db) { // TODO Auto-generated method stub db.execSQL("create table stuinfo(_id integer primary key autoincrement,name varchar(20),age integer)"); } @Override public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) { // TODO Auto-generated method stub } }
<?xml version="1.0" encoding="UTF-8"?> <LinearLayout android:padding="16dp" android:orientation="vertical" android:background="@drawable/bg" android:layout_height="match_parent" android:layout_width="match_parent" xmlns:android="http://schemas.android.com/apk/res/android"> <LinearLayout android:layout_height="wrap_content" android:layout_width="match_parent" android:layout_marginTop="130dp"> <TextView android:layout_height="wrap_content" android:layout_width="wrap_content" android:textSize="18sp" android:text="姓 名 :"/> <EditText android:layout_height="wrap_content" android:layout_width="match_parent" android:textSize="16sp" android:hint="请输入姓名" android:id="@+id/et_name"/> </LinearLayout> -<LinearLayout android:layout_height="wrap_content" android:layout_width="match_parent" android:layout_marginBottom="10dp"> <TextView android:layout_height="wrap_content" android:layout_width="wrap_content" android:textSize="18sp" android:text="年 龄:"/> <EditText android:layout_height="wrap_content" android:layout_width="match_parent" android:textSize="16sp" android:hint="输入年龄" android:id="@+id/et_age"/> </LinearLayout> -<LinearLayout android:layout_height="wrap_content" android:layout_width="match_parent"> <Button android:background="#B9B9FF" android:layout_height="wrap_content" android:layout_width="0dp" android:textSize="18sp" android:text="添加" android:id="@+id/btn_add" android:onClick="add" android:layout_weight="1" android:layout_marginRight="2dp"/> <Button android:background="#DCB5FF" android:layout_height="wrap_content" android:layout_width="0dp" android:textSize="18sp" android:text="查询" android:id="@+id/btn_query" android:onClick="search" android:layout_weight="1" android:layout_marginRight="2dp"/> <Button android:background="#E6CAFF" android:layout_height="wrap_content" android:layout_width="0dp" android:textSize="18sp" android:text="修改" android:id="@+id/btn_update" android:onClick="update" android:layout_weight="1" android:layout_marginRight="2dp"/> <Button android:background="#ACD6FF" android:layout_height="wrap_content" android:layout_width="0dp" android:textSize="18sp" android:text="删除" android:id="@+id/btn_delete" android:onClick="delete" android:layout_weight="1"/> </LinearLayout> -<ScrollView android:layout_height="wrap_content" android:layout_width="match_parent"> <TextView android:layout_height="wrap_content" android:layout_width="match_parent" android:layout_marginTop="25dp" android:textSize="20sp" android:id="@+id/tv_show"/> </ScrollView> </LinearLayout>
标签:SQLiteDatabase,db,改查,增删,import,android,StuOpenHelper,public 来源: https://www.cnblogs.com/xxy02160216/p/13944601.html