Android.5 _Android

男儿欲遂平生志，六经勤向窗前读。这篇文章主要讲述Android.5相关的知识，希望能为你提供帮助。

import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; import androidx.annotation.Nullable; public class StuOpenHelper extends SQLiteOpenHelper { public StuOpenHelper(@Nullable Context context) { super(context, "stu.db", null, 1); }@Override public void onCreate(SQLiteDatabase sqLiteDatabase) { sqLiteDatabase.execSQL("create table student (id integer primary key autoincrement ,name varchar(20),price integer)"); }@Override public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {} }

【Android.5】

import androidx.appcompat.app.AppCompatActivity; import android.annotation.SuppressLint; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.os.Bundle; import android.view.View; import android.widget.TextView; import android.widget.Toast; public class MainActivity extends AppCompatActivity {@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); }@SuppressLint("WrongConstant") public void add(View view){ String name = ((TextView)findViewById(R.id.et_name)).getText().toString(); int age = Integer.parseInt(((TextView)findViewById(R.id.et_age)).getText().toString()); StuOpenHelper stuOpenHelper=new StuOpenHelper(this); SQLiteDatabase db = stuOpenHelper.getReadableDatabase(); db.execSQL("insert into student (name,price) values(?,?)",new Object[]{name,age}); Toast.makeText(this,"ok",0).show(); }public void serch(View view){ StuOpenHelper stuOpenHelper=new StuOpenHelper(this); SQLiteDatabase db = stuOpenHelper.getReadableDatabase(); String s=""; Cursor cursor = db.rawQuery("SELECT * from student", null); while (cursor.getCount()!=0){ while (cursor.moveToNext()){ s+=cursor.getInt(0)+" "+cursor.getInt(1)+" "+cursor.getInt(2)+" "; } } ((TextView)(findViewById(R.id.tv_show))).setText(s); } } 复制代码

< ?xml version="1.0" encoding="utf-8"?> < LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@drawable/bg" android:padding="16dp" android:orientation="vertical"> < LinearLayout android:layout_marginTop="130dp" android:layout_width="match_parent" android:layout_height="wrap_content"> < TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="姓名：" android:textSize="18sp" /> < EditText android:id="@+id/et_name" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="请输入姓名" android:textSize="16sp" /> < /LinearLayout> < LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginBottom="10dp"> < TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="年龄：" android:textSize="18sp" /> < EditText android:id="@+id/et_age" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="输入年龄" android:textSize="16sp" /> < /LinearLayout> < LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content"> < Button android:id="@+id/btn_add" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_marginRight="2dp" android:layout_weight="1" android:background="#B9B9FF" android:text="添加" android:textSize="18sp" android:onClick="add" /> < Button android:id="@+id/btn_query" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_marginRight="2dp" android:layout_weight="1" android:background="#DCB5FF" android:text="查询" android:textSize="18sp" android:onClick="serch"/> < Button android:id="@+id/btn_update" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_marginRight="2dp" android:layout_weight="1" android:background="#E6CAFF" android:text="修改" android:textSize="18sp" android:onClick="update"/> < Button android:id="@+id/btn_delete" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:background="#ACD6FF" android:text="删除" android:textSize="18sp" android:onClick="delete" /> < /LinearLayout> < TextView android:id="@+id/tv_show" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="25dp" android:textSize="20sp" /> < /LinearLayout>