第七

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:background="@drawable/bg"
 6     android:padding="16dp"
 7     android:orientation="vertical">
 8     <LinearLayout
 9         android:layout_marginTop="130dp"
10         android:layout_width="match_parent"
11         android:layout_height="wrap_content">
12         <TextView
13             android:layout_width="wrap_content"
14             android:layout_height="wrap_content"
15             android:text="姓  名 ："
16             android:textSize="18sp" />
17         <EditText
18             android:id="@+id/et_name"
19             android:layout_width="match_parent"
20             android:layout_height="wrap_content"
21             android:hint="请输入姓名"
22             android:textSize="16sp" />
23     </LinearLayout>
24     <LinearLayout
25         android:layout_width="match_parent"
26         android:layout_height="wrap_content"
27         android:layout_marginBottom="10dp">
28  
29         <TextView
30             android:layout_width="wrap_content"
31             android:layout_height="wrap_content"
32             android:text="年  龄："
33             android:textSize="18sp" />
34  
35         <EditText
36             android:id="@+id/et_age"
37             android:layout_width="match_parent"
38             android:layout_height="wrap_content"
39             android:hint="输入年龄"
40             android:textSize="16sp" />
41     </LinearLayout>
42     <LinearLayout
43         android:layout_width="match_parent"
44         android:layout_height="wrap_content">
45         <Button
46             android:id="@+id/btn_add"
47             android:layout_width="0dp"
48             android:layout_height="wrap_content"
49             android:layout_marginRight="2dp"
50             android:layout_weight="1"
51             android:background="#B9B9FF"
52             android:text="添加"
53             android:textSize="18sp"
54             android:onClick="add" />
55         <Button
56             android:id="@+id/btn_query"
57             android:layout_width="0dp"
58             android:layout_height="wrap_content"
59             android:layout_marginRight="2dp"
60             android:layout_weight="1"
61             android:background="#DCB5FF"
62             android:text="查询"
63             android:textSize="18sp"
64             android:onClick="serch"/>
65         <Button
66             android:id="@+id/btn_update"
67             android:layout_width="0dp"
68             android:layout_height="wrap_content"
69             android:layout_marginRight="2dp"
70             android:layout_weight="1"
71             android:background="#E6CAFF"
72             android:text="修改"
73             android:textSize="18sp"
74             android:onClick="update"/>
75         <Button
76             android:id="@+id/btn_delete"
77             android:layout_width="0dp"
78             android:layout_height="wrap_content"
79             android:layout_weight="1"
80             android:background="#ACD6FF"
81             android:text="删除"
82             android:textSize="18sp"
83             android:onClick="delete" />
84     </LinearLayout>
85     <TextView
86         android:id="@+id/tv_show"
87         android:layout_width="match_parent"
88         android:layout_height="wrap_content"
89         android:layout_marginTop="25dp"
90         android:textSize="20sp" />
91 </LinearLayout>

StuOpenHelper

 1 package com.example.zsgc;
 2  
 3 import android.content.Context;
 4 import android.database.sqlite.SQLiteDatabase;
 5 import android.database.sqlite.SQLiteOpenHelper;
 6  
 7 import androidx.annotation.Nullable;
 8  
 9 public class StuOpenHelper extends SQLiteOpenHelper {
10     public StuOpenHelper(@Nullable Context context) {
11         super(context, "stu.db", null, 1);
12     }
13  
14     @Override
15     public void onCreate(SQLiteDatabase sqLiteDatabase) {
16         sqLiteDatabase.execSQL("create table student (id integer primary key autoincrement ,name varchar(20),price integer)");
17     }
18  
19     @Override
20     public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
21  
22     }
23 }

MainActivity

 1 package com.example.aaaapps;
 2  
 3 import androidx.appcompat.app.AppCompatActivity;
 4  
 5 import android.annotation.SuppressLint;
 6 import android.database.Cursor;
 7 import android.database.sqlite.SQLiteDatabase;
 8 import android.os.Bundle;
 9 import android.view.View;
10 import android.widget.TextView;
11 import android.widget.Toast;
12  
13 public class MainActivity extends AppCompatActivity {
14  
15     @Override
16     protected void onCreate(Bundle savedInstanceState) {
17         super.onCreate(savedInstanceState);
18         setContentView(R.layout.activity_main);
19     }
20  
21     @SuppressLint("WrongConstant")
22     public void add(View view){
23         String name = ((TextView)findViewById(R.id.et_name)).getText().toString();
24         int age = Integer.parseInt(((TextView)findViewById(R.id.et_age)).getText().toString());
25         StuOpenHelper stuOpenHelper=new StuOpenHelper(this);
26         SQLiteDatabase db = stuOpenHelper.getReadableDatabase();
27         db.execSQL("insert into student (name,price) values(?,?)",new Object[]{name,age});
28         Toast.makeText(this,"ok",0).show();
29     }
30  
31     public void serch(View view){
32         StuOpenHelper stuOpenHelper=new StuOpenHelper(this);
33         SQLiteDatabase db = stuOpenHelper.getReadableDatabase();
34         String s="";
35         Cursor cursor = db.rawQuery("SELECT * from student", null);
36         while (cursor.getCount()!=0){
37             while (cursor.moveToNext()){
38                 s+=cursor.getInt(0)+" "+cursor.getInt(1)+" "+cursor.getInt(2)+"
";
39             }
40         }
41         ((TextView)(findViewById(R.id.tv_show))).setText(s);
42     }
43 }