5。建庫，表，增刪改查
阿新 • • 發佈：2020-11-13
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) {
}
}
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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)+"\n";
}
}
((TextView)(findViewById(R.id.tv_show))).setText(s);
}
}
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<?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="請輸入姓名"
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 齡："
android:textSize="18sp" />
<EditText
android:id="@+id/et_age"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="輸入年齡"
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="新增"
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="查詢"
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="刪除"
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>
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