半期考试二三题 (书籍维护数据库）

结构：

主活动xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"android:orientation="vertical"tools:context=".MainActivity"><ListViewandroid:id="@+id/listView"android:layout_width="match_parent"android:layout_height="0dp"android:layout_weight="1" /><Buttonandroid:id="@+id/add"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_gravity="center"android:onClick="btnAdd"android:text="Add"tools:ignore="OnClick" /></LinearLayout>

MainActivity2 xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"android:orientation="vertical"tools:context=".MainActivity2"><EditTextandroid:id="@+id/book_name"android:layout_width="match_parent"android:layout_height="wrap_content"android:hint="输入书名：" /><EditTextandroid:id="@+id/book_price"android:layout_width="match_parent"android:layout_height="wrap_content"android:hint="输入价格："android:inputType="number"/><LinearLayoutandroid:layout_width="match_parent"android:layout_height="wrap_content"><LinearLayoutandroid:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"><Buttonandroid:id="@+id/button_cancel"android:layout_width="wrap_content"android:layout_height="match_parent"android:onClick="cancel"android:text="取消"tools:ignore="OnClick" /></LinearLayout><Buttonandroid:id="@+id/button_ok"android:layout_width="wrap_content"android:layout_height="wrap_content"android:onClick="confirm"android:text="确定"tools:ignore="OnClick" /></LinearLayout></LinearLayout>

书籍实体类

package com.example.second;import java.io.Serializable;public class Book implements Serializable {private String bookName;private float bookPrice;private int bookID;public int getBookID() {return bookID;}public void setBookID(int bookID) {this.bookID = bookID;}public Book( String bookName, float bookPrice) {this.bookName = bookName;this.bookPrice = bookPrice;}public Book(int bookID, String bookName, float bookPrice) {this.bookID = bookID;this.bookName = bookName;this.bookPrice = bookPrice;}public String getBookName() {return bookName;}public void setBookName(String bookName) {this.bookName = bookName;}public float getBookPrice() {return bookPrice;}public void setBookPrice(float bookPrice) {this.bookPrice = bookPrice;}
}

数据库操作类：

package com.example.second;import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;import androidx.annotation.Nullable;public class SQLHelper extends SQLiteOpenHelper {public static final String BookTable = "book";public SQLHelper(@Nullable Context context, @Nullable String name, @Nullable SQLiteDatabase.CursorFactory factory, int version) {super(context, name, factory, version);}@Overridepublic void onCreate(SQLiteDatabase db) {db.execSQL("create table book(_id integer primary key autoincrement,name text,price text)");}@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {}
}

主活动 .java

package com.example.second;import androidx.appcompat.app.AppCompatActivity;import android.content.ContentValues;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.CursorAdapter;
import android.widget.ListView;
import android.widget.PopupMenu;
import android.widget.SimpleCursorAdapter;import java.util.ArrayList;
import java.util.List;public class MainActivity extends AppCompatActivity {private SimpleCursorAdapter adpter;private SQLiteDatabase db;private SQLHelper sqlHelper;private Cursor cursor;private ListView listView;private List<Book> bookList = new ArrayList<>();private Intent intent;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);intent = new Intent(MainActivity.this,MainActivity2.class);listView = findViewById(R.id.listView);sqlHelper = new SQLHelper(this,"book.db",null,1);db = sqlHelper.getWritableDatabase();//创建数据库readDB();cursor = db.query("book",null,null,null,null,null,null);adpter = new SimpleCursorAdapter(this,android.R.layout.simple_list_item_2,cursor,new String[]{"name","price"},new int[]{android.R.id.text1,android.R.id.text2}, CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER);listView.setAdapter(adpter);listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {@Overridepublic void onItemClick(AdapterView<?> parent, View view, final int position, long id) {PopupMenu popupMenu = new PopupMenu(MainActivity.this, view);popupMenu.inflate(R.menu.main_menu);popupMenu.show();popupMenu.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {@Overridepublic boolean onMenuItemClick(MenuItem item) {switch (item.getItemId()){case R.id.edit:intent.putExtra("position",position);intent.putExtra("bookToUpdate",bookList.get(position));//  startActivityForResult(intent,1);break;case R.id.delete:String bookName = bookList.get(position).getBookName();db.delete(SQLHelper.BookTable,"name=?",new String[]{bookName});reload();break;}return true;}});}});}private void readDB(){Cursor c = sqlHelper.getReadableDatabase().rawQuery("select * from book", null);int columnSize = c.getColumnCount();while(c.moveToNext()){for(int i=0;i<columnSize;i++){bookList.add(new Book(c.getInt(0),c.getString(1),c.getFloat(2)));}}}private void reload(){Cursor cursor = db.query(SQLHelper.BookTable,null,null,null,null,null,null,null);adpter.swapCursor(cursor);}public void btnAdd(View v){//Intent intent = new Intent(MainActivity.this,Main2Activity.class);startActivityForResult(intent,1);}@Overrideprotected void onActivityResult(int requestCode, int resultCode, Intent data) {super.onActivityResult(requestCode, resultCode, data);if(requestCode ==1){if(resultCode==RESULT_OK){Book book = (Book) data.getSerializableExtra("book");int position = (Integer)data.getIntExtra("position",0);if(book!=null){ContentValues contentValues = new ContentValues();contentValues.put("name",book.getBookName());contentValues.put("price",book.getBookPrice());db.insert(SQLHelper.BookTable,null,contentValues);reload();readDB();}}}}
}

MainActivity2 .java

package com.example.second;import androidx.appcompat.app.AppCompatActivity;import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;public class MainActivity2 extends AppCompatActivity {private EditText book_name;private EditText book_price;private int position;private  String bookName;private String bookPrice;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main2);book_name = findViewById(R.id.book_name);book_price = findViewById(R.id.book_price);}public void cancel(View view) {book_name.setText("");book_price.setText("");// 结束当前窗口的生命周期finish();}public void confirm(View v){bookName = book_name.getText().toString();bookPrice = book_price.getText().toString();if(bookName.isEmpty()){book_name.setText("");book_price.setText("");Toast.makeText(MainActivity2.this,"书名不能为空！",Toast.LENGTH_LONG).show();return;}if(bookPrice.isEmpty()){book_name.setText("");book_price.setText("");Toast.makeText(MainActivity2.this,"价格不能为空！",Toast.LENGTH_LONG).show();return;}if(Integer.parseInt(bookPrice)<=0){book_name.setText("");book_price.setText("");Toast.makeText(MainActivity2.this, "价格需要大于0 !", Toast.LENGTH_SHORT).show();return;}Intent intent = new Intent(MainActivity2.this,MainActivity.class);intent.putExtra("book",new Book(bookName,Float.valueOf(bookPrice)));intent.putExtra("position",position);setResult(RESULT_OK,intent);finish();}}

main_menu.xml:

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"><item android:id="@+id/edit"android:title="编辑"/><item android:id="@+id/delete"android:title="删除"/></menu>

在这里插入图片描述

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半期考试二三题 (书籍维护数据库）

主活动xml

MainActivity2 xml

书籍实体类

数据库操作类：

主活动 .java

MainActivity2 .java

半期考试二三题 (书籍维护数据库）相关推荐

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半期考试 二三题 (书籍维护 数据库）

主活动xml

MainActivity2 xml

书籍实体类

数据库操作类：

主活动 .java

MainActivity2 .java

半期考试 二三题 (书籍维护 数据库）相关推荐

最新文章

热门文章

半期考试二三题 (书籍维护数据库）

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