exam02-3

activity_main.xml

<?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:orientation="vertical">

    <ListView
        android:id="@+id/listView"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />

    <Button
        android:id="@+id/add"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:onClick="btnAdd"
        android:text="Add" />

</LinearLayout>

activity_main2.xml

<?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:layout_margin="10dp"
    android:orientation="vertical">

    <EditText
        android:id="@+id/book_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="输入书名：" />

    <EditText
        android:id="@+id/book_price"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="输入价格："
        android:inputType="number"/>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <LinearLayout
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1">

            <Button
                android:id="@+id/button_cancel"
                android:layout_width="wrap_content"
                android:layout_height="match_parent"
                android:onClick="cancel"
                android:text="取消" />

        </LinearLayout>

        <Button
            android:id="@+id/button_ok"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="confirm"
            android:text="确定" />

    </LinearLayout>

</LinearLayout>

MainActivity.java

package com.example.exam02_03;

import android.content.ContentValues;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
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;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        intent = new Intent(MainActivity.this,Main2Activity.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() {
            @Override
            public 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() {
                    @Override
                    public 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);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable 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();
                }
            }
        }
    }
}

Main2Activity.java

package com.example.exam02_03;

import android.content.Intent;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class Main2Activity extends AppCompatActivity {

    private EditText book_name;
    private EditText book_price;
    private int position;

    private  String bookName;
    private String bookPrice;
    @Override
    protected 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);

//        Intent intent = getIntent();
//        position = intent.getIntExtra("position",0);
//        Book book1= (Book)intent.getSerializableExtra("bookToUpdate");
//        book_name.setText(book1.getBookName());
//        book_price.setText(book1.getBookPrice()+"");

    }

    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(Main2Activity.this,"书名不能为空！",Toast.LENGTH_LONG).show();
            return;
        }
        if(bookPrice.isEmpty()){
            book_name.setText("");
            book_price.setText("");
            Toast.makeText(Main2Activity.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(Main2Activity.this, "价格需要大于0 !", Toast.LENGTH_SHORT).show();
            return;
        }

        Intent intent = new Intent(Main2Activity.this,MainActivity.class);
        intent.putExtra("book",new Book(bookName,Float.valueOf(bookPrice)));
        intent.putExtra("position",position);
        setResult(RESULT_OK,intent);
        finish();
    }


}

Book.java

package com.example.exam02_03;

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;
    }
}

SQLHelper.java

package com.example.exam02_03;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class SQLHelper extends SQLiteOpenHelper {

    public static final String BookTable = "book";
    public SQLHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
        super(context, name, factory, version);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table book(_id integer primary key autoincrement,name text,price text)");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }
}