半期考试 第一题（加法器）

Posted 2022-11-23 梦想家哈儿和他的bug

结构：

主活动xml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:orientation="vertical">

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

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="数字一" />

        <EditText
            android:id="@+id/editText_one"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="Please input one"
            android:inputType="textPersonName" />

    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="数字二" />
        <EditText
            android:id="@+id/editText_two"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="Please input two"
            android:inputType="number"
            />

    </LinearLayout>

    <TextView
        android:id="@+id/num_result"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="10dp"
        android:layout_marginTop="10dp"
        android:text="Result is :" />

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

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

        <Button
            android:id="@+id/history"
            android:text="历史"
            android:layout_marginLeft="50dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>

    </LinearLayout>

</LinearLayout>

历史活动代码：

<?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"
    tools:context=".HistoryActivity">

    <ListView
        android:id="@+id/id_listview"
        android:layout_width="395dp"
        android:layout_height="715dp"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="16dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</LinearLayout>

主活动.java

package com.example.thefirst;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity 

    private EditText editText_one;
    private EditText editText_two;
    private TextView textView_result;
    private Button btn_add;
    private Button btn_his;
    private ArrayList<String> res_list;
    @Override
    protected void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        init();

    
    public void init()
        editText_one = findViewById(R.id.editText_one);
        editText_two = findViewById(R.id.editText_two);
        textView_result = findViewById(R.id.num_result);
        res_list = new ArrayList<>();
        btn_add = findViewById(R.id.add);
        btn_his = findViewById(R.id.history);
        btn_his.setOnClickListener(new View.OnClickListener() 
            @Override
            public void onClick(View v) 
                Intent intent = new Intent(MainActivity.this, HistoryActivity.class);
                //intent.putStringArrayListExtra("history",res_list);
                startActivity(intent);
            
        );
    

    public void add(View v)
        int add_one = Integer.valueOf(editText_one.getText().toString());
        int add_two = Integer.valueOf(editText_two.getText().toString());
        int result = add_one+add_two;
        res_list.add(add_one+" + "+add_two+" = "+result);
        textView_result.setText("Result is："+result);
        saveHistory();
    

    public void saveHistory()
        SharedPreferences.Editor editor = getSharedPreferences("historyDataList", MODE_PRIVATE).edit();
        editor.putInt("historyNum",res_list.size());
        for(int i=0;i<res_list.size();i++)
            editor.putString("item_"+i,res_list.get(i));
        
        editor.apply();
        // editor.commit();
    

历史活动.java

package com.example.thefirst;

import androidx.appcompat.app.AppCompatActivity;

import android.content.SharedPreferences;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;

import java.util.ArrayList;

public class HistoryActivity extends AppCompatActivity 

    private ArrayList<String> history = new ArrayList<>();
    private ListView listView;
    @Override
    protected void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_history);
        listView = findViewById(R.id.id_listview);
        SharedPreferences pref = getSharedPreferences("historyDataList", MODE_PRIVATE);
        int size = pref.getInt("historyNum",0);
        for(int i=0;i<size;i++)
            history.add(pref.getString("item_"+i,""));
        
        ArrayAdapter<String> adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, history);
        listView.setAdapter(adapter);