【android】安卓大作业「课程日历」

项目要求

项目: 课程日历
-项目概况： 项目记录一周的课程信息。
?用户可以编辑周一～周五的课程表（每天最多安排5门课程） ；
?用户可以按日查看课程表。
-项目要求：
?项目包含2个活动及其对应的布局：
①　显示课程活动：单击“周一”～“周五”按钮中的一个，按时间顺序显示当日的课程信息（上课时间、课程名称、教室）；单击“编辑”按钮，进入下一个活动；
②　编辑课程活动：针对选定的周几，可以新增、修改或删除当日的课程。编辑完毕后，用户单击“保存”按钮则更新当日课程表，或单击“撤销”按钮取消刚才的编辑操作，或单击“返回”按钮，回到显示课程活动。
?布局设计：
①　显示课程活动布局：选用合适的视图控件显示课程信息；
②　编辑课程活动布局：选用恰当的视图控件提供课程编辑方式。
?功能设计：
①　能完成活动之间的跳转；
②　用数据库、数据表存储课程信息；
③　能编辑和查询单日课程信息。

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项目流程图

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结果展示

原始界面：
?

点击周一按钮后界面：（其余周数就不进行展示了，差不多）

选中周数后点击编辑按钮：

没有选中周数就点击编辑按钮出现的提示Toast：

输入相关课程信息后点击新增按钮：

在新增后点击撤销按钮：

在之前没有编辑操作或者已经撤销一次之后再次点击撤销会弹出提示：

三个editview如果有一个为空时点击新增按钮会出现的提示：

一天内课程数为5再点击新建：

点击listview中的课程会进行提示：

在选中课程之后点击删除按钮：

在删除操作后点击撤销按钮：

在没有选中课程就点击删除按钮出现的提示：

在选中第一个课程后并且在输入框中输入新的时间以及教室后点击保存按钮：

在保存之后点击撤销按钮：

点击返回按钮：

UI设计

在MainActivity中有使用六个按钮，分别对应的是周一，周二，周三，周四，周五和返回。在下方还有一个listview，用来显示查询出来的课程信息。
listView对应的layout使用的也是相对布局，包含三个TextView，用来分别显示课程的名称，时间以及上课教室。
EditActivity里面包含一个listview，用来显示查询出来的课程信息以及供用户进行选中，五个按钮，分别对应的是新增，删除，保存，撤销以及返回，还有一个textview用来对用户进行提示，3个EditText用来读取需要编辑的课程信息。
MainActivity：

EditActivity：

Listview的layout：

activity_main.xml代码

<?xml?version="1.0"?encoding="utf-8"?><androidx.constraintlayout.widget.ConstraintLayout?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=".MainActivity">

????<Button
????????android:id="@+id/button3"
????????android:layout_width="79dp"
????????android:layout_height="54dp"
????????android:text="周三"
????????android:textSize="20sp"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintHorizontal_bias="0.524"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="parent"
????????app:layout_constraintVertical_bias="0.048"?/>

????<Button
????????android:id="@+id/button4"
????????android:layout_width="79dp"
????????android:layout_height="54dp"
????????android:text="周四"
????????android:textSize="20sp"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintHorizontal_bias="0.762"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="parent"
????????app:layout_constraintVertical_bias="0.048"?/>

????<Button
????????android:id="@+id/button2"
????????android:layout_width="79dp"
????????android:layout_height="54dp"
????????android:text="周二"
????????android:textSize="20sp"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintHorizontal_bias="0.286"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="parent"
????????app:layout_constraintVertical_bias="0.048"?/>

????<Button
????????android:id="@+id/button1"
????????android:layout_width="79dp"
????????android:layout_height="54dp"
????????android:text="周一"
????????android:textSize="20sp"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintHorizontal_bias="0.048"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="parent"
????????app:layout_constraintVertical_bias="0.048"?/>

????<Button
????????android:id="@+id/button5"
????????android:layout_width="79dp"
????????android:layout_height="54dp"
????????android:text="周五"
????????android:textSize="20sp"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintHorizontal_bias="0.996"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="parent"
????????app:layout_constraintVertical_bias="0.048"?/>

????<ListView
????????android:id="@+id/list1"
????????android:layout_width="413dp"
????????android:layout_height="367dp"
????????android:layout_marginTop="104dp"
????????app:layout_constraintTop_toTopOf="parent"
????????tools:layout_editor_absoluteX="-1dp"?/>

????<Button
????????android:id="@+id/buttonEdit"
????????android:layout_width="wrap_content"
????????android:layout_height="wrap_content"
????????android:text="编辑"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintHorizontal_bias="0.498"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="parent"
????????app:layout_constraintVertical_bias="0.953"?/></androidx.constraintlayout.widget.ConstraintLayout>12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879808182838485868788899091929394

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activity_edit.xml代码

<?xml?version="1.0"?encoding="utf-8"?><androidx.constraintlayout.widget.ConstraintLayout?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=".EditActivity">

????<TextView
????????android:id="@+id/textView3"
????????android:layout_width="wrap_content"
????????android:layout_height="wrap_content"
????????android:text="时间："
????????android:textSize="24sp"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintHorizontal_bias="0.233"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="parent"
????????app:layout_constraintVertical_bias="0.615"?/>

????<Button
????????android:id="@+id/buttonDelete"
????????android:layout_width="103dp"
????????android:layout_height="57dp"
????????android:text="删除"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintHorizontal_bias="0.334"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="parent"
????????app:layout_constraintVertical_bias="0.905"?/>

????<Button
????????android:id="@+id/buttonZ"
????????android:layout_width="103dp"
????????android:layout_height="57dp"
????????android:text="撤销"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintHorizontal_bias="1.0"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="parent"
????????app:layout_constraintVertical_bias="0.905"?/>

????<Button
????????android:id="@+id/buttonAdd"
????????android:layout_width="103dp"
????????android:layout_height="57dp"
????????android:text="新增"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintHorizontal_bias="0.0"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="parent"
????????app:layout_constraintVertical_bias="0.905"?/>

????<Button
????????android:id="@+id/buttonSave"
????????android:layout_width="103dp"
????????android:layout_height="57dp"
????????android:text="保存"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintHorizontal_bias="0.668"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="parent"
????????app:layout_constraintVertical_bias="0.905"?/>

????<ListView
????????android:id="@+id/list2"
????????android:layout_width="411dp"
????????android:layout_height="282dp"
????????tools:layout_editor_absoluteX="0dp"
????????tools:layout_editor_absoluteY="0dp"?/>

????<TextView
????????android:id="@+id/textView"
????????android:layout_width="wrap_content"
????????android:layout_height="wrap_content"
????????android:text="如需修改，请先选中其中一节课"
????????android:textSize="20sp"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="@+id/list2"
????????app:layout_constraintVertical_bias="0.802"?/>

????<EditText
????????android:id="@+id/editTextTime"
????????android:layout_width="wrap_content"
????????android:layout_height="wrap_content"
????????android:ems="10"
????????android:inputType="textPersonName"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintHorizontal_bias="0.781"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="@+id/list2"
????????app:layout_constraintVertical_bias="0.607"?/>

????<EditText
????????android:id="@+id/editTextName"
????????android:layout_width="wrap_content"
????????android:layout_height="wrap_content"
????????android:ems="10"
????????android:inputType="textPersonName"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintHorizontal_bias="0.781"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="parent"
????????app:layout_constraintVertical_bias="0.507"?/>

????<EditText
????????android:id="@+id/editTextRoom"
????????android:layout_width="wrap_content"
????????android:layout_height="wrap_content"
????????android:ems="10"
????????android:inputType="textPersonName"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintHorizontal_bias="0.786"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="@+id/list2"
????????app:layout_constraintVertical_bias="0.699"?/>

????<TextView
????????android:id="@+id/textView4"
????????android:layout_width="wrap_content"
????????android:layout_height="wrap_content"
????????android:text="教室："
????????android:textSize="24sp"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintHorizontal_bias="0.233"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="parent"
????????app:layout_constraintVertical_bias="0.705"?/>

????<TextView
????????android:id="@+id/textView2"
????????android:layout_width="wrap_content"
????????android:layout_height="wrap_content"
????????android:text="课程名："
????????android:textSize="24sp"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintHorizontal_bias="0.174"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="parent"
????????app:layout_constraintVertical_bias="0.516"?/>

????<Button
????????android:id="@+id/buttonBack"
????????android:layout_width="wrap_content"
????????android:layout_height="wrap_content"
????????android:text="返回"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintHorizontal_bias="0.498"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="parent"
????????app:layout_constraintVertical_bias="0.992"?/></androidx.constraintlayout.widget.ConstraintLayout>123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166

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activity_class.xml代码

<?xml?version="1.0"?encoding="utf-8"?><androidx.constraintlayout.widget.ConstraintLayout?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">

????<TextView
????????android:id="@+id/textViewName"
????????android:layout_width="151dp"
????????android:layout_height="58dp"
????????android:text="TextView"
????????android:textSize="20sp"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintHorizontal_bias="0.026"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="parent"
????????app:layout_constraintVertical_bias="0.021"?/>

????<TextView
????????android:id="@+id/textViewTime"
????????android:layout_width="107dp"
????????android:layout_height="46dp"
????????android:text="TextView"
????????android:textSize="34sp"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintHorizontal_bias="0.527"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="parent"
????????app:layout_constraintVertical_bias="0.023"?/>

????<TextView
????????android:id="@+id/textViewRoom"
????????android:layout_width="108dp"
????????android:layout_height="44dp"
????????android:text="TextView"
????????android:textSize="34sp"
????????app:layout_constraintBottom_toBottomOf="parent"
????????app:layout_constraintEnd_toEndOf="parent"
????????app:layout_constraintHorizontal_bias="0.881"
????????app:layout_constraintStart_toStartOf="parent"
????????app:layout_constraintTop_toTopOf="parent"
????????app:layout_constraintVertical_bias="0.023"?/></androidx.constraintlayout.widget.ConstraintLayout>1234567891011121314151617181920212223242526272829303132333435363738394041424344454647

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功能设计

简单功能说明

在MainActivity中有一个编辑按钮，按下可以跳转到EditActivity中。其中的Intent包括了Bundle，里面存储着当前选中的日子中从数据库查询出来的课程信息总和，即list_class（因为需要传递的数据是Arraylist类型的，所以首先需要把Class类Parcel化了才行）,以及所选的是周几。
在EditActivity中接收来自MainActivity传递过来的Intent，并读取其中包含的Bundle中的课程数据，并展示在listview2中。
EditActivity中有个返回按钮，按下可以通过Intent重新回到MainActivity中
我创建了一个类，MyHelper，来当做调用SQLite数据库的工具类。在里面的onCreate方法里创建数据表，以及插入一些基本课程信息。
在进入EditActivity界面后，我设置了四个按钮新增，删除，保存，撤销。分别对应不同的方法来进行数据库操作。
在点击新增按钮之后，会首先进行判断，是否三个textview都不为空，一旦有一个为空就会提示用户“不能为空”并且终止操作，因为一旦不进行检测会导致空数据的存入。如都不为空，就将三个editview中的数据传入到insert方法中，调用MyHelper中的getWritableDatabase方法来获取db，将课程信息存入values中，再通过db.insert存入数据库中。然后把课程信息加入到list_class中（这样才可以实现listview的动态刷新），接着调用MyAdapter的notifyDataSetChanged方法来刷新listview，显示新增的课程。

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以下代码附有注释

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MainActivity.java代码

package?com.example.a2022finalproject;import?androidx.appcompat.app.AppCompatActivity;import?android.annotation.SuppressLint;import?android.content.Context;import?android.content.Intent;import?android.database.Cursor;import?android.database.sqlite.SQLiteDatabase;import?android.os.Bundle;import?android.os.Parcelable;import?android.view.LayoutInflater;import?android.view.View;import?android.view.ViewGroup;import?android.widget.BaseAdapter;import?android.widget.Button;import?android.widget.ListView;import?android.widget.TextView;import?android.widget.Toast;import?java.util.ArrayList;import?java.util.Collections;import?java.util.Comparator;import?java.util.List;public?class?MainActivity?extends?AppCompatActivity?implements?View.OnClickListener?{
????private?Button?btn1,?btn2,?btn3,?btn4,?btn5,?btn6;
????private?ListView?lv;
????private?MyHelper?myHelper?=?new?MyHelper(this);
????private?MyAdapter?ma?=?new?MyAdapter();
????private?String?weekNo?=?"0";
????//Class类信息的存储对象
????private?List<Class>?list_class?=?new?ArrayList<>();
????@Override
????protected?void?onCreate(Bundle?savedInstanceState)?{
????????super.onCreate(savedInstanceState);
????????setContentView(R.layout.activity_main);
????????//初始化
????????init();
????}
????//?初始化
????public?void?init()?{
????????btn1?=?findViewById(R.id.button1);
????????btn2?=?findViewById(R.id.button2);
????????btn3?=?findViewById(R.id.button3);
????????btn4?=?findViewById(R.id.button4);
????????btn5?=?findViewById(R.id.button5);
????????btn6?=?findViewById(R.id.buttonEdit);
????????lv?=?findViewById(R.id.list1);
????????btn1.setOnClickListener(this);
????????btn2.setOnClickListener(this);
????????btn3.setOnClickListener(this);
????????btn4.setOnClickListener(this);
????????btn5.setOnClickListener(this);
????????btn6.setOnClickListener(this);
????}

????//?查找数据库中的课程信息
????@SuppressLint("Range")
????public?void?query(String?day)?{
????????SQLiteDatabase?db?=?myHelper.getReadableDatabase();
????????Cursor?cursor?=?db.query("class",?null,?"weekNo=?",?new?String[]{day},?null,?null,?null);
????????if?(cursor.getCount()?!=?0)?{
????????????while?(cursor.moveToNext())?{
????????????????//?加入list_class中存储
????????????????list_class.add(new?Class(day,?cursor.getString(cursor.getColumnIndex("name")),?cursor.getString(cursor.getColumnIndex("time")),?cursor.getString(cursor.getColumnIndex("room"))));
????????????}
????????}
????????db.close();
????}
????//?按照时间排序函数
????public?static?class?TimeSort?implements?Comparator<Class>?{
????????@Override
????????public?int?compare(Class?aClass,?Class?t1)?{
????????????return?aClass.getTime().compareTo(t1.getTime());
????????}
????}

????@Override
????public?void?onClick(View?view)?{
????????switch?(view.getId())?{
????????????//?周一
????????????case?R.id.button1:
????????????????weekNo?=?"1";
????????????????list_class?=?new?ArrayList<>();
????????????????query("1");
????????????????Collections.sort(list_class,?new?TimeSort());//按照时间排序
????????????????lv.setAdapter(ma);//显示在listview中
????????????????break;
????????????//?周二
????????????case?R.id.button2:
????????????????weekNo?=?"2";
????????????????list_class?=?new?ArrayList<>();
????????????????query("2");
????????????????Collections.sort(list_class,?new?TimeSort());
????????????????lv.setAdapter(ma);
????????????????break;
????????????//?周三
????????????case?R.id.button3:
????????????????weekNo?=?"3";
????????????????list_class?=?new?ArrayList<>();
????????????????query("3");
????????????????Collections.sort(list_class,?new?TimeSort());
????????????????lv.setAdapter(ma);
????????????????break;
????????????//?周四
????????????case?R.id.button4:
????????????????weekNo?=?"4";
????????????????list_class?=?new?ArrayList<>();
????????????????query("4");
????????????????Collections.sort(list_class,?new?TimeSort());
????????????????lv.setAdapter(ma);
????????????????break;
????????????//?周五
????????????case?R.id.button5:
????????????????weekNo?=?"5";
????????????????list_class?=?new?ArrayList<>();
????????????????query("5");
????????????????Collections.sort(list_class,?new?TimeSort());
????????????????lv.setAdapter(ma);
????????????????break;
????????????//?修改课程信息
????????????case?R.id.buttonEdit:
????????????????//?判断是否选中了某一天
????????????????if?(weekNo?==?"0"){
????????????????????Toast.makeText(this,?"请先选择一天从而进行编辑操作",?Toast.LENGTH_LONG).show();
????????????????}
????????????????else{
????????????????????//?因为需要传递的数据时ArrayList所以需要使用Bundle来进行传递
????????????????????Intent?intent?=?new?Intent(MainActivity.this,?EditActivity.class);
????????????????????Bundle?bundle?=?new?Bundle();
????????????????????//?注意，对应的Class类需要进行Parcelable化
????????????????????bundle.putParcelableArrayList("list_class",?(ArrayList<??extends?Parcelable>)?list_class);
????????????????????bundle.putString("weekNo",?weekNo);
????????????????????intent.putExtras(bundle);
????????????????????startActivity(intent);
????????????????}
????????????????break;
????????}
????}

????public?class?MyAdapter?extends?BaseAdapter?{
????????@Override
????????public?int?getCount()?{
????????????return?list_class.size();
????????}

????????@Override
????????public?Object?getItem(int?i)?{
????????????return?list_class.get(i);
????????}

????????@Override
????????public?long?getItemId(int?i)?{
????????????return?i;
????????}

????????@Override
????????public?View?getView(int?i,?View?view,?ViewGroup?viewGroup)?{
????????????//?配置listview中的显示效果
????????????View?newView?=?View.inflate(MainActivity.this,?R.layout.activity_class,?null);
????????????TextView?textView1?=?newView.findViewById(R.id.textViewName);
????????????TextView?textView2?=?newView.findViewById(R.id.textViewTime);
????????????TextView?textView3?=?newView.findViewById(R.id.textViewRoom);
????????????textView1.setText(list_class.get(i).getName());
????????????textView2.setText(list_class.get(i).getTime());
????????????textView3.setText(list_class.get(i).getRoom());
????????????return?newView;
????????}
????}}123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171

EditActivity.java代码

package?com.example.a2022finalproject;import?androidx.appcompat.app.AppCompatActivity;import?android.content.ContentValues;import?android.content.Intent;import?android.database.sqlite.SQLiteDatabase;import?android.os.Bundle;import?android.view.View;import?android.view.ViewGroup;import?android.widget.AdapterView;import?android.widget.BaseAdapter;import?android.widget.Button;import?android.widget.EditText;import?android.widget.ListView;import?android.widget.TextView;import?android.widget.Toast;import?java.util.ArrayList;import?java.util.Collections;import?java.util.Comparator;import?java.util.List;public?class?EditActivity?extends?AppCompatActivity?implements?View.OnClickListener?{
????private?Button?btnAdd,?btnDelete,?btnZ,?btnSave,?btnBack;
????private?EditText?etName,?etTime,?etRoom;
????private?ListView?list2;
????private?List<Class>?list_class?=?new?ArrayList<>();
????private?MyAdapter?ma?=?new?MyAdapter();
????private?MyHelper?myHelper?=?new?MyHelper(this);
????private?String?name,?time,?room,?weekNo;
????private?int?chosenItem?=?-1;//?选中的课程序号
????private?int?showItem;
????private?String?changedIndex?=?"0";//0代表先前没有进行操作
????private?Class?changedItem,?changedItem2;

????@Override
????protected?void?onCreate(Bundle?savedInstanceState)?{
????????super.onCreate(savedInstanceState);
????????setContentView(R.layout.activity_edit);
????????init();
????}
????//初始化
????public?void?init()?{
????????btnAdd?=?findViewById(R.id.buttonAdd);
????????btnDelete?=?findViewById(R.id.buttonDelete);
????????btnZ?=?findViewById(R.id.buttonZ);
????????btnSave?=?findViewById(R.id.buttonSave);
????????btnBack?=?findViewById(R.id.buttonBack);
????????list2?=?findViewById(R.id.list2);
????????//设置listview的点击实践，实现点击课程记录下它对应的序号
????????list2.setOnItemClickListener(new?AdapterView.OnItemClickListener()?{
????????????@Override
????????????public?void?onItemClick(AdapterView<?>?adapterView,?View?view,?int?i,?long?l)?{
????????????????chosenItem?=?i;
????????????????showItem?=?chosenItem?+?1;
????????????????Toast.makeText(EditActivity.this,?"你已选中第"?+?showItem?+?"项",?Toast.LENGTH_SHORT).show();
????????????}
????????});
????????btnAdd.setOnClickListener(this);
????????btnDelete.setOnClickListener(this);
????????btnZ.setOnClickListener(this);
????????btnSave.setOnClickListener(this);
????????btnBack.setOnClickListener(this);
????????etName?=?findViewById(R.id.editTextName);
????????etTime?=?findViewById(R.id.editTextTime);
????????etRoom?=?findViewById(R.id.editTextRoom);
????????//接受来自MainActivity中的信息
????????Intent?intent?=?getIntent();
????????Bundle?bundle?=?intent.getExtras();
????????list_class?=?bundle.getParcelableArrayList("list_class");
????????weekNo?=?bundle.getString("weekNo");
????????//展示在list2中
????????list2.setAdapter(ma);
????}

????//插入方法
????private?boolean?insert(String?name,?String?time,?String?room)?{
????????changedIndex?=?"insert";//记录本次操作，便于撤销
????????SQLiteDatabase?db?=?myHelper.getWritableDatabase();
????????ContentValues?values?=?new?ContentValues();
????????values.put("weekNo",?weekNo);
????????values.put("name",?name);
????????values.put("time",?time);
????????values.put("room",?room);
????????long?id?=?db.insert("class",?null,?values);
????????db.close();
????????Class?classNew?=?new?Class(weekNo,?name,?time,?room);
????????//需要同时对list_class中的进行修改，不然notifyDataSetChanged方法不会生效，就不能实现动态刷新
????????list_class.add(classNew);
????????Collections.sort(list_class,?new?MainActivity.TimeSort());//时间排序
????????changedItem?=?classNew;//记录下插入的课程信息，便于撤销时删除
????????ma.notifyDataSetChanged();//刷新listview
????????return?id?>?0;
????}

????//用于撤销中对应删除的反操作
????private?boolean?insert(Class?item)?{
????????SQLiteDatabase?db?=?myHelper.getWritableDatabase();
????????ContentValues?values?=?new?ContentValues();
????????values.put("weekNo",?weekNo);
????????values.put("name",?item.getName());
????????values.put("time",?item.getTime());
????????values.put("room",?item.getRoom());
????????long?id?=?db.insert("class",?null,?values);
????????db.close();
????????list_class.add(item);
????????Collections.sort(list_class,?new?MainActivity.TimeSort());
????????ma.notifyDataSetChanged();
????????changedIndex?=?"0";//重置操作信息，避免多次撤销
????????return?id?>?0;
????}

????//删除操作
????private?boolean?delete(int?chosenItem)?{
????????changedIndex?=?"delete";//记录操作
????????Class?item?=?(Class)?list2.getItemAtPosition(chosenItem);
????????changedItem?=?item;//记录删除的课程信息
????????SQLiteDatabase?db?=?myHelper.getWritableDatabase();
????????long?id?=?db.delete("class",?"name?=???and?weekNo?=??",?new?String[]{item.getName(),?weekNo});
????????db.close();
????????//动态刷新
????????list_class.remove(item);
????????ma.notifyDataSetChanged();
????????return?id?>?0;
????}
????//用于撤销中的新增的反操作
????private?boolean?delete(Class?item)?{
????????SQLiteDatabase?db?=?myHelper.getWritableDatabase();
????????long?id?=?db.delete("class",?"name?=???and?weekNo?=??",?new?String[]{item.getName(),?weekNo});
????????db.close();
????????list_class.remove(item);
????????ma.notifyDataSetChanged();
????????changedIndex?=?"0";
????????return?id?>?0;
????}

????//保存操作，即update
????private?boolean?save(String?name,?String?time,?String?room)?{
????????changedIndex?=?"save";//记录操作
????????Class?item?=?(Class)?list2.getItemAtPosition(chosenItem);
????????changedItem?=?item;//记录修改的原课程信息
????????SQLiteDatabase?db?=?myHelper.getWritableDatabase();
????????ContentValues?values?=?new?ContentValues();
????????Class?item2?=?new?Class();//记录更新后的课程信息
????????if?(!name.isEmpty()){//对于为空的字段判断为不进行修改，保持原状
????????????values.put("name",?name);
????????????item2.setName(name);
????????}else{
????????????item2.setName(item.getName());
????????}
????????if?(!time.isEmpty()){
????????????values.put("time",?time);
????????????item2.setTime(time);
????????}else{
????????????item2.setTime(item.getTime());
????????}
????????if?(!room.isEmpty()){
????????????values.put("room",?room);
????????????item2.setRoom(room);
????????}else{
????????????item2.setRoom(item.getRoom());
????????}
????????//通过周几和课程名称来确定一门课程
????????int?updateCount?=?db.update("class",?values,?"name?=???and?time?=??",?new?String[]{item.getName(),?item.getTime()});
????????db.close();
????????//动态刷新
????????list_class.remove(item);
????????list_class.add(item2);
????????Collections.sort(list_class,?new?MainActivity.TimeSort());
????????changedItem2?=?item2;
????????ma.notifyDataSetChanged();
????????return?updateCount?>?0;
????}

????//用于撤销操作中保存操作的反操作
????private?boolean?save(Class?item,?Class?item2)?{
????????SQLiteDatabase?db?=?myHelper.getWritableDatabase();
????????ContentValues?values?=?new?ContentValues();
????????if(item.getName()?!=?item2.getName()){
????????????values.put("name",?item.getName());
????????}
????????if(item.getTime()?!=?item2.getTime()){
????????????values.put("time",?item.getTime());
????????}
????????if(item.getRoom()?!=?item2.getRoom()){
????????????values.put("room",?item.getRoom());
????????}
????????int?updateCount?=?db.update("class",?values,?"name?=???and?time?=??",?new?String[]{item2.getName(),?item2.getTime()});
????????db.close();
????????//动态刷新
????????list_class.remove(item2);
????????list_class.add(item);
????????Collections.sort(list_class,?new?MainActivity.TimeSort());
????????ma.notifyDataSetChanged();
????????changedIndex?=?"0";//还原操作标记
????????return?updateCount?>?0;
????}

????@Override
????public?void?onClick(View?view)?{
????????switch?(view.getId())?{
????????????case?R.id.buttonAdd:
????????????????if(list_class.size()?>=?5){
????????????????????Toast.makeText(EditActivity.this,?"新建失败，课程最多一天5门",?Toast.LENGTH_SHORT).show();
????????????????????break;
????????????????}
????????????????name?=?etName.getText().toString().trim();
????????????????time?=?etTime.getText().toString().trim();
????????????????room?=?etRoom.getText().toString().trim();
????????????????if(name.isEmpty()?||?time.isEmpty()?||?room.isEmpty()){//判断是否为空，避免插入空信息的课程
????????????????????Toast.makeText(EditActivity.this,?"课程名称，时间，教室不能为空",?Toast.LENGTH_SHORT).show();
????????????????????break;
????????????????}
????????????????if?(insert(name,?time,?room))?{
????????????????????Toast.makeText(EditActivity.this,?"新增成功",?Toast.LENGTH_SHORT).show();
????????????????}
????????????????break;
????????????case?R.id.buttonDelete:
????????????????if?(chosenItem?==?-1){//判断是否选中了课程
????????????????????Toast.makeText(EditActivity.this,?"请先选择一节课",?Toast.LENGTH_SHORT).show();
????????????????}else{
????????????????????if?(delete(chosenItem))?{
????????????????????????changedIndex?=?"-1";?//?重置，防止误删
????????????????????????Toast.makeText(EditActivity.this,?"删除成功",?Toast.LENGTH_SHORT).show();
????????????????????}
????????????????}
????????????????break;
????????????case?R.id.buttonZ:
????????????????if(changedIndex?==?"0"){//判断是否进行过操作
????????????????????Toast.makeText(EditActivity.this,?"没有需要撤回的操作",?Toast.LENGTH_SHORT).show();
????????????????}else?if(changedIndex?==?"insert"){
????????????????????if(delete(changedItem)){
????????????????????????Toast.makeText(EditActivity.this,?"撤回新增成功",?Toast.LENGTH_SHORT).show();
????????????????????}
????????????????}else?if(changedIndex?==?"delete"){
????????????????????if(insert(changedItem)){
????????????????????????Toast.makeText(EditActivity.this,?"撤回删除成功",?Toast.LENGTH_SHORT).show();
????????????????????}

????????????????}else?if(changedIndex?==?"save"){
????????????????????if(save(changedItem,?changedItem2)){
????????????????????????Toast.makeText(EditActivity.this,?"撤回保存成功",?Toast.LENGTH_SHORT).show();
????????????????????}
????????????????}
????????????????break;
????????????case?R.id.buttonSave:
????????????????if?(chosenItem?==?-1){//判断是否选中课
????????????????????Toast.makeText(EditActivity.this,?"请先选择一节课",?Toast.LENGTH_SHORT).show();
????????????????}else{
????????????????????name?=?etName.getText().toString().trim();
????????????????????time?=?etTime.getText().toString().trim();
????????????????????room?=?etRoom.getText().toString().trim();
????????????????????if?(save(name,?time,?room))?{
????????????????????????Toast.makeText(EditActivity.this,?"保存成功",?Toast.LENGTH_SHORT).show();
????????????????????}
????????????????}
????????????????break;
????????????case?R.id.buttonBack:
????????????????Intent?intent?=?new?Intent(EditActivity.this,?MainActivity.class);
????????????????startActivity(intent);
????????????????break;
????????}
????}

????public?class?MyAdapter?extends?BaseAdapter?{
????????@Override
????????public?int?getCount()?{
????????????return?list_class.size();
????????}

????????@Override
????????public?Object?getItem(int?i)?{
????????????return?list_class.get(i);
????????}

????????@Override
????????public?long?getItemId(int?i)?{
????????????return?i;
????????}

????????@Override
????????public?View?getView(int?i,?View?view,?ViewGroup?viewGroup)?{
????????????View?newView?=?View.inflate(EditActivity.this,?R.layout.activity_class,?null);
????????????TextView?textView1?=?newView.findViewById(R.id.textViewName);
????????????TextView?textView2?=?newView.findViewById(R.id.textViewTime);
????????????TextView?textView3?=?newView.findViewById(R.id.textViewRoom);
????????????textView1.setText(list_class.get(i).getName());
????????????textView2.setText(list_class.get(i).getTime());
????????????textView3.setText(list_class.get(i).getRoom());
????????????return?newView;
????????}
????}}

Class.java代码

package?com.example.a2022finalproject;import?android.os.Parcel;import?android.os.Parcelable;public?class?Class?implements?Parcelable?{
????private?String?weekNo;
????private?String?name;
????private?String?time;
????private?String?room;
????public?Class(String?weekNo,?String?name,?String?time,?String?room){
????????this.weekNo?=?weekNo;
????????this.name?=?name;
????????this.time?=?time;
????????this.room?=?room;
????}
????public?Class(){

????}
????//Parcel
????protected?Class(Parcel?in)?{
????????weekNo?=?in.readString();
????????name?=?in.readString();
????????time?=?in.readString();
????????room?=?in.readString();
????}

????public?static?final?Creator<Class>?CREATOR?=?new?Creator<Class>()?{
????????@Override
????????public?Class?createFromParcel(Parcel?in)?{
????????????return?new?Class(in);
????????}

????????@Override
????????public?Class[]?newArray(int?size)?{
????????????return?new?Class[size];
????????}
????};

????public?String?getName(){
????????return?name;
????}
????public?void?setName(String?name){
????????this.name?=?name;
????}
????public?String?getWeekNo(){
????????return?weekNo;
????}
????public?void?setWeekNo(String?weekNo){
????????this.weekNo?=?weekNo;
????}
????public?String?getTime(){
????????return?time;
????}
????public?void?setTime(String?time){
????????this.time?=?time;
????}
????public?String?getRoom(){
????????return?room;
????}
????public?void?setRoom(String?room){
????????this.room?=?room;
????}

????@Override
????public?int?describeContents()?{
????????return?0;
????}

????@Override
????public?void?writeToParcel(Parcel?parcel,?int?i)?{
????????parcel.writeString(weekNo);
????????parcel.writeString(name);
????????parcel.writeString(time);
????????parcel.writeString(room);
????}}

MyHelper.java代码

package?com.example.a2022finalproject;import?android.content.ContentValues;import?android.content.Context;import?android.database.sqlite.SQLiteDatabase;import?android.database.sqlite.SQLiteOpenHelper;import?androidx.annotation.Nullable;import?java.sql.Time;//数据库操作类public?class?MyHelper?extends?SQLiteOpenHelper?{
????public?MyHelper(@Nullable?Context?context)?{
????????super(context,?"class.db",?null,?1);
????}

????@Override
????public?void?onCreate(SQLiteDatabase?db)?{
????????//初始化数据库，存入一些基本课程信息
????????db.execSQL("CREATE?TABLE?class(weekNo?VATCHAR(20),?name?VARCHAR(20),?time?VATCHAR(20),?room?VARCHAR(20))");
????????ContentValues?values?=?new?ContentValues();
????????values.put("weekNo",?"1");
????????values.put("name",?"Web应用程序开发");
????????values.put("time",?"09:40");
????????values.put("room",?"29-106");
????????db.insert("class",?null,?values);
????????values?=?new?ContentValues();
????????values.put("weekNo",?"1");
????????values.put("name",?"智能移动设备软件开发");
????????values.put("time",?"14:00");
????????values.put("room",?"29-106");
????????db.insert("class",?null,?values);
????????values?=?new?ContentValues();
????????values.put("weekNo",?"2");
????????values.put("name",?"编译原理实验");
????????values.put("time",?"10:35");
????????values.put("room",?"29-106");
????????db.insert("class",?null,?values);
????????values?=?new?ContentValues();
????????values.put("weekNo",?"2");
????????values.put("name",?"软件项目管理");
????????values.put("time",?"14:00");
????????values.put("room",?"23-213");
????????db.insert("class",?null,?values);
????????values?=?new?ContentValues();
????????values.put("weekNo",?"2");
????????values.put("name",?"软件项目管理实验");
????????values.put("time",?"15:40");
????????values.put("room",?"20-109");
????????db.insert("class",?null,?values);
????????values?=?new?ContentValues();
????????values.put("weekNo",?"3");
????????values.put("name",?"马克思主义基本原理");
????????values.put("time",?"08:00");
????????values.put("room",?"16-103");
????????db.insert("class",?null,?values);
????????values?=?new?ContentValues();
????????values.put("weekNo",?"4");
????????values.put("name",?"编译原理");
????????values.put("time",?"10:35");
????????values.put("room",?"23-319");
????????db.insert("class",?null,?values);
????????values?=?new?ContentValues();
????????values.put("weekNo",?"5");
????????values.put("name",?"Python与数据分析");
????????values.put("time",?"08:45");
????????values.put("room",?"25-315");
????????db.insert("class",?null,?values);
????????values?=?new?ContentValues();
????????values.put("weekNo",?"5");
????????values.put("name",?"Python与数据分析实验");
????????values.put("time",?"10:35");
????????values.put("room",?"20-206");
????????db.insert("class",?null,?values);
????}

????@Override
????public?void?onUpgrade(SQLiteDatabase?sqLiteDatabase,?int?i,?int?i1)?{

????}}

---

总结反思

1. 一开始困扰我的是关于listview的问题：就是在MainActivity中，尽管我的listview是放在中下方的位置的，距离顶部还有三分之一的距离，大小也做了限制，但是在实际运行过程中发现课程信息还是会显示在屏幕的最顶上，好像是没有做限制一样。想了半天不知道怎么一回事，后来发现只需要给listview加一个marginTop属性就可以解决这个问题了。

2. 第二个是关于跨Activity传递数据的问题，本来可以简单的直接使用Intent，然后putExtra就可以了，但是我发现好像这样是不能传递ArrayList类型的，所以我使用了bundle来存储ArrayList，然后发现这样的话需要将Class类Parcelabled才可以，这样才最终完成了将list_class传递给编辑界面的功能。

3. 第三个是关于怎么按照时间排序的，一开始没什么头绪，后来找到可以使用Collection.sort来搞定，不过需要写一个TimeSort的函数。

4. 第四个是怎么选中listview上的课程，因为删除和保存两个功能都是需要提前选中课程才可以进行操作的，所以怎么选中要进行操作的课程就是个问题了。后来发现可以给listview2设置点击监听器，通过setOnItemClickListener这个方法来设置，参数new一个AdapterView.OnItemClickListener实例，重写OnItemClick方法就可以实现了。

5. 第五个是怎么使得在我们对数据库课程信息做出了编辑操作之后实时在listview中体现出来。一开始我只是加了一个适配器的notifyDataSetChanged方法，但是发现并没有生效。原来是需要把list_class中的内容也更改了，这样才会使得可以实现动态刷新。

6. 第六个是在保存时，如果只是想修改课程时间，而不修改课程名称和教室，那么就需要重新输入一遍信息，要不然就会变成空白。所以后来我在save函数里加入了判断，如果edittext中为空白就不存入values中，这样也就解决了这个问题。

本项目我觉得还是有很多地方可以提升和改进的。比如可以在MainActivity中设置成左右滑切换哪一天。还有在EditActivity中可以给每一节课加一个单选框，这样相比起Toast来提示选择的哪一节课更直观。还有关于数据库的数据结构设计还可以更好一点（其实是依托答辩 ），添加主键可以防止出现一些错误。关于撤回可以设计成使用数据库的事务回滚来完成。