Question

我需要创建一个可以管理备忘录的程序。

创建＆＃34; MyMemoInfoList＆＃34;程序
- 通过MyMeMoEditor程序以列表形式打印出内容。（备忘录，标题，日期）
- 在选择项目后单击编辑按钮时，应在MyMemoEditor屏幕上显示详细内容，编辑完内容后，更新的内容将反映在列表中。
- 当您选择一个项目并单击删除按钮时，它将从列表中删除该项目。
- 如果按下添加按钮，它将弹出MyMemoEditor屏幕，您可以在其中输入内容并按保存按钮进行保存。此外，它应该出现在列表中。
创建MyMemoEditor程序。
- 在列表主屏幕上注册新备忘录时，将保存新备忘录。
- 执行编辑菜单时，它将更新原始备忘录。
MyMemoMain / MyMemoInfoList类的实现
- MyMemoMain班级＆＃39;事件应该以匿名的嵌套类形式实现。
- MyMemoInfoList类＆＃39;应该通过继承Listener来实现事件。

我认为我需要应用的方法是service，BroadcastReceiver，android UI，android UI事件和adapterview。

我很难切换不同的活动。

提前致谢。

Answer 1

首先，你的MyMemoInfoList.xml将如下所示：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MyMemoInfoList"
    android:orientation="vertical"
     >

    <ListView
        android:id="@+id/infolist"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
         >
    </ListView>


</LinearLayout>

=============================================== ================================= 接下来，您的editor.xml将如下所示（xml）：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MyMemoEditor" >

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

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

        <EditText
            android:id="@+id/memoId"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1" />
    </LinearLayout>



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

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

        <EditText
            android:id="@+id/title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1" />
    </LinearLayout>

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

    <EditText
        android:id="@+id/content"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_weight="1"
        android:lines="3" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="date(2014-02-XX)" />

    <EditText
        android:id="@+id/date"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" />

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

        <Button
            android:id="@+id/btnSave"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="save" 
            android:layout_weight="1"
            />


        <Button
            android:id="@+id/btnQuit"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="quit"
            android:layout_weight="1" />
    </LinearLayout>

</LinearLayout>

=============================================== ================================== 现在，让我们转到MyMemoInfoList（活动）：

package com.example.mymemomain2;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;

public class MyMemoInfoList extends Activity {
    ArrayAdapter<MemoItem> adt = null;
    ListView list = null;
    MemoItem currentItem = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_my_memo_info_list);

        MemoItemMgr.getInstance().open(this);

        adt = new ArrayAdapter<MemoItem>(this,
                android.R.layout.simple_list_item_single_choice,
                MemoItemMgr.getInstance().list);
        list = (ListView) findViewById(R.id.infolist);
        list.setAdapter(adt);
        list.setChoiceMode(ListView.CHOICE_MODE_SINGLE);

        list.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> listview, View textview,
                    int position, long arg3) {
                ArrayAdapter adapter = (ArrayAdapter) listview.getAdapter();

                currentItem = (MemoItem) adapter.getItem(position);

            }

        });
    }

    protected void onResume() {
        super.onResume();
        adt.notifyDataSetChanged();
    }

    @Override
    protected void onPause() {
        super.onPause();
        MemoItemMgr.getInstance().save(this);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        menu.add(0, #, 0, "add");
        menu.add(0, #, 0, "delete");
        menu.add(0, #, 0, "edit");
        menu.add(0, #, 0, "save");
        menu.add(0, #, 0, "send");
//# = consecutive integers starting from 1
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (item.getItemId() == #) {
            add();
        } else if (item.getItemId() == #) {
            delete();
        } else if (item.getItemId() == #) {
            goModify();
        } else if (item.getItemId() == #) {
            MemoItemMgr.getInstance().save(this);
        } else if (item.getItemId() == #) {
            MemoClient client = new MemoClient(MemoItemMgr.getInstance()
                    .getList());
            client.start();
        }

        return super.onOptionsItemSelected(item);
    }

    public void goHome(View v) {
        finish();

    }

    public void add() {
        Intent i = new Intent(MyMemoInfoList.this, MyMemoEditor.class);
        i.putExtra("mode", 0);
        startActivity(i);
    }

    public void delete() {
        int position = list.getCheckedItemPosition();
        if (position != -1) {
            MemoItem item = adt.getItem(position);
            adt.remove(item);
        } else {
            Toast.makeText(this, "Please make a selection to delete", Toast.LENGTH_SHORT).show();
        }

        // if (currentItem != null) {
        // adt.remove(currentItem);
        // }else {
        // Toast.makeText(this, "Please make a selection to delete", Toast.LENGTH_SHORT).show();
        // }
    }

    public void goModify() {
        if (currentItem != null) {

            Intent intent = new Intent(MyMemoInfoList.this, MyMemoEditor.class);

            intent.putExtra("mode", 1);
            intent.putExtra("id", currentItem.getMemoId());
            startActivity(intent);
            // finish();
        } else {
            Toast.makeText(this, "Please make a selection to edit", Toast.LENGTH_SHORT).show();
        }
    }
}

=============================================== ======================== 现在让我们来看看经理类（类）：

package com.example.mymemomain2;

import java.io.EOFException;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.StreamCorruptedException;
import java.util.ArrayList;
import java.util.DuplicateFormatFlagsException;
import java.util.Iterator;

import android.content.Context;

public class MemoItemMgr {
    private static String fileName = "memo.data";
    private static MemoItemMgr instance = new MemoItemMgr();

    public static MemoItemMgr getInstance(){
        return MemoItemMgr.instance;
    }

    int index = 0; 
    ArrayList<MemoItem> list = new ArrayList<MemoItem>();
    private MemoItemMgr(){

    }

    public void open(Context ctx){
        File file = new File(ctx.getFilesDir() , fileName);
        list.clear();
        if(file.exists()){
            ObjectInputStream in = null;
            try {
                in = new ObjectInputStream(ctx.openFileInput(fileName));
                while(true){
                    try{
                    MemoItem item = (MemoItem)in.readObject();
                    add(item);
                    }catch(EOFException e){
                    break;
                    } catch(DuplicateException e){

                    }
                }
            } catch (StreamCorruptedException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            } catch (FileNotFoundException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            } catch (IOException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }catch (ClassNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }finally{
                try {
                    in.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }else{
            try {
                add(new MemoItem(1, "Conference call", "Conf. call with international subsidiary", "2014-01-15"));
                add(new MemoItem(2, "Dev Meeting", "weekly updates", "2014-02-15"));
                add(new MemoItem(3, "blind date", "hosting a blind date", "2014-03-15"));
                add(new MemoItem(4, "alumni meeting", "Harvard alumni night", "2014-04-15"));
                add(new MemoItem(5, "colleague meeting", "MS meeting", "2014-05-15"));
                add(new MemoItem(6, "boys' night out", "Yale friends", "2014-06-15"));
            } catch (DuplicateException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }

    }

    public void save(Context ctx){
        ObjectOutputStream out = null;
        try{
        out = new ObjectOutputStream(ctx.openFileOutput(fileName, Context.MODE_WORLD_WRITEABLE));
        for(int i = 0 ; i < list.size(); i++){
                out.writeObject(list.get(i));
        }
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }finally{
                try{
                    out.close();
                }catch(IOException e){
                    e.printStackTrace();
                }
            }
        }



    public void add(MemoItem m)throws DuplicateException{
        if(search(m.getMemoId()) == null){
        list.add(m);    
        }else{
            throw new DuplicateException();
        }

    }

//  public void add(String title, String content, String date){
//      MemoItem item = new MemoItem(index++, title, content,date);
//      add(item);
//      
//  }

    public void update(int id, String title, String content, String date){
        MemoItem item = search(id);
        if(item != null){
            item.setTitle(title);
            item.setContent(content);
            item.setDate(date);
        }

    }


    public MemoItem search(int id){
        Iterator<MemoItem> iter = list.iterator();
        while(iter.hasNext()){
            MemoItem item = iter.next();
            if(id == item.getMemoId()){
                return item;
            }
        }
        return null;

    }

    public ArrayList<MemoItem> getList(){
        return list;
    }


}

=============================================== ================================= 接下来，让我们看一下MemoItem（类）设置变量并获取getters / setters / constructor / toString

package com.example.mymemomain2;

import java.io.Serializable;

public class MemoItem implements Serializable {

    private int memoId;
    private String title;
    private String content;
    private String date;

    public MemoItem(){

    }

    public MemoItem(int memoId, String title, String content, String date) {
        super();
        this.setMemoId(memoId);
        this.setTitle(title);
        this.setContent(content);
        this.setDate(date);
    }

    public int getMemoId() {
        return memoId;
    }

    public void setMemoId(int memoId) {
        this.memoId = memoId;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }

    public String getDate() {
        return date;
    }

    public void setDate(String date) {
        this.date = date;
    }


    @Override
    public String toString() {
        return  "ID:" + getMemoId() + ","
                + getTitle() + ":" +getDate();
    }





}

=============================================== =================================== 现在，让我们转到MyMemoEditor（活动）：

package com.example.mymemomain2;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MyMemoEditor extends Activity {

    int mode = 0;
    int id = 0;

    EditText edt1=null;
    EditText edt2=null;
    EditText edt3=null;
    EditText edt4=null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_my_memo_editor);

        edt1 = (EditText) findViewById(R.id.memoId);
        edt2 = (EditText) findViewById(R.id.title);
        edt3 = (EditText) findViewById(R.id.content);
        edt4 = (EditText) findViewById(R.id.date);

        Intent intent = getIntent();
        mode = intent.getIntExtra("mode", 0);
        if (mode == 1) {
            id = intent.getIntExtra("id", -1);  //write random number that doesn't make any sense
            if(id!= -1){
                MemoItem item = MemoItemMgr.getInstance().search(id);
                edt1.setText(item.getMemoId() + "");
                edt1.setEnabled(false); //this will prevent you from editing
                edt2.setText(item.getTitle());
                edt3.setText(item.getContent());
                edt4.setText(item.getDate());
            }
        }

        Button btnSave = (Button) findViewById(R.id.btnSave);
        Button btnQuit = (Button) findViewById(R.id.btnQuit);

        btnQuit.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                quit(v);
            }
        });

        btnSave.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                save(v);
            }
        });

    }

    public void save(View v) {

        int memoId = Integer.parseInt(edt1.getText().toString());

        String title = edt2.getText().toString();

        String content = edt3.getText().toString();

        String date = edt4.getText().toString();

        if (mode == 0) {
            try {
                MemoItemMgr.getInstance().add(new MemoItem(memoId, title, content, date));
                finish();
            } catch (DuplicateException e) {
                Toast.makeText(this, "Duplicative ID. Please write a different ID", Toast.LENGTH_LONG).show();
                edt1.setText("");
                edt1.requestFocus();
            }
        } else if (mode == 1) {
            MemoItemMgr.getInstance().update(id, title, content, date);
            finish();
        }



    }

    public void quit(View v) {
        finish();
    }

}

=============================================== ==================== 现在让我们来看看客户端（类）：

package com.example.mymemomain2;

import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.ArrayList;

public class MemoClient extends Thread {


    ArrayList list = null;
    public MemoClient(ArrayList list){
        this.list = list;
    }




    @Override
    public void run() {
        super.run();
        ObjectOutputStream objOut = null;
        Socket socket = null;
        try {
            socket = new Socket("70.12.109.92", 7777);
            OutputStream out = socket.getOutputStream();
            objOut = new ObjectOutputStream(out);
            for(int i = 0; i < list.size(); i++){
                objOut.writeObject(list.get(i));
        } 
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally{
            try {
                objOut.close();
                socket.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }


        }
    }

}

=============================================== ====================================== 最后，创建一个新项目（java）并创建一个服务器（类）：

import java.io.EOFException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.net.ServerSocket;
import java.net.Socket;

import com.example.mymemomain2.MemoItem;

public class MemoServer {

    public static void main(String[] args) throws Exception {
        ServerSocket server = new ServerSocket(7777);

        while (true) {
            System.out.println("waiting...");
            Socket socket = server.accept();
            InputStream in = socket.getInputStream();
            ObjectInputStream objIn = new ObjectInputStream(in);
            while (true) {
                try {
                    MemoItem item = (MemoItem) objIn.readObject();
                    System.out.println(item);
                } catch (EOFException e) {
                    break;
                }
            }
        }
    }
}

Answer 2

*******************************************************************************    
********************Just FYI, here is another example.**************************
*******************************************************************************

=============================================== =========================

Fist，让我们编辑xml文件。

=============================================== ==========================

这是主页面的主要xml （确保根据给出的问题更改布局格式）

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".NotePadActivity" >

    <ListView
        android:id="@+id/listview"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        />

</RelativeLayout>

=============================================== ===================================== 接下来，让我们转到note edit xml文件。

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".NoteEditActivity" 
    android:orientation="vertical">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="ID" />
    <EditText 
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/edtId"
        />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Title" />
    <EditText 
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/edtTitle"
        />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Content" />
    <EditText 
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/edtContent"
        />

    <LinearLayout 
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        >
        <Button 
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Save"
            android:id="@+id/btnSave"
            />

         <Button 
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Cancel"
            android:id="@+id/btnCancel"
            />

    </LinearLayout>

</LinearLayout>

=============================================== ================================

现在，让我们处理主要活动（NotePadActivity）

package com.example.notepad;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

public class NotePadActivity extends Activity {

    public static final int MODE_ADD = 0;
    public static final int MODE_EDIT = 1;

    public static final int MENU_ADD = 1;
    public static final int MENU_EDIT = 2;
    public static final int MENU_DELETE = 3;
    public static final int MENU_SEND = 4;
    public static final int MENU_EXIT = 5;

    ListView listview = null;
    ArrayAdapter<Note> adt = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        NoteManager.getInstance().open(this);

        adt = new ArrayAdapter<Note>(this,
                android.R.layout.simple_list_item_single_choice, NoteManager
                        .getInstance().getList());
        listview = (ListView) findViewById(R.id.listview);
        listview.setAdapter(adt);
        listview.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        menu.add(0, MENU_ADD, 0, "Add");
        menu.add(0, MENU_EDIT, 0, "Edit");
        menu.add(0, MENU_DELETE, 0, "Delete");
        menu.add(0, MENU_SEND, 0, "Send");
        menu.add(0, MENU_EXIT, 0, "Exit");
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (item.getItemId() == MENU_ADD) {
            add();
        } else if (item.getItemId() == MENU_EDIT) {
            edit();
        } else if (item.getItemId() == MENU_DELETE) {
            delete();
        } else if (item.getItemId() == MENU_SEND) {
            send();
        } else if (item.getItemId() == MENU_EXIT) {
            exit();
        }

        return super.onOptionsItemSelected(item);
    }

    @Override
    protected void onPause() {
        super.onPause();
        NoteManager.getInstance().close(this);
    }

    private void exit() {
        finish();
    }

    private void send() {
        NoteClient client = new NoteClient(NoteManager.getInstance().getList());
        client.start();

    }

    private void delete() {
        int position = listview.getCheckedItemPosition();
        if (position != -1) {
            Note note = adt.getItem(position);
            adt.remove(note);
        } else {
            Toast.makeText(this, "Please select the one that you want to delete", Toast.LENGTH_LONG).show();
        }

    }

    private void edit() {
        int position = listview.getCheckedItemPosition();
        if (position != -1) {
            Note note = adt.getItem(position);

            int id = note.getId();

            Intent intent = new Intent(this, NoteEditActivity.class);
            intent.putExtra("mode", MODE_EDIT);
            intent.putExtra("id", id);
            startActivity(intent);
        } else {
            Toast.makeText(this, "Please select the one that you want to edit", Toast.LENGTH_LONG).show();
        }
    }

    private void add() {
        Intent intent = new Intent(this, NoteEditActivity.class);
        intent.putExtra("mode", MODE_ADD);
        startActivity(intent);

    }

    @Override
    protected void onResume() {
        super.onResume();
        adt.notifyDataSetChanged();
    }

}

=============================================== ==========================================

现在让我们创建一个Note（类）：

package com.example.notepad;

import java.io.Serializable;

public class Note implements Serializable {
    private int id;
    private String title;
    private String content;



    public Note(int id, String title, String content) {
        super();
        this.id = id;
        this.title = title;
        this.content = content;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }
    public String getContent() {
        return content;
    }
    public void setContent(String content) {
        this.content = content;
    }
    @Override
    public String toString() {
        return "[" + id + "]" + title;
    }




}

=============================================== =================================== 我们将创建的下一个类是NoteManager（类）：

package com.example.notepad;

import java.io.EOFException;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.ArrayList;

import android.content.Context;

public class NoteManager {
    // need to use singleton

    private static NoteManager instance = new NoteManager();

    public static NoteManager getInstance(){
        return instance;
    }

    private String fileName = "note.ser";
    private ArrayList<Note> list = new ArrayList<Note>();

    private NoteManager(){

    }

    public void open(Context ctx){
        File file = new File(ctx.getFilesDir(), fileName);
        if(file.exists()){

                    //use FileStream to read the file and add by using add()
            ObjectInputStream objIn = null;
            try {
                FileInputStream fin = ctx.openFileInput(fileName);
                objIn = new ObjectInputStream(fin);
                while(true){
                    try{
                    Note note = (Note)objIn.readObject();
                    add(note);
                    }catch(EOFException e){
                        break;
                    }
                }
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }finally{
                try {
                    objIn.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }

        }else{
            //force add the content by using add()
            try {
                add(new Note(123, "Ethical quotes", "Content blah blah"));
                add(new Note(124, "Todo", "bla she bla she"));
                add(new Note(1, "Grocery", "hohoho"));
                add(new Note(13, "Bus route", "hong hong hong"));

            } catch (DuplicateException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

    public void close(Context ctx){
        ObjectOutputStream objOut = null;

        try {
            FileOutputStream fin = ctx.openFileOutput(fileName, Context.MODE_WORLD_WRITEABLE);
            objOut = new ObjectOutputStream(fin);

            for(int i = 0; i < list.size(); i++){
                Note note = list.get(i);
                objOut.writeObject(note);
            }

        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally{
            try {
                objOut.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

    public void add(Note note) throws DuplicateException{
        //repetition check
        if(search(note.getId()) == null){
        list.add(note);
        }else{
            throw new DuplicateException();
        }
    }

    public Note search(int id){
        for (int i = 0; i < list.size(); i++) {
            Note note = list.get(i);
            if(id == note.getId()){
                return note;
            }
        }
        return null;
    }

    public ArrayList<Note> getList(){
        return list;

    }

    public void update(int id, String title, String content){
        Note note = search(id);
        note.setTitle(title);
        note.setContent(content);
    }

    public boolean remove(int id){
        Note note = search(id);
        return list.remove(note);
    }





}

=============================================== ====================================

现在，我们进行另一项活动（NoteEditActivity）：

package com.example.notepad;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class NoteEditActivity extends Activity {
    int mode = 0;

    EditText edtId;
    EditText edtTitle;
    EditText edtContent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_note_edit);

        edtId = (EditText) findViewById(R.id.edtId);
        edtTitle = (EditText) findViewById(R.id.edtTitle);
        edtContent = (EditText) findViewById(R.id.edtContent);

        Intent intent = getIntent();
        mode = intent.getIntExtra("mode", NotePadActivity.MODE_ADD);
        if (mode == NotePadActivity.MODE_EDIT) {
            edtId.setEnabled(false);
            int id = intent.getIntExtra("id", -1);
            Note note = NoteManager.getInstance().search(id);
            edtId.setText(id + "");
            edtTitle.setText(note.getTitle());
            edtContent.setText(note.getContent());
        }

        Button btnSave = (Button) findViewById(R.id.btnSave);
        Button btnCancel = (Button) findViewById(R.id.btnCancel);
        btnCancel.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                finish();
            }
        });

        btnSave.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                int id = Integer.parseInt(edtId.getText().toString());
                String title = edtTitle.getText().toString();
                String content = edtContent.getText().toString();

                if (mode == NotePadActivity.MODE_ADD) {
                    try {
                        NoteManager.getInstance().add(
                                new Note(id, title, content));
                        finish();
                    } catch (DuplicateException e) {
                        Toast.makeText(NoteEditActivity.this,
                                "Duplicate ID, please use different ID", Toast.LENGTH_LONG)
                                .show();

                    }
                } else if (mode == NotePadActivity.MODE_EDIT) {
                    NoteManager.getInstance().update(id, title, content);
                    finish();
                }

            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.note_edit, menu);
        return true;
    }

}

=============================================== ===================================== 最后我们创建客户端/服务器：首先，让我们创建一个服务器（新的java项目+类）：另外，不要忘记从清单文件中更改权限设置。

import java.io.EOFException;
import java.io.ObjectInputStream;
import java.net.ServerSocket;
import java.net.Socket;


public class NoteServer {

    public static void main(String[] args) throws Exception {
        ServerSocket server = new ServerSocket(8888);
        System.out.println("waiting....");
        while(true){
            Socket socket = server.accept();
            ObjectInputStream in = new ObjectInputStream(socket.getInputStream());
            while(true){
                try{
//                  Note note = in.readObject();
                    String note = (String)in.readObject(); //use this if you don't remember.
                    System.out.println(note);

                }catch(EOFException e){
                    break;
                }
            }
        }

    }

}

=============================================== ============================== 最后，我们将创建新的客户端类：

package com.example.notepad;

import java.io.IOException;
import java.io.ObjectOutputStream;
import java.net.Socket;
import java.util.ArrayList;

public class NoteClient extends Thread {

    ArrayList<Note> list = null;
    public NoteClient(ArrayList<Note> list){
        this.list = list;
    }

    @Override
    public void run() {
        super.run();
        Socket socket = null;
        ObjectOutputStream out = null;
        try{
            socket = new Socket("70.12.109.92", 8888);
            out = new ObjectOutputStream(socket.getOutputStream());
            for (int i = 0; i < list.size(); i++) {
                Note note = list.get(i);
//              out.writeObject(note);
                out.writeObject(note.toString());               //if used toString in Server

            }

        }catch(Exception e){
            e.printStackTrace();
        }finally{
            try {
                out.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            try {
                socket.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

}

基于组件的Android

2 个答案: