android簡單記事本

近段學習資料存儲寫個小程式，簡單記事本，實作點選檢視删除，添加儲存。閑話不多說直接步入正題。

一、上圖看着更直覺。

1、這是該程式的主界面。上邊是一個Button，下邊是ListView顯示記錄的筆記

android簡單記事本

2、點選添加按鈕顯示的界面，非常簡單，輸入，儲存，取消

android簡單記事本

3、這是點選主界面筆記後的顯示，筆記，删除，傳回

android簡單記事本

二、下邊開始實作階段：

1》先寫布局檔案

1、主布局檔案activity_main.xml

一個添加按鈕，一個ListView，代碼如下：

<?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">
        <Button
            android:id="@+id/main_add"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="添加"/>
    </LinearLayout>
    <ListView
        android:id="@+id/main_list"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

</LinearLayout>

2、點選添加之後的跳轉界面add_list.xml

上邊是一個EditText，下邊是兩個按鈕儲存和删除

<?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">

    <EditText
        android:id="@+id/add_etv"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:background="@null"
        android:gravity="top"
        android:hint="記 錄 點 滴，改 變 生 活" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="5dp"
        android:gravity="center"
        android:orientation="horizontal">

        <Button
            android:id="@+id/add_save"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="儲存" />

        <Button
            android:id="@+id/add_delete"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="80dp"
            android:text="取消" />
    </LinearLayout>
</LinearLayout>

3、點選主界面的筆記跳轉的界面，進行檢視或者删除。select.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">

    <TextView
        android:id="@+id/s_tv"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1" />

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

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

        <Button
            android:id="@+id/s_back"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="傳回" />
    </LinearLayout>

</LinearLayout>

4、記錄筆記顯示在主界面的布局檔案。list.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">

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="100dp"
        android:gravity="center_vertical"
        android:orientation="vertical">

        <TextView
            android:id="@+id/list_content"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="tv" />

        <TextView
            android:id="@+id/list_time"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="tv" />
    </LinearLayout>
</LinearLayout>

2》不同功能的類檔案

1、建NotesDB.class檔案用來建表寫入資料類型

package com.example.guo.my_account;

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

public class NotesDB extends SQLiteOpenHelper {

    public static final String TABLE_NAME = "notes";
    public static final String CONTENT = "content";
    public static final String ID = "_id";
    public static final String TIME = "time";

    public NotesDB(Context context) {
        super(context, "notes", null, );
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table " + TABLE_NAME + " (" + ID + " integer primary key autoincrement,"
                + CONTENT + " text not null," + TIME + " text not null)");
    }

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

    }
}

2、建立自定義資料檔案MyAdapter.class

package com.example.guo.my_account;

import android.content.Context;
import android.database.Cursor;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.LinearLayout;
import android.widget.TextView;

public class MyAdapter extends BaseAdapter {

    private Context context;
    private Cursor cursor;
    private LinearLayout layout;

    public MyAdapter(MainActivity context, Cursor cursor){
        this.context = context;
        this.cursor = cursor;
    }
    @Override
    public int getCount() {
        return cursor.getCount();
    }

    @Override
    public Object getItem(int position) {
        return cursor.getPosition();
    }

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        LayoutInflater inflater = LayoutInflater.from(context);
        layout = (LinearLayout) inflater.inflate(R.layout.list,null);
        TextView contenttv = (TextView) layout.findViewById(R.id.list_content);
        TextView timetv = (TextView) layout.findViewById(R.id.list_time);
        cursor.moveToPosition(position);
        String content = cursor.getString(cursor.getColumnIndex("content"));
        String time = cursor.getString(cursor.getColumnIndex("time"));
        contenttv.setText(content);
        timetv.setText(time);
        return layout;
    }
}

3、建立添加資料檔案Addcontent.class

package com.example.guo.my_account;

import android.app.Activity;
import android.content.ContentValues;
import android.content.Intent;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

import java.util.Date;
import java.text.SimpleDateFormat;

public class Addcontent extends Activity implements View.OnClickListener {


    private Button savebtn, deletebtn;
    private EditText ettext;
    private NotesDB notesDB;
    private SQLiteDatabase dbWriter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.add_list);
        savebtn = (Button) findViewById(R.id.add_save);
        deletebtn = (Button) findViewById(R.id.add_delete);
        ettext = (EditText) findViewById(R.id.add_etv);
        savebtn.setOnClickListener(this);
        deletebtn.setOnClickListener(this);
        notesDB = new NotesDB(this);
        dbWriter = notesDB.getWritableDatabase();
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.add_save:
                addDB();
                finish();
                break;
            case R.id.add_delete:
                finish();
                break;
        }
    }

    private void addDB() {
        ContentValues cv = new ContentValues();
        cv.put(NotesDB.CONTENT, ettext.getText().toString());
        cv.put(NotesDB.TIME, getTime());
        dbWriter.insert(NotesDB.TABLE_NAME, null, cv);
    }

    public String getTime() {
        SimpleDateFormat format = new SimpleDateFormat("yyy年MM月dd日 HH:mm:ss");
        Date curDate = new Date();
        String str = format.format(curDate);
        return str;
    }
}

4、建立修改删除檔案Select.class

package com.example.guo.my_account;

import android.app.Activity;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class SelectAct extends Activity implements View.OnClickListener {

    private Button s_delete, s_back;
    private TextView s_tv;
    private NotesDB notesDB;
    private SQLiteDatabase dbWriter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.select);
        s_back = (Button) findViewById(R.id.s_back);
        s_delete = (Button) findViewById(R.id.s_delete);
        s_tv = (TextView) findViewById(R.id.s_tv);
        notesDB = new NotesDB(this);
        dbWriter = notesDB.getWritableDatabase();


        s_back.setOnClickListener(this);
        s_delete.setOnClickListener(this);

        s_tv.setText(getIntent().getStringExtra(NotesDB.CONTENT));
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.s_delete:
                deleteDate();
                finish();
                break;

            case R.id.s_back:
                finish();
                break;
        }
    }

    private void deleteDate() {
        dbWriter.delete(NotesDB.TABLE_NAME, "_id=" + getIntent().getIntExtra(NotesDB.ID, ), null);

    }
}

5、MainActivity.class

package com.example.guo.my_account;

import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ListView;

import java.util.Timer;

public class MainActivity extends Activity implements View.OnClickListener {

    private Button addbtn;
    private ListView lv;
    private Intent i;
    private SQLiteDatabase dbReader;
    private Cursor cursor;
    private NotesDB notesDB;
    private MyAdapter adapter;

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


    }

    private void initView() {
        addbtn = (Button) findViewById(R.id.main_add);
        lv = (ListView) findViewById(R.id.main_list);
        addbtn.setOnClickListener(this);
        notesDB = new NotesDB(this);
        dbReader = notesDB.getReadableDatabase();
        lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                cursor.moveToPosition(position);
                Intent i = new Intent(MainActivity.this, SelectAct.class);
                i.putExtra(NotesDB.ID, cursor.getInt(cursor.getColumnIndex(NotesDB.ID)));
                i.putExtra(notesDB.CONTENT, cursor.getString(cursor.getColumnIndex(NotesDB.CONTENT)));
                i.putExtra(notesDB.TIME, cursor.getString(cursor.getColumnIndex(NotesDB.TIME)));
                startActivity(i);
            }
        });
    }

    @Override
    public void onClick(View v) {
        i = new Intent(this, Addcontent.class);
        startActivity(i);
    }

    private void selectDB() {
        cursor = dbReader.query(NotesDB.TABLE_NAME, null, null, null, null, null, null);
        adapter = new MyAdapter(this, cursor);
        lv.setAdapter(adapter);
    }

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

3》不要忘了在AndroidManifest.xml檔案中聲明

代碼如下

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.guo.my_account">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@android:style/Theme.Light.NoTitleBar">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".Addcontent"/>
        <activity android:name=".SelectAct"/>

    </application>

</manifest>

自己寫的，不是很簡單實用，有聲明不足的希望留言，會改進。Thanks.後邊會上傳源碼，多多學習。

android簡單記事本

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