安卓程序-日记

部分代码还有待优化，奋斗吧，呆萌一族 ~ ~ ~

功能实现

1. 实现注册与登录功能
2. 可以在页面中编辑日记
3. 使用数据库对日记内容进行存储

源码分析

1. 在数据库中定义title作为标题,定义content作为内容

   public static final String CREATE_BOOK = "create table Book ("            + "id integer primary key autoincrement,"            + "title text,"            + "content text)";

2. 使用SharePreferferences这样的键值对来进行注册与登录

   SharedPreferences pref = getSharedPreferences("myShar", MODE_APPEND);                        SharedPreferences.Editor editor = pref.edit();                        editor.putString(user, p1);                        editor.apply();

   
   
3. 进行登录的用户名密码验证

   if (!user.equals("")) {                    SharedPreferences preferences = getSharedPreferences("myShar", MODE_APPEND);                    String pass = password.getText().toString();                    if (pass.equals(preferences.getString(user, ""))) {                        Intent intent = new Intent();                        intent.putExtra("name",user);                        intent.setClass(Login.this, Main.class);                        Login.this.startActivity(intent);                    } else {                        Toast.makeText(Login.this, "用户名或密码错误", Toast.LENGTH_SHORT).show();                    }                } else {                    Toast.makeText(Login.this, "用户名不为空", Toast.LENGTH_SHORT).show();                }

   
   
4. 从数据库中取出数据

   dbHelper = new MyDatabaseHelper(this, name + ".db", null, 2);        SQLiteDatabase db = dbHelper.getWritableDatabase();        Cursor cursor = db.query("Book", null, null, null, null, null, null);        if (cursor.moveToFirst()) {            do {                String title = cursor.getString(cursor.getColumnIndex("title"));                String content = cursor.getString(cursor.getColumnIndex("content"));                Fruit fruit = new Fruit(title, content);                fruitList.add(fruit);                Log.d("Main.java", "title:" + title);                Log.d("Main.java", "content" + content);            } while (cursor.moveToNext());        }        cursor.close();

   
   
5. 确保实时更新日记,对添加的数据能够得到及时反馈

   @Override    protected void onResume() {        super.onResume();        fruitList = new ArrayList<Fruit>();        init();        FruitAdapter fruitAdapter = new FruitAdapter(Main.this, R.layout.mylist, fruitList);        listView.setAdapter(fruitAdapter);    }

成品图片

全部代码

• MainActivity:第一个页面

  package com.example.application.application;import android.content.Intent;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.Button;public class MainActivity extends AppCompatActivity {    private Button login;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        login = (Button) findViewById(R.id.login);        login.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                Intent intent = new Intent();                intent.setClass(MainActivity.this, Login.class);                MainActivity.this.startActivity(intent);            }        });    }}

  
  
• Login登录页面:

  package com.example.application.application;import android.app.Activity;import android.content.Intent;import android.content.SharedPreferences;import android.os.Bundle;import android.support.annotation.Nullable;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;public class Login extends Activity {    private Button register;    private Button go_login;    private EditText username;    private EditText password;    @Override    protected void onCreate(@Nullable Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.login);        register = (Button) findViewById(R.id.register);        go_login = (Button) findViewById(R.id.go_login);        username = (EditText) findViewById(R.id.login_username);        password = (EditText) findViewById(R.id.login_password);        register.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                Intent intent = new Intent();                intent.setClass(Login.this, Register.class);                Login.this.startActivity(intent);            }        });        go_login.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                String user = username.getText().toString();                if (!user.equals("")) {                    SharedPreferences preferences = getSharedPreferences("myShar", MODE_APPEND);                    String pass = password.getText().toString();                    if (pass.equals(preferences.getString(user, ""))) {                        Intent intent = new Intent();                        intent.putExtra("name", user);                        intent.setClass(Login.this, Main.class);                        Login.this.startActivity(intent);                    } else {                        Toast.makeText(Login.this, "用户名或密码错误", Toast.LENGTH_SHORT).show();                    }                } else {                    Toast.makeText(Login.this, "用户名不为空", Toast.LENGTH_SHORT).show();                }            }        });    }}

  
  
• 注册页面:

  package com.example.application.application;import android.app.Activity;import android.content.Intent;import android.content.SharedPreferences;import android.os.Bundle;import android.support.annotation.Nullable;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;public class Register extends Activity {    private EditText username;    private EditText pass1;    private EditText pass2;    private Button reset;    private Button confirm_register;    private MyDatabaseHelper dbHelper;    @Override    protected void onCreate(@Nullable Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.register);        username = (EditText) findViewById(R.id.username);        pass1 = (EditText) findViewById(R.id.pass1);        pass2 = (EditText) findViewById(R.id.pass2);        reset = (Button) findViewById(R.id.reset);        confirm_register = (Button) findViewById(R.id.confirm_register);        reset.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                username.setText("");                pass1.setText("");                pass2.setText("");                Toast.makeText(Register.this, "已重置", Toast.LENGTH_SHORT).show();            }        });        confirm_register.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                String user = username.getText().toString();                if (!user.equals("")) {                    String p1 = pass1.getText().toString();                    String p2 = pass2.getText().toString();                    if (p1.equals(p2)) {                        SharedPreferences pref = getSharedPreferences("myShar", MODE_APPEND);                        SharedPreferences.Editor editor = pref.edit();                        editor.putString(user, p1);                        editor.apply();                        //创建专属库                        dbHelper = new MyDatabaseHelper(Register.this,user+".db",null,1);                        dbHelper.getWritableDatabase();                        //跳转                        Intent intent = new Intent();                        intent.setClass(Register.this, Login.class);                        Register.this.startActivity(intent);                    } else {                        Toast.makeText(Register.this, "两次密码不正确", Toast.LENGTH_SHORT).show();                    }                } else {                    Toast.makeText(Register.this, "用户名不能为空", Toast.LENGTH_SHORT).show();                }            }        });    }}

  
  
• 作为数据库的辅助类:

  package com.example.application.application;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;import android.widget.Toast;public class MyDatabaseHelper extends SQLiteOpenHelper {    public static final String CREATE_BOOK = "create table Book ("            + "id integer primary key autoincrement,"            + "title text,"            + "content text)";    private Context mContext;    public MyDatabaseHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {        super(context, name, factory, version);        mContext = context;    }    @Override    public void onCreate(SQLiteDatabase db) {        db.execSQL(CREATE_BOOK);        Toast.makeText(mContext, "创建成功", Toast.LENGTH_SHORT).show();    }    @Override    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {    }}

• 主界面:

  package com.example.application.application;import android.app.Activity;import android.content.Intent;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.os.Bundle;import android.support.annotation.Nullable;import android.util.Log;import android.view.View;import android.widget.Button;import android.widget.ListView;import android.widget.TextView;import java.util.ArrayList;import java.util.List;public class Main extends Activity {    private Button add;    private TextView username;    private ListView listView;    private List<Fruit> fruitList = new ArrayList<Fruit>();    String name;    private MyDatabaseHelper dbHelper;    @Override    protected void onCreate(@Nullable Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        username = (TextView) findViewById(R.id.name);        listView = (ListView) findViewById(R.id.list_view);        final Intent intent = getIntent();        name = intent.getStringExtra("name");        username.setText(name);        //init();        add = (Button) findViewById(R.id.add_log);        add.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                Intent intent1 = new Intent();                intent1.putExtra("name", name);                intent1.setClass(Main.this, SetList.class);                Main.this.startActivity(intent1);            }        });        //FruitAdapter fruitAdapter = new FruitAdapter(Main.this, R.layout.mylist, fruitList);        //listView.setAdapter(fruitAdapter);    }    private void init() {        //从数据库中取数据        dbHelper = new MyDatabaseHelper(this, name + ".db", null, 2);        SQLiteDatabase db = dbHelper.getWritableDatabase();        Cursor cursor = db.query("Book", null, null, null, null, null, null);        if (cursor.moveToFirst()) {            do {                String title = cursor.getString(cursor.getColumnIndex("title"));                String content = cursor.getString(cursor.getColumnIndex("content"));                Fruit fruit = new Fruit(title, content);                fruitList.add(fruit);                Log.d("Main.java", "title:" + title);                Log.d("Main.java", "content" + content);            } while (cursor.moveToNext());        }        cursor.close();    }    @Override    protected void onResume() {        super.onResume();        fruitList = new ArrayList<Fruit>();        init();        FruitAdapter fruitAdapter = new FruitAdapter(Main.this, R.layout.mylist, fruitList);        listView.setAdapter(fruitAdapter);    }}

• 两个作为List的列表辅助类:

  package com.example.application.application;import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.ArrayAdapter;import android.widget.TextView;import java.util.List;public class FruitAdapter extends ArrayAdapter<Fruit> {    private int resourceId;    public FruitAdapter(Context context, int textViewResourceId, List<Fruit> objects) {        super(context, textViewResourceId, objects);        resourceId = textViewResourceId;    }    @Override    public View getView(int position, View contentView, ViewGroup parent) {        Fruit fruit = getItem(position);        View view = LayoutInflater.from(getContext()).inflate(resourceId, null);        TextView my_title = (TextView) view.findViewById(R.id.my_title);        TextView my_content = (TextView) view.findViewById(R.id.my_content);        my_title.setText(fruit.getTitle());        my_content.setText(fruit.getContent());        return view;    }}

  
  

  package com.example.application.application;public class Fruit {    private String title;    private String content;    public Fruit(String title,String content){        this.title = title;        this.content = content;    }    public String getTitle() {        return title;    }    public String getContent() {        return content;    }}

  
  
• 最后一个页面:新建日记的页面:

  package com.example.application.application;import android.app.Activity;import android.content.ContentValues;import android.content.Intent;import android.database.sqlite.SQLiteDatabase;import android.os.Bundle;import android.support.annotation.Nullable;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;public class SetList extends Activity {    private Button set_confirm;    private EditText set_title;    private EditText set_content;    private MyDatabaseHelper dbHelper;    @Override    protected void onCreate(@Nullable Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.setlist);        set_title = (EditText) findViewById(R.id.set_title);        set_content = (EditText) findViewById(R.id.set_content);        set_confirm = (Button) findViewById(R.id.set_confirm);        final Intent intent = getIntent();        final String name = intent.getStringExtra("name");        set_confirm.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                String title = set_title.getText().toString();                String content = set_content.getText().toString();                if (!(title.equals("") || content.equals(""))) {                    dbHelper = new MyDatabaseHelper(SetList.this, name + ".db", null, 2);                    SQLiteDatabase database = dbHelper.getWritableDatabase();                    ContentValues values = new ContentValues();                    values.put("title", title);                    values.put("content", content);                    database.insert("Book", null, values);                    Toast.makeText(SetList.this, "日志添加成功", Toast.LENGTH_SHORT).show();                    finish();                } else {                    Toast.makeText(SetList.this, "请填写完整", Toast.LENGTH_SHORT).show();                }            }        });    }}

  
  
• 之后就是布局文件了
  
  
• 主界面的布局:

  <?xml version="1.0" encoding="utf-8"?><android.support.constraint.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"    android:background="@drawable/main2"    tools:context="com.example.application.application.MainActivity">    <Button        android:id="@+id/login"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentBottom="true"        android:layout_alignParentEnd="true"        android:background="@android:color/holo_blue_light"        android:text="进入应用"        tools:layout_editor_absoluteX="0dp"        tools:layout_editor_absoluteY="0dp" /></android.support.constraint.ConstraintLayout>

  
  
  
  
• 登录页面:

  <?xml version="1.0" encoding="utf-8"?><RelativeLayout 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/textView3"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:gravity="center"        android:padding="10sp"        android:text="Welcome"        android:textSize="50sp" />    <TextView        android:id="@+id/textView2"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_alignParentStart="true"        android:layout_below="@+id/textView3"        android:layout_marginTop="102dp"        android:text="用户名"        android:textSize="20sp" />    <EditText        android:id="@+id/login_username"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_alignParentStart="true"        android:layout_below="@+id/textView2"        android:ems="10" />    <TextView        android:id="@+id/textView4"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_alignParentStart="true"        android:layout_below="@+id/login_username"        android:paddingTop="20sp"        android:text="密码"        android:textSize="20sp" />    <EditText        android:id="@+id/login_password"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_alignParentStart="true"        android:layout_below="@+id/textView4"        android:inputType="textPassword"        android:paddingBottom="20sp" />    <Button        android:id="@+id/register"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentStart="true"        android:layout_below="@+id/login_password"        android:text="注册" />    <Button        android:id="@+id/go_login"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentEnd="true"        android:layout_below="@+id/login_password"        android:text="登录" /></RelativeLayout>

  
  
• 注册界面:

  <?xml version="1.0" encoding="utf-8"?><RelativeLayout 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/textView5"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_alignParentStart="true"        android:layout_alignParentTop="true"        android:gravity="center"        android:padding="20sp"        android:text="欢迎注册"        android:textSize="30sp" />    <TextView        android:id="@+id/textView"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_alignParentStart="true"        android:layout_below="@+id/textView5"        android:layout_marginTop="142dp"        android:text="用户名"        android:textSize="20sp"/>    <EditText        android:id="@+id/username"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:ems="10"        android:inputType="textPersonName"        android:layout_below="@+id/textView"        android:layout_alignParentStart="true"        android:paddingBottom="10sp"/>    <TextView        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="密码"        android:id="@+id/textView6"        android:layout_below="@+id/username"        android:layout_alignParentStart="true"        android:textSize="20sp"/>    <EditText        android:id="@+id/pass1"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_alignParentStart="true"        android:layout_below="@+id/textView6"        android:inputType="textPassword"        android:paddingBottom="10sp" />    <TextView        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_below="@+id/pass1"        android:layout_alignParentStart="true"        android:textSize="20sp"        android:text="确认密码"        android:id="@+id/textView7" />    <EditText        android:id="@+id/pass2"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_alignParentStart="true"        android:layout_below="@+id/textView7"        android:inputType="textPassword" />    <Button        android:id="@+id/confirm_register"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentEnd="true"        android:layout_below="@+id/pass2"        android:text="确认" />    <Button        android:id="@+id/reset"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentStart="true"        android:layout_below="@+id/pass2"        android:text="重置" /></RelativeLayout>

• 日记列表的主界面:

  <?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">    <RelativeLayout        android:layout_width="match_parent"        android:layout_height="wrap_content">        <TextView            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="Welcome:"            android:textSize="30sp"            android:id="@+id/textView8" />        <TextView            android:id="@+id/name"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:textSize="30sp"            android:layout_alignBaseline="@+id/add_log"            android:layout_alignBottom="@+id/add_log"            android:layout_toEndOf="@+id/textView8" />        <Button            android:id="@+id/add_log"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:gravity="center"            android:text="添加日记"            android:layout_alignParentTop="true"            android:layout_alignParentEnd="true" />    </RelativeLayout>    <ListView        android:id="@+id/list_view"        android:layout_width="match_parent"        android:layout_height="match_parent">    </ListView></LinearLayout>

  
  
• 用来定制列表项的布局文件:

  <?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/my_title"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:textSize="20sp"/>    <TextView        android:id="@+id/my_content"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:gravity="top"        android:maxLines="10"        android:minLines="5"        android:scrollbars="vertical"        android:padding="10sp"/></LinearLayout>

  
  
• 用来创建日记的布局文件:

  <?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:layout_width="match_parent"        android:layout_height="wrap_content"        android:gravity="center"        android:padding="20sp"        android:text="创建日记"        android:textSize="20sp" />    <TextView        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="标题:"        android:textSize="20sp" />    <EditText        android:id="@+id/set_title"        android:layout_width="match_parent"        android:layout_height="wrap_content" />    <TextView        android:id="@+id/textView9"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="日记内容:"        android:textSize="20sp" />    <EditText        android:id="@+id/set_content"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:gravity="top"        android:maxLines="10"        android:minLines="5"        android:scrollbars="vertical"/>    <Button        android:id="@+id/set_confirm"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="确认" /></LinearLayout>