℃江让您从精通到入门：写诗APP的制作诠析

柔情只为你懂 2022-09-30 15:54 114阅读 0赞

**一款类备忘录形式的记事本：写诗APP。**

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首先看一下目录结构如下：  
![这里写图片描述][SouthEast]  
演示效果如图如下：  
![这里写图片描述][SouthEast 1]

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做这个APP的目的完全是为了练手，目前也已经在线上跑着，整理下分享给大家。下面进行分步讲解：  
源码地址：  
链接：[https://pan.baidu.com/s/1lu8mUSanDnf-KuT5QBWafg][https_pan.baidu.com_s_1lu8mUSanDnf-KuT5QBWafg]  
\- 1、首先用到一定要用到Android Studio，当然了，做这个小案例，你不需要导入任何的包，你只需要知道，Android Studio导包方式与ADT不同就好了。  
\- 2、Android用到的是自己的数据库，叫做SQLite,总结下来，简单，好用，高效。  
\- 3、当然了，在做这个项目之前，你先要知道自己在做什么，那就是数据库的增删改查，写诗嘛！顾名思义，你要有Title，有Content，id主要是为了在做删除和修改时有区分，在这里一定要注意一下。所以你要写一个实体类在vo目录下：“Poem”类中的代码如下：

package com.example.mypoem.vo;
    
    
    /** * Created by Dujiang0311 on 2017/1/9. */
    
    public class Poem { 
        private int id;
        private String title;
        private String 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;
        }
    }

*  4、实体类写好了，就是数据库的工具类的书写了，在这里你要完成建表，以及新增数据列的操作，“SQLIiteHelper”具体实现代码如下：

package com.example.mypoem.sqlite;
    
    import android.content.Context;
    import android.database.sqlite.SQLiteDatabase;
    import android.database.sqlite.SQLiteOpenHelper;
    
    /** * Created by Dujiang0311 on 2017/2/9. */
    
    public class SQLiteHelper extends SQLiteOpenHelper { 
    
        /*SQLiteHelper的四个参数，上下文，数据库名字，null,版本号（任意数字）*/
        public SQLiteHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
            super(context, name, factory, version);
        }
    
        /*上面那个太过复杂，所以需要重载一个简单的方法：通过构造方法，完成数据库的创建*/
        public SQLiteHelper(Context context){
            super(context,"mydb",null,1);
        }
        //当sqliteOpenHelper中新添加了execSQL语句的时候一定要注意，将之前已经运行的MyWealth进行卸载
        /*通过OnCreate方法，实现数据表的创建*/
        @Override
        public void onCreate(SQLiteDatabase db) {
            db.execSQL("create table poem (id integer primary key autoincrement,title varchar2(20),content varchar2(50))");
        }
    
        @Override
        public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
    
        }
    }

*  5、接下来数据的操作类了，也就是所谓的dao层，里面包含了对于数据库的增删改查。“FileDao”代码如下：

package com.example.mypoem.dao;
    
    import android.content.ContentValues;
    import android.content.Context;
    import android.database.Cursor;
    import android.database.sqlite.SQLiteDatabase;
    
    import com.example.mypoem.sqlite.SQLiteHelper;
    import com.example.mypoem.vo.Poem;
    
    import java.util.ArrayList;
    import java.util.List;
    
    /** * Created by Dujiang0311 on 2017/2/9. */
    
    public class FileDao { 
        private SQLiteHelper sqLiteHelper;
    
        private SQLiteDatabase db;
    
    
        public FileDao(Context context) {
            sqLiteHelper = new SQLiteHelper(context);
    
        }
    
        //新增我的诗篇删除功能
        public int poemDelete(Integer id) {
            db = sqLiteHelper.getWritableDatabase();
            return db.delete("poem", "id = ?", new String[]{String.valueOf(id)});
        }
        //新增我的诗篇修改功能
        public int poemUpdate(int id, String title, String content) {
            db = sqLiteHelper.getWritableDatabase();
            ContentValues cv = new ContentValues();
            cv.put("id",id);
            cv.put("title", title);
            cv.put("content", content);
            return db.update("poem", cv, "id = ?", new String[]{String.valueOf(id)});
        }
    
        //新增我的诗篇查询功能
        public List<Poem> myPoems() {
            List<Poem> list = new ArrayList<Poem>();
            db = sqLiteHelper.getReadableDatabase();
            Cursor cursor = db.query("poem", new String[]{
       "id","title", "content"}, null, null, null, null, null);
            while (cursor.moveToNext()) {
                Poem poem = new Poem();
                poem.setId(cursor.getInt(0));
                poem.setTitle(cursor.getString(1));
                poem.setContent(cursor.getString(2));
                list.add(poem);
            }
            return list;
        }
        //新增我的诗篇新增功能
        public Long addPoem(Poem poem){
            /*由于当前需要实现的是添加功能，所以我们需要调用getWritableDatabase()*/
            db = sqLiteHelper.getWritableDatabase();
            /*创建ContentValues对象*/
            ContentValues cv = new ContentValues();
            cv.put("title", poem.getTitle());
            cv.put("content",poem.getContent());
            return db.insert("poem",null,cv);
        }
    }

*  6、当然，有的人代码潦草，随便把它写在该用的地方，也是没问题的，不过小项目还好，大项目还是规矩点的好。
 *  7、接下来就是UI的实现了，MainActivity主要是个载体，用来向AddPoemActivity和MyPoemActivity用Intent跳转的。其中MainActivity中代码如下：

package com.example.mypoem;
    
    import android.content.Intent;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.ImageView;
    
    public class MainActivity extends AppCompatActivity { 
    
        private ImageView iv_add_poem;
        private ImageView iv_select_poem;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            iv_add_poem = (ImageView) findViewById(R.id.iv_add_poem);
            iv_add_poem.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    Intent intentIn = new Intent(MainActivity.this,AddPoemActivity.class);
                    startActivity(intentIn);
                }
            });
    
            iv_select_poem = (ImageView) findViewById(R.id.iv_select_poem);
            iv_select_poem.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    Intent intentMyPoem = new Intent(MainActivity.this,MyPoemActivity.class);
                    startActivity(intentMyPoem);
                }
            });
        }
    }

*  8、下面是诗篇的新增功能，通过调用FileDao中的addPoem的方法实现数据的保存。AddPoemActivity代码如下：

package com.example.mypoem;
    
    import android.content.Intent;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.Toast;
    
    import com.example.mypoem.dao.FileDao;
    import com.example.mypoem.vo.Poem;
    
    
    
    public class AddPoemActivity extends AppCompatActivity { 
    
        private EditText et_title, et_content;
        private Poem poem;
        private Button btn_save, btn_cacel;
        private FileDao fileDao;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_add_poem);
            fileDao = new FileDao(this);
    
            //获取控件
    
            et_title = (EditText) findViewById(R.id.et_title);
            et_content = (EditText) findViewById(R.id.et_content);
            btn_save = (Button) findViewById(R.id.btn_save);
            btn_cacel = (Button) findViewById(R.id.btn_cancel);
    
            btn_save.setOnClickListener(new OnClick());
            btn_cacel.setOnClickListener(new OnClick());
    
    
        }
    
        private class OnClick implements View.OnClickListener { 
    
            @Override
            public void onClick(View view) {
    
                switch (view.getId()) {
                    case R.id.btn_save:
                        Poem poem = new Poem();
                        poem.setTitle(et_title.getText().toString().trim());
                        poem.setContent(et_content.getText().toString().trim());
                       if (fileDao.addPoem(poem) < 0) {
                            Toast.makeText(AddPoemActivity.this, "没有成功添加...", Toast.LENGTH_LONG).show();
                        } else {
                            Toast.makeText(AddPoemActivity.this, "已经成功添加...", Toast.LENGTH_LONG).show();
                            Intent intent = new Intent(AddPoemActivity.this, MainActivity.class);
                            startActivity(intent);
                        }
                        break;
                    case R.id.btn_cancel:
                        finish();
                        break;
                }
    
            }
        }
    
    }

*  9、诗篇的查询功能的实现，在这里核心操作同样是调用封装好的方法myPoem() ，在这里为了显示多条数据，需要用到适配器SimpleAdapter，这里我没有封装，因为只在这一个地方用到了，不至于封装。但是在这里强调一下，适配器最好单独写一个类。目前笔者现在遇到的，ListView和GridView都需要适配器。，MyPoemActivity中的代码如下：

package com.example.mypoem;
    
    import android.content.Intent;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.AdapterView;
    import android.widget.ListView;
    import android.widget.SimpleAdapter;
    
    import com.example.mypoem.dao.FileDao;
    import com.example.mypoem.vo.Poem;
    
    import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    
    public class MyPoemActivity extends AppCompatActivity {
    
        private ListView lv_my_poem;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_my_poem);
    
            lv_my_poem = (ListView) findViewById(R.id.lv_my_poem);
    
            FileDao dao = new FileDao(this);
            List<Poem> list0 = dao.myPoems();
            List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
    
            final SimpleAdapter adapter ;
            for (Poem poem :list0){
                Map<String, Object> map = new HashMap<String, Object>();
                map.put("id",poem.getId());
                map.put("title",poem.getTitle());
                map.put("content",poem.getContent());
                list.add(map);
            }
    
            adapter = new SimpleAdapter(this,list,R.layout.activity_my_poem_lv,
                    new String[]{
       "id","title","content"},
                    new int[]{R.id.tv_my_poem_lv_id,R.id.tv_my_poem_lv_title,R.id.tv_my_poem_lv_content});
    
            lv_my_poem.setAdapter(adapter);
            lv_my_poem.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> adapterView, View view, int position, long id1) {
                    Map<String,Object> map = (Map<String, Object>) adapter.getItem(position);
                    Integer id = Integer.valueOf(map.get("id").toString());
                    String title = map.get("title").toString();
                    String content = map.get("content").toString();
    
                    Intent intent = new Intent(MyPoemActivity.this,ManageMyPoemActivity.class);
                    intent.putExtra("id",id);
                    intent.putExtra("title",title);
                    intent.putExtra("content",content);
                    startActivity(intent);
                }
            });
    
        }
    }

*  10、修改和删除，笔者写在了一个Activity里面，都是调用封装好的方法操作。但是注意一点，删除时按照id删除，如果是按照标题或内容删除，很容易把有着同样标题诗篇删除，这也是我在后期调试的时候发现的，所以按照id删除，不会删错。至于修改模块，在MyPoemActivity和ManageMyPoemActivity之间，需要用到Intent传递一个Key和Value。ManageMyPoemActivity的代码如下：

package com.example.mypoem;
    
    import android.content.DialogInterface;
    import android.content.Intent;
    import android.support.v7.app.AlertDialog;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.Toast;
    
    import com.example.mypoem.dao.FileDao;
    
    public class ManageMyPoemActivity extends AppCompatActivity {
    
        //声明控件
        private EditText et_manage_title,et_manage_content,et_manage_id;
        private Button btn_delete, btn_update, btn_cancel;
        private FileDao dao;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_manage_my_poem);
    
            //获取控件
            et_manage_title  = (EditText) findViewById(R.id.et_manage_title);
            et_manage_content = (EditText) findViewById(R.id.et_manage_content);
            et_manage_id = (EditText) findViewById(R.id.et_manage_id);
    
            dao = new FileDao(this);
    
            btn_cancel = (Button) findViewById(R.id.btn_manage_cancel);
            btn_delete = (Button) findViewById(R.id.btn_manage_delete);
            btn_update = (Button) findViewById(R.id.btn_manage_update);
    
            //接收从前面传递过来的值
            //接收上面传递过来的值
            Intent intent = getIntent();
            et_manage_id.setId(intent.getIntExtra("id",1));
            et_manage_title.setText(intent.getStringExtra("title"));
            et_manage_content.setText(intent.getStringExtra("content"));
    
            //点击“取消”按钮
            btn_cancel.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    finish();
                }
            });
            btn_delete.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
    
                    //创建一个对话框
                    AlertDialog.Builder builder = new AlertDialog.Builder(ManageMyPoemActivity.this);
                    builder.setTitle("删除Poem");
                    builder.setMessage("你确定要删除你的灵感吗?");
                    builder.setPositiveButton("删除", new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialogInterface, int i) {
                            if (dao.poemDelete(Integer.valueOf(et_manage_id.getId())) > 0) {
                                Toast.makeText(ManageMyPoemActivity.this, "删除成功！！！", Toast.LENGTH_SHORT).show();
                                Intent intent2 = new Intent(ManageMyPoemActivity.this, MainActivity.class);
                                startActivity(intent2);
                            } else {
                                Toast.makeText(ManageMyPoemActivity.this, "删除失败！！！", Toast.LENGTH_SHORT).show();
                            }
                        }
                    });
                    builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialogInterface, int i) {
    
                        }
                    });
    
                    builder.create().show();
                }
            });
            btn_update.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    //第三步、注意数据顺序不能错位
                    //String time, String type, String address, String other, Double money
                    if (dao.poemUpdate(et_manage_id.getId(),
                            et_manage_title.getText().toString(),
                            et_manage_content.getText().toString())> 0) {
                        Toast.makeText(ManageMyPoemActivity.this, "修改成功！！！", Toast.LENGTH_SHORT).show();
                        Intent intent1 = new Intent(ManageMyPoemActivity.this, MainActivity.class);
                        startActivity(intent1);
                    } else {
                        Toast.makeText(ManageMyPoemActivity.this, "修改失败", Toast.LENGTH_SHORT).show();
                    }
    
                }
            });
        }
    }

*  11、闪屏页面的话，最大的特色就是倒计时功能（在网上抄的），实现代码如下：

package com.example.mypoem;
    
    import android.content.Intent;
    import android.content.SharedPreferences;
    import android.database.Cursor;
    import android.database.sqlite.SQLiteDatabase;
    import android.os.Bundle;
    import android.os.Handler;
    import android.support.v7.app.AppCompatActivity;
    import android.view.View;
    import android.view.animation.Animation;
    import android.view.animation.AnimationUtils;
    
    import android.widget.Button;
    import android.widget.TextView;
    
    
    public class SplashActivity extends AppCompatActivity { 
    
        //倒计时控件声明
    
        private TextView textView ;
    
        private int count = 5 ;
    
        private Animation animation ;
       // private Button btnGoLogin;
    
    
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_splash);
    
    
            textView = (TextView) findViewById(R.id.tv_adv);
    
            //先声明Handler，再书写下面的延迟。
    
            handler.sendEmptyMessageDelayed(0,1000) ;
    
            animation= AnimationUtils.loadAnimation(this,R.anim.animation_text);
    
    
            new Handler().sendEmptyMessageDelayed(0,1000);
            //5秒钟自动进入登录界面
            /*new Handler().postDelayed(new Runnable() { @Override public void run() { Intent intent = new Intent(); intent.setClass(FirstActivity.this, LoginActivity.class); startActivity(intent); finish(); } }, 3000);*/
    
    
           /* this.btnGoLogin = (Button) findViewById(R.id.btn_go_login); this.btnGoLogin.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { Intent intent = new Intent(); // 设置跳转参数 intent.setClass(SplashActivity.this, MainActivity.class); // 进行跳转 startActivity(intent); // 销毁当前Activity finish(); } });*/
             /* @Override public void onClick(View v) { // String msg = "你好呀"; // 跳转到主界面 // 实例化意图 Intent intent = new Intent(); // 设置跳转参数 intent.setClass(FirstActivity.this, LoginActivity.class); // 放置传递的数据 // intent.putExtra("message",msg); // 进行跳转 startActivity(intent); // 销毁当前Activity finish(); } });*/
        }
        private int getCount(){
            count-- ;
            if (count == 0){
                Intent intent = new Intent();
                intent.setClass(this, MainActivity.class);
                startActivity(intent);
                finish();
            }
            return count;
        }
        private Handler handler = new Handler(){
            public void handleMessage(android.os.Message msg){
                if (msg.what == 0){
                    textView.setText(getCount()+"");
                    handler.sendEmptyMessageDelayed(0,1000) ;
                    animation.reset();
                    textView.startAnimation(animation);
                }
            }
        };
    }

*  12、布局文件不太难，大家就在源码里面看好了，指得注意的是圆形按键的实现，是调用了btn\_circle.xml文件实现，在drawable目录下。
 *  13、**大家如果想看APP的具体实现效果，可以去下载啊，apk地址如下：[http://shouji.baidu.com/software/10937287.html][http_shouji.baidu.com_software_10937287.html]**

[SouthEast]: /images/20220705/ae23e96e4baf423b9029670979c404e6.png
[SouthEast 1]: /images/20220705/c3a67cef88f8423188aef7eed61a1753.png
[https_pan.baidu.com_s_1lu8mUSanDnf-KuT5QBWafg]: https://pan.baidu.com/s/1lu8mUSanDnf-KuT5QBWafg
[http_shouji.baidu.com_software_10937287.html]: http://shouji.baidu.com/software/10937287.html