结对作业6

PSP0（Personal Software Process Stages ）

所需时间（TIME）

Planning(计划)	今天把安卓端的数据库又搞了搞
estimate[估计这个任务需要多少时间 ]	2h

Development (开发 )
· Design [具体设计 ]	1
· Coding [具体编码 ]	2
· Test [测试（自我测试，修改代码，提交修改）]	2

Reporting(报告 )
· Postmortem & Process Improvement Plan [事后总结, 并提出过程改进计划 ]	1h

合计

8h

安卓数据库的操作：今天主要学了下安卓数据库方面的简单知识。数据库主要用于复杂的数据储存。
安卓数据库简介：安卓SQLite数据库是一款轻量级的关系型数据库，它的运算速度非常快，占用资源很 少，通常只需要几百KB的内存就足够了。SQLite不仅支持标 准的SQL语法，还遵循了数据库的ACID事务，所以只要你以前使用过其他的关系型数据库，就 可以很快地上手SQLite。而SQLite又比一般的数据库要简单得多，它甚至不用设置用户名和密码 就可以使用。
数据库的创建：Android为了让我们能够更加方便地管理数据库，专门提供了一个SQLiteOpenHelper帮助类，借 助这个类就可以非常简单地对数据库进行创建和升级。
新建一个Java类继承SQLiteOpenHelper类，在主活动中调用该类即可实现对数据库的创建。
~~~

public class MyDatabaseHelper extends SQLiteOpenHelper {
</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">static</span> final String CREATE_BOOK = <span style="color: #800000;">"</span><span style="color: #800000;">create table book ( </span><span style="color: #800000;">"</span> +
        <span style="color: #800000;">"</span><span style="color: #800000;">id integer primary key autoincrement,</span><span style="color: #800000;">"</span> +
        <span style="color: #800000;">"</span><span style="color: #800000;">author text,</span><span style="color: #800000;">"</span> +
        <span style="color: #800000;">"</span><span style="color: #800000;">price real,</span><span style="color: #800000;">"</span> +
        <span style="color: #800000;">"</span><span style="color: #800000;">pages integer,</span><span style="color: #800000;">"</span> +
        <span style="color: #800000;">"</span><span style="color: #800000;">name text )</span><span style="color: #800000;">"</span><span style="color: #000000;">;

</span><span style="color: #0000ff;">private</span><span style="color: #000000;"> Context mContext;

</span><span style="color: #0000ff;">public</span> MyDatabaseHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, <span style="color: #0000ff;">int</span><span style="color: #000000;"> version) {
    super(context, name, factory, version);
    mContext </span>=<span style="color: #000000;"> context;
}

@Override
</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> onCreate(SQLiteDatabase db) {
    db.execSQL(CREATE_BOOK);
    Toast.makeText(mContext, </span><span style="color: #800000;">"</span><span style="color: #800000;">数据库成功创建</span><span style="color: #800000;">"</span><span style="color: #000000;">, Toast.LENGTH_SHORT).show();
}

@Override
</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span> onUpgrade(SQLiteDatabase db, <span style="color: #0000ff;">int</span> oldVersion, <span style="color: #0000ff;">int</span><span style="color: #000000;"> newVersion) {
      
}

}

~~~
<span style="color: #0000ff;">public</span> <span style="color: #0000ff;">class</span><span style="color: #000000;"> NormalActivity extends AppCompatActivity {
    </span><span style="color: #0000ff;">private</span><span style="color: #000000;"> MyDatabaseHelper dbHelper;

    @Override
    </span><span style="color: #0000ff;">protected</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.normal_layout);
　　　dbHelper </span>= <span style="color: #0000ff;">new</span> MyDatabaseHelper(<span style="color: #0000ff;">this</span>, <span style="color: #800000;">"</span><span style="color: #800000;">BookStore.db</span><span style="color: #800000;">"</span>, <span style="color: #0000ff;">null</span>, <span style="color: #800080;">1</span><span style="color: #000000;">);　　
          Button bt3 </span>=<span style="color: #000000;"> findViewById(R.id.create_database);
             bt3.setOnClickListener(</span><span style="color: #0000ff;">new</span><span style="color: #000000;"> View.OnClickListener() {
            @Override
            </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> onClick(View v) {
                dbHelper.getWritableDatabase();
            }
        });
    }
}
</span>~~~<span style="color: #000000;">

如果想建立多个数据库，由于就需要对数据库进行更新升级，这里建立两个数据库，重写onUpgrade() 方 法。

```
@Override
</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span> onUpgrade(SQLiteDatabase db, <span style="color: #0000ff;">int</span> oldVersion, <span style="color: #0000ff;">int</span><span style="color: #000000;"> newVersion) {
        db.execSQL(</span><span style="color: #800000;">"</span><span style="color: #800000;">drop table if exists Book</span><span style="color: #800000;">"</span><span style="color: #000000;">);
        db.execSQL(</span><span style="color: #800000;">"</span><span style="color: #800000;">drop table if exists Category</span><span style="color: #800000;">"</span><span style="color: #000000;">);
        onCreate(db);
}
```

数据库的增改删查

</span>~~~<span style="color: #000000;">
add.setOnClickListener(</span><span style="color: #0000ff;">new</span><span style="color: #000000;"> View.OnClickListener() {
            @Override
            </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> onClick(View v) {
                SQLiteDatabase db </span>=<span style="color: #000000;"> dbHelper.getWritableDatabase();
                ContentValues values </span>= <span style="color: #0000ff;">new</span><span style="color: #000000;"> ContentValues();
                values.put(</span><span style="color: #800000;">"</span><span style="color: #800000;">name</span><span style="color: #800000;">"</span>, <span style="color: #800000;">"</span><span style="color: #800000;">暴走大漫画</span><span style="color: #800000;">"</span><span style="color: #000000;">);
                values.put(</span><span style="color: #800000;">"</span><span style="color: #800000;">author</span><span style="color: #800000;">"</span>, <span style="color: #800000;">"</span><span style="color: #800000;">张子豪</span><span style="color: #800000;">"</span><span style="color: #000000;">);
                values.put(</span><span style="color: #800000;">"</span><span style="color: #800000;">pages</span><span style="color: #800000;">"</span>, <span style="color: #800080;">514</span><span style="color: #000000;">);
                values.put(</span><span style="color: #800000;">"</span><span style="color: #800000;">price</span><span style="color: #800000;">"</span>, <span style="color: #800080;">18.9</span><span style="color: #000000;">);
                db.insert(</span><span style="color: #800000;">"</span><span style="color: #800000;">Book</span><span style="color: #800000;">"</span>, <span style="color: #0000ff;">null</span><span style="color: #000000;">, values);
                values.clear();
                values.put(</span><span style="color: #800000;">"</span><span style="color: #800000;">name</span><span style="color: #800000;">"</span>, <span style="color: #800000;">"</span><span style="color: #800000;">金刚大力手</span><span style="color: #800000;">"</span><span style="color: #000000;">);
                values.put(</span><span style="color: #800000;">"</span><span style="color: #800000;">author</span><span style="color: #800000;">"</span>, <span style="color: #800000;">"</span><span style="color: #800000;">王子顺</span><span style="color: #800000;">"</span><span style="color: #000000;">);
                values.put(</span><span style="color: #800000;">"</span><span style="color: #800000;">pages</span><span style="color: #800000;">"</span>, <span style="color: #800080;">60</span><span style="color: #000000;">);
                values.put(</span><span style="color: #800000;">"</span><span style="color: #800000;">price</span><span style="color: #800000;">"</span>, <span style="color: #800080;">5</span><span style="color: #000000;">);
                db.insert(</span><span style="color: #800000;">"</span><span style="color: #800000;">Book</span><span style="color: #800000;">"</span>, <span style="color: #0000ff;">null</span><span style="color: #000000;">, values);
                Toast.makeText(NormalActivity.</span><span style="color: #0000ff;">this</span>, <span style="color: #800000;">"</span><span style="color: #800000;">添加数据成功</span><span style="color: #800000;">"</span><span style="color: #000000;">, Toast.LENGTH_SHORT).show();
            }
        });
</span>~~~

~~~<span style="color: #000000;">
update.setOnClickListener(</span><span style="color: #0000ff;">new</span><span style="color: #000000;"> View.OnClickListener() {
            @Override
            </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> onClick(View v) {
                SQLiteDatabase db </span>=<span style="color: #000000;"> dbHelper.getWritableDatabase();
                ContentValues values </span>= <span style="color: #0000ff;">new</span><span style="color: #000000;"> ContentValues();
                values.put(</span><span style="color: #800000;">"</span><span style="color: #800000;">price</span><span style="color: #800000;">"</span>, <span style="color: #800080;">10</span><span style="color: #000000;">);
                db.update(</span><span style="color: #800000;">"</span><span style="color: #800000;">Book</span><span style="color: #800000;">"</span>, values, <span style="color: #800000;">"</span><span style="color: #800000;">name=?</span><span style="color: #800000;">"</span>, <span style="color: #0000ff;">new</span> String[]{<span style="color: #800000;">"</span><span style="color: #800000;">暴走大漫画</span><span style="color: #800000;">"</span><span style="color: #000000;">});
            }
        });
</span>~~~

~~~<span style="color: #000000;">
delete.setOnClickListener(</span><span style="color: #0000ff;">new</span><span style="color: #000000;"> View.OnClickListener() {
            @Override
            </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> onClick(View v) {
                SQLiteDatabase db</span>=<span style="color: #000000;">dbHelper.getWritableDatabase();
                db.delete(</span><span style="color: #800000;">"</span><span style="color: #800000;">Book</span><span style="color: #800000;">"</span>,<span style="color: #800000;">"</span><span style="color: #800000;">pages&gt;?</span><span style="color: #800000;">"</span>,<span style="color: #0000ff;">new</span> String[]{<span style="color: #800000;">"</span><span style="color: #800000;">500</span><span style="color: #800000;">"</span><span style="color: #000000;">});
            }
        });
</span>~~~

~~~<span style="color: #000000;">
query.setOnClickListener(</span><span style="color: #0000ff;">new</span><span style="color: #000000;"> View.OnClickListener() {
            @Override
            </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> onClick(View v) {
                SQLiteDatabase db</span>=<span style="color: #000000;">dbHelper.getWritableDatabase();
                Cursor cursor</span>=db.query(<span style="color: #800000;">"</span><span style="color: #800000;">Book</span><span style="color: #800000;">"</span>,<span style="color: #0000ff;">null</span>,<span style="color: #800000;">"</span><span style="color: #800000;">pages&gt;?</span><span style="color: #800000;">"</span>,<span style="color: #0000ff;">new</span> String[]{<span style="color: #800000;">"</span><span style="color: #800000;">10</span><span style="color: #800000;">"</span>},<span style="color: #0000ff;">null</span>,<span style="color: #0000ff;">null</span>,<span style="color: #0000ff;">null</span>,<span style="color: #0000ff;">null</span><span style="color: #000000;">);
                </span><span style="color: #0000ff;">if</span><span style="color: #000000;">(cursor.moveToFirst()){
                    </span><span style="color: #0000ff;">do</span><span style="color: #000000;">{
                        String name</span>=cursor.getString(cursor.getColumnIndex(<span style="color: #800000;">"</span><span style="color: #800000;">name</span><span style="color: #800000;">"</span><span style="color: #000000;">));
                        String author</span>=cursor.getString(cursor.getColumnIndex(<span style="color: #800000;">"</span><span style="color: #800000;">author</span><span style="color: #800000;">"</span><span style="color: #000000;">));
                        </span><span style="color: #0000ff;">int</span> pages=cursor.getInt(cursor.getColumnIndex(<span style="color: #800000;">"</span><span style="color: #800000;">pages</span><span style="color: #800000;">"</span><span style="color: #000000;">));
                        </span><span style="color: #0000ff;">double</span> price= cursor.getDouble(cursor.getColumnIndex(<span style="color: #800000;">"</span><span style="color: #800000;">price</span><span style="color: #800000;">"</span><span style="color: #000000;">));
                        Log.d(</span><span style="color: #800000;">"</span><span style="color: #800000;">数据库查找</span><span style="color: #800000;">"</span>,<span style="color: #800000;">"</span><span style="color: #800000;">书名：</span><span style="color: #800000;">"</span>+<span style="color: #000000;">name);
                        Log.d(</span><span style="color: #800000;">"</span><span style="color: #800000;">数据库查找</span><span style="color: #800000;">"</span>,<span style="color: #800000;">"</span><span style="color: #800000;">作者：</span><span style="color: #800000;">"</span>+<span style="color: #000000;">author);
                        Log.d(</span><span style="color: #800000;">"</span><span style="color: #800000;">数据库查找</span><span style="color: #800000;">"</span>,<span style="color: #800000;">"</span><span style="color: #800000;">页数：</span><span style="color: #800000;">"</span>+<span style="color: #000000;">pages);
                        Log.d(</span><span style="color: #800000;">"</span><span style="color: #800000;">数据库查找</span><span style="color: #800000;">"</span>,<span style="color: #800000;">"</span><span style="color: #800000;">价格：</span><span style="color: #800000;">"</span>+<span style="color: #000000;">price);
                    }</span><span style="color: #0000ff;">while</span><span style="color: #000000;"> (cursor.moveToNext());
                }
                cursor.close();
            }
        });
</span>~~~</pre>
</div>
<p>&nbsp;</p>