将数据库复制到scard

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视乎在android4.4以后没有root的手机不能查看data/data目录，所以有时候创建了数据库但是不能很清晰的查看里面的信息。为了更清晰的查看数据库信息可以选择模拟器，或者将数据库复制到sdcard然后导出到电脑使用sqlitespy查看

下面来个demo

1.DBHelper.java

/** * Created by tiankonglanlande on 2017/3/8. */public class DBHelper extends SQLiteOpenHelper {    private static final String TAG = "DBHelper";    public static final String DB_NAME ="copy.db" ;    public static final String TB_USER ="user_tb" ;    private String TB_USER_USERNAME="username";    private String TB_USER_AGE="age";    public DBHelper(Context context) {        super(context,DB_NAME, null, 1);    }    @Override    public void onCreate(SQLiteDatabase db) {        Log.e(TAG, "onCreate: ");        String sql="create table "+TB_USER+"( _id Integer primary key autoincrement," +                TB_USER_USERNAME+" text," +                TB_USER_AGE+" Integer" +                ")";        db.execSQL(sql);        // 插入测试数据        insertData(db);    }    private void insertData(SQLiteDatabase db) {        for (int i=0;i<50;i++){            ContentValues values=new ContentValues();            values.put("username","用户"+i);            values.put("age",10+i);            long count=db.insert(TB_USER,null,values);            if (count>0){                Log.e(TAG, "insertData: 插入第"+i+"条数据");            }        }    }    @Override    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {        String sql="drop table if exists "+TB_USER;        db.execSQL(sql);        onCreate(db);    }}

2.CopyDBBiz.java/** * Created by tiankonglanlande on 2017/3/8. * 将本应用的数据库复制到sdcard */public class CopyDBBiz {    private final Context context;    public static String DataBaseName= DBHelper.DB_NAME;//需要复制到sdcard的数据库名称    public CopyDBBiz(Context context){        this.context=context;        File oldFile=context.getDatabasePath(DataBaseName);        String oldPath=oldFile.getPath();        if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){            String newPath= Environment.getExternalStorageDirectory().getPath()+File.separator+DataBaseName;            copy(oldPath,newPath);        }else{            try {                throw new Exception("please make sure permision and SdCard exist !");            } catch (Exception e) {                e.printStackTrace();            }        }    }    /**     * 复制操作     * @param oldPath     * @param newPath     */    private void copy(String oldPath, String newPath) {        InputStream in=null;        OutputStream os=null;        try {            //判断文件是否存在            File oldfile=new File(oldPath);            File newfile=new File(newPath);            if (!newfile.exists()){                newfile.createNewFile();            }            if (oldfile!=null){                in=new FileInputStream(oldPath);                byte buffer[]=new byte[1024];                int read=-1;                os=new FileOutputStream(newPath);                while((read=in.read(buffer))!=-1){                    os.write(buffer,0,read);                }            }        } catch (IOException e) {            e.printStackTrace();        }finally {            try {                if (in!=null) in.close();                if (os!=null) os.close();            } catch (IOException e) {                e.printStackTrace();            }        }    }}

3.MainActivity.java
public class MainActivity extends AppCompatActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        DBHelper helper=new DBHelper(this);        helper.getWritableDatabase();        CopyDBBiz copyDBBiz=new CopyDBBiz(this);    }}
MainActivity.java创建helper以及调用getWritableDatabase方法是为了促使数据库创建。因为SqliteOpenHelper的onCreate是在getWritableDatabase，或getReadableDatabase的情况下去调用的

4.添加权限

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>    <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>

5.导出到电脑使用sqliteSpy查看效果图：

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