数据库使用的方法：注意只有19版本以才能观看数据库的使用

public class DButile {
private static final String DB_PATH = "data/data/com.bf.com.myapplication/databases";
private static final String DB_NAME = "newcom.db";


static {
    copyDb();
}

private static int i = 0;

private static void copyDb() {
    File path = new File(DB_PATH);
    if (!path.exists()) path.mkdirs();
    InputStream is = null;
    FileOutputStream fos = null;
    try {
        is = App.appContent.getAssets().open("newcom.db");
        fos = new FileOutputStream(DB_PATH + "/" + DB_NAME);
        int len = 0;
        byte[] bytes = new byte[1024];
        while ((len = is.read(bytes)) != -1) {
            fos.write(bytes, 0, len);
        }
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        try {
            if (fos != null) fos.close();
            if (is != null) is.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
//获取数据库
public static SQLiteDatabase getDB(){
    SQLiteDatabase db = SQLiteDatabase.openOrCreateDatabase(DB_PATH + "/" + DB_NAME, null);
    return db;
}
//添加
public  static void addDB(String title,String ioce,String time,String url){
    i++;
    Log.e("size","已经jia"+ i);
    getDB().execSQL("insert into url_list(id,title, ioce,time,url) values(?,?,?,?,?)",
            new Object[]{null,title,ioce,time,url});
}
//删除
public static void deleteDB(String title){
    getDB().execSQL("delete from url_list where title=?", new Object[]{title});
}
//更新
public void update(IntentEntiy intentEntiy){
    getDB().execSQL("update url_list set title=?,ioce=?,time=?,url=?, where id=?",
            new Object[]{intentEntiy.getTitle(), intentEntiy.getBitmap(), intentEntiy.getTime(),intentEntiy.getDocurl(),intentEntiy.getId()});
}
//查询
public static List<DBfavorite> findDB(){
    List<DBfavorite> data=new ArrayList<>();
    Cursor cursor = getDB().rawQuery("select * from url_list",null);
    while (cursor.moveToNext()){
        i++;
        int UtilId = cursor.getInt(cursor.getColumnIndex("id"));
        String title = cursor.getString(cursor.getColumnIndex("title"));
        String ioce = cursor.getString(cursor.getColumnIndex("ioce"));
        String time = cursor.getString(cursor.getColumnIndex("time"));
        String url = cursor.getString(cursor.getColumnIndex("url"));
        DBfavorite list=new DBfavorite(title,ioce,time,url);
        data.add(list);

    }
    cursor.close();
    return data;
}
}