在Android 中调用sqlite数据库

1在Android studio 工程中gradle文件夹右击新建assets文件夹。将建好的sqlite数据库导入其中。　

2在主activity中判断app是否是第一次启动调用如下方法：

/**检查APP是否为第一次启动*/private int CheckFirstActivate(){    /*设定数据库转移状态*/    int SetSQLiteDatabase_state = 0;    /*检查APP是否为第一次启动&转移数据库*/    SharedPreferences sharedPreferences = getSharedPreferences("Activate_State", Context.MODE_PRIVATE);    Boolean User_first_activate_state = sharedPreferences.getBoolean("FIRST",true);    if(User_first_activate_state){        sharedPreferences.edit().putBoolean("FIRST",false).apply();        AppDatabase appDatabase = new AppDatabase();        SetSQLiteDatabase_state = appDatabase.SetSQLiteDatabase(getApplicationContext());        return SetSQLiteDatabase_state;    }else{        return SetSQLiteDatabase_state;    }}

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public class AppDatabase {    public int SetSQLiteDatabase(Context context){

String DB_PATH = "/data/data/com.example.administrator.search/databases/";        String DB_NAME = "testdb.db";        try{            /*检查路径是否存在，不存在就构成路径*/            File file = new File(DB_PATH);            if(!file.exists()){                file.mkdir();            }

/*以asset文件夹下的db文件作为输入流*/            InputStream inputStream = context.getAssets().open(DB_NAME);

/*生成程序根目录下的数据库放置路径*/            String outFileName = DB_PATH + DB_NAME;

/*产生输出流*/            OutputStream outputStream = new FileOutputStream(outFileName);

/*设置byte并进行转换*/            byte[] buffer = new byte[8192];            int lenhth;            while((lenhth = inputStream.read(buffer))>0){                outputStream.write(buffer,0,lenhth);            }

/*关闭IO流*/            outputStream.flush();            outputStream.close();            inputStream.close();        }catch (IOException e){            e.printStackTrace();            return 0;        }        return 1;    }

}----------------3写一个自定义工具类，用来调用数据库利用sql语句找到要获取的数据

public class GetTreeObject {    public GetTreeObject() {    }　　//静态类用于调用数据库并返回TreeKePu表对象。    public static TreeKePu treeKePu(String s) {        String sql_statement = s;        String DB_PATH = "/data/data/com.example.administrator.search/databases/";        String DB_NAME = "testdb.db";        String DB_URL = DB_PATH + DB_NAME;        SQLiteDatabase sqLiteDatabase = SQLiteDatabase.openOrCreateDatabase(DB_URL, null);

Cursor cursor = sqLiteDatabase.rawQuery(sql_statement, null);        TreeKePu treeKePu = new TreeKePu();        if (cursor.moveToFirst()) {

try {                treeKePu.setTid(cursor.getInt(cursor.getColumnIndex("Tid")));                treeKePu.setTstyle(cursor.getString(cursor.getColumnIndex("Tstyle")));                treeKePu.setTtype(cursor.getString(cursor.getColumnIndex("Ttype")));                treeKePu.setTname(cursor.getString(cursor.getColumnIndex("Tname")));                treeKePu.setTMoral(cursor.getString(cursor.getColumnIndex("TMoral")));                treeKePu.setThabit(cursor.getString(cursor.getColumnIndex("Thabit")));                treeKePu.setTlooktype(cursor.getString(cursor.getColumnIndex("Tlooktype")));                treeKePu.setTdiscribe(cursor.getString(cursor.getColumnIndex("Tdiscribe")));                treeKePu.setTalias(cursor.getString(cursor.getColumnIndex("Talias")));            } catch (Exception e) {                e.printStackTrace();            }        }        cursor.close();        sqLiteDatabase.close();

return treeKePu;    }

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public class TreeKePu {

public int getTid(){        return Tid;    }    public String getTtype(){return Ttype;}

public String getTname() {        return Tname;    }

public String getTalias() {        return Talias;    }

public String getTstyle() {        return Tstyle;    }

public String getTMoral() {        return TMoral;    }

public String getThabit() {        return Thabit;    }

public String getTlooktype() {        return Tlooktype;    }

public String getTdiscribe() {        return Tdiscribe;    }

public void setTid(int tid) {        Tid = tid;    }

public void setTdiscribe(String tdiscribe) {        Tdiscribe = tdiscribe;    }

public void setTlooktype(String tlooktype) {        Tlooktype = tlooktype;    }

public void setThabit(String thabit) {        Thabit = thabit;    }

public void setTMoral(String TMoral) {        this.TMoral = TMoral;    }

public void setTstyle(String tstyle) {        Tstyle = tstyle;    }

public void setTalias(String talias) {        Talias = talias;    }

public void setTname(String tname) {        Tname = tname;    }

public void setTtype(String ttype) {        Ttype = ttype;    }    private int Tid;    private String Ttype;    private String Tname;    private String Talias;    private String Tstyle;    private String TMoral;    private String Thabit;    private String Tlooktype;    private String Tdiscribe;    {        Ttype=" ";        Talias=" ";        TMoral=" ";    }}