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;
    }
}

----------------------

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;
    }

------

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=" ";
    }
}