sqliteDatabase db= sqliteDatabase.openOrCreateDatabase(this.getFilesDir()+"/Diary_aks.db3",null);//在Oncreate中打开数据库Diary_aks.db3

if(tabIsExist("User")){//查找表USer是不为空 则跳转到LoginActivity
intent=new Intent(IndexActivity.this,LoginActivity.class);
}
else{//查找表USer为空 则跳转到RegistActivity
intent=new Intent(IndexActivity.this,RegistActivity.class);
}
startActivity(intent);
}

/**
* 判断表tabName是否为空
* @param tabName 表名
* @return boolean
*/

public boolean tabIsExist(String tabName){

boolean result = false; if(tabName == null){ return false; } Cursor cursor = null; try { DataBaSEOpenHelper dbh=new DataBaSEOpenHelper(IndexActivity.this);// String sql = "select count(*) from User ";//USer表名 cursor = dbh.getReadableDatabase().rawQuery(sql,null); if(cursor.moveToNext()){ int count = cursor.getInt(0); if(count>0){ result = true; } } } catch (Exception e) { // TODO: handle exception } return result; } 原文链接：https://www.f2er.com/sqlite/202296.html