如何从数据库中检索位置对象？

发布于 2024-10-03 03:43:11 字数 1043 浏览 4 评论 0原文

我想将 Location 对象存储到我的数据库中，然后能够加载它们。如何根据 Location 对象的属性构建 Location 对象？

我应该创建一个空白位置然后设置属性吗？（如果是，如何？）
我应该使用我的数据库作为 LocationProvider 吗？（如果是，怎么做？）

谢谢！

编辑：到目前为止，我发现的唯一可行的解决方案是检索当前位置，并覆盖所有属性......必须有更好的方法！

我的代码：

public Location selectLocationById(int id){
    String query = "SELECT * FROM " + LOCATIONS_TABLE + " WHERE id = " + id + ";";
    Cursor c = db.rawQuery(query, null);
    Location l = null;
    if(c.getCount() == 1) {
        c.moveToFirst();
        if(c.getColumnCount() == 8){
            l = new Location(MyProject.getCurrentLoc());
            l.setAccuracy(c.getFloat(1));
            l.setAltitude(c.getDouble(2));
            l.setBearing(c.getFloat(3));
            l.setLatitude(c.getDouble(4));
            l.setLongitude(c.getDouble(5));
            l.setSpeed(c.getFloat(6));
            l.setTime(c.getLong(7));
        }
    }

    if(c != null && !c.isClosed()) {
        c.close();
    }

    return l;
}

原文

I want to store Location objects into my database, and then be able to load them. How can I build a Location object from its attributes?

Should I create a blank Location and then set the attributes? (If yes, how?)
Should I use my database as a LocationProvider? (If yes, how?)

Thanks!

EDIT: The only working solution I found so far is to retrieve the current Location, and override all the attributes... There has to be a better way!

my code:

public Location selectLocationById(int id){
    String query = "SELECT * FROM " + LOCATIONS_TABLE + " WHERE id = " + id + ";";
    Cursor c = db.rawQuery(query, null);
    Location l = null;
    if(c.getCount() == 1) {
        c.moveToFirst();
        if(c.getColumnCount() == 8){
            l = new Location(MyProject.getCurrentLoc());
            l.setAccuracy(c.getFloat(1));
            l.setAltitude(c.getDouble(2));
            l.setBearing(c.getFloat(3));
            l.setLatitude(c.getDouble(4));
            l.setLongitude(c.getDouble(5));
            l.setSpeed(c.getFloat(6));
            l.setTime(c.getLong(7));
        }
    }

    if(c != null && !c.isClosed()) {
        c.close();
    }

    return l;
}

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当梦初醒 2024-10-10 03:43:11

这是有道理的。我相信您可以使用

l = new Location(null);

这样您就不必获取当前位置。这仍然应该创建一个新的位置，但提供者字符串为 null，使用其他位置构造函数：

Location(String provider)

请参阅 http://developer.android.com/reference/android/location/Location.html

This makes sense. I believe you could use

l = new Location(null);

So that you don't have to get your current location. This should still create a new Location, but with a provider string of null, using the other Location constructor: