Question

您好我有一个关于我正在处理的类项目应用程序的问题。我有一个Notes应用程序，它非常简单地将编辑文本中的文本输入记录到SQLite数据库中，然后将每个文本检索到列表片段供用户查看。他们还可以点击每个列表项，然后打开另一个片段，显示条目的“详细信息”，即主题，正文内容，时间和输入的日期。我想添加一个记录用户当前GPS /网络位置的特定条目（地理标记）。我在注释详细信息片段中有一个浮动操作按钮，它应该链接到一个Map片段，其上有一个标记，对应于该条目的记录位置。我对Android很新，所以还在学习这一切。只是有点挂了这个。有没有人对提交条目时如何将位置保存到同一个数据库（lat，long）有一个很好的解释，然后当用户单击详细信息片段中的FAB时，它会显示一个带有每个相应条目的位置标记的地图？如果有人可以提供帮助，或者我是否需要任何数据库类，请告诉我？

还想补充一点，我确实在谷歌上找了很多地方，但我不太确定我是否使用了错误的术语或者什么，但结果似乎是关闭我正在寻找的东西。

Answer 1

这里有一个获取位置的课程：

public class MyLocation {
private static final int REQUEST_PERMISSIONS = 1;
private Timer timer1;
private LocationManager lm;
private LocationResult locationResult;
private boolean gps_enabled = false;
private boolean network_enabled = false;
private String[] permissions = new String[]{
        Manifest.permission.ACCESS_FINE_LOCATION,
        Manifest.permission.ACCESS_COARSE_LOCATION
};

public boolean getLocation(final Context context, LocationResult result) {
    //I use LocationResult callback class to pass location value from MyLocation to user code.
    locationResult = result;
    if (lm == null)
        lm = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);

    //exceptions will be thrown if provider is not permitted.
    try {
        gps_enabled = lm.isProviderEnabled(LocationManager.GPS_PROVIDER);
    } catch (Exception ex) {
    }
    try {
        network_enabled = lm.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
    } catch (Exception ex) {
    }

    //don't start listeners if no provider is enabled
    if (!gps_enabled && !network_enabled)
        return false;
    try {
        boolean allPermissionsGranted = true;
        for(int i=0; i<permissions.length;i++) {
            if(!Utils.PermissionGranted(permissions[i], context)) allPermissionsGranted = false;
        }
        if(!allPermissionsGranted) {
            ActivityCompat.requestPermissions((Activity)context, permissions, REQUEST_PERMISSIONS);
            return false;
        }

        if (gps_enabled) {
            ((Activity) context).runOnUiThread(new Runnable() {
                public void run() {
                    lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListenerGps);
                }
            });
        }
        if (network_enabled) {
            ((Activity) context).runOnUiThread(new Runnable() {
                public void run() {
                    lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListenerNetwork);
                }
            });
        }

    } catch (SecurityException e) {
        Utils.Toast(context, e.getMessage());
    }
    timer1 = new Timer();
    timer1.schedule(new GetLastLocation(), 5000);

    return true;
}

private LocationListener locationListenerGps = new LocationListener() {
    public void onLocationChanged(Location location) {
        timer1.cancel();
        locationResult.gotLocation(location);
        lm.removeUpdates(this);
        lm.removeUpdates(locationListenerNetwork);
    }
    public void onProviderDisabled(String provider) {}
    public void onProviderEnabled(String provider) {}
    public void onStatusChanged(String provider, int status, Bundle extras) {}
};

private LocationListener locationListenerNetwork = new LocationListener() {
    public void onLocationChanged(Location location) {
        timer1.cancel();
        locationResult.gotLocation(location);
        lm.removeUpdates(this);
        lm.removeUpdates(locationListenerGps);
    }
    public void onProviderDisabled(String provider) {}
    public void onProviderEnabled(String provider) {}
    public void onStatusChanged(String provider, int status, Bundle extras) {}
};

private class GetLastLocation extends TimerTask {
    @Override
    public void run() {
        lm.removeUpdates(locationListenerGps);
        lm.removeUpdates(locationListenerNetwork);

        Location net_loc = null, gps_loc = null;
        if(gps_enabled)
            gps_loc = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
        if(network_enabled)
            net_loc = lm.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);

        //if there are both values use the latest one
        if(gps_loc != null && net_loc != null){
            if(gps_loc.getTime() > net_loc.getTime())
                locationResult.gotLocation(gps_loc);
            else
                locationResult.gotLocation(net_loc);
            return;
        }

        if(gps_loc != null){
            locationResult.gotLocation(gps_loc);
            return;
        }
        if(net_loc != null){
            locationResult.gotLocation(net_loc);
            return;
        }
        locationResult.gotLocation(null);
    }
}

public static abstract class LocationResult{
    public abstract void gotLocation(Location location);
}
}

当您即将添加新笔记时，请执行以下操作：

MyLocation.LocationResult locationResult = new MyLocation.LocationResult(){ 
        @Override 
        public void gotLocation(Location location){ 
            mCurrentLocation = location;
            mActivity.runOnUiThread(new Runnable() { 
                @Override 
                public void run() { 
                    //Any UI related code 
                } 
            }); 
        } 
    };

然后是地图：

转到https://developer.android.com/training/maps/index.html。您必须为数据库中的每个位置添加标记。

SQLite条目的GPS /网络位置

1 个答案: