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我正在尝试使用此处建议的解决方案移动 Google Maps v2 中的“我的位置”按钮。

我遇到的问题是我得到了一个 nullpointerexception，结果this.getView()返回 null，这很奇怪，因为当到达那条线时，已经创建了片段。onCreateView() 例程已经完成，对地图进行了一些初始化，所以我确定它存在。应用程序的其余部分也可以很好地访问此地图对象。

我的 main.xml 文件的相关部分（当然，这个 RelativeLayout 中还有很多，但这是唯一存在的地图片段）：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:map="http://schemas.android.com/apk/res-auto"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >

<fragment
    android:id="@+id/map"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    class="com.squirrel.hkairpollution.MySupportMapFragment"
/>

和代码：

package com.squirrel.hkairpollution;

(imports omitted)

public class MySupportMapFragment extends SupportMapFragment {

private static final String TAG = HKAirPollution.TAG;

public MySupportMapFragment() {
    return;
}

@Override
public View onCreateView(LayoutInflater arg0, ViewGroup arg1, Bundle arg2) {
    Log.v(TAG, "In overridden onCreateView.");
    View v = super.onCreateView(arg0, arg1, arg2);
    Log.v(TAG, "Initialising map.");
    initMap();
    Log.v(TAG, "Moving the MyPositionButton");
    resetMyPositionButton();
    return v;
}

private void initMap(){
    UiSettings settings = getMap().getUiSettings();
    settings.setAllGesturesEnabled(true);
    settings.setMyLocationButtonEnabled(true);
    LatLng latLong = new LatLng(22.320542, 114.185715);
    getMap().moveCamera(CameraUpdateFactory.newLatLngZoom(latLong,11));
}


/**
 * Move my position button at the bottom of map
 */
private void resetMyPositionButton()
{
    //deep paths for map controls
    ViewGroup v1 = (ViewGroup)this.getView();
    ViewGroup v2 = (ViewGroup)v1.getChildAt(0);
    ViewGroup v3 = (ViewGroup)v2.getChildAt(0);
    ViewGroup v4 = (ViewGroup)v3.getChildAt(1);

    //my position button
    View position =  (View)v4.getChildAt(0);

    int positionWidth = position.getLayoutParams().width;
    int positionHeight = position.getLayoutParams().height;

    //lay out position button
    RelativeLayout.LayoutParams positionParams = new RelativeLayout.LayoutParams(positionWidth,positionHeight);
    int margin = positionWidth/5;
    positionParams.setMargins(0, 0, 0, margin);
    positionParams.addRule(RelativeLayout.CENTER_HORIZONTAL, RelativeLayout.TRUE);
    positionParams.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM, RelativeLayout.TRUE);
    position.setLayoutParams(positionParams);
} 
}
4

1 回答 1

1

这是一个快速的解决方案，太好了。这是完整且有效的代码：

package com.squirrel.hkairpollution;

import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.RelativeLayout;

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.UiSettings;
import com.google.android.gms.maps.model.LatLng;

public class MySupportMapFragment extends SupportMapFragment {

private static final String TAG = HKAirPollution.TAG;

public MySupportMapFragment() {
    return;
}

@Override
public View onCreateView(LayoutInflater arg0, ViewGroup arg1, Bundle arg2) {
    Log.v(TAG, "In overridden onCreateView.");
    View v = super.onCreateView(arg0, arg1, arg2);
    Log.v(TAG, "Initialising map.");
    initMap();
    return v;
}

@Override
 public void onViewCreated (View view, Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    resetMyPositionButton();
}

private void initMap(){
    UiSettings settings = getMap().getUiSettings();
    settings.setAllGesturesEnabled(true);
    settings.setMyLocationButtonEnabled(true);
    LatLng latLong = new LatLng(22.320542, 114.185715);
    getMap().moveCamera(CameraUpdateFactory.newLatLngZoom(latLong,11));
}


/**
 * Move my position button at the bottom of map
 */
private void resetMyPositionButton()
{
    //deep paths for map controls
    ViewGroup v1 = (ViewGroup)this.getView();
    ViewGroup v2 = (ViewGroup)v1.getChildAt(0);
    ViewGroup v3 = (ViewGroup)v2.getChildAt(0);
    ViewGroup v4 = (ViewGroup)v3.getChildAt(1);

    //my position button
    View position =  (View)v4.getChildAt(0);

    int positionWidth = position.getLayoutParams().width;
    int positionHeight = position.getLayoutParams().height;

    //lay out position button
    RelativeLayout.LayoutParams positionParams = new RelativeLayout.LayoutParams(positionWidth,positionHeight);
    int margin = positionWidth/5;
    positionParams.setMargins(0, 0, 0, margin);
    positionParams.addRule(RelativeLayout.CENTER_HORIZONTAL, RelativeLayout.TRUE);
    positionParams.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM, RelativeLayout.TRUE);
    position.setLayoutParams(positionParams);
} 
}
于 2013-03-17T16:37:51.337 回答