Question

我只是想在谷歌地图上启用“我的位置”按钮，但是当我添加这个时，应用程序会一直崩溃：

googleMap.setMyLocationEnabled（true）

显示Google地图的方法

这是我的代码：

    package com.example.safezone;
    import com.google.android.gms.location.LocationClient;
    import com.google.android.gms.maps.GoogleMap;
    import com.google.android.gms.maps.model.LatLng;
    import android.os.Bundle;
    import android.support.v4.app.FragmentActivity;
    import android.view.View;


public class MainActivity extends FragmentActivity {

    GoogleMap mMap;
     LatLng myPosition;
     LocationClient mLocationClient;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void mapSearch(View v) {
        setContentView(R.layout.activity_search);

    }

    public void myLocation(View v) {
        setContentView(R.layout.activity_my_location);
        mMap.setMyLocationEnabled(true);
    }     
}

错误：

11-25 14:42:27.865: E/AndroidRuntime(3521): FATAL EXCEPTION: main
11-25 14:42:27.865: E/AndroidRuntime(3521): java.lang.IllegalStateException: Could not execute method of the activity
11-25 14:42:27.865: E/AndroidRuntime(3521):     at android.view.View$1.onClick(View.java:3691)
11-25 14:42:27.865: E/AndroidRuntime(3521):     at android.view.View.performClick(View.java:4211)
11-25 14:42:27.865: E/AndroidRuntime(3521):     at android.view.View$PerformClick.run(View.java:17267)
11-25 14:42:27.865: E/AndroidRuntime(3521):     at android.os.Handler.handleCallback(Handler.java:615)
11-25 14:42:27.865: E/AndroidRuntime(3521):     at android.os.Handler.dispatchMessage(Handler.java:92)
11-25 14:42:27.865: E/AndroidRuntime(3521):     at android.os.Looper.loop(Looper.java:137)
11-25 14:42:27.865: E/AndroidRuntime(3521):     at android.app.ActivityThread.main(ActivityThread.java:4898)
11-25 14:42:27.865: E/AndroidRuntime(3521):     at java.lang.reflect.Method.invokeNative(Native Method)
11-25 14:42:27.865: E/AndroidRuntime(3521):     at java.lang.reflect.Method.invoke(Method.java:511)
11-25 14:42:27.865: E/AndroidRuntime(3521):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006)
11-25 14:42:27.865: E/AndroidRuntime(3521):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773)
11-25 14:42:27.865: E/AndroidRuntime(3521):     at dalvik.system.NativeStart.main(Native Method)
11-25 14:42:27.865: E/AndroidRuntime(3521): Caused by: java.lang.reflect.InvocationTargetException
11-25 14:42:27.865: E/AndroidRuntime(3521):     at java.lang.reflect.Method.invokeNative(Native Method)
11-25 14:42:27.865: E/AndroidRuntime(3521):     at java.lang.reflect.Method.invoke(Method.java:511)
11-25 14:42:27.865: E/AndroidRuntime(3521):     at android.view.View$1.onClick(View.java:3686)
11-25 14:42:27.865: E/AndroidRuntime(3521):     ... 11 more
11-25 14:42:27.865: E/AndroidRuntime(3521): Caused by: java.lang.NullPointerException
11-25 14:42:27.865: E/AndroidRuntime(3521):     at com.example.safezone.MainActivity.myLocation(MainActivity.java:31)
11-25 14:42:27.865: E/AndroidRuntime(3521):     ... 14 more

如果我不添加setMyLocationEnabled（），并且Google地图出现，该方法就可以正常运行。

Answer 1

您的变量mMap为空。您尚未为其分配任何对象实例。根据布局xml，您需要为其赋值或初始化它。

Answer 2

它崩溃是因为你没有得到地图所以当你试图访问它时你的mMap对象为空

mMap = getSupportFragmentManager().findFagmentById(r.id.yourfragment).getMap();

setMyLocationEnabled（）谷歌地图错误？

2 个答案: