0

问候....我是新来的android和我正在制作一个应用程序,显示一个选项卡上的路线和在另一个选项卡中的路线的导航说明的地图....我跟着一个教程,以获得滑动选项卡布局完成与三个标签..以前我已经显示地图与路线在一个单独的应用程序..现在我想显示它在第二个选项卡...使用滑动标签布局的片段

我有将每个片段的单独活动关联以实现该目的,如果是这样,那么该怎么做

我试图在tab2片段中的map上工作,但我陷入了实现,因为我在googleMap中获取null bject试图与getMap() ....

我的主要活动代码初始化它的时候是:

package com.example.rafaqatrasool.optiroute; 

import android.os.Bundle; 
import android.support.v4.app.FragmentManager; 
import android.support.v4.app.FragmentTransaction; 
import android.support.v4.view.ViewPager; 
import android.support.v7.app.ActionBarActivity; 
import android.support.v7.widget.Toolbar; 
import android.view.Menu; 
import android.view.MenuItem; 


public class MainActivity extends ActionBarActivity { 


    // Declaring Your View and Variables 

    Toolbar toolbar; 
    ViewPager pager; 
    ViewPagerAdapter adapter; 
    SlidingTabLayout tabs; 
    CharSequence Titles[]={"Home","Map","Directions"}; 
    int Numboftabs =3; 

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



     // Creating The Toolbar and setting it as the Toolbar for the activity 

     toolbar = (Toolbar) findViewById(R.id.tool_bar); 
     setSupportActionBar(toolbar); 



     // Creating The ViewPagerAdapter and Passing Fragment Manager, Titles fot the Tabs and Number Of Tabs. 
     adapter = new ViewPagerAdapter(getSupportFragmentManager(),Titles,Numboftabs); 

     // Assigning ViewPager View and setting the adapter 
     pager = (ViewPager) findViewById(R.id.pager); 
     pager.setAdapter(adapter); 

     // Assiging the Sliding Tab Layout View 
     tabs = (SlidingTabLayout) findViewById(R.id.tabs); 
     tabs.setDistributeEvenly(true); // To make the Tabs Fixed set this true, This makes the tabs Space Evenly in Available width 

     // Setting Custom Color for the Scroll bar indicator of the Tab View 
     tabs.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() { 
      @Override 
      public int getIndicatorColor(int position) { 
       return getResources().getColor(R.color.tabsScrollColor); 
      } 
     }); 

     // Setting the ViewPager For the SlidingTabsLayout 
     tabs.setViewPager(pager); 

    } 



    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.menu_main, menu); 
     return true; 
    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     // Handle action bar item clicks here. The action bar will 
     // automatically handle clicks on the Home/Up button, so long 
     // as you specify a parent activity in AndroidManifest.xml. 
     int id = item.getItemId(); 

     //noinspection SimplifiableIfStatement 
     if (id == R.id.action_settings) { 
      return true; 
     } 

     return super.onOptionsItemSelected(item); 
    } 
} 

我ViewPagerAdaper代码

package com.example.rafaqatrasool.optiroute; 


import android.support.v4.app.Fragment; 
import android.support.v4.app.FragmentManager; 
import android.support.v4.app.FragmentStatePagerAdapter; 

/** 
* Created by Rafaqat Rasool on 5/26/2015. 
*/ 
public class ViewPagerAdapter extends FragmentStatePagerAdapter { 

    CharSequence Titles[]; // This will Store the Titles of the Tabs which are Going to be passed when ViewPagerAdapter is created 
    int NumbOfTabs; // Store the number of tabs, this will also be passed when the ViewPagerAdapter is created 


    // Build a Constructor and assign the passed Values to appropriate values in the class 
    public ViewPagerAdapter(FragmentManager fm, CharSequence mTitles[], int mNumbOfTabsumb) { 
     super(fm); 

     this.Titles = mTitles; 
     this.NumbOfTabs = mNumbOfTabsumb; 

    } 

    //This method return the fragment for the every position in the View Pager 
    @Override 
    public Fragment getItem(int position) { 

     if (position == 0) // if the position is 0 we are returning the First tab 
     { 
      Tab1 tab1 = new Tab1(); 
      return tab1; 
     }else if(position == 1){ 
      Tab2 tab2 = new Tab2(); 
      return tab2; 

     } 
     else    // As we are having 3 tabs if the position is now 1 it must be 2 so we are returning third tab 
     { 
      Tab3 tab3 = new Tab3(); 
      return tab3; 
     } 


    } 

    // This method return the titles for the Tabs in the Tab Strip 

    @Override 
    public CharSequence getPageTitle(int position) { 
     return Titles[position]; 
    } 

    // This method return the Number of tabs for the tabs Strip 

    @Override 
    public int getCount() { 
     return NumbOfTabs; 
    } 
} 

第二个选项卡中的代码,我想在地图上工作是

package com.example.rafaqatrasool.optiroute; 

import android.app.Dialog; 
import android.os.Bundle; 
import android.support.annotation.Nullable; 
import android.support.v4.app.Fragment; 
import android.util.Log; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 

import com.google.android.gms.common.ConnectionResult; 
import com.google.android.gms.common.GooglePlayServicesUtil; 
import com.google.android.gms.maps.GoogleMap; 
import com.google.android.gms.maps.SupportMapFragment; 


/** 
* Created by Rafaqat Rasool on 5/26/2015. 
*/ 
public class Tab2 extends Fragment { 

    GoogleMap googleMap; 
    @Override 
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { 

     View v = inflater.inflate(R.layout.tab_2, container, false); 

     return v; 
    } 

    @Override 
    public void onActivityCreated(@Nullable Bundle savedInstanceState) { 
     super.onActivityCreated(savedInstanceState); 
     // Getting Google Play availability status 
     int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getActivity().getBaseContext()); 

     // Showing status 
     if(status!= ConnectionResult.SUCCESS){ // Google Play Services are not available 

      int requestCode = 10; 
      Dialog dialog = GooglePlayServicesUtil.getErrorDialog(status, getActivity(), requestCode); 
      dialog.show(); 

     }else if(googleMap == null){ 
      Log.d("IN ON ACTIVITY CREATED ","Looking for the fragment"); 
      googleMap= ((SupportMapFragment) getActivity().getSupportFragmentManager().findFragmentById(R.id.map)).getMap(); 
     } 
     if(googleMap!=null) googleMap.setMyLocationEnabled(true); 
    } 
} 
05-31 09:01:44.357 9546-9546/com.example.rafaqatrasool.optiroute E/AndroidRuntime﹕ FATAL EXCEPTION: main 
    Process: com.example.rafaqatrasool.optiroute, PID: 9546 
    java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.android.gms.maps.GoogleMap com.google.android.gms.maps.SupportMapFragment.getMap()' on a null object reference 
      at com.example.rafaqatrasool.optiroute.Tab2.onActivityCreated(Tab2.java:47) 
      at android.support.v4.app.Fragment.performActivityCreated(Fragment.java:1797) 
      at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:979) 
      at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1138) 
      at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:740) 
      at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1501) 
      at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:490) 
      at android.support.v4.app.FragmentStatePagerAdapter.finishUpdate(FragmentStatePagerAdapter.java:163) 
      at android.support.v4.view.ViewPager.populate(ViewPager.java:1072) 
      at android.support.v4.view.ViewPager.populate(ViewPager.java:918) 
      at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1440) 
      at android.view.View.measure(View.java:17547) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535) 
      at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436) 
      at android.widget.LinearLayout.measureVertical(LinearLayout.java:722) 
      at android.widget.LinearLayout.onMeasure(LinearLayout.java:613) 
      at android.view.View.measure(View.java:17547) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535) 
      at android.widget.FrameLayout.onMeasure(FrameLayout.java:436) 
      at android.support.v7.internal.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:124) 
      at android.view.View.measure(View.java:17547) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535) 
      at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436) 
      at android.widget.LinearLayout.measureVertical(LinearLayout.java:722) 
      at android.widget.LinearLayout.onMeasure(LinearLayout.java:613) 
      at android.view.View.measure(View.java:17547) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535) 
      at android.widget.FrameLayout.onMeasure(FrameLayout.java:436) 
      at android.view.View.measure(View.java:17547) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535) 
      at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436) 
      at android.widget.LinearLayout.measureVertical(LinearLayout.java:722) 
      at android.widget.LinearLayout.onMeasure(LinearLayout.java:613) 
      at android.view.View.measure(View.java:17547) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535) 
      at android.widget.FrameLayout.onMeasure(FrameLayout.java:436) 
      at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2615) 
      at android.view.View.measure(View.java:17547) 
      at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2015) 
      at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1173) 
      at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1379) 
      at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1061) 
      at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5885) 
      at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767) 
      at android.view.Choreographer.doCallbacks(Choreographer.java:580) 
      at android.view.Choreographer.doFrame(Choreographer.java:550) 
      at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753) 
      at android.os.Handler.handleCallback(Handler.java:739) 
      at android.os.Handler.dispatchMessage(Handler.java:95) 
      at android.os.Looper.loop(Looper.java:135) 
      at android.app.ActivityThread.main(ActivityThread.java:5254) 
      at java.lang.reflect.Method.invoke(Native Method) 
      at java.lang.reflect.Method.invoke(Method.java:372) 
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) 
      at com.android.internal.os.ZygoteInit.main(ZygoteInit. 
05-31 09:01:54.805 9546-9546/com.example.rafaqatrasool.optiroute I/Process﹕ Sending signal. PID: 9546 SIG: 9 

标签2的XML是

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent"> 


    <fragment xmlns:android="http://schemas.android.com/apk/res/android" 
     android:id="@+id/map" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:name="com.google.android.gms.maps.SupportMapFragment"/> 


</RelativeLayout> 

我寻觅了:这里时

googleMap= ((SupportMapFragment) getActivity().getSupportFragmentManager().findFragmentById(R.id.map)).getMap(); 
      } 

的logcat的GetMap()intialized我得到了GoogleMap对象空很多在谷歌,我现在很沮丧,我来到这里寻求帮助...我是新来的机器人,我没有已经任何想法如何解决这一问题?

**请人帮我**

+0

你是只在模拟器上,还是在真实的设备上试过这个?谷歌地图往往不适用于模拟器。 – EpicPandaForce

+0

你有没有找到这个解决方案?..如果是这样,请share.thanks – Ramz

回答

0

那么,如果你还没有已经找到了问题,不onActivityCreated方法初始化片段的任何财产。尽可能避免在代码中使用方法onActivityCreated。如果该属性是由活动实现的接口,则在onAttach方法中执行初始化。 在你的情况下,我会建议使用FrameLayout而不是片段标签,并在膨胀视图后在onCreateView方法中动态添加谷歌地图。您应该使用view.findViewById,然后用片段替换该视图。 您应该看到fragment lifecycle以便更好地理解。