谷歌地圖不顯示在android系統

Question

標記我下面toturial在Google Developers網站給出在MapsActivity.java

package com.pro.soft.inzi.track_trace; 

import android.content.Intent; 
import android.os.Bundle; 
import android.support.v4.app.FragmentActivity; 
import android.view.View; 
import android.widget.Button; 

import com.google.android.gms.maps.CameraUpdateFactory; 
import com.google.android.gms.maps.GoogleMap; 
import com.google.android.gms.maps.OnMapReadyCallback; 
import com.google.android.gms.maps.model.LatLng; 
import com.google.android.gms.maps.model.MarkerOptions; 

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback { 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_maps); 

     Button sign_in_btn = (Button) findViewById(R.id.b1); 
     sign_in_btn.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 
       Intent intent = new Intent(getApplicationContext(),Live.class); 
       startActivity(intent); 
      } 
     }); 
     Button history_btn = (Button) findViewById(R.id.b2); 
     history_btn.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 
       Intent intent = new Intent(getApplicationContext(), History.class); 
       startActivity(intent); 
      } 
     }); 
    } 
    @Override 
    public void onMapReady(GoogleMap googleMap) { 

     // Add a marker in Pakistan and move the camera 
     LatLng Pakistan = new LatLng(31, 71); 
     googleMap.addMarker(new MarkerOptions().position(Pakistan).title("Marker in Pakistan")); 
     googleMap.moveCamera(CameraUpdateFactory.newLatLng(Pakistan)); 
    } 
} 

這些都是AndroidManifest.xml文件

<uses-permission android:name="android.permission.INTERNET" /> 
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> 
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> 
    <uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" /> 
    <!-- 
The ACCESS_COARSE/FINE_LOCATION permissions are not required to use 
     Google Maps Android API v2, but are recommended. 
    --> 
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" /> 
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> 

    <!-- 
    To retrieve OAuth 2.0 tokens or invalidate tokens to disconnect a user. This disconnect 
    option is required to comply with the Google+ Sign-In developer policies 
    --> 
    <uses-permission android:name="android.permission.USE_CREDENTIALS" /> 
    <!-- To retrieve the account name (email) as part of sign-in: --> 
    <uses-permission android:name="android.permission.GET_ACCOUNTS" /> 
    <!-- To auto-complete the email text field in the login form with the user's emails --> 
    <uses-permission android:name="android.permission.READ_PROFILE" /> 
    <uses-permission android:name="android.permission.READ_CONTACTS" /> 

    <permission 
     android:name="your.package.name.permission.MAPS_RECEIVE" 
     android:protectionLevel="signature" /> 
    <uses-permission android:name="your.package.name.permission.MAPS_RECEIVE"/> 
    <uses-feature 
     android:glEsVersion="0x00020000" 
     android:required="true"/> 

的一切權限，該代碼除了一個Marker做工精細我遵循這個網站上的相關問題和網絡上的說明但是都是徒勞的。
標記未顯示在地圖中 請告訴我什麼是錯的。

編輯：這裏是activity_maps代碼，包括MapFragment在它

<RelativeLayout 
    android:layout_height="match_parent" 
    android:layout_width="match_parent" 
    xmlns:android="http://schemas.android.com/apk/res/android"> 

    <Button 
     android:id="@+id/b1" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="@string/b1_text" 
     /> 
    <Button 
     android:id="@+id/b2" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="@string/b2_text" 
     android:layout_toRightOf="@+id/b1"/> 
    <Button android:id="@+id/b3" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="@string/b3_text" 
     android:layout_toRightOf="@+id/b2"/> 

    <RelativeLayout 
     android:id="@+id/mainP" 
     android:layout_width="match_parent" 
     android:layout_height="400dp" 
     android:layout_below="@+id/b2"> 

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

    </RelativeLayout> 
    <EditText 
     android:id="@+id/info" 
     android:layout_width="160dp" 
     android:layout_height="wrap_content" 
     android:hint="@string/info_1" 
     android:layout_below="@+id/mainP" 
     /> 
    <EditText 
     android:layout_width="160dp" 
     android:layout_height="wrap_content" 
     android:hint="@string/info_2" 
     android:layout_below="@+id/mainP" 
     android:layout_toRightOf="@+id/info"/> 
</RelativeLayout> 

Answer 1

首先，你應該初始化您googleMap Object在onCreate(....)

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

Answer 2

試試這個

googleMap.addMarker(new MarkerOptions() 
      .position(Pakistan) 
      .title("Marker in Pakistan") 
      .icon(BitmapDescriptorFactory 
      .defaultMarker(BitmapDescriptorFactory.HUE_GREEN))); 

Answer 3

add this ,it works 

googleMap.addMarker（新的MarkerOptions（）.POSITION（新經緯度（緯度，經度））。title（「我的位置」）.snippet（「kochi」）。draggable（true））;

Answer 4

你onMapReady(GoogleMap googleMap)不會被調用。 你需要調用getMapAsync在地圖上的片段設置OnMapReadyCallback

從the documentation

公共無效getMapAsync（OnMapReadyCallback回調）

設置將被觸發時的GoogleMap的回調對象 實例已準備就緒可以使用。

你onCreate函數的末尾添加以下代碼：

MapFragment mapFragment = (MapFragment) getFragmentManager().findFragmentById(R.id.map); 
mapFragment.getMapAsync(this);