最初我开始制作一张地图来显示谷歌地图，方法是fragment在RelativeLayout内使用Unable to resume activity，它在前几次工作，但由于某种原因，它＆ ＃39; s停止工作并抛出import android.app.Fragment;
import android.app.FragmentManager;
import android.location.Location;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;
public class MapActivity extends FragmentActivity {
SessionManager session;
// Google Map
private GoogleMap googleMap;
private Location userLocation = null;
@Override
protected void onStart() {
session = new SessionManager(getApplicationContext());
session.checkLogin();
try {
// Loading map
initializeMap();
} catch (Exception e) {
e.printStackTrace();
}
super.onStart();
}
public void showToast(final String toast)
{
runOnUiThread(new Runnable() {
public void run()
{
Toast.makeText(MapActivity.this, toast, Toast.LENGTH_SHORT).show();
}
});
}
/**
* function to load map. If map is not created it will create it for you
* */
private void initializeMap() {
if (googleMap == null) {
FragmentManager fm = getFragmentManager();
fm.executePendingTransactions();
// ---------v Here value of mf = null always
MapFragment mf = (MapFragment) fm.findFragmentById(R.id.map);
googleMap = mf.getMap(); // <-- This is where the error occurs
// check if map is created successfully or not
if (googleMap == null) {
Toast.makeText(getApplicationContext(),
"Sorry! unable to create maps", Toast.LENGTH_SHORT)
.show();
}
}
}
@Override
protected void onResume() {
super.onResume();
Log.d("Update", "Inside onResume");
initializeMap();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.map, 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();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public boolean authLogout(MenuItem item) {
session.logoutUser();
return true;
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_map, container,
false);
return rootView;
}
}
}
。
这是我的活动 -
fragment_map.xml和<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<fragment
android:id="@+id/map"
android:name="com.google.android.gms.maps.MapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</RelativeLayout>
档案 -
activity_map.xml Eclipse在生成空白活动时也创建了一个名为<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.lokay2.MapActivity"
tools:ignore="MergeRootFrame" />
的文件 -
03-23 15:29:34.353: E/AndroidRuntime(8432): FATAL EXCEPTION: main
03-23 15:29:34.353: E/AndroidRuntime(8432): java.lang.RuntimeException: Unable to resume activity {com.example.lokay2/com.example.lokay2.MapActivity}: java.lang.NullPointerException
03-23 15:29:34.353: E/AndroidRuntime(8432): at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2870)
03-23 15:29:34.353: E/AndroidRuntime(8432): at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:2899)
03-23 15:29:34.353: E/AndroidRuntime(8432): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2363)
03-23 15:29:34.353: E/AndroidRuntime(8432): at android.app.ActivityThread.access$600(ActivityThread.java:153)
03-23 15:29:34.353: E/AndroidRuntime(8432): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1247)
03-23 15:29:34.353: E/AndroidRuntime(8432): at android.os.Handler.dispatchMessage(Handler.java:99)
03-23 15:29:34.353: E/AndroidRuntime(8432): at android.os.Looper.loop(Looper.java:137)
03-23 15:29:34.353: E/AndroidRuntime(8432): at android.app.ActivityThread.main(ActivityThread.java:5227)
03-23 15:29:34.353: E/AndroidRuntime(8432): at java.lang.reflect.Method.invokeNative(Native Method)
03-23 15:29:34.353: E/AndroidRuntime(8432): at java.lang.reflect.Method.invoke(Method.java:511)
03-23 15:29:34.353: E/AndroidRuntime(8432): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
03-23 15:29:34.353: E/AndroidRuntime(8432): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562)
03-23 15:29:34.353: E/AndroidRuntime(8432): at dalvik.system.NativeStart.main(Native Method)
03-23 15:29:34.353: E/AndroidRuntime(8432): Caused by: java.lang.NullPointerException
03-23 15:29:34.353: E/AndroidRuntime(8432): at com.example.lokay2.MapActivity.initializeMap(MapActivity.java:60)
03-23 15:29:34.353: E/AndroidRuntime(8432): at com.example.lokay2.MapActivity.onResume(MapActivity.java:75)
03-23 15:29:34.353: E/AndroidRuntime(8432): at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1185)
03-23 15:29:34.353: E/AndroidRuntime(8432): at android.app.Activity.performResume(Activity.java:5182)
03-23 15:29:34.353: E/AndroidRuntime(8432): at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2860)
03-23 15:29:34.353: E/AndroidRuntime(8432): ... 12 more
Logcat -
{{1}}
我遇到了同样问题的很多的问题。他们中的大多数建议使用SupportMapFragment。但是从this tutorial -
仅在您定位API 12及更高版本时才使用此课程。否则，请使用SupportMapFragment。
在大多数问题中，原因与其他问题不同。如果您要将其标记为重复，请好好考虑一下。
我定位API 17.有什么想法吗？
答案 0 :(得分：0)
您的MapActivity没有布局，因此无法找到具有该ID的片段。在setContentView(R.layout.fragment_map)方法中致电onCreate()。还将fragment_map布局重命名为activity_map，因为您将其用于活动，所以更有意义。