我尝试使用谷歌地图启动导航抽屉，但由于某种原因它崩溃了我。 （它甚至不会加载第一张地图）。 我认为问题在于适配器或xml的文件。 LogCat说问题出在第102行：
mDrawerList.setAdapter(new ArrayAdapter<String>(this,
但我无法找到这条线的错误。 我附加了xml文件，Java和LogCat。 正如在官方Android开发者网站上提到的那样，我兴奋地跟着......但我仍然没有在我的代码中弄错。 我怀疑它是关于XML之一的。也许Fragment FrameLayout需要使用drawerlayout.xml中的map的FrameLayout进行更改？ 我有点困惑。什么可以使应用程序运行而不会崩溃？（它崩溃逃跑，并没有加载地图） 谢谢。
drawer_layout.xml
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<!-- The main content view -->
<FrameLayout
android:id="@+id/content_frame"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<!-- The navigation drawer -->
<ListView android:id="@+id/left_drawer"
android:layout_width="240dp"
android:layout_height="match_parent"
android:layout_gravity="start"
android:choiceMode="singleChoice"
android:divider="@android:color/transparent"
android:dividerHeight="0dp"
android:background="#111"/>
activitymain.xml
<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/map"
android:name="com.google.android.gms.maps.MapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent" />
MainActivity.Java
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.res.Configuration;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationManager;
import android.os.Bundle;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.widget.DrawerLayout;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.GoogleMap.OnMyLocationButtonClickListener;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.model.LatLng;
public class MainActivity extends Activity implements LocationListener {
// maps&location global variables
GoogleMap map;
public double longitude;
public double latitude;
Location location;
// navigation drawer global variables
private String[] mNavigationTitles;
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ActionBarDrawerToggle mDrawerToggle;
private CharSequence mDrawerTitle;
private CharSequence mTitle;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
map = ((MapFragment) getFragmentManager().findFragmentById(R.id.map))
.getMap();
map.setMyLocationEnabled(true);
// get location code
final Criteria criteria = new Criteria();
final LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
lm.getBestProvider(criteria, true);
final Location location = lm
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
// animates the camera in zoom 7 to the location of the user
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
LatLng UserLoc = new LatLng(latitude, longitude);
map.animateCamera(CameraUpdateFactory.newLatLngZoom(UserLoc, 7));
}
// else {
// Toast.makeText(getApplicationContext(), "cant get loc",
// Toast.LENGTH_LONG).show();
// }
// LocationButtonListener
map.setOnMyLocationButtonClickListener(new OnMyLocationButtonClickListener() {
@Override
public boolean onMyLocationButtonClick() {
// if the Gps is off it openes a dialog to turn it off
if (!lm.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
buildAlertMessageNoGps();
} else /* if (location == null) */{
// if it on, animates to the current position
final Location location = lm
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
latitude = location.getLatitude();
longitude = location.getLongitude();
map.animateCamera(CameraUpdateFactory.newLatLngZoom(
new LatLng(location.getLatitude(), location
.getLongitude()), 15));
return false;
}
return false;
}
});
// navigation drawer declarations&adapter
mNavigationTitles = getResources().getStringArray(
R.array.Navigation_Drawer);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerList = (ListView) findViewById(R.id.left_drawer);
// Set the adapter for the list view
mDrawerList.setAdapter(new ArrayAdapter<String>(this,
R.layout.drawer_layout, mNavigationTitles));
// Set the list's click listener
mDrawerList.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// TODO Auto-generated method stub
selectItem(position);
}
});
mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
R.drawable.firstlogo, R.string.Yes, R.string.no) {
/** Called when a drawer has settled in a completely closed state. */
public void onDrawerClosed(View view) {
super.onDrawerClosed(view);
getActionBar().setTitle(mTitle);
invalidateOptionsMenu(); // creates call to
// onPrepareOptionsMenu()
}
/** Called when a drawer has settled in a completely open state. */
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
getActionBar().setTitle(mDrawerTitle);
invalidateOptionsMenu(); // creates call to
// onPrepareOptionsMenu()
}
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
getActionBar().setDisplayHomeAsUpEnabled(true);
getActionBar().setHomeButtonEnabled(true);
// end of OnCreate function
}
@Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
// Sync the toggle state after onRestoreInstanceState has occurred.
mDrawerToggle.syncState();
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
mDrawerToggle.onConfigurationChanged(newConfig);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Pass the event to ActionBarDrawerToggle, if it returns
// true, then it has handled the app icon touch event
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
// Handle your other action bar items...
return super.onOptionsItemSelected(item);
}
private void selectItem(int position) {
// Create a new fragment and specify the planet to show based on
// position
switch (position) {
case 1:
Toast.makeText(getApplicationContext(), "cant get loc",
Toast.LENGTH_LONG).show();
break;
default:
break;
}
// Highlight the selected item, update the title, and close the drawer
mDrawerList.setItemChecked(position, true);
setTitle(mNavigationTitles[position]);
mDrawerLayout.closeDrawer(mDrawerList);
}
@Override
public void setTitle(CharSequence title) {
mTitle = title;
getActionBar().setTitle(mTitle);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
protected void onResume() {
// TODO Auto-generated method stub
setUpMapIfNeeded();
super.onResume();
}
private void setUpMapIfNeeded() {
// Do a null check to confirm that we have not already instantiated the
// map.
if (map == null) {
map = ((MapFragment) getFragmentManager()
.findFragmentById(R.id.map)).getMap();
if (map != null) {
}
}
}
// function that opened an activity to turn on the GPS
private void buildAlertMessageNoGps() {
final AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("GPS is off ")
.setCancelable(true)
.setPositiveButton("Yes",
new DialogInterface.OnClickListener() {
public void onClick(final DialogInterface dialog,
final int id) {
startActivity(new Intent(
android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS));
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(final DialogInterface dialog,
final int id) {
dialog.cancel();
}
});
final AlertDialog alert = builder.create();
alert.show();
}
@Override
public void onLocationChanged(Location location) {
longitude = location.getLongitude();
latitude = location.getLatitude();
}
}
logcat的：
06-05 12:15:53.816: E/AndroidRuntime(22316): FATAL EXCEPTION: main
06-05 12:15:53.816: E/AndroidRuntime(22316): java.lang.RuntimeException: Unable to start activity ComponentInfo{nir.rauch.flantir/nir.rauch.flantir.MainActivity}: java.lang.NullPointerException
06-05 12:15:53.816: E/AndroidRuntime(22316): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2295)
06-05 12:15:53.816: E/AndroidRuntime(22316): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2349)
06-05 12:15:53.816: E/AndroidRuntime(22316): at android.app.ActivityThread.access$700(ActivityThread.java:159)
06-05 12:15:53.816: E/AndroidRuntime(22316): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1316)
06-05 12:15:53.816: E/AndroidRuntime(22316): at android.os.Handler.dispatchMessage(Handler.java:99)
06-05 12:15:53.816: E/AndroidRuntime(22316): at android.os.Looper.loop(Looper.java:137)
06-05 12:15:53.816: E/AndroidRuntime(22316): at android.app.ActivityThread.main(ActivityThread.java:5419)
06-05 12:15:53.816: E/AndroidRuntime(22316): at java.lang.reflect.Method.invokeNative(Native Method)
06-05 12:15:53.816: E/AndroidRuntime(22316): at java.lang.reflect.Method.invoke(Method.java:525)
06-05 12:15:53.816: E/AndroidRuntime(22316): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1187)
06-05 12:15:53.816: E/AndroidRuntime(22316): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)
06-05 12:15:53.816: E/AndroidRuntime(22316): at dalvik.system.NativeStart.main(Native Method)
06-05 12:15:53.816: E/AndroidRuntime(22316): Caused by: java.lang.NullPointerException
06-05 12:15:53.816: E/AndroidRuntime(22316): at nir.rauch.flantir.MainActivity.onCreate(MainActivity.java:102)
06-05 12:15:53.816: E/AndroidRuntime(22316): at android.app.Activity.performCreate(Activity.java:5372)
06-05 12:15:53.816: E/AndroidRuntime(22316): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1104)
06-05 12:15:53.816: E/AndroidRuntime(22316): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2257)
06-05 12:15:53.816: E/AndroidRuntime(22316): ... 11 more
答案 0 :(得分：0)
你的实际问题在下面 取代
setContentView(R.layout.activity_main);
带
setContentView(R.layout.drawer_layout);
你绑定错误的xml并且你没有在相同的活动上加载片段和抽屉 还会在创建时注释所有地图代码并将其放在新的片段类上......并在片段类中加载不在活动类中的地图。