Android ArrayAdapter抛出空指针错误

我正在尝试添加一个导航抽屉，我使用的是相同的谷歌代码示例

但我在ArrayAdapter上得到一个空错误

public class HomeActivity extends AbstractBaseActivity {
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ActionBarDrawerToggle mDrawerToggle;

private CharSequence mDrawerTitle;
private CharSequence mTitle;
private String[] mSettiltles;

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

    mSettiltles = getResources().getStringArray(R.array.menu_items);
    mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
    mDrawerList = (ListView) findViewById(R.id.left_drawer);

    // set a custom shadow that overlays the main content when the drawer opens
    //  mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START);
    // set up the drawer's list view with items and click listener
    mDrawerList.setAdapter(new ArrayAdapter<String>(this,
            R.layout.drawer_list_item, mSettiltles));
    mDrawerList.setOnItemClickListener(new DrawerItemClickListener());

    // enable ActionBar app icon to behave as action to toggle nav drawer
    getActionBar().setDisplayHomeAsUpEnabled(true);
    getActionBar().setHomeButtonEnabled(true);

    // ActionBarDrawerToggle ties together the the proper interactions
    // between the sliding drawer and the action bar app icon
    mDrawerToggle = new ActionBarDrawerToggle(
            this,                  /* host Activity */
            mDrawerLayout,         /* DrawerLayout object */
            R.drawable.ic_drawer,  /* nav drawer image to replace 'Up' caret */
            R.string.drawer_open,  /* "open drawer" description for accessibility */
            R.string.drawer_close  /* "close drawer" description for accessibility */
    ) {
        public void onDrawerClosed(View view) {
            getActionBar().setTitle(mTitle);
            invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
        }

        public void onDrawerOpened(View drawerView) {
            getActionBar().setTitle(mDrawerTitle);
            invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
        }
    };
    mDrawerLayout.setDrawerListener(mDrawerToggle);

    if (savedInstanceState == null) {
        selectItem(0);
    }
}

在android.app.ActivityThread.access$600（ActivityThread.java:141） 在android.app.ActivityThread$H.handleMessage（ActivityThread.java:1234） 位于android.os.Handler.dispatchMessage（Handler.java:99） 位于android.os.Looper.loop（Looper.java:137） 位于android.app.ActivityThread.main（ActivityThread.java:5041） 位于java.lang.reflect.Method.Invokenactive（本机方法） 位于java.lang.reflect.Method.invoke（Method.java:511） 在com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run（ZygoteInit.java:793）上 位于com.android.internal.os.ZygoteInit.main（ZygoteInit.java:560） 在dalvik.system.NativeStart.main（本机方法）`

我想第49行是这样的：

mDrawerList.setAdapter(new ArrayAdapter<String>(this,
            R.layout.drawer_list_item, mSettiltles));

mDrawerList.setAdapter（新阵列适配器，
R.layout.drawer_list_item，msettiles））；

因此，NPE只能源自

mDrawerList

为

null

。

---

因此，很明显，您的布局不包含id为左抽屉的视图，我猜是这样的：

setContentView（R.layout.activity\u home）

您可能会将ListView放在另一个布局中，如。尝试更改
setContentView
以指向可以找到ListView的布局。
mTitle=mDrawerTitle=getitle（）的目的是什么？？？为什么在
onCreate
方法中要将布局膨胀两次？
getTitle（）包含什么内容？
现在可以忽略getTitle。错误在ArrayAdapter中。GrlsHu-这是复制粘贴错误。您的
activity\u home
布局是否包含id为
left\u drawer
的视图？
12-18 06:33:41.690    1486-1486/com.myntra.delivery E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.myntra.delivery/com.myntra.delivery.activities.HomeActivity}: java.lang.NullPointerException
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
        at android.app.ActivityThread.access$600(ActivityThread.java:141)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:137)
        at android.app.ActivityThread.main(ActivityThread.java:5041)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:511)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
        at dalvik.system.NativeStart.main(Native Method)
 Caused by: java.lang.NullPointerException
        at com.myntra.delivery.activities.HomeActivity.onCreate(HomeActivity.java:49)
        at android.app.Activity.performCreate(Activity.java:5104)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)

mDrawerList.setAdapter(new ArrayAdapter<String>(this,
            R.layout.drawer_list_item, mSettiltles));