我正在通过调整http://developer.android.com/training/implementing-navigation/nav-drawer.html
上的“示例应用”代码来制作自己的导航抽屉我不想使用碎片。每当我在抽屉中选择一个选项时，我只想进入一个新的活动。 问题是，当我从我的activity_main.xml中删除FrameLayout时，我得到一个NullPointerException但是如果我不删除它我没有得到异常...我不明白为什么会发生这种情况因为我不是在任何地方使用FrameLayout。
这是我的MainActivity。
public class MainActivity extends Activity {
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ActionBarDrawerToggle mDrawerToggle;
// slide menu items
private String[] navMenuTitles;
private TypedArray navMenuIcons;
private ArrayList<NavDrawerItem> navDrawerItems;
private NavDrawerListAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// load slide menu items
navMenuTitles = getResources().getStringArray(R.array.nav_drawer_items);
// nav drawer icons from resources
navMenuIcons = getResources()
.obtainTypedArray(R.array.nav_drawer_icons);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerList = (ListView) findViewById(R.id.list_slidermenu);
navDrawerItems = new ArrayList<NavDrawerItem>();
// adding nav drawer items to array
// History
navDrawerItems.add(new NavDrawerItem(navMenuTitles[0], navMenuIcons.getResourceId(0, -1)));
// Contacts
navDrawerItems.add(new NavDrawerItem(navMenuTitles[1], navMenuIcons.getResourceId(1, -1)));
// Information
navDrawerItems.add(new NavDrawerItem(navMenuTitles[2], navMenuIcons.getResourceId(2, -1)));
// Check out
navDrawerItems.add(new NavDrawerItem(navMenuTitles[3], navMenuIcons.getResourceId(3, -1)));
// Recycle the typed array
navMenuIcons.recycle();
mDrawerList.setOnItemClickListener(new SlideMenuClickListener());
// setting the nav drawer list adapter
adapter = new NavDrawerListAdapter(getApplicationContext(),
navDrawerItems);
mDrawerList.setAdapter(adapter);
// enabling action bar app icon and behaving it as toggle button
getActionBar().setDisplayShowHomeEnabled(true);
getActionBar().setDisplayHomeAsUpEnabled(true);
mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
R.drawable.ic_drawer, //nav menu toggle icon
R.string.app_name, // nav drawer open - description for accessibility
R.string.app_name // nav drawer close - description for accessibility
) {
public void onDrawerClosed(View view) {
getActionBar().setTitle(R.string.empty);
// calling onPrepareOptionsMenu() to show action bar icons
// invalidateOptionsMenu();
}
public void onDrawerOpened(View drawerView) {
getActionBar().setTitle(R.string.back_to_JobList);
// calling onPrepareOptionsMenu() to hide action bar icons
invalidateOptionsMenu();
}
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
}
/**
* Slide menu item click listener
* */
private class SlideMenuClickListener implements
ListView.OnItemClickListener {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
// display view for selected nav drawer item
displayView(position);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public boolean onOptionsItemSelected(MenuItem item) {
// toggle nav drawer on selecting action bar app icon/title
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
// Handle action bar actions click
// Handle presses on the action bar items
switch (item.getItemId()) {
case R.id.map_view:
Toast.makeText(getApplicationContext(), "Map view pressed",
Toast.LENGTH_LONG).show();
//startActivity(GoogleMapsActivity.class);
return true;
case R.id.infrastucture_only:
Toast.makeText(getApplicationContext(),
"Infrastucture only pressed", Toast.LENGTH_LONG).show();
return true;
case R.id.infrastucture_map:
Toast.makeText(getApplicationContext(),
"Infrastucture + map pressed", Toast.LENGTH_LONG).show();
return true;
case R.id.camera_only:
Toast.makeText(getApplicationContext(), "Camera only pressed",
Toast.LENGTH_LONG).show();
return true;
case R.id.camera_infrastucture:
Toast.makeText(getApplicationContext(),
"Infrastucture + Camera pressed", Toast.LENGTH_LONG).show();
//startActivity(MetaioActivity.class);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
/* *
* Called when invalidateOptionsMenu() is triggered
*/
@Override
public boolean onPrepareOptionsMenu(Menu menu) {
// if nav drawer is opened, hide the action items
boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);
menu.findItem(R.id.dots_menu).setVisible(!drawerOpen);
return super.onPrepareOptionsMenu(menu);
}
/**
* Diplaying fragment view for selected nav drawer list item
* */
private void displayView(int position) {
switch (position) {
case 0:
Toast.makeText(getApplicationContext(),
"History pressed", Toast.LENGTH_LONG).show();
Intent intent = new Intent(this, Teste.class);
startActivity(intent);
break;
case 1:
Toast.makeText(getApplicationContext(),
"Contacts pressed", Toast.LENGTH_LONG).show();
break;
case 2:
Toast.makeText(getApplicationContext(),
"Information pressed", Toast.LENGTH_LONG).show();
break;
case 3:
Toast.makeText(getApplicationContext(),
"Check out pressed", Toast.LENGTH_LONG).show();
break;
default:
break;
}
}
/**
* When using the ActionBarDrawerToggle, you must call it during
* onPostCreate() and onConfigurationChanged()...
*/
@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);
// Pass any configuration change to the drawer toggls
mDrawerToggle.onConfigurationChanged(newConfig);
}
}
这是我的activity_main.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">
<!-- Framelayout to display Fragments -->
<FrameLayout
android:id="@+id/frame_container"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<!-- Listview to display slider menu -->
<ListView
android:id="@+id/list_slidermenu"
android:layout_width="240dp"
android:layout_height="match_parent"
android:layout_gravity="start"
android:choiceMode="singleChoice"
android:divider="@color/list_divider"
android:dividerHeight="1dp"
android:listSelector="@drawable/list_selector"
android:background="@color/list_background"/>
</android.support.v4.widget.DrawerLayout>
并且很好，这是log-cat输出
03-03 15:00:07.317: E/Trace(810): error opening trace file: No such file or directory (2)
03-03 15:00:08.058: I/Choreographer(810): Skipped 41 frames! The application may be doing too much work on its main thread.
03-03 15:00:08.087: D/gralloc_goldfish(810): Emulator without GPU emulation detected.
03-03 15:00:10.867: E/InputEventReceiver(810): Exception dispatching input event.
03-03 15:00:10.867: E/MessageQueue-JNI(810): Exception in MessageQueue callback: handleReceiveCallback
03-03 15:00:10.938: E/MessageQueue-JNI(810): java.lang.NullPointerException
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.support.v4.widget.DrawerLayout.isContentView(DrawerLayout.java:853)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.support.v4.widget.DrawerLayout.onInterceptTouchEvent(DrawerLayout.java:879)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1822)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2176)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1877)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2176)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1877)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2176)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1877)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1925)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1379)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.app.Activity.dispatchTouchEvent(Activity.java:2396)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1873)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.view.View.dispatchPointerEvent(View.java:7307)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:3174)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:3119)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:4155)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:4134)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:4226)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:171)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.os.MessageQueue.nativePollOnce(Native Method)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.os.MessageQueue.next(MessageQueue.java:125)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.os.Looper.loop(Looper.java:124)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at android.app.ActivityThread.main(ActivityThread.java:4745)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at java.lang.reflect.Method.invokeNative(Native Method)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at java.lang.reflect.Method.invoke(Method.java:511)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
03-03 15:00:10.938: E/MessageQueue-JNI(810): at dalvik.system.NativeStart.main(Native Method)
03-03 15:00:10.938: D/AndroidRuntime(810): Shutting down VM
03-03 15:00:10.938: W/dalvikvm(810): threadid=1: thread exiting with uncaught exception (group=0x40a13300)
03-03 15:00:11.058: E/AndroidRuntime(810): FATAL EXCEPTION: main
03-03 15:00:11.058: E/AndroidRuntime(810): java.lang.NullPointerException
03-03 15:00:11.058: E/AndroidRuntime(810): at android.support.v4.widget.DrawerLayout.isContentView(DrawerLayout.java:853)
03-03 15:00:11.058: E/AndroidRuntime(810): at android.support.v4.widget.DrawerLayout.onInterceptTouchEvent(DrawerLayout.java:879)
03-03 15:00:11.058: E/AndroidRuntime(810): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1822)
03-03 15:00:11.058: E/AndroidRuntime(810): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2176)
03-03 15:00:11.058: E/AndroidRuntime(810): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1877)
03-03 15:00:11.058: E/AndroidRuntime(810): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2176)
03-03 15:00:11.058: E/AndroidRuntime(810): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1877)
03-03 15:00:11.058: E/AndroidRuntime(810): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2176)
03-03 15:00:11.058: E/AndroidRuntime(810): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1877)
03-03 15:00:11.058: E/AndroidRuntime(810): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.j ava:1925)
03-03 15:00:11.058: E/AndroidRuntime(810): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1379)
03-03 15:00:11.058: E/AndroidRuntime(810): at android.app.Activity.dispatchTouchEvent(Activity.java:2396)
03-03 15:00:11.058: E/AndroidRuntime(810): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1873)
03-03 15:00:11.058: E/AndroidRuntime(810): at android.view.View.dispatchPointerEvent(View.java:7307)
03-03 15:00:11.058: E/AndroidRuntime(810): at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:3174)
03-03 15:00:11.058: E/AndroidRuntime(810): at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:3119)
03-03 15:00:11.058: E/AndroidRuntime(810): at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:4155)
03-03 15:00:11.058: E/AndroidRuntime(810): at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:4134)
03-03 15:00:11.058: E/AndroidRuntime(810): at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:4226)
03-03 15:00:11.058: E/AndroidRuntime(810): at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:171)
03-03 15:00:11.058: E/AndroidRuntime(810): at android.os.MessageQueue.nativePollOnce(Native Method)
03-03 15:00:11.058: E/AndroidRuntime(810): at android.os.MessageQueue.next(MessageQueue.java:125)
03-03 15:00:11.058: E/AndroidRuntime(810): at android.os.Looper.loop(Looper.java:124)
03-03 15:00:11.058: E/AndroidRuntime(810): at android.app.ActivityThread.main(ActivityThread.java:4745)
03-03 15:00:11.058: E/AndroidRuntime(810): at java.lang.reflect.Method.invokeNative(Native Method)
03-03 15:00:11.058: E/AndroidRuntime(810): at java.lang.reflect.Method.invoke(Method.java:511)
03-03 15:00:11.058: E/AndroidRuntime(810): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
03-03 15:00:11.058: E/AndroidRuntime(810): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
03-03 15:00:11.058: E/AndroidRuntime(810): at dalvik.system.NativeStart.main(Native Method)
03-03 15:00:11.168: D/dalvikvm(810): GC_CONCURRENT freed 257K, 10% free 7438K/8199K, paused 74ms+16ms, total 207ms
03-03 15:05:11.188: I/Process(810): Sending signal. PID: 810 SIG: 9
答案 0 :(得分：1)
如您所附链接中所述：
要添加导航抽屉，请使用DrawerLayout对象声明用户界面作为布局的根视图。在DrawerLayout内，添加一个包含屏幕主要内容的视图（隐藏抽屉时的主要布局）和另一个包含导航抽屉内容的视图。
这意味着DrawerLayout希望得到2个视图 - 一个是主视图，另一个是抽屉。 如果删除FrameLayout，则需要添加虚拟视图。
答案 1 :(得分：0)
根据Android Doc about create an Navigation Drawer，您需要为包含两个子视图的布局创建android.support.v4.widget.DrawerLayout作为根：FragmentLayout和ListView
因为 the XML order implies z-ordering and the drawer must be on top of the content.
如果您不需要使用FragmentLayout视图，则可以visibility gone
<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">
<!-- Framelayout to display Fragments -->
<FrameLayout
android:id="@+id/frame_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:visibility="gone" />
<!-- Listview to display slider menu -->
<ListView
android:id="@+id/list_slidermenu"
android:layout_width="240dp"
android:layout_height="match_parent"
android:layout_gravity="start"
android:choiceMode="singleChoice"
android:divider="@color/list_divider"
android:dividerHeight="1dp"
android:listSelector="@drawable/list_selector"
android:background="@color/list_background"/>
</android.support.v4.widget.DrawerLayout>