我正在使用ActionBarSherlock库来创建幻灯片菜单。我的Activity没有错误，但是当我调试我的应用时，它停在了：
getSupportActionBar().setHomeButtonEnabled(true);
我不知道为什么会停止。你能告诉我我做错了什么吗？
活动代码
package com.example.phonebook;
public class SlidingMenuDrawer extends SherlockFragmentActivity{
DrawerLayout mDrawerLayout;
ListView mDrawerList;
ActionBarDrawerToggle mDrawerToggle;
MenuListAdapter mMenuAdapter;
String[] title;
String[] subtitle;
int[] icon;
ImageView image;
Bitmap bitmap;
Fragment fragment1 = new Welcome();
//Fragment fragment2 = new Fragment2();
//Fragment fragment3 = new Fragment3();
private CharSequence mDrawerTitle;
private CharSequence mTitle;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Get the view from drawer_main.xml
setContentView(R.layout.drawer_main);
UserModel user=(UserModel) getIntent().getSerializableExtra("User");
// Get the Title
mTitle = mDrawerTitle = getTitle();
// Generate title
title = new String[] { "Title Fragment 1", "Title Fragment 2",
"Title Fragment 3" };
// Generate subtitle
subtitle = new String[] { "Subtitle Fragment 1", "Subtitle Fragment 2",
"Subtitle Fragment 3" };
// Generate icon
icon = new int[] { R.drawable.action_about, R.drawable.action_settings,
R.drawable.collections_cloud };
// Locate DrawerLayout in drawer_main.xml
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
// Locate ListView in drawer_main.xml
mDrawerList = (ListView) findViewById(R.id.listview_drawer);
// Set a custom shadow that overlays the main content when the drawer
// opens
mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow,
GravityCompat.START);
// Pass string arrays to MenuListAdapter
mMenuAdapter = new MenuListAdapter(SlidingMenuDrawer.this, title, subtitle,
icon);
// Set the MenuListAdapter to the ListView
mDrawerList.setAdapter(mMenuAdapter);
// Capture listview menu item click
mDrawerList.setOnItemClickListener(new DrawerItemClickListener());
// Enable ActionBar app icon to behave as action to toggle nav drawer
getSupportActionBar().setHomeButtonEnabled(true);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
// ActionBarDrawerToggle ties together the the proper interactions
// between the sliding drawer and the action bar app icon
mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
R.drawable.ic_drawer, R.string.drawer_open,
R.string.drawer_close) {
public void onDrawerClosed(View view) {
// TODO Auto-generated method stub
super.onDrawerClosed(view);
}
public void onDrawerOpened(View drawerView) {
// TODO Auto-generated method stub
// Set the title on the action when drawer open
getSupportActionBar().setTitle(mDrawerTitle);
super.onDrawerOpened(drawerView);
}
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
if (savedInstanceState == null) {
selectItem(0);
}
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
if (item.getItemId() == android.R.id.home) {
if (mDrawerLayout.isDrawerOpen(mDrawerList)) {
mDrawerLayout.closeDrawer(mDrawerList);
} else {
mDrawerLayout.openDrawer(mDrawerList);
}
}
return super.onOptionsItemSelected(item);
}
// ListView click listener in the navigation drawer
private class DrawerItemClickListener implements
ListView.OnItemClickListener {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
selectItem(position);
}
}
private void selectItem(int position) {
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
// Locate Position
switch (position) {
case 0:
ft.replace(R.id.content_frame, fragment1);
UserModel user= GetUser();
break;
case 1:
ft.replace(R.id.content_frame, fragment1);
break;
case 2:
ft.replace(R.id.content_frame, fragment1);
break;
}
ft.commit();
mDrawerList.setItemChecked(position, true);
// Get the title followed by the position
setTitle(title[position]);
// Close drawer
mDrawerLayout.closeDrawer(mDrawerList);
}
@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 toggles
mDrawerToggle.onConfigurationChanged(newConfig);
}
@Override
public void setTitle(CharSequence title) {
mTitle = title;
getSupportActionBar().setTitle(mTitle);
}
public UserModel GetUser()
{
image.setImageBitmap(bitmap);
ImageLoader imageLoader=new ImageLoader(getApplicationContext(),getParent());
UserModel user=new UserModel();
user.setImageBitMap(bitmap);
return user;
}
public Bitmap getBitmap(String url) {
// I identify images by hashcode. Not a perfect solution, good for the
// demo.
if (url != null && !(url.equals(""))) {
String filename = String.valueOf(url.hashCode());
File cacheDir = null;
File f = new File(cacheDir, filename);
/*
* // from SD cache Bitmap b = decodeFile(f); if (b != null) return
* b;
*/
// from web
try {
bitmap = null;
InputStream is = new URL(url).openStream();
OutputStream os = new FileOutputStream(f);
Utils.CopyStream(is, os);
os.close();
bitmap = decodeFile(f);
return bitmap;
} catch (Exception ex) {
ex.printStackTrace();
return null;
}
}
return bitmap;
}
//decode file
public Bitmap decodeFile(File f) {
try {
// decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
BitmapFactory.decodeStream(new FileInputStream(f), null, o);
// Find the correct scale value. It should be the power of 2.
final int REQUIRED_SIZE=300;
int width_tmp=o.outWidth, height_tmp=o.outHeight;
int scale=1;
while(true){
if(width_tmp/2<REQUIRED_SIZE || height_tmp/2<REQUIRED_SIZE)
break;
width_tmp/=2;
height_tmp/=2;
scale*=2;
}
// decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
} catch (FileNotFoundException e) {
}
return null;
}
}
logcat的
07-18 14:12:41.869: E/AndroidRuntime(2005): FATAL EXCEPTION: main
07-18 14:12:41.869: E/AndroidRuntime(2005): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.phonebook/com.example.phonebook.SlidingMenuDrawer}: java.lang.NullPointerException
07-18 14:12:41.869: E/AndroidRuntime(2005): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2067)
07-18 14:12:41.869: E/AndroidRuntime(2005): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2092)
07-18 14:12:41.869: E/AndroidRuntime(2005): at android.app.ActivityThread.access$600(ActivityThread.java:133)
07-18 14:12:41.869: E/AndroidRuntime(2005): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1203)
07-18 14:12:41.869: E/AndroidRuntime(2005): at android.os.Handler.dispatchMessage(Handler.java:99)
07-18 14:12:41.869: E/AndroidRuntime(2005): at android.os.Looper.loop(Looper.java:137)
07-18 14:12:41.869: E/AndroidRuntime(2005): at android.app.ActivityThread.main(ActivityThread.java:4794)
07-18 14:12:41.869: E/AndroidRuntime(2005): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:556)
07-18 14:12:41.869: E/AndroidRuntime(2005): at dalvik.system.NativeStart.main(Native Method)
07-18 14:12:41.869: E/AndroidRuntime(2005): Caused by: java.lang.NullPointerException
07-18 14:12:41.869: E/AndroidRuntime(2005): at com.example.phonebook.SlidingMenuDrawer.onCreate(SlidingMenuDrawer.java:94)
07-18 14:12:41.869: E/AndroidRuntime(2005): at android.app.Activity.performCreate(Activity.java:5008)
07-18 14:12:41.869: E/AndroidRuntime(2005): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
07-18 14:12:41.869: E/AndroidRuntime(2005): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2031)
答案 0 :(得分：0)
确保已将Sherlock主题添加到清单文件
中的应用程序标记检查此Android: getSupportActionBar() always returns null in ActionBarSherlock library
答案 1 :(得分：0)
你在com.example.phonebook.SlidingMenuDrawer.onCreate（SlidingMenuDrawer.java：94）中有一个null
方法getSupportActionBar（）很可能返回null。
在此处设置断点，当执行在此断点处暂停时，选择方法并按Ctrl + Shift + I检查返回值。
此致
答案 2 :(得分：0)
如果您在某些特定活动中使用操作栏，而不是在setTheme(R.style.Theme_Sherlock);之后将此行添加到super.onCreate(savedInstanceState);，并且如果您在整个应用程序中使用ActionBar，请将此主题添加到您的清单文件如下：android:theme="@android:style/Theme_Sherlock"。