public class MainActivity extends FragmentActivity implements ActionBar.TabListener, OnMenuItemClickListener, OnClickListener {
private PopupMenu popupMenu;
private final static int ONE = 1;
private final static int TWO = 2;
private final static int THREE = 3;
/**
* The {@link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {@link android.support.v4.app.FragmentPagerAdapter} derivative, which
* will keep every loaded fragment in memory. If this becomes too memory
* intensive, it may be best to switch to a
* {@link android.support.v4.app.FragmentStatePagerAdapter}.
*/
SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {@link ViewPager} that will host the section contents.
*/
ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// Set up the action bar.
final ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// Create the adapter that will return a fragment for each of the three
// primary sections of the app.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
// When swiping between different sections, select the corresponding
// tab. We can also use ActionBar.Tab#select() to do this if we have
// a reference to the Tab.
mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
});
// For each of the sections in the app, add a tab to the action bar.
for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
// Create a tab with text corresponding to the page title defined by
// the adapter. Also specify this Activity object, which implements
// the TabListener interface, as the callback (listener) for when
// this tab is selected.
actionBar.addTab(
actionBar.newTab()
.setText(mSectionsPagerAdapter.getPageTitle(i))
.setTabListener(this));
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.action_settings:
/*View menuItemView = findViewById(R.id.action_settings);
PopupMenu popupMenu = new PopupMenu(this, menuItemView);
popupMenu.inflate(R.menu.counters_overflow);
popupMenu.show();*/
popupMenu = new PopupMenu(this, findViewById(R.id.action_settings));
popupMenu.getMenu().add(Menu.NONE, ONE, Menu.NONE, "Set Password");
popupMenu.getMenu().add(Menu.NONE, TWO, Menu.NONE, "About");
//popupMenu.getMenu().add(Menu.NONE, THREE, Menu.NONE, "Item 3");
popupMenu.setOnMenuItemClickListener(this);
findViewById(R.id.action_settings).setOnClickListener(this);
}
return (super.onOptionsItemSelected(item));
}
@Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
// When the given tab is selected, switch to the corresponding page in
// the ViewPager.
mViewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
@Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a DummySectionFragment (defined as a static inner class
// below) with the page number as its lone argument.
Fragment fragment = new DummySectionFragment();
Bundle args = new Bundle();
args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, position + 1);
fragment.setArguments(args);
return fragment;
}
@Override
public int getCount() {
// Show 4 total pages.
return 4;
}
@Override
public CharSequence getPageTitle(int position) {
Locale l = Locale.getDefault();
switch (position) {
case 0:
return getString(R.string.title_section1).toUpperCase(l);
case 1:
return getString(R.string.title_section2).toUpperCase(l);
case 2:
return getString(R.string.title_section3).toUpperCase(l);
case 3:
return getString(R.string.title_section4).toUpperCase(l);
}
return null;
}
}
/**
* A dummy fragment representing a section of the app, but that simply
* displays dummy text.
*/
public static class DummySectionFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
public static final String ARG_SECTION_NUMBER = "section_number";
public DummySectionFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main_dummy, container, false);
TextView dummyTextView = (TextView) rootView.findViewById(R.id.section_label);
dummyTextView.setText(Integer.toString(getArguments().getInt(ARG_SECTION_NUMBER)));
return rootView;
}
}
@Override
public boolean onMenuItemClick(MenuItem item) {
// TODO Auto-generated method stub
switch (item.getItemId()) {
case ONE:
getActionBar().hide();
//setContentView(R.layout.setpassword);
Intent intent = new Intent(this, SetPassword.class);
startActivity(intent);
break;
case TWO:
break;
}
return false;
}
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
popupMenu.show();
}
}
LOG CAT
06-10 09:38:36.836: E/AndroidRuntime(790): FATAL EXCEPTION: main 06-10 09:38:36.836: E/AndroidRuntime(790): java.lang.RuntimeException: Unable to start activity ComponentInfo{split.pack.doasplit/split.pack.doasplit.SetPassword}: java.lang.NullPointerException 06-10 09:38:36.836: E/AndroidRuntime(790):
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 06-10 09:38:36.836: E/AndroidRuntime(790):
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 06-10 09:38:36.836: E/AndroidRuntime(790):
at android.app.ActivityThread.access$600(ActivityThread.java:141) 06-10 09:38:36.836: E/AndroidRuntime(790):
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 06-10 09:38:36.836: E/AndroidRuntime(790):
at android.os.Handler.dispatchMessage(Handler.java:99) 06-10 09:38:36.836: E/AndroidRuntime(790):
at android.os.Looper.loop(Looper.java:137) 06-10 09:38:36.836: E/AndroidRuntime(790):
at android.app.ActivityThread.main(ActivityThread.java:5041) 06-10 09:38:36.836: E/AndroidRuntime(790):
at java.lang.reflect.Method.invokeNative(Native Method) 06-10 09:38:36.836: E/AndroidRuntime(790):
at java.lang.reflect.Method.invoke(Method.java:511) 06-10 09:38:36.836: E/AndroidRuntime(790):
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 06-10 09:38:36.836: E/AndroidRuntime(790):
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 06-10 09:38:36.836: E/AndroidRuntime(790):
at dalvik.system.NativeStart.main(Native Method) 06-10 09:38:36.836: E/AndroidRuntime(790):
Caused by: java.lang.NullPointerException 06-10 09:38:36.836: E/AndroidRuntime(790):
at split.pack.doasplit.SetPassword.onCreate(SetPassword.java:32) 06-10 09:38:36.836: E/AndroidRuntime(790):
at android.app.Activity.performCreate(Activity.java:5104) 06-10 09:38:36.836: E/AndroidRuntime(790):
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 06-10 09:38:36.836: E/AndroidRuntime(790):
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 06-10 09:38:36.836: E/AndroidRuntime(790):
... 11 more
答案 0 :(得分：0)
您在创建NullPointerException活动时收到SetPassword，具体地说，在SetPassword.java的第32行（检查logcat的底部）。
在onMenuItemClick方法中，您正在创建一个意图并启动活动SetPassword，这会引发异常。
答案 1 :(得分：0)
编辑：
Exception在你的SetPassword类中不在这一个帖子中发布setpassword的代码或检查SetPassword类中的第32行。
检查您在应用程序的android清单文件中所采取的主题，即您当前的主题是否有操作栏，因为您编写了getActionBar（）。hide（）;在代码中，如果您选择的主题没有操作栏，则可能会抛出异常。