当我试图抛出示例面临这个错误。与java空指针异常java.lang.RuntimeException:无法启动活动java.lang.NullPointerException
我得到NullPointerException在这行actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
TabAdapter = new TabPagerAdapter(getSupportFragmentManager());
Tab = (ViewPager) findViewById(R.id.pager);
Tab.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
actionBar = getActionBar();
actionBar.setSelectedNavigationItem(position);
}
});
Tab.setAdapter(TabAdapter);
actionBar = getActionBar();
// Enable Tabs on Action Bar
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
ActionBar.TabListener tabListener = new ActionBar.TabListener() {
@Override
public void onTabReselected(android.app.ActionBar.Tab tab,
FragmentTransaction ft) {
// TODO Auto-generated method stub
}
@Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
Tab.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(android.app.ActionBar.Tab tab,
FragmentTransaction ft) {
// TODO Auto-generated method stub
}
};
// Add New Tab
actionBar.addTab(actionBar.newTab().setText("Android").setTabListener(tabListener));
actionBar.addTab(actionBar.newTab().setText("iOS").setTabListener(tabListener));
actionBar.addTab(actionBar.newTab().setText("Windows").setTabListener(tabListener));
}
发布堆栈跟踪请 – 2015-01-21 12:05:11
所以'actionBar'为空,请检查,什么是最低sdk版本?如果你的版本低于14,你必须使用'getSupportActionBar' – 2015-01-21 12:05:12