Java 自定义ActionBar NullPointerException
对不起我的英语。我有TabActivity，希望创建自定义操作栏，但出现以下错误： 04-25 20:11:17.777:E/AndroidRuntime（8083）： java.lang.RuntimeException:无法启动活动 ComponentInfo{com.example.bonsitelazyl/com.example.bonsitelazyl.MainActivity}： java.lang.RuntimeException:无法启动活动 ComponentInfo{com.example.bonsitelazyl/com.example.bonsitelazyl.News}： java.lang.NullPointerException 主要活动：Java 自定义ActionBar NullPointerException,java,android,nullpointerexception,Java,Android,Nullpointerexception,对不起我的英语。我有TabActivity，希望创建自定义操作栏，但出现以下错误： 04-25 20:11:17.777:E/AndroidRuntime（8083）： java.lang.RuntimeException:无法启动活动 ComponentInfo{com.example.bonsitelazyl/com.example.bonsitelazyl.MainActivity}： java.lang.RuntimeException:无法启动活动 ComponentInfo{com.
public class MainActivity extends TabActivity {
TabHost tabHost;
ProgressDialog pDialog;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tabHost = getTabHost();
setTabs();
}
private void setTabs()
{
addTab("", R.drawable.tab_news, News.class);
addTab("", R.drawable.tab_servises, News.class);
addTab("", R.drawable.tab_profile, News.class);
addTab("", R.drawable.tab_contacts, News.class);
}
private void addTab(String labelId, int drawableId, Class<?> c)
{
Intent intent = new Intent(this, c);
TabHost.TabSpec spec = tabHost.newTabSpec("tab" + labelId);
View tabIndicator = LayoutInflater.from(this).inflate(R.layout.tab_indicator, getTabWidget(), false);
TextView title = (TextView) tabIndicator.findViewById(R.id.title);
title.setText(labelId);
ImageView icon = (ImageView) tabIndicator.findViewById(R.id.icon);
icon.setImageResource(drawableId);
spec.setIndicator(tabIndicator);
spec.setContent(intent);
tabHost.addTab(spec);
}
}
getSupportActionBar().setDisplayShowCustomEnabled(true);
View customNav = LayoutInflater.from(this).inflate(R.layout.custom_actionbar, null);
getSupportActionBar().setCustomView(customNav);
getSupportActionBar().setDisplayShowTitleEnabled(false);
getSupportActionBar().setCustomView(customNav);
TabActivity是不推荐使用的类。要向类中添加选项卡，请使用上面的代码 MainActivity2Activity.java
import java.util.Locale;
import android.support.v7.app.ActionBarActivity;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.os.Bundle;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
public class MainActivity2Activity extends ActionBarActivity {
SectionsPagerAdapter mSectionsPagerAdapter;
ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_activity2);
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main_activity2, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
return PlaceholderFragment.newInstance(position + 1);
}
@Override
public int getCount() {
return 3;
}
@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);
}
return null;
}
}
public static class PlaceholderFragment extends Fragment {
private static final String ARG_SECTION_NUMBER = "section_number";
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main_activity2, container, false);
return rootView;
}
}
}
<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="georgeoikonomou.fishinggps.MainActivity2Activity"/>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context="georgeoikonomou.fishinggps.MainActivity2Activity$PlaceholderFragment">
<TextView
android:id="@+id/section_label"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</RelativeLayout>
<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="georgeoikonomou.fishinggps.MainActivity2Activity"/>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context="georgeoikonomou.fishinggps.MainActivity2Activity$PlaceholderFragment">
<TextView
android:id="@+id/section_label"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</RelativeLayout>
因为@Giorgos Oikonomou遇到了
TabActivity操作栏ActionBar操作栏OnCreategetSupportActionBar().setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM);
getSupportActionBar().setCustomView(R.layout.action_bar);