Android 滑动标签安卓

我想为我的项目实现一个滑动选项卡。有人有合适的教程吗？这是因为我遵循了一些教程，一些函数被弃用，从而导致空指针异常错误

以下是我的主要活动：

package com.psm.app.createtab20;

import android.os.Bundle;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.view.ViewPager;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends ActionBarActivity implements ActionBar.TabListener {

android.support.v7.app.ActionBar actionbar;
ViewPager viewpager;
FragmentPageAdapter ft;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    viewpager = (ViewPager) findViewById(R.id.pager);
    ft = new FragmentPageAdapter(getSupportFragmentManager());
    actionbar = getSupportActionBar();
    viewpager.setAdapter(ft);
    actionbar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
        actionbar.addTab(actionbar.newTab().setText("Java").setTabListener(this));
    actionbar.addTab(actionbar.newTab().setText("Php").setTabListener(this));
    actionbar.addTab(actionbar.newTab().setText(".Net").setTabListener(this));

    viewpager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
        @Override
        public void onPageSelected(int arg0) {
            actionbar.setSelectedNavigationItem(arg0);
        }
        @Override
        public void onPageScrolled(int arg0, float arg1, int arg2) {
// TODO Auto-generated method stub
        }
        @Override
        public void onPageScrollStateChanged(int arg0) {
// TODO Auto-generated method stub
        }
    });

}

@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, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

//noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

@Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
}
@Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
    viewpager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
}
}

我希望无人能帮助我