android - addOnPageChangeListener 未定义

Question

我从Github上下载了一个代码。我无法运行程序。问题是方法addOnPageChangeListener未定义。这是错误:

The method addOnPageChangeListener(TabLayout.TabLayoutOnPageChangeListener) is undefined for the type ViewPager

我该怎么办？我应该使用其他方法吗？这是代码:

import android.support.design.widget.CollapsingToolbarLayout;
import android.support.design.widget.CoordinatorLayout;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;

import java.util.ArrayList;


public class FourthActivity extends AppCompatActivity {

// Need this to link with the Snackbar
private CoordinatorLayout mCoordinator;
//Need this to set the title of the app bar
private CollapsingToolbarLayout mCollapsingToolbarLayout;
private FloatingActionButton mFab;
private Toolbar mToolbar;
private DrawerLayout mDrawerLayout;
private ActionBarDrawerToggle mDrawerToggle;
private ViewPager mPager;
private YourPagerAdapter mAdapter;
private TabLayout mTabLayout;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_fourth);
    mCoordinator = (CoordinatorLayout) findViewById(R.id.root_coordinator);

    mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout, mToolbar, R.string.drawer_open, R.string.drawer_close);
    mDrawerLayout.setDrawerListener(mDrawerToggle);
    mDrawerToggle.syncState();

    mTabLayout = (TabLayout) findViewById(R.id.tab_layout);
    mAdapter = new YourPagerAdapter(getSupportFragmentManager());
    mPager = (ViewPager) findViewById(R.id.view_pager);
    mPager.setAdapter(mAdapter);
    //Notice how the Tab Layout links with the Pager Adapter
    mTabLayout.setTabsFromPagerAdapter(mAdapter);

    //Notice how The Tab Layout adn View Pager object are linked
    mTabLayout.setupWithViewPager(mPager);
    mPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(mTabLayout));


    mFab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            //Notice how the Coordinator Layout object is used here
            Snackbar.make(mCoordinator, "FAB Clicked", Snackbar.LENGTH_SHORT).setAction("DISMISS", null).show();
        }
    });

    //Notice how the title is set on the Collapsing Toolbar Layout instead of the Toolbar
    mCollapsingToolbarLayout.setTitle(getResources().getString(R.string.title_activity_fourth));
}

Answer 1

在build.gradle中找到你的android support-v4库的依赖，升级版本到22.2.1或者23.0.1，一行是这样的

compile 'com.android.support:support-v4:23.0.1'