问题
My HomeActivity extends AppCompatActivity that uses 2 tabs.
public class HomeActivity extends AppCompatActivity {
private SectionsPagerAdapter mSectionsPagerAdapter;
private TabLayout tabLayout;
...
@Override
protected void onCreate(Bundle savedInstanceState) {
...
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mViewPager);
}
...
How to listen to tab change event? Let me know if I need to add any more code for clarity.
回答1:
You can use OnTabChangeListener.See below
TabLayout tabLayout = new TabLayout(this);
tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
@Override
public void onTabSelected(TabLayout.Tab tab) {
//do stuff here
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
hope it help.
回答2:
Use the ViewPager.onPageChangeListener:
mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
}
@Override
public void onPageScrollStateChanged(int state) {
}
});
}
回答3:
You can use addOnTabSelectedListener method:
tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
@Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
if (tab.getPosition() == 0) {
toolBarTitle.setText("Tab one");
} else if (tab.getPosition() == 1) {
toolBarTitle.setText("Tab two");
} else {
toolBarTitle.setText("Tab three");
}
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
回答4:
From the Documentation
You need to implement TabLayout.OnTabSelectedListener
public class HomeActivity extends AppCompatActivity implements TabLayout.OnTabSelectedListener
override the following the method to listen for event:
@Override
public void onTabSelected(TabLayout.Tab tab) {
int position = tab.getPosition();
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}
回答5:
You should implement OnTabChangeListener to the TabActivity class rather than the contents of the Tab.
In your TabActivity implement OnTabChangeListener
then set the listener for the TabHost mTabHost.setOnTabChangedListener(this);
Ex.1
@Override
public void onTabChanged(String tabId) {
Log.i("selected tab ", tabId);
}
Ex.2
public class HelloTabWidget extends TabActivity implements OnTabChangeListener{
private TabHost mTabHost;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Resources res = getResources();
TabHost tabHost = getTabHost();
TabHost.TabSpec spec;
Intent intent;
mTabHost = getTabHost();
intent = new Intent().setClass(this, BarActivity.class);
spec = tabHost.newTabSpec("Name").setIndicator("Name",res.getDrawable(R.drawable.ic_tab_name)).setContent(intent);
tabHost.addTab(spec);
intent = new Intent().setClass(this, CityActivity.class);
spec = tabHost.newTabSpec("city").setIndicator("City",res.getDrawable(R.drawable.ic_tab_city)).setContent(intent);
tabHost.addTab(spec);
intent = new Intent().setClass(this, MapsActivity.class);
spec = tabHost.newTabSpec("Country").setIndicator("Country",res.getDrawable(R.drawable.ic_tab_map)).setContent(intent);
tabHost.addTab(spec);
tabHost.setCurrentTab(2);
mTabHost.setOnTabChangedListener(this);
}
public void onTabChanged(String tabId) {
Toast.makeText(getApplicationContext(), "Selected Tab "+tabId, Toast.LENGTH_LONG).show();
Log.i("selected tab index", "Current index - "+ mTabHost.getCurrentTab());
}}
回答6:
Depends on what you want. If you just want to know if the tab page changes, or find out which tab position was selected, use:
mViewPager.setOnPageChangeListener(new OnPageChangeListener() {
public void onPageScrollStateChanged(int state) {
}
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
public void onPageSelected(int position) {
}
});
Else, if you want to keep track of the tab itself, you will have to implement TabLayout.OnTabSelectedListener like this:
public class HomeActivity extends AppCompatActivity implements TabLayout.OnTabSelectedListener
And add this methods to your HomeActivity class:
@Override
public void onTabSelected(TabLayout.Tab tab) {
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}
来源：https://stackoverflow.com/questions/43045672/tab-change-listener-android