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Tab change listener android

Posted by: admin April 23, 2020 Leave a comment

Questions:

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.

How to&Answers:

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.

Answer:

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) {

        }
    });
}

Answer:

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) {

        }
    });

Answer:

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) {

    }

Answer:

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());      
}} 

Answer:

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) {

}