CODEWITHSUNDEEP
androidandroid-tablayoutonbackpressed
user4292106
user4292106

Reputation: 451

Back button and ViewPager

I am using viewPager with android.support.design.widget.TabLayout. My xml is 

<RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <android.support.v4.view.ViewPager
            android:id="@+id/home_container"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_marginBottom="@dimen/custom_tab_layout_height"
            app:layout_behavior="@string/appbar_scrolling_view_behavior" />

        <!-- tabs -->
        <android.support.design.widget.TabLayout
            android:id="@+id/home_tabs"
            android:layout_width="match_parent"
            android:layout_height="@dimen/custom_tab_layout_height"
            android:layout_alignParentBottom="true"
            app:tabGravity="fill"
            android:background="@color/light_blue_low_opacity"
            app:tabIndicatorHeight="0dp"
            app:tabMode="fixed"
            app:tabPaddingEnd="0dp"
            app:tabPaddingStart="0dp"
            app:tabSelectedTextColor="@color/light_green"
            app:tabTextAppearance="@style/HomeTabsTextAppearance"
            app:tabTextColor="@color/white" />

    </RelativeLayout>

I set viewPager as below

 mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());

        mViewPager = (ViewPager) findViewById(R.id.home_container);
        mViewPager.setAdapter(mSectionsPagerAdapter);
        mViewPager.setPagingEnabled(false);
        mViewPager.setOffscreenPageLimit(5);

        tabLayout = (TabLayout) findViewById(R.id.home_tabs);
        tabLayout.setTabTextColors(ContextCompat.getColorStateList(this, R.color.color_home_tabs));
        tabLayout.setupWithViewPager(mViewPager);

My tabListener is 

 tabLayout.setOnTabSelectedListener(
                new TabLayout.ViewPagerOnTabSelectedListener(mViewPager) {
                    @Override
                    public void onTabSelected(TabLayout.Tab tab) {
                        super.onTabSelected(tab);
                        int position = tab.getPosition();
                    mViewPager.setCurrentItem(position);

                    String tab0TextUnSelected = "<font color='" + ContextCompat.getColor(getApplicationContext(), R.color.white) + "'> " + getResources().getString(R.string.home_tab1) + " </font>";
                    String tab1TextUnSelected = "<font color='" + ContextCompat.getColor(getApplicationContext(), R.color.white) + "'> " + getResources().getString(R.string.home_tab2) + "</font>";
                    String tab2TextUnSelected = "<font color='" + ContextCompat.getColor(getApplicationContext(), R.color.white) + "'> " + getResources().getString(R.string.home_tab3) + "</font>";
                    String tab3TextUnSelected = "<font color='" + ContextCompat.getColor(getApplicationContext(), R.color.white) + "'> " + getResources().getString(R.string.home_tab4) + "</font>";
                    String tab4TextUnSelected = "<font color='" + ContextCompat.getColor(getApplicationContext(), R.color.white) + "'> " + getResources().getString(R.string.home_tab5) + "</font>";


                    String tab0TextSelected = "<font color='" + ContextCompat.getColor(getApplicationContext(), R.color.light_green) + "'> " + getResources().getString(R.string.home_tab1) + " </font>";
                    String tab1TextSelected = "<font color='" + ContextCompat.getColor(getApplicationContext(), R.color.light_green) + "'> " + getResources().getString(R.string.home_tab2) + "</font>";
                    String tab2TextSelected = "<font color='" + ContextCompat.getColor(getApplicationContext(), R.color.light_green) + "'> " + getResources().getString(R.string.home_tab3) + "</font>";
                    String tab3TextSelected = "<font color='" + ContextCompat.getColor(getApplicationContext(), R.color.light_green) + "'> " + getResources().getString(R.string.home_tab4) + "</font>";
                    String tab4TextSelected = "<font color='" + ContextCompat.getColor(getApplicationContext(), R.color.light_green) + "'> " + getResources().getString(R.string.home_tab5) + "</font>";

                    TabLayout.Tab tab0 = tabLayout.getTabAt(0);
                    TabLayout.Tab tab1 = tabLayout.getTabAt(1);
                    TabLayout.Tab tab2 = tabLayout.getTabAt(2);
                    TabLayout.Tab tab3 = tabLayout.getTabAt(3);
                    TabLayout.Tab tab4 = tabLayout.getTabAt(4);


                    if (tab0 != null) {
                        tab0.setIcon(R.drawable.ic_home_profile_unselected);
                        tab0.setText(Html.fromHtml(tab0TextUnSelected));
                    }

                    if (tab1 != null) {
                        tab1.setIcon(R.drawable.ic_home_rewards_unselected);
                        tab1.setText(Html.fromHtml(tab1TextUnSelected));
                    }

                    if (tab2 != null) {
                        tab2.setIcon(R.drawable.ic_home_gallups_unselected);
                        tab2.setText(Html.fromHtml(tab2TextUnSelected));
                    }

                    if (tab3 != null) {
                        tab3.setIcon(R.drawable.ic_home_statistics_unselected);
                        tab3.setText(Html.fromHtml(tab3TextUnSelected));
                    }

                    if (tab4 != null) {
                        tab4.setIcon(R.drawable.ic_home_settings_unselected);
                        tab4.setText(Html.fromHtml(tab4TextUnSelected));
                    }

                    if (position == 0) {
                        if (tab0 != null) {
                            tab0.setIcon(R.drawable.ic_home_profile_selected);
                            tab0.setText(Html.fromHtml(tab0TextSelected));
                        }
                    } else if (position == 1) {
                        if (tab1 != null) {
                            tab1.setIcon(R.drawable.ic_home_rewards_selected);
                            tab1.setText(Html.fromHtml(tab1TextSelected));
                        }
                    } else if (position == 2) {
                        if (tab2 != null) {
                            tab2.setIcon(R.drawable.ic_home_gallups_selected);
                            tab2.setText(Html.fromHtml(tab2TextSelected));
                        }
                    } else if (position == 3) {
                        if (tab3 != null) {
                            tab3.setIcon(R.drawable.ic_home_statistics_selected);
                            tab3.setText(Html.fromHtml(tab3TextSelected));
                        }
                    } else if (position == 4) {
                        if (tab4 != null) {
                            tab4.setIcon(R.drawable.ic_home_settings_selected);
                            tab4.setText(Html.fromHtml(tab4TextSelected));
                        }
                    }

                }


            });

I have override the onBackPressed method as follow

 if (mViewPager.getCurrentItem() != 0) {
     mViewPager.setCurrentItem(mViewPager.getCurrentItem() - 1, true);
}

To sum up, I have tabs with icons and texts. When a tab is selected then the icon is changed and the text turned in green color. When a tab is unselected then the icon is changed and the text turned in white color. This worked fine when the user clicks on tabs. When the user clicks on back button then the icon and the text color are changed correctly but for the previous tab the text remains on green color.

Upvotes: 4

Views: 9122

Answers (4)

Pradeep Gupta
Pradeep Gupta

Reputation: 1770

try this,

@Override
    public void onBackPressed() {

        if (viewPager.getCurrentItem() != 0) {
            viewPager.setCurrentItem(viewPager.getCurrentItem() - 1,false);
        }else{
             finish();
        }

    }

but do not call super.onBackPressed() method.

Upvotes: 16

Sasha Shpota
Sasha Shpota

Reputation: 10300

Override onBackPressed() method of your Activity with the following code:

@Override
public void onBackPressed() {
    int currentItem = viewPager.getCurrentItem();
    if (currentItem != 0) {
        viewPager.setCurrentItem(currentItem - 1, true);
    } else {
        super.onBackPressed();
    }
}

Upvotes: 3

Eric Liu
Eric Liu

Reputation: 1536

Your ViewPager needs an OnPageChangeListener to change the selected Tab.

    mViewPager.setOnPageChangeListener(
        new ViewPager.SimpleOnPageChangeListener() {
            @Override
            public void onPageSelected(int position) {
                // When swiping between pages, select the
                // corresponding tab.
                getActionBar().setSelectedNavigationItem(position);
            }
        });
...

Upvotes: 0

user3673952
user3673952

Reputation: 967

No sure if I understood your problem correctly, but try to call

super.onBackPressed();

after you if statement.

Upvotes: 1

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