在Android的TabLayout中为标签添加图标

Question

我想在Android的TabLayout中为我的标签添加图标。我尝试了图标数组和getTitle方法。我没有得到任何图标。制表符只保留标题文本，标题文本数组中的文本根本不使用。下面是我的代码:

import statements...
public class scatter extends FragmentActivity {
    some variable declarations...
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_scatter);
        sensorUID = getIntent().getStringExtra("sUID");
        tankname = getIntent().getStringExtra("tNAME");
        SCALE_C = (getIntent().getStringExtra("tSCALEC"));
        SCALE_M = (getIntent().getStringExtra("tSCALEM"));
        DPs = (getIntent().getStringExtra("tDP"));
        UNITs = (getIntent().getStringExtra("tUNIT"));
        numVar = Integer.parseInt(DPs);
       final ViewPager pager = (ViewPager) findViewById(R.id.viewPager);
        pager.setAdapter(new MyPagerAdapter(getSupportFragmentManager()));
        TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
        tabLayout.addTab(tabLayout.newTab().setText("Graph"));
        tabLayout.addTab(tabLayout.newTab().setText("Values"));
        tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
        pager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
        tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                pager.setCurrentItem(tab.getPosition());
            }
            @Override
            public void onTabUnselected(TabLayout.Tab tab) {
            }
            @Override
            public void onTabReselected(TabLayout.Tab tab) {
            }
        });
    }

    private class MyPagerAdapter extends FragmentPagerAdapter {

        public MyPagerAdapter(FragmentManager fm) {
            super(fm);
        }
        @Override
        public Fragment getItem(int pos) {
            Fragment fragment;
            Bundle args = new Bundle();
            args.putString("senID", sensorUID);
            args.putInt("numVar", numVar);
            switch (pos) {
                case 0:
                    fragment = FirstFragment.newInstance("FirstFragment, Instance 1");
                    break;
                case 1:
                    fragment = SecondFragment.newInstance("SecondFragment, Instance 1");
                    break;
                default:
                    fragment = FirstFragment.newInstance("FirstFragment, Instance 1");
                    break;
            }
            fragment.setArguments(args);
            return fragment;
        }

        @Override
        public int getCount() {
            return 2;
        }
    }
}

Answer 1

TabLayout.Tab有一个setIcon()方法

    TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
    tabLayout.addTab(tabLayout.newTab().setText("Graph").setIcon(R.drawable.ic_graph));
    tabLayout.addTab(tabLayout.newTab().setText("Values").setIcon(R.drawable.ic_values));

Answer 2

正如activesence所说，因为你可以使用自定义标签布局

在styles.xml中定义自定义样式，然后将该样式应用于TabLayout:

<style name="MyCustomTabLayout" parent="Widget.Design.TabLayout">
<item name="tabIndicatorColor">#0000FF</item>
</style>

你可以在你的TabLayout中重写这个样式:

<android.support.design.widget.TabLayout
    android:id="@+id/tabs"
    style="@style/MyCustomTabLayout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">
</android.support.design.widget.TabLayout>

可以为TabLayout配置其他几个样式:

<style name="MyCustomTabLayout" parent="Widget.Design.TabLayout">
<item name="tabMaxWidth">@dimen/tab_max_width</item>
<item name="tabIndicatorColor">?attr/colorAccent</item>
<item name="tabIndicatorHeight">2dp</item>
<item name="tabPaddingStart">12dp</item>
<item name="tabPaddingEnd">12dp</item>
<item name="tabBackground">?attr/selectableItemBackground</item>
<item name="tabTextAppearance">@style/MyCustomTabTextAppearance</item>
<item name="tabSelectedTextColor">?android:textColorPrimary</item>
</style>
<style name="MyCustomTabTextAppearance" parent="TextAppearance.Design.Tab">
<item name="android:textSize">14sp</item>
<item name="android:textColor">?android:textColorSecondary</item>
<item name="textAllCaps">true</item>
</style>

目前，TabLayout类并没有提供一个清晰的抽象模型来允许在选项卡中使用图标。有许多发布的解决方案，其中之一是返回一个SpannableString，包含你的图标在一个ImageSpan，从你的

PagerAdapter的getPageTitle(position)方法，如下面的代码片段所示:

private int[] imageResId = {
    R.drawable.ic_one,
    R.drawable.ic_two,
    R.drawable.ic_three};
public CharSequence getPageTitle(int position) {     
Drawable image = ContextCompat.getDrawable(context, imageResId[position]);
 image.setBounds(0, 0, image.getIntrinsicWidth(),          
image.getIntrinsicHeight());
SpannableString sb = new SpannableString(" ");
ImageSpan imageSpan = new ImageSpan(image, ImageSpan.ALIGN_BOTTOM);
sb.setSpan(imageSpan, 0, 1, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
return sb;}

默认情况下，TabLayout创建的选项卡将textAllCaps属性设置为true，这将阻止ImageSpans被渲染。您可以通过更改tabTextAppearance属性来覆盖此行为。

<style name="MyCustomTabLayout" parent="Widget.Design.TabLayout">
  <item name="tabTextAppearance">@style/MyCustomTextAppearance</item>
</style>
<style name="MyCustomTextAppearance" parent="TextAppearance.Design.Tab">
  <item name="textAllCaps">false</item>
</style>

你可以添加图标和文本，如下所示@OverridegetPageTitle(int position) {//根据项目位置生成标题Drawable image = context.getResources().getDrawable(imageResId[position]);的形象。setBounds(0,0, image.getIntrinsicWidth()，

image.getIntrinsicHeight());
// Replace blank spaces with image icon
SpannableString sb = new SpannableString("   " + tabTitles[position]);
ImageSpan imageSpan = new ImageSpan(image, ImageSpan.ALIGN_BOTTOM);
sb.setSpan(imageSpan, 0, 1, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
return sb;
}