使用 DataBinding 时在 TabLayout 中显示图标和文本

Question

我在我的应用程序中使用带有数据绑定的 MVVM 架构。我正在尝试显示图标以及顶部的图标和下方的文本以及位于屏幕底部的 TabLayout 等文本。代码如下：

activity_main.xml:

 <?xml version="1.0" encoding="utf-8"?>
    <layout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:bind="http://schemas.android.com/tools"
        xmlns:app="http://schemas.android.com/apk/res-auto">

        <data>
            <import type="android.view.View" />
            <variable
                name="handler"
                type="com.abc.MainActivity" />

            <variable
                name="manager"
                type="android.support.v4.app.FragmentManager" />
        </data>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical">

            <include
                android:id="@+id/main_toolbar"
                layout="@layout/toolbar" />

            <android.support.v4.view.ViewPager
                android:id="@+id/pager"
                android:layout_width="match_parent"
                android:layout_height="0dp"
                android:layout_weight="1"
                android:background="@color/white"
                app:handler="@{handler}" />

            <android.support.design.widget.TabLayout
                android:id="@+id/tab_layout"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="@color/black"
                app:tabTextColor="@color/white"
                app:pager="@{(pager)}">
            </android.support.design.widget.TabLayout>

        </LinearLayout>
    </layout>

MainActivity.java:

package com.abc;

import android.databinding.BindingAdapter;
import android.databinding.DataBindingUtil;
import android.os.Handler;
import android.support.design.widget.TabLayout;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.webkit.WebView;

import com.abc.databinding.ActivityMainBinding;

public class MainActivity extends AppCompatActivity {

    WebView wv;
    Handler uiHandler = new Handler();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ActivityMainBinding binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
        binding.setHandler(this);
        binding.setManager(getSupportFragmentManager());

    }

    @BindingAdapter({"bind:handler"})
    public static void bindViewPagerAdapter(final ViewPager view, final MainActivity activity)
    {
        final MainActionsAdapter adapter = new MainActionsAdapter(view.getContext(), activity.getSupportFragmentManager());

        view.setAdapter(adapter);
    }

    @BindingAdapter({"bind:pager"})
    public static void bindViewPagerTabs(final TabLayout view, final ViewPager pagerView)
    {
        view.setupWithViewPager(pagerView, true);

    }

}

MainActionsAdapter.java

package com.finchart;

import android.content.Context;
import android.graphics.drawable.Drawable;
import android.os.Build;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.text.SpannableStringBuilder;
import android.text.Spanned;
import android.text.style.DynamicDrawableSpan;
import android.text.style.ImageSpan;

import com.finchart.Fragments.ChartFragment;
import com.finchart.Fragments.MarketFragment;
import com.finchart.Fragments.MoreFragment;

public class MainActionsAdapter extends FragmentPagerAdapter
{
    private static final int MARKETS = 0;
    private static final int CHARTS = 1;
    private static final int MORE = 2;

    private static final int[] TABS = new int[]{MARKETS,CHARTS, MORE};

    private Context mContext;

    private Drawable myDrawable;
    private String title;

    public MainActionsAdapter(final Context context, final FragmentManager fm)
    {
        super(fm);
        mContext = context.getApplicationContext();
    }

    @Override
    public Fragment getItem(int position)
    {
        switch (TABS[position])
        {
            case MARKETS:
                return MarketFragment.newInstance("","");
            case CHARTS:
                return ChartFragment.newInstance("","");
            case MORE:
                return MoreFragment.newInstance("","");
        }
        return null;
    }

    @Override
    public int getCount() {
        return TABS.length;
    }

    @Override
    public CharSequence getPageTitle(int position)
    {
        switch (TABS[position])
        {
            case MARKETS:
                myDrawable = getDrawableObject(R.drawable.baseline_account_balance_white_24);
                title =  mContext.getResources().getString(R.string.market_fragment);
                break;
            case CHARTS:
                myDrawable =getDrawableObject(R.drawable.baseline_trending_up_24);
                title =  mContext.getResources().getString(R.string.chart_fragment);
                break;
            case MORE:
                myDrawable = getDrawableObject(R.drawable.baseline_menu_white_24);
                title = mContext.getResources().getString(R.string.more_fragment);
                break;
        }

        SpannableStringBuilder sb = new SpannableStringBuilder(" " + title);
        try {
            myDrawable.setBounds(5, 5, myDrawable.getIntrinsicWidth(), myDrawable.getIntrinsicHeight());
            ImageSpan span = new ImageSpan(myDrawable, DynamicDrawableSpan.ALIGN_BASELINE);
            sb.setSpan(span, 0, 1, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
            return sb;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    private Drawable getDrawableObject(int image){
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            return mContext.getDrawable(image);
        } else {
            return mContext.getResources().getDrawable(image);
        }
    }
}

toolbar.xml:

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="?attr/colorPrimary"
    android:minHeight="?attr/actionBarSize"
    app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
    app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" />

我经历过各种类似的 SO 线程，但其中 none 在我的案例中有效，线程如

所以请告诉我我在这里做错了什么，是否有可能实现这个或任何替代方案也不错。谢谢。

Answer 1

在 MainActivity.java 的 bindViewPagerTabs(...) 中，我更新了以下代码：

@BindingAdapter({"bind:pager"})
    public static void bindViewPagerTabs(final TabLayout view, final ViewPager pagerView)
    {
        view.setupWithViewPager(pagerView, true);
        view.getTabAt(0).setIcon(R.drawable.white_24);
        view.getTabAt(1).setIcon(R.drawable.up_24);
        view.getTabAt(2).setIcon(R.drawable.baseline_24);

    }

并删除了 MainActionsAdapter 中的所有额外代码。

使用 DataBinding 时在 TabLayout 中显示图标和文本

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