Question

我在应用程序中使用具有数据绑定的MVVM体系结构。我正在尝试在顶部显示图标，并在其下方显示文本，并在屏幕底部显示TabLayout。代码如下：

activity_main.xml：

Button logOut = new Button("Log Out");
logOut.setOnAction(e -> 
     MobileApplication.getInstance().goHome());

MainActivity.java：

 <?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>

MainActionsAdapter.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);

    }

}

toolbar.xml：

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);
        }
    }
}

我经历过各种类似的SO线程，但是在我的情况下，它们都无法正常工作，例如enter link description here

因此，请告诉我我在这里做错了什么，是否有可能实现这一目标，或者任何替代方法也都很好。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);

    }

并从MainActionsAdapter中删除了所有多余的代码。

使用DataBinding时在TabLayout中显示图标以及文本

1 个答案: