Android，拖动时TabLayout图标颜色不变 [英] Android, TabLayout icon color doesn't change when dragging

问题描述

所以，我有这样的代码:

So, I have code like this:

tabLayout.setOnTabSelectedListener(
        new TabLayout.ViewPagerOnTabSelectedListener(tabViewPager) {

            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                super.onTabSelected(tab);

                //set selected icon color
                Drawable icon = tab.getIcon();
                icon = DrawableCompat.wrap(icon);
                DrawableCompat.setTint(icon, ContextCompat.getColor(MainActivity.this,
                        R.color.colorAccent));
                tab.setIcon(icon);
            }

            @Override
            public void onTabUnselected(TabLayout.Tab tab) {
                super.onTabUnselected(tab);

                //set unselected icon color
                Drawable icon = tab.getIcon();
                icon = DrawableCompat.wrap(icon);
                DrawableCompat.setTint(icon, ContextCompat.getColor(MainActivity.this,
                        R.color.white));
                tab.setIcon(icon);
            }

            @Override
            public void onTabReselected(TabLayout.Tab tab) {
                super.onTabReselected(tab);
            }
        });

当我单击TabLayout图标更改页面时，一切正常，但是当我拖动viewPager时，图标的颜色不会改变，看起来像这样:

When I click on TabLayout icon to change page, everything is ok, but when I drag viewPager, the color of icon doesn't change and it looks like this:

推荐答案

那不是应该做的事情. TabLayout 可以根据 state_selected ://developer.android.com/reference/android/graphics/drawable/StateListDrawable.html"rel =" nofollow> StateListDrawable

That is not how it should be done. TabLayout can choose the icon based on state_selected from StateListDrawable

有两种创建StateListDrawable的方法:

1.仅限API 21+解决方案

像这样创建标签:

mTabLayout = (TabLayout) findViewById(R.id.tab_layout);
for (int i = 0; i < 4; ++i) {
    TabLayout.Tab tab = mTabLayout.newTab();
    tab.setIcon(R.drawable.icon);
    mTabLayout.addTab(tab, i);
}

其中R.drawable.icon是可绘制状态:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/drawable_unselected" android:state_selected="false"/>
    <item android:drawable="@drawable/drawable_selected" android:state_selected="true"/>
</selector>

R.drawable.drawable_unselected是您的图像，而R.drawable.drawable_selected看起来像这样:

R.drawable.drawable_unselected is you image and R.drawable.drawable_selected looks like this:

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <bitmap
            android:src="@drawable/drawable_unselected"
            android:tint="@color/answer_color"/>
    </item>
</layer-list>

2. API 4+兼容解决方案

不幸的是，API 21中引入了可绘制xml中bitmap标记内的android:tint.在较低的API上，需要编程解决方案.

Unfortunately, android:tint inside bitmap tag in drawable xml has been introduced in API 21. On lower API's, programmatic solution is needed.

在这里修改以前的代码:

Here modify the previous code:

mTabLayout = (TabLayout) findViewById(R.id.tab_layout);
for (int i = 0; i < 4; ++i) {
    TabLayout.Tab tab = mTabLayout.newTab();
    StateListDrawable stateDrawable = new StateListDrawable();
    Drawable unSelectedDrawable = ContextCompat.getDrawable(this, R.drawable.drawable_unselected);
    Drawable selectedDrawable = createdSelectedDrawable(this, R.drawable.drawable_unselected);
    stateDrawable.addState(new int[]{-android.R.attr.state_selected}, unSelectedDrawable);
    stateDrawable.addState(new int[]{android.R.attr.state_selected}, selectedDrawable);
    tab.setIcon(stateDrawable);
    mTabLayout.addTab(tab, i);
}

用于创建state_selected的功能:

private Drawable createdSelectedDrawable(Context context, int iconResource) {
    Bitmap one = BitmapFactory.decodeResource(getResources(), iconResource);
    Bitmap oneCopy = Bitmap.createBitmap(one.getWidth(), one.getHeight(), Bitmap.Config.ARGB_8888);
    Canvas c = new Canvas(oneCopy);
    Paint p = new Paint();
    p.setColorFilter(new PorterDuffColorFilter(ContextCompat.getColor(context, android.R.color.holo_red_dark), PorterDuff.Mode.SRC_ATOP));
    c.drawBitmap(one, 0, 0, p);
    return new BitmapDrawable(getResources(), oneCopy);
}

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