我使用以下代码更改了Floating Action Button
的backgroundTintList颜色:
fab.setBackgroundTintList(ColorStateList.valueOf(mResources.getColor(R.color.fab_color)));
但是在API 4.4.2上,我最终得到了以下结果:
在API 21及以下版本中,FAB存在问题,而在API 21及以上版本中,一切看起来都很好。
我是通过编程方式创建FAB的,代码如下:
FloatingActionButton fab = new FloatingActionButton(this);
CoordinatorLayout.LayoutParams layoutParams = new CoordinatorLayout.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
fab.setLayoutParams(layoutParams);
layoutParams.rightMargin = mResources.getDimensionPixelSize(R.dimen.activity_horizontal_margin);
((CoordinatorLayout) findViewById(R.id.coordinatorLayout)).addView(fab);
CoordinatorLayout.LayoutParams p = (CoordinatorLayout.LayoutParams) fab.getLayoutParams();
p.setAnchorId(R.id.appBarLayout);
p.anchorGravity = Gravity.BOTTOM | Gravity.END;
fab.setLayoutParams(p);
fab.setVisibility(View.VISIBLE);
fab.setBackgroundTintList(ColorStateList.valueOf(mResources.getColor(R.color.fab_color)));
fab.setImageDrawable(getResources().getDrawable(R.drawable.ic_button));
我偶然看到了FloatingActionButton
的官方源代码,发现他们在这里实例化了一个borderDrawable:
@Override
void setBackgroundDrawable(Drawable originalBackground, ColorStateList backgroundTint,
PorterDuff.Mode backgroundTintMode, int rippleColor, int borderWidth) {
// Now we need to tint the original background with the tint
mShapeDrawable = DrawableCompat.wrap(originalBackground.mutate());
DrawableCompat.setTintList(mShapeDrawable, backgroundTint);
if (backgroundTintMode != null) {
DrawableCompat.setTintMode(mShapeDrawable, backgroundTintMode);
}
final Drawable rippleContent;
if (borderWidth > 0) { // BORDER DRAWABLE RIGHT HERE!!
mBorderDrawable = createBorderDrawable(borderWidth, backgroundTint);
rippleContent = new LayerDrawable(new Drawable[]{mBorderDrawable, mShapeDrawable});
} else {
mBorderDrawable = null;
rippleContent = mShapeDrawable;
}
mRippleDrawable = new RippleDrawable(ColorStateList.valueOf(rippleColor),
rippleContent, null);
mShadowViewDelegate.setBackgroundDrawable(mRippleDrawable);
mShadowViewDelegate.setShadowPadding(0, 0, 0, 0);
}