场景
在实现设置TextView上方显示图片的时候遇到不显示的现象。代码如下
private void clickShowOrHiddenFlightDetail(View view) {
Drawable rightDrawable = (mRvFlightSegment.getVisibility() == View.VISIBLE ) ? ContextCompat.getDrawable(this, R.drawable.ic_top_jiantou) : ContextCompat.getDrawable(this, R.drawable.ic_down_jiantou);
mTvFlightDetail.setCompoundDrawables(null, null, rightDrawable, null);
}
API 解释
Sets the Drawables (if any) to appear to the left of, above, to the right of, and below the text. Use null if you do not want a Drawable there. The Drawables must already have had setBounds(Rect) called.
即对 Drawable 进行宽高设置即可
解决方案1：
根据官方api解释，对 drawable.setBounds(Rect) ；
解决方案2：
不用setCompoundDrawables(left, top, right, bottom)，而调用setCompoundDrawablesWithIntrinsicBounds(left, top, right, bottom)。意思是设置Drawable显示在text的左、上、右、下位置。
private void clickShowOrHiddenFlightDetail(View view) {
Drawable rightDrawable = (mRvFlightSegment.getVisibility() == View.VISIBLE ) ? ContextCompat.getDrawable(this, R.drawable.ic_top_jiantou) : ContextCompat.getDrawable(this, R.drawable.ic_down_jiantou);
mTvFlightDetail.setCompoundDrawablesWithIntrinsicBounds(null, null, rightDrawable, null);
}
两者有些区别详解：
setCompoundDrawables(left, top, right, bottom)和setCompoundDrawablesWithIntrinsicBounds(left, top, right, bottom)：
setCompoundDrawables 画的drawable的宽高是按drawable.setBound()设置的宽高，
所以才有The Drawables must already have had setBounds(Rect) called.即使用之前必须使用Drawable.setBounds设置Drawable的长宽。
setCompoundDrawablesWithIntrinsicBounds是画的drawable的宽高是按drawable固定的宽高，所以才有The Drawables' bounds will be set to their intrinsic bounds.即通过getIntrinsicWidth()与getIntrinsicHeight()获得。
