如何在编辑文本中获取每行的高度

Question

我想在添加或删除新行时为键盘设置动画，就像电报一样。 我可以这样添加 animation：

private void doAnimation(int linesCount, String s){
        Toast.makeText(this, "" + linesCount, Toast.LENGTH_SHORT).show();
        if (linesCount == 1){
            binding.message.getLayoutParams().height = defEditTextHeight;
            return;
        }
        if (linesCount < binding.message.getLineCount()) {
            ValueAnimator anim = ValueAnimator.ofInt(binding.message.getHeight(), binding.message.getHeight() + 60)
                    .setDuration(250);
            anim.addUpdateListener(animation -> {
                binding.message.getLayoutParams().height = (int) animation.getAnimatedValue();
                binding.message.requestLayout();
            });
            anim.start();
        }else if( linesCount > binding.message.getLineCount()){
            ValueAnimator anim = ValueAnimator.ofInt(binding.message.getHeight(), binding.message.getHeight() - 60)
                    .setDuration(250);
            anim.addUpdateListener(animation -> {
                binding.message.getLayoutParams().height = (int) animation.getAnimatedValue();
                binding.message.requestLayout();
            });
            anim.start();
        }
    }

但是，如您所见，对于 animation，我添加了一个随机值，如 60。但是，这对所有设备来说都不可靠。

那么，我怎样才能得到每一行的高度，以便我可以添加它并得到一个好的 animation？

提前致谢

Answer 1

EditText 每行的高度由 EditText创建的StaticLayout指定。

// Get vertical padding of the EditText
int padding = binding.message.getPaddingTop() + binding.message.getPaddingBottom();

// Get the total height of the EditText
int totalHeight = binding.message.getLayout().getHeight() + padding;
// or
int totalHeight = binding.message.getHeight();

// Get the height that line i contributes to the EditText. 
int height = binding.message.getLayout().getLineBottom(i) - binding.message.getLayout().getLineTop(i);

因此，您的 animation 定义将如下所示：

int i = linesCount - 1;
int height = binding.message.getLayout().getLineBottom(i) - binding.message.getLayout().getLineTop(i);
ValueAnimator anim = ValueAnimator.ofInt(binding.message.getHeight(), binding.message.getHeight() + height)
                .setDuration(250);

如果需要等待布局，可以使用如下：

binding.message.addOnLayoutChangeListener((v, left, top, right, bottom, oldLeft, oldTop, oldRight, oldBottom) -> {
    // code here 
};