根据文本、字体和可用宽度获取换行建议

Question

我有一个想要手动绘制和布局的文本。 为了让它看起来不错，我想使用一种内置方法，该方法根据我的文本、可用宽度以及使用的字体和字体大小建议换行符。
iOS 有 CTTypesetter.SuggestLineBreak，这正是我所需要的。

Android 中有类似的东西吗？

Answer 1

你应该使用StaticLayout，你以后只需要调用draw(Canvas)方法

编辑：

这是一个创建真正按钮的自定义跨度：

abstract class ButtonSpan extends ReplacementSpan implements OnClickListener {
    Button mButton;
    ViewGroup mParent;
    FrameLayout.LayoutParams mParams;

    public ButtonSpan(ViewGroup parent, String text) {
        mParent = parent;
        mButton = new Button(parent.getContext(), null, android.R.attr.buttonStyleSmall);
        mButton.setText(text);
        mButton.setOnClickListener(this);
        mParams = new FrameLayout.LayoutParams(0, 0, Gravity.NO_GRAVITY);
    }

    @Override
    public int getSize(Paint paint, CharSequence text, int start, int end, FontMetricsInt fm) {
        mButton.setTextSize(paint.getTextSize());
        mButton.measure(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
        mParams.width = mButton.getMeasuredWidth();
        mParams.height = mButton.getMeasuredHeight();
//        if (fm != null) {
//            fm.top = fm.ascent = -button.getMeasuredHeight() / 2;
//            fm.bottom = fm.descent = button.getMeasuredHeight() / 2;
//        }
        return mButton.getMeasuredWidth();
    }

    @Override
    public void draw(Canvas canvas, CharSequence text, int start, int end, float x, int top, int y, int bottom, Paint paint) {
        mParams.setMargins((int) x, top, 0, 0);
        if (mButton.getParent() == null) {
            mParent.addView(mButton, mParams);
            AnimationSet set = new AnimationSet(true);
            Animation alpha = new AlphaAnimation(0, 1);
            int duration = 750;
            alpha.setDuration(duration);
            set.addAnimation(alpha);
            Animation scale = new ScaleAnimation(0, 1, 0, 1, mParams.width / 2, mParams.height / 2);
            scale.setDuration(duration);
            set.addAnimation(scale);
            mButton.startAnimation(set);
        }
    }
}

class MyButtonSpan extends ButtonSpan {
    public MyButtonSpan(ViewGroup parent, String text) {
        super(parent, text);
    }

    @Override
    public void onClick(View v) {
        Log.d(TAG, "onClick [" + ((Button) v).getText() + "]");
    }
}

测试代码：

ScrollView sv = new ScrollView(this);
setContentView(sv);

FrameLayout layout = new FrameLayout(this);
SpannableStringBuilder ssb = new SpannableStringBuilder();
ssb.append("Lorem ipsum dolor sit amet, consectetur adipiscing elit. "
    + "Proin ac nisl nisl. Nullam [feugiat] sapien non libero semper suscipit. "
    + "Nulla nec convallis velit, vel [tincidunt] augue. \n\n"
    + "Integer urna sapien, [faucibus] a ipsum nec, blandit euismod lectus. "
    + "Cras eget tincidunt eros. Cras commodo [tempus] lorem, eu fringilla diam ultricies vel. "
    + "Donec massa ante, [consequat] sit amet orci non, rutrum interdum dolor. \n\n"
    + "Nullam gravida enim sit amet sapien bibendum, sed gravida nisl varius. "
    + "Sed hendrerit metus nec purus tempor faucibus. [Quisque] hendrerit vehicula urna sed interdum. "
    + "Proin imperdiet urna ac quam [euismod], vitae posuere metus pharetra. "
    + "Donec euismod lorem vel malesuada mollis. ");
int cnt = ssb.length();
int start = 0;
for (int i = 0; i < cnt; i++) {
    char c = ssb.charAt(i);
    if (c == '[') {
        start = i;
    } else
    if (c == ']') {
        int end = i + 1;
        Object span = new MyButtonSpan(layout, ssb.subSequence(start + 1, end - 1).toString());
        ssb.setSpan(span, start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
    }
}
TextView textView = new TextView(this);
textView.setTextSize(23);
textView.setTextColor(0xffeeeeee);
textView.setText(ssb);
layout.addView(textView);
sv.addView(layout);

Answer 2

看起来Paint.breakText 可以完成这项工作。