Ellipsize 对于具有任意最大高度的多行 TextView 无法正常工作 [英] Ellipsize not working properly for a multiline TextView with an arbitrary maximum height

问题描述

我有一个最大高度未知的 TextView，这取决于设备的 DPI/屏幕分辨率.因此，例如，在 MDPI 设备上，这个最大高度使得一次只能显示 2 行成为可能，这个值可以增加到一个未定义的数字.

I have a TextView with an unknown maximum height, which is dependent on the device's DPI/screen resolution. So, for instance, on and MDPI device this maximum height makes it possible to show only 2 lines at a time, a value that can be increased up to an undefined number.

我的问题与 ellipsize 功能有关.假设某个设备允许显示 4 行.如果我手动设置最大行数，像这样...

My issue is related with the ellipsize functionality. Let's suppose that a certain device allows for 4 lines to be displayed. If I manually set the maximum number of lines, like this...

<TextView
    android:id="@+id/some_id"
    android:layout_width="fill_parent"
    android:layout_height="0dip"
    android:ellipsize="end" 
    android:maxLines="4"
    android:singleLine="false"
    android:layout_weight="1"
    android:gravity="center_vertical"
    android:text="This is some really really really really really long text"
    android:textSize="15sp" />

...一切正常.如果文本不合适，则在第四行末尾添加省略号，如下所示:

...everything works OK. If the text doesn't fit properly, then the ellipsis are added at the end of the fourth line, like this:

This is some
really really
really really
really long...

但我宁愿不将行数设置为静态变量，因为我更愿意支持 DPI/屏幕分辨率的任意组合.因此，如果我删除 maxLines 省略号将不再正确显示在第四行，而是显示不完整的文本部分:

But I'd rather not set the number of lines as a static variable, as I would prefer to include support for any combination of DPI/screen resolution. So if I remove maxLines the ellipsis is no longer correctly shown at line four, showing instead an incomplete portion of text:

This is some
really really
really really
really long

如果我稍微增加 TextView 的大小，我可以看到其余的文本仍在其他 Views 的后面"绘制.设置变量 maxHeight 似乎也不起作用.

If I slightly increase the TextView size, I can see that the rest of the text is still being drawn "behind" the other Views. Setting the variable maxHeight doesn't seem to work either.

我似乎真的找不到这个问题的解决方案.有任何想法吗?如果有帮助，我只使用 Android v4.0.3 及更高版本(API 级别 15).

I really can't seem to find a solution for this issue. Any ideas? If it helps, I'm working only with Android v4.0.3 and up (API level 15).

推荐答案

用 TextView#getHeight() 和 TextView 计算 TextView 有多少行#getLineHeight().然后调用 TextView#setMaxLines().

Calculate how many lines fit into the TextView with TextView#getHeight() and TextView#getLineHeight(). Then call TextView#setMaxLines().

ViewTreeObserver observer = textView.getViewTreeObserver();
observer.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
    @Override
    public void onGlobalLayout() {
        int maxLines = (int) textView.getHeight()
                / textView.getLineHeight();
        textView.setMaxLines(maxLines);
        textView.getViewTreeObserver().removeGlobalOnLayoutListener(
                this);
    }
});

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