构建SpannableStringBuilder中的标志变量是什么

Question

我读了google docs中的flag参数，但我找不到它到底在做什么。例如在下面的代码中：

SpannableStringBuilder builder1 = new SpannableStringBuilder();
builder1.append("hi");
builder1.append("this is test");
builder1.setSpan(new ForegroundColorSpan(Color.RED), 0, 7, Spanned.SPAN_INCLUSIVE_EXCLUSIVE);
myTextView.setText(builder1);

如果你改变第四个参数并像这样设置变量: Spanned.SPAN_INCLUSIVE_INCLUSIVE，Spanned.SPAN_INCLUSIVE_EXCLUSIVE，Spanned.SPAN_EXCLUSIVE_EXCLUSIVE，Spanned.SPAN_EXCLUSIVE_EXCLUSIVE，没有区别。

在结果上没有区别。

但是当运行这段代码时：

SpannableStringBuilder builder1 = new SpannableStringBuilder();
builder1.append("hi");
builder1.append("this is test");
builder1.setSpan(new ForegroundColorSpan(Color.RED), 0, 7, Spanned.SPAN_INCLUSIVE_EXCLUSIVE);

SpannableStringBuilder builder2 = new SpannableStringBuilder();
builder1.append("second test this is going to be different");
builder1.setSpan(new BackgroundColorSpan(Color.BLUE), 10, 15, Spanned.SPAN_INCLUSIVE_EXCLUSIVE);

SpannableStringBuilder all = new SpannableStringBuilder();
all.append(builder2);
all.insert(0, "\n");
all.insert(0, builder1);

有人能解释一下为什么会发生这种情况吗？

Answer 1

该标志被设置在正被用来在输入法的组成文本上应用临时样式信息的跨度上，使得当正在替换组成文本时可以找到它们并将其移除