年前的这几天,一直在看代码,发现自己之前对很多技术点的理解都不全面,甚至根本就是想当然。所以有这样一个想法,要把之前理解很粗浅的东西慢慢整理一遍,补一下技术上的短板。
这个过程会比较长,准备把涉及到的不同技术点写一个系列文章,系列名字嘛,就直白点:其实你不懂,是不是很直白O(∩_∩)O~
其实你不懂:Android之Spanned flag就作为'其实你不懂'系列的开篇!
1:Spanned flag都有哪些可选值
- SPAN_POINT_MARK_MASK
- SPAN_MARK_MARK
- SPAN_MARK_POINT
- SPAN_POINT_MARK
- SPAN_POINT_POINT
- SPAN_PARAGRAPH
- SPAN_PARAGRAPH
- SPAN_INCLUSIVE_EXCLUSIVE(常用)
- SPAN_INCLUSIVE_INCLUSIVE(常用)
- SPAN_EXCLUSIVE_EXCLUSIVE(常用)
- SPAN_EXCLUSIVE_INCLUSIVE(常用)
- SPAN_COMPOSING
- SPAN_INTERMEDIATE
- SPAN_USER_SHIFT
- SPAN_USER
- SPAN_PRIORITY_SHIFT
- SPAN_PRIORITY
2:Spanned flag常用值的效果
- SPAN_INCLUSIVE_INCLUSIVE
- 前后都包括,在指定范围前后插入新字符,都会应用新样式
- SPAN_EXCLUSIVE_EXCLUSIVE
- 前后都不包括,在指定范围前后插入新字符,样式无变化
- SPAN_INCLUSIVE_EXCLUSIVE
- 前面包括,后面不包括
- SPAN_EXCLUSIVE_INCLUSIVE
- 后面包括,前面不包括
3:不同的值flag,当EditText文本内容发生改变,表现有何区别?(不包含SPAN_POINT_MARK_MASK,SPAN_PARAGRAPH)
实验初始设置:不同的EditText初始的文本都是"一二三四五六七八九十"构造的SpannableString,都使用相同的AbsoluteSizeSpan,ForegroundColorSpan实例设置文本样式,区别只在于flag的值。
//设置初始内容
String str = "一二三四五六七八九十";
//1:构造SpannableString实例
SpannableString spannableStringEE = new SpannableString(str);
SpannableString spannableStringII = new SpannableString(str);
SpannableString spannableStringEI = new SpannableString(str);
SpannableString spannableStringIE = new SpannableString(str);
//2:构造指定类型的Span,这里使用AbsoluteSizeSpan,ForegroundColorSpan
AbsoluteSizeSpan sizeSpan = new AbsoluteSizeSpan(24,true);
ForegroundColorSpan colorSpan = new ForegroundColorSpan(Color.RED);
//3:将构造的AbsoluteSizeSpan实例,ForegroundColorSpan实例应用于SpannableString实例,只有 flags 有区别
不同的EditText实例,初始内容如下:
原始1.png原始2.png
3.1:向EditText中继续插入文字:
插入文字1.png插入文字2.png
通过图片可以得到结论,单纯插入文字:
SPAN_POINT_MARK 作用等同于 SPAN_INCLUSIVE_INCLUSIVE;
SPAN_POINT_MARK 作用等同于 SPAN_EXCLUSIVE_EXCLUSIVE;
SPAN_POINT_POINT 作用等同于 SPAN_EXCLUSIVE_INCLUSIVE;
SPAN_COMPOSING 关联的EditText中所有内容都失去新样式;
其余flag值作用等同于 SPAN_INCLUSIVE_EXCLUSIVE;
3.2:将EditText中内容完全删除后重新输入:
完全删除后重新输入.png完全删除后重新输入.gif
看GIF动图可能表述的更清晰。
通过图片可以得到结论,内容完全删除后重新输入:
SPAN_POINT_MARK 和 SPAN_INCLUSIVE_INCLUSIVE 关联的EditText中所有内容都会保持新样式;
其余所有的flag值,都会失去新样式;
3.3:按照EditText中新样式的起止值,进行文字替换:
按照原始的起止位置进行文字不等长替换.png按照原始的起止位置进行文字不等长替换.gif
通过图片可以得到结论,按照EditText中新样式的起止值,进行文字替换:
SPAN_COMPOSING 关联的EditText中所有内容都失去新样式;
其余任意flag关联的EditText,替换来的文字都保持了新样式;
3.4:新替换文字的起止值范围大于EditText中新样式的起止值,进行文字替换:
起止位置超过原始起止位置替换.gif通过图片可以得到结论,新替换文字的起止值范围大于EditText中新样式的起止值,进行文字替换:
SPAN_POINT_MARK 和 SPAN_INCLUSIVE_INCLUSIVE 关联的EditText,新替换文字会保持新样式;
其余所有的flag值,都会失去新样式;
4:SPAN_POINT_MARK_MASK,SPAN_PARAGRAPH,当EditText文本内容发生改变,表现有何区别?
4.1:为什么这两个flag值的表现要单独分析?
我在实验过程中,出现过2个异常,描述如下:
PARAGRAPH span must start at paragraph boundary
PARAGRAPH span must end at paragraph boundary
后来看了SDK中这两个flag值的描述,在java代码中进行实验,理解了这两个flag值使用的特殊条件:
- start值必须为 0(SpannableString的开头)或 \n(换行符)所在的索引值+1;
- end必须要为 \n(换行符)所在的索引值+1 或 SpannableString的结尾字符索引值+1(SpannableString的长度值)
- start值有误 :报异常 PARAGRAPH span must start at paragraph boundary
- end值有误 :报异常 PARAGRAPH span must end at paragraph boundary
- 同样,要是start<0或者end>=length,也会报错。
怎么理解呢?就是这两个flag值,对于新样式的设定,是针对于“段落”的,何为“段落”?就是EditText中1:所有的文本或者2:完整的1行或者多行。如果你在调用SpannableString的setSpan方法时候,start和end的值所指定的文本不属于1:所有的文本或者2:完整的1行或者多行,那么就会报上面提到的异常。
setSpan(Object what, int start, int end, int flags))]
此处的‘行’,指的是\n(换行符)引起的换行;
看了下面的实际演示,应该更容易理解。
4.2:EditText中的文本,完全删除后重新输入
P-完全删除后重新输入.gif通过图片可以得到结论,EditText中的文本,完全删除后重新输入:
新输入的文本未使用新样式;
4.3:在EditText实例新样式的左侧,进行不完全的替换
P-起始小于原始起始终止大于原始起始小于原始终止 替换.gif通过图片可以得到结论,在EditText实例新样式的左侧,进行不完全的替换:
替换的文字所涉及到的完整的的新样式丢失;
替换的文字没有涉及到的完整行,新样式依然保留;
4.4:在EditText实例新样式的右侧,进行不完全的替换
P-起始大于原始起始小于原始终止终止大于原始终止 替换.gif通过图片可以得到结论,在EditText实例新样式的右侧,进行不完全的替换:
替换文字起始位置所在的完整行,新样式依然保留,
且
新样式一直到延伸到替换文字终止位置所在的完整行;
5:涉及到的代码
java文件:
public class SpannedActivity extends AppCompatActivity implements View.OnClickListener{
private ScrollView activitySpanned;
// private EditText tvSpanExclusiveExclusive;
// private EditText tvSpanInclusiveInclusive;
// private EditText tvSpanExclusiveInclusive;
// private EditText tvSpanInclusiveExclusive;
private EditText tv_span_point_mark_mask;
// private EditText tv_span_mark_mark;
// private EditText tv_span_mark_point;
// private EditText tv_span_point_mark;
// private EditText tv_span_point_point;
private EditText tv_span_paragraph;
// private EditText tv_span_composing;
// private EditText tv_span_intermediate;
// private EditText tv_span_user_shift;
// private EditText tv_span_user;
// private EditText tv_span_priority_shift;
// private EditText tv_span_priority;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_spanned);
initViews();
}
private void initViews() {
activitySpanned = (ScrollView) findViewById(R.id.activity_spanned);
// tvSpanExclusiveExclusive = (EditText)findViewById(R.id.tv_span_exclusive_exclusive);
// tvSpanInclusiveInclusive = (EditText) findViewById(R.id.tv_span_inclusive_inclusive);
// tvSpanExclusiveInclusive = (EditText) findViewById(R.id.tv_span_exclusive_inclusive);
// tvSpanInclusiveExclusive = (EditText) findViewById(R.id.tv_span_inclusive_exclusive);
tv_span_point_mark_mask = (EditText) findViewById(R.id.tv_span_point_mark_mask);
// tv_span_mark_mark = (EditText) findViewById(R.id.tv_span_mark_mark);
// tv_span_mark_point = (EditText) findViewById(R.id.tv_span_mark_point);
// tv_span_point_mark = (EditText) findViewById(R.id.tv_span_point_mark);
// tv_span_point_point = (EditText) findViewById(R.id.tv_span_point_point);
tv_span_paragraph = (EditText) findViewById(R.id.tv_span_paragraph);
// tv_span_composing = (EditText) findViewById(R.id.tv_span_composing);
// tv_span_intermediate = (EditText) findViewById(R.id.tv_span_intermediate);
// tv_span_user_shift = (EditText) findViewById(R.id.tv_span_user_shift);
// tv_span_user = (EditText) findViewById(R.id.tv_span_user);
// tv_span_priority_shift = (EditText) findViewById(R.id.tv_span_priority_shift);
// tv_span_priority = (EditText) findViewById(R.id.tv_span_priority);
//设置初始内容
String str = "一二三四五六七八九十";
//1:构造SpannableString实例
SpannableString spannableStringEE = new SpannableString(str);
SpannableString spannableStringII = new SpannableString(str);
SpannableString spannableStringEI = new SpannableString(str);
SpannableString spannableStringIE = new SpannableString(str);
//2:构造指定类型的Span,这里使用 AbsoluteSizeSpan,ForegroundColorSpan
AbsoluteSizeSpan sizeSpan = new AbsoluteSizeSpan(24,true);
ForegroundColorSpan colorSpan = new ForegroundColorSpan(Color.RED);
//3:将构造的AbsoluteSizeSpan实例,ForegroundColorSpan实例应用于SpannableString实例,只有 flags 有区别
/**
{@link SpannableString#setSpan(Object, int, int, int)}
*/
spannableStringEE.setSpan(sizeSpan,2,4, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
spannableStringII.setSpan(sizeSpan,2,4, Spanned.SPAN_INCLUSIVE_INCLUSIVE);
spannableStringEI.setSpan(sizeSpan,2,4, Spanned.SPAN_EXCLUSIVE_INCLUSIVE);
spannableStringIE.setSpan(sizeSpan,2,4, Spanned.SPAN_INCLUSIVE_EXCLUSIVE);
spannableStringEE.setSpan(colorSpan,2,4, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
spannableStringII.setSpan(colorSpan,2,4, Spanned.SPAN_INCLUSIVE_INCLUSIVE);
spannableStringEI.setSpan(colorSpan,2,4, Spanned.SPAN_EXCLUSIVE_INCLUSIVE);
spannableStringIE.setSpan(colorSpan,2,4, Spanned.SPAN_INCLUSIVE_EXCLUSIVE);
//4:将SpannableString实例应用于对应的EditText实例
// tvSpanExclusiveExclusive.setText(spannableStringEE);
// tvSpanInclusiveInclusive.setText(spannableStringII);
// tvSpanExclusiveInclusive.setText(spannableStringEI);
// tvSpanInclusiveExclusive.setText(spannableStringIE);
SpannableString spannableStringPMM = new SpannableString("一二三四五六七八九十\n一二三四五六七八九十\n一二三四五六七八九十\n一二三四五六七八九十\n一二三四五六七八九十");
spannableStringPMM.setSpan(sizeSpan,11,33, Spanned.SPAN_POINT_MARK_MASK);
spannableStringPMM.setSpan(colorSpan,11,33, Spanned.SPAN_POINT_MARK_MASK);
tv_span_point_mark_mask.setText(spannableStringPMM);
SpannableString spannableStringMM = new SpannableString(str);
spannableStringMM.setSpan(sizeSpan,2,4, Spanned.SPAN_MARK_MARK);
spannableStringMM.setSpan(colorSpan,2,4, Spanned.SPAN_MARK_MARK);
// tv_span_mark_mark.setText(spannableStringMM);
SpannableString spannableStringMP = new SpannableString(str);
spannableStringMP.setSpan(sizeSpan,2,4, Spanned.SPAN_MARK_POINT);
spannableStringMP.setSpan(colorSpan,2,4, Spanned.SPAN_MARK_POINT);
// tv_span_mark_point.setText(spannableStringMP);
SpannableString spannableStringPM = new SpannableString(str);
spannableStringPM.setSpan(sizeSpan,2,4, Spanned.SPAN_POINT_MARK);
spannableStringPM.setSpan(colorSpan,2,4, Spanned.SPAN_POINT_MARK);
// tv_span_point_mark.setText(spannableStringPM);
SpannableString spannableStringPP = new SpannableString(str);
spannableStringPP.setSpan(sizeSpan,2,4, Spanned.SPAN_POINT_POINT);
spannableStringPP.setSpan(colorSpan,2,4, Spanned.SPAN_POINT_POINT);
// tv_span_point_point.setText(spannableStringPP);
SpannableString spannableStringParagraph = new SpannableString("一二三四五六七八九十\n一二三四五六七八九十\n一二三四五六七八九十\n一二三四五六七八九十\n一二三四五六七八九十");
spannableStringParagraph.setSpan(sizeSpan,11,33, Spanned.SPAN_PARAGRAPH);
spannableStringParagraph.setSpan(colorSpan,11,33, Spanned.SPAN_PARAGRAPH);
tv_span_paragraph.setText(spannableStringParagraph);
SpannableString spannableStringComposing = new SpannableString(str);
spannableStringComposing.setSpan(sizeSpan,2,4, Spanned.SPAN_COMPOSING);
spannableStringComposing.setSpan(colorSpan,2,4, Spanned.SPAN_COMPOSING);
// tv_span_composing.setText(spannableStringComposing);
SpannableString spannableStringIntermediate = new SpannableString(str);
spannableStringIntermediate.setSpan(sizeSpan,2,4, Spanned.SPAN_INTERMEDIATE);
spannableStringIntermediate.setSpan(colorSpan,2,4, Spanned.SPAN_INTERMEDIATE);
// tv_span_intermediate.setText(spannableStringIntermediate);
SpannableString spannableStringUserShift = new SpannableString(str);
spannableStringUserShift.setSpan(sizeSpan,2,4, Spanned.SPAN_USER_SHIFT);
spannableStringUserShift.setSpan(colorSpan,2,4, Spanned.SPAN_USER_SHIFT);
// tv_span_user_shift.setText(spannableStringUserShift);
SpannableString spannableStringUser = new SpannableString(str);
spannableStringUser.setSpan(sizeSpan,2,4, Spanned.SPAN_USER);
spannableStringUser.setSpan(colorSpan,2,4, Spanned.SPAN_USER);
// tv_span_user.setText(spannableStringUser);
SpannableString spannableStringPriorityShift = new SpannableString(str);
spannableStringPriorityShift.setSpan(sizeSpan,2,4, Spanned.SPAN_PRIORITY_SHIFT);
spannableStringPriorityShift.setSpan(colorSpan,2,4, Spanned.SPAN_PRIORITY_SHIFT);
// tv_span_priority_shift.setText(spannableStringPriorityShift);
SpannableString spannableStringPriority = new SpannableString(str);
spannableStringPriority.setSpan(sizeSpan,2,4, Spanned.SPAN_PRIORITY);
spannableStringPriority.setSpan(colorSpan,2,4, Spanned.SPAN_PRIORITY);
// tv_span_priority.setText(spannableStringPriority);
}
@Override
public void onClick(View view) {
switch (view.getId()) {
default:
break;
}
}
}
xml文件:
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_spanned"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.jet.coordbehsnack.SpannedActivity">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<!--
<TextView android:textColor="@android:color/black"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="SPAN_EXCLUSIVE_EXCLUSIVE" />
<EditText
android:id="@+id/tv_span_exclusive_exclusive"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="SPAN_EXCLUSIVE_EXCLUSIVE" />
<TextView android:textColor="@android:color/black"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="SPAN_INCLUSIVE_INCLUSIVE" />
<EditText
android:id="@+id/tv_span_inclusive_inclusive"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="SPAN_INCLUSIVE_INCLUSIVE" />
<TextView android:textColor="@android:color/black"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="SPAN_EXCLUSIVE_INCLUSIVE" />
<EditText
android:id="@+id/tv_span_exclusive_inclusive"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="SPAN_EXCLUSIVE_INCLUSIVE" />
<TextView android:textColor="@android:color/black"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="SPAN_INCLUSIVE_EXCLUSIVE" />
<EditText
android:id="@+id/tv_span_inclusive_exclusive"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="SPAN_INCLUSIVE_EXCLUSIVE" />
-->
<TextView android:textColor="@android:color/black"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="SPAN_POINT_MARK_MASK" />
<EditText
android:id="@+id/tv_span_point_mark_mask"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="SPAN_POINT_MARK_MASK" />
<!--
<TextView android:textColor="@android:color/black"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="SPAN_MARK_MARK" />
<EditText
android:id="@+id/tv_span_mark_mark"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="SPAN_MARK_MARK" />
<TextView android:textColor="@android:color/black"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="SPAN_MARK_POINT" />
<EditText
android:id="@+id/tv_span_mark_point"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="SPAN_MARK_POINT" />
<TextView android:textColor="@android:color/black"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="SPAN_POINT_MARK" />
<EditText
android:id="@+id/tv_span_point_mark"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="SPAN_POINT_MARK" />
<TextView android:textColor="@android:color/black"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="SPAN_POINT_POINT" />
<EditText
android:id="@+id/tv_span_point_point"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="SPAN_POINT_POINT" />
-->
<TextView android:textColor="@android:color/black"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="SPAN_PARAGRAPH" />
<EditText
android:id="@+id/tv_span_paragraph"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="SPAN_PARAGRAPH" />
<!--
<TextView android:textColor="@android:color/black"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="SPAN_COMPOSING" />
<EditText
android:id="@+id/tv_span_composing"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="SPAN_COMPOSING" />
<TextView android:textColor="@android:color/black"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="SPAN_INTERMEDIATE" />
<EditText
android:id="@+id/tv_span_intermediate"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="SPAN_INTERMEDIATE" />
<TextView android:textColor="@android:color/black"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="SPAN_USER_SHIFT" />
<EditText
android:id="@+id/tv_span_user_shift"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="SPAN_USER_SHIFT" />
<TextView android:textColor="@android:color/black"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="SPAN_USER" />
<EditText
android:id="@+id/tv_span_user"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="SPAN_USER" />
<TextView android:textColor="@android:color/black"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="SPAN_PRIORITY_SHIFT" />
<EditText
android:id="@+id/tv_span_priority_shift"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="SPAN_PRIORITY_SHIFT" />
<TextView android:textColor="@android:color/black"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="SPAN_PRIORITY" />
<EditText
android:id="@+id/tv_span_priority"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="SPAN_PRIORITY" />
-->
</LinearLayout>
</ScrollView>
以上就是个人实验和分析的一点结果,若有错误,请各位同学留言告知!
希望能给大家一点点的收获!也希望‘其实你不懂’系列文章真的可以写完并得到大家的指教和喜欢!
That's all !
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