blocks|key|4385864|text|这看起来很整洁：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4385865|passwordEditText.setOnEditorActionListener+{+
++++textView,+keyCode,+keyEvent+->
++++val+DONE+=+6

++++if+(keyCode+==+DONE)+{+++++++++++++++++++++++
+++++++++//+your+code+here
++++}
++++false
}|code-block|syntax|javascript|4385866|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This looks neat:

<pre><code>passwordEditText.setOnEditorActionListener { 
 textView, keyCode, keyEvent -&gt;
 val DONE = 6

 if (keyCode == DONE) { 
 // your code here
 }
 false
}
</code></pre>

blocks|key|4386646|text|添加此核心ktx依赖项|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4386647|implementation+'androidx.core:core-ktx:1.0.0'|code-block|syntax|javascript|4386648|你只需要做|4386649|passwordEditText.doAfterTextChanged{+}|offset|length|style|CODE|4386650|entityMap^0|0|0|0|0|12|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|T|8|@$K|U|L|V|M|N]]|9|@]|A|$]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

Add this core ktx dependence

<pre><code>implementation 'androidx.core:core-ktx:1.0.0'
</code></pre>

You simply have to do 

<code>passwordEditText.doAfterTextChanged{ }</code>

blocks|key|4385942|text|有点老了，但是使用Kotlin+Android扩展你可以做这样的事情：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4385943|editTextRequest.textChangedListener+{
++++++++++++afterTextChanged+{
++++++++++++++++//+Do+something+here...
++++++++++++}
}|code-block|syntax|javascript|4385944|不需要额外的代码，只需添加：|4385945|implementation+'androidx.core:core-ktx:1.0.0'|4385946|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

A bit old, but using Kotlin Android extensions you can do something like that:

<pre><code>editTextRequest.textChangedListener {
 afterTextChanged {
 // Do something here...
 }
}
</code></pre>

No extra code needed, just add:

<pre><code>implementation 'androidx.core:core-ktx:1.0.0'
</code></pre>

blocks|key|4386624|text|测试它：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4386625|passwordEditText.addTextChangedListener(object:TextWatcher{override+fun+afterTextChanged(s:+Editable?)+{

++++}

++++override+fun+beforeTextChanged(s:+CharSequence?,+start:+Int,+count:+Int,+after:+Int)+{
++++}

++++override+fun+onTextChanged(s:+CharSequence?,+start:+Int,+before:+Int,+count:+Int)+{

++++}

})|code-block|syntax|javascript|4386626|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Test it :

<pre><code>passwordEditText.addTextChangedListener(object:TextWatcher{override fun afterTextChanged(s: Editable?) {

 }

 override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, after: Int) {
 }

 override fun onTextChanged(s: CharSequence?, start: Int, before: Int, count: Int) {

 }

})
</code></pre>

blocks|key|4386525|text|希望这篇Kotlin示例能帮助我们更清楚地了解：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4386526|class+MainFragment+:+Fragment()+{

++++private+lateinit+var+viewModel:+MainViewModel

override+fun+onCreateView(inflater:+LayoutInflater,+container:+ViewGroup?,
++++++++++++++++++++++++++savedInstanceState:+Bundle?):+View+{
++++val+view+=+inflater.inflate(R.layout.main_fragment,+container,+false)

++++view.user.addTextChangedListener(object+:+TextWatcher+{
++++++++override+fun+beforeTextChanged(s:+CharSequence,+start:+Int,+count:+Int,+after:+Int)+{

++++++++}

++++++++override+fun+onTextChanged(s:+CharSequence,+start:+Int,+before:+Int,+count:+Int)+{

++++++++}

++++++++override+fun+afterTextChanged(s:+Editable)+{
++++++++++++++++userLayout.error+=
++++++++++++++++++++++++if+(s.length+>+userLayout.counterMaxLength)+{
++++++++++++++++++++++++++++"Max+character+length+is:+${userLayout.counterMaxLength}"
++++++++++++++++++++++++}+else+null
++++++++}
++++})
++++return+view
}

override+fun+onActivityCreated(savedInstanceState:+Bundle?)+{
++++super.onActivityCreated(savedInstanceState)
++++viewModel+=+ViewModelProviders.of(this).get(MainViewModel::class.java)
++++//+TODO:+Use+the+ViewModel
+++}
}|code-block|syntax|javascript|4386527|使用此XML布局：|4386528|<android.support.design.widget.TextInputLayout
++++android:id="@%2Bid/userLayout"
++++android:layout_width="match_parent"
++++android:layout_height="wrap_content"
++++app:counterMaxLength="5"
++++app:counterEnabled="true"
++++android:hint="user_name">

++++<android.support.design.widget.TextInputEditText
++++++++android:id="@%2Bid/user"
++++++++android:layout_width="match_parent"
++++++++android:layout_height="wrap_content"+/>
</android.support.design.widget.TextInputLayout>|4386529|这个Gradle|4386530|android+{
++++compileSdkVersion+'android-P'
...
}
++++api+'com.android.support:design:28.0.0-alpha1'

++++implementation+'com.android.support:appcompat-v7:28.0.0-alpha1'+//+appcompat+library|4386531|entityMap^0|4|6|0|0|3|3|0|0|2|6|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|Y|8|@$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|M|3|N|5|H|7|11|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|12|8|@$9|13|A|14|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|H|7|15|8|@]|D|@]|E|$I|J]]|$1|S|3|-4|5|6|7|16|8|@]|D|@]|E|$]]]|T|$]]

hope this <code>Kotlin</code> sample help making it clear:

<pre><code>class MainFragment : Fragment() {

 private lateinit var viewModel: MainViewModel

override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
 savedInstanceState: Bundle?): View {
 val view = inflater.inflate(R.layout.main_fragment, container, false)

 view.user.addTextChangedListener(object : TextWatcher {
 override fun beforeTextChanged(s: CharSequence, start: Int, count: Int, after: Int) {

 }

 override fun onTextChanged(s: CharSequence, start: Int, before: Int, count: Int) {

 }

 override fun afterTextChanged(s: Editable) {
 userLayout.error =
 if (s.length &gt; userLayout.counterMaxLength) {
 "Max character length is: ${userLayout.counterMaxLength}"
 } else null
 }
 })
 return view
}

override fun onActivityCreated(savedInstanceState: Bundle?) {
 super.onActivityCreated(savedInstanceState)
 viewModel = ViewModelProviders.of(this).get(MainViewModel::class.java)
 // TODO: Use the ViewModel
 }
}
</code></pre>

With this <code>XML</code> layout:

<pre><code>&lt;android.support.design.widget.TextInputLayout
 android:id="@+id/userLayout"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 app:counterMaxLength="5"
 app:counterEnabled="true"
 android:hint="user_name"&gt;

 &lt;android.support.design.widget.TextInputEditText
 android:id="@+id/user"
 android:layout_width="match_parent"
 android:layout_height="wrap_content" /&gt;
&lt;/android.support.design.widget.TextInputLayout&gt;
</code></pre>

And this <code>Gradle</code>:

<pre><code>android {
 compileSdkVersion 'android-P'
...
}
 api 'com.android.support:design:28.0.0-alpha1'

 implementation 'com.android.support:appcompat-v7:28.0.0-alpha1' // appcompat library
</code></pre>

blocks|key|4385988|text|如果你使用implementation+'androidx.core:core-ktx:1.1.0-alpha05'，你可以使用|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4385989|For+android.widget.TextView
TextWatcher+
TextView.doBeforeTextChanged(crossinline+action:+(text:+CharSequence?,+start:+Int,+count:+Int,+after:+Int)+->+Unit)
Add+an+action+which+will+be+invoked+before+the+text+changed.

TextWatcher+
TextView.doOnTextChanged(crossinline+action:+(text:+CharSequence?,+start:+Int,+count:+Int,+after:+Int)+->+Unit)
Add+an+action+which+will+be+invoked+when+the+text+is+changing.

TextWatcher+
TextView.doAfterTextChanged(crossinline+action:+(text:+Editable?)+->+Unit)|code-block|syntax|javascript|4385990|https://developer.android.com/reference/kotlin/androidx/core/widget/package-summary#extension-functions|4385991|entityMap|0|LINK|mutability|MUTABLE|url^0|5|1H|0|0|0|2V|0|0^^$0|@$1|2|3|4|5|6|7|T|8|@$9|U|A|V|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|W|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|X|8|@]|D|@$9|Y|A|Z|1|10]]|E|$]]|$1|M|3|-4|5|6|7|11|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|L]]]]

if you use <code>implementation 'androidx.core:core-ktx:1.1.0-alpha05'</code> you can use 

<pre><code>For android.widget.TextView
TextWatcher 
TextView.doBeforeTextChanged(crossinline action: (text: CharSequence?, start: Int, count: Int, after: Int) -&gt; Unit)
Add an action which will be invoked before the text changed.

TextWatcher 
TextView.doOnTextChanged(crossinline action: (text: CharSequence?, start: Int, count: Int, after: Int) -&gt; Unit)
Add an action which will be invoked when the text is changing.

TextWatcher 
TextView.doAfterTextChanged(crossinline action: (text: Editable?) -&gt; Unit)
</code></pre>

<a href="https://developer.android.com/reference/kotlin/androidx/core/widget/package-summary#extension-functions" rel="noreferrer">https://developer.android.com/reference/kotlin/androidx/core/widget/package-summary#extension-functions</a>

blocks|key|4386692|text|抱歉来迟了!|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4386693|如果将implementation+'androidx.core:core-ktx:1.1.0'添加到模块的build.gradle文件中，则可以使用|offset|length|style|CODE|4386694|etPlayer1.doOnTextChanged+{+text,+start,+count,+after+->+//+Do+stuff+}|code-block|syntax|javascript|4386695|entityMap^0|0|3|19|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@$D|Q|E|R|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|S|8|@]|9|@]|A|$K|L]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Sorry for being late!

If you add <code>implementation 'androidx.core:core-ktx:1.1.0'</code> to your module's build.gradle file then you can use

<pre><code>etPlayer1.doOnTextChanged { text, start, count, after -&gt; // Do stuff }
</code></pre>

blocks|key|4386145|text|添加核心ktx依赖项|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4386146|implementation+'androidx.core:core-ktx:1.3.0'|offset|length|style|CODE|4386147|你可以像这样简单地实现|4386148|++++edit_text.addTextChangedListener+{+it:+Editable?+->
++++++//+Do+your+stuff+here
++++}|code-block|syntax|javascript|4386149|entityMap^0|0|0|19|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@$D|S|E|T|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|U|8|@]|9|@]|A|$]]|$1|J|3|K|5|L|7|V|8|@]|9|@]|A|$M|N]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

Add the core ktx dependency

<code>implementation 'androidx.core:core-ktx:1.3.0'</code>

And you can simply implement like this

<pre class="lang-java prettyprint-override"><code> edit_text.addTextChangedListener { it: Editable? -&gt;
 // Do your stuff here
 }
</code></pre>

blocks|key|4386767|text|如果您使用的是Material+Filled+text+field或Outlined+text+field，请尝试分别响应文档中提到的输入文本更改：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|4386768|filledTextField.editText?.doOnTextChanged+{+inputText,+_,+_,+_+->
++++//+Respond+to+input+text+change
}|code-block|syntax|javascript|4386769|和|4386770|outlinedTextField.editText?.doOnTextChanged+{+inputText,+_,+_,+_+->
++++//+Respond+to+input+text+change
}|4386771|entityMap|0|LINK|mutability|MUTABLE|url|https://material.io/components/text-fields/android#filled-text-field|1|https://material.io/components/text-fields/android#outlined-text-field^0|G|H|0|Y|J|1|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]|$A|10|B|11|1|12]]|C|$]]|$1|D|3|E|5|F|7|13|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|14|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|15|8|@]|9|@]|C|$G|H]]|$1|M|3|-4|5|6|7|16|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]|U|$5|P|Q|R|C|$S|V]]]]

In case you're using Material <a href="https://material.io/components/text-fields/android#filled-text-field" rel="noreferrer">Filled text field</a> or <a href="https://material.io/components/text-fields/android#outlined-text-field" rel="noreferrer">Outlined text field</a>, attempt to respond to input text change as mentioned by documentation, respectively:
<pre><code>filledTextField.editText?.doOnTextChanged { inputText, _, _, _ -&gt;
 // Respond to input text change
}
</code></pre>
and
<pre><code>outlinedTextField.editText?.doOnTextChanged { inputText, _, _, _ -&gt;
 // Respond to input text change
}
</code></pre>

blocks|key|4386473|text|另一种选择是KAndroid库-|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4386474|implementation+'com.pawegio.kandroid:kandroid:0.8.7@aar'|4386475|然后你可以做这样的事情..。|4386476|editText.textWatcher+{+afterTextChanged+{+doSomething()+}+}|code-block|syntax|javascript|4386477|显然，使用整个库来解决您的问题是多余的，但它还附带了一系列其他有用的扩展，这些扩展消除了Android+SDK中的样板代码。|4386478|entityMap^0|6|8|0|0|1K|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|V|8|@$9|W|A|X|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|Y|8|@]|D|@]|E|$]]|$1|J|3|K|5|L|7|Z|8|@]|D|@]|E|$M|N]]|$1|O|3|P|5|6|7|10|8|@]|D|@]|E|$]]|$1|Q|3|-4|5|6|7|11|8|@]|D|@]|E|$]]]|R|$]]

Another alternative is the <code>KAndroid</code> library -

<code>implementation 'com.pawegio.kandroid:kandroid:0.8.7@aar'</code>

Then you could do something like this...

<pre><code>editText.textWatcher { afterTextChanged { doSomething() } }
</code></pre>

Obviously it is excessive to use an entire library to solve your problem, but it also comes with a range of other useful extensions that eliminate boilerplate code in the Android SDK.

blocks|key|4386016|text|您可以使用kotlin的命名参数：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4386017|private+val+beforeTextChangedStub:+(CharSequence,+Int,+Int,+Int)+->+Unit+=+{+_,+_,+_,+_+->+}
private+val+onTextChangedStub:+(CharSequence,+Int,+Int,+Int)+->+Unit+=+{+_,+_,+_,+_+->+}
private+val+afterTextChangedStub:+(Editable)+->+Unit+=+{}

fun+EditText.addChangedListener(
++++++++beforeTextChanged:+(CharSequence,+Int,+Int,+Int)+->+Unit+=+beforeTextChangedStub,
++++++++onTextChanged:+(CharSequence,+Int,+Int,+Int)+->+Unit+=+onTextChangedStub,
++++++++afterTextChanged:+(Editable)+->+Unit+=+afterTextChangedStub
)+=+addTextChangedListener(object+:+TextWatcher+{
++++override+fun+beforeTextChanged(charSequence:+CharSequence,+i:+Int,+i1:+Int,+i2:+Int)+{
++++++++beforeTextChanged(charSequence,+i,+i1,+i2)
++++}

++++override+fun+onTextChanged(charSequence:+CharSequence,+i:+Int,+i1:+Int,+i2:+Int)+{
++++++++onTextChanged(charSequence,+i,+i1,+i2)
++++}

++++override+fun+afterTextChanged(editable:+Editable)+{
++++++++afterTextChanged(editable)
++++}
})|code-block|syntax|javascript|4386018|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You can make use of kotlin's named parameters:

<pre><code>private val beforeTextChangedStub: (CharSequence, Int, Int, Int) -&gt; Unit = { _, _, _, _ -&gt; }
private val onTextChangedStub: (CharSequence, Int, Int, Int) -&gt; Unit = { _, _, _, _ -&gt; }
private val afterTextChangedStub: (Editable) -&gt; Unit = {}

fun EditText.addChangedListener(
 beforeTextChanged: (CharSequence, Int, Int, Int) -&gt; Unit = beforeTextChangedStub,
 onTextChanged: (CharSequence, Int, Int, Int) -&gt; Unit = onTextChangedStub,
 afterTextChanged: (Editable) -&gt; Unit = afterTextChangedStub
) = addTextChangedListener(object : TextWatcher {
 override fun beforeTextChanged(charSequence: CharSequence, i: Int, i1: Int, i2: Int) {
 beforeTextChanged(charSequence, i, i1, i2)
 }

 override fun onTextChanged(charSequence: CharSequence, i: Int, i1: Int, i2: Int) {
 onTextChanged(charSequence, i, i1, i2)
 }

 override fun afterTextChanged(editable: Editable) {
 afterTextChanged(editable)
 }
})
</code></pre>

How do you build a lambda expression for the EditText addTextChangeListener in Kotlin? Below gives an error:

<pre><code>passwordEditText.addTextChangedListener { charSequence -&gt;
 try {
 password = charSequence.toString()
 } catch (error: Throwable) {
 raise(error)
 }
}
</code></pre>

Kotlin addTextChangeListener lambda?

Android

Kotlin

如何在Kotlin中为EditText addTextChangeListener构建lambda表达式？下面给出一个错误：passwordEditText.addTextChangedListener { charSequence  ->    try {        password = charSequence.toString()    } catch (error: Throwable

问Kotlin addTextChangeListener lambda？
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回答 11

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问Kotlin addTextChangeListener lambda？EN

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问Kotlin addTextChangeListener lambda？
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