Android 我可以将错误消息绑定到TextInputLayout吗?
我想将错误消息直接绑定到Android 我可以将错误消息绑定到TextInputLayout吗?,android,android-layout,android-databinding,Android,Android Layout,Android Databinding,我想将错误消息直接绑定到android.support.design.widget.TextInputLayout。我找不到通过布局设置错误的方法。这可能吗 这就是我想象的工作原理: <?xml version="1.0" encoding="utf-8"?> <layout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/a
android.support.design.widget.TextInputLayout
。我找不到通过布局设置错误的方法。这可能吗
这就是我想象的工作原理:
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools">
<data>
<import type="android.view.View" />
<variable
name="error"
type="String" />
</data>
<android.support.v7.widget.LinearLayoutCompat
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:errorEnabled="true"
app:errorText="@{error}">
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="@string/username"
android:inputType="textEmailAddress" />
</android.support.design.widget.TextInputLayout>
</android.support.v7.widget.LinearLayoutCompat>
</layout>
在撰写此答案(2016年5月)时,没有与setError()
方法对应的XML属性,因此您无法直接在XML中设置错误消息,知道存在errorEnabled
有点奇怪。但是,通过创建一个可以填补空白并提供缺失的实现的模型,可以很容易地解决这个问题。大概是这样的:
@BindingAdapter("app:errorText")
public static void setErrorMessage(TextInputLayout view, String errorMessage) {
view.setError(errorMessage);
}
请参阅“属性设置器”一节,特别是“自定义设置器”
编辑
可能是个愚蠢的问题,但我应该把这个放在哪里呢?我需要扩展
TextInputLayout
并将其放入其中吗
这其实根本不是一个愚蠢的问题,因为你无法通过阅读官方文件得到完整的答案。幸运的是,它非常简单:您不需要扩展任何内容,只需将该方法放到项目中的任何地方即可。您可以创建单独的类(即,
DataBindingAdapters
),也可以将此方法添加到项目中的任何现有类中—这并不重要。只要你用@BindingAdapter
注释这个方法,并确保它是公共的
和静态的
,它就与它所在的类无关。我已经做了一个绑定,就像我在上面的回答一样。但这次它使用了TextInputLayout作为示例,就像上一次一样
这一想法的目的:
标记进行设置
首先,实现静态绑定方法和相关的字符串验证规则进行准备。
装订
@BindingAdapter({"app:validation", "app:errorMsg"})
public static void setErrorEnable(TextInputLayout textInputLayout, StringRule stringRule,
final String errorMsg) {
}
条规
public static class Rule {
public static StringRule NOT_EMPTY_RULE = s -> TextUtils.isEmpty(s.toString());
public static StringRule EMAIL_RULE = s -> s.toString().length() > 18;
}
public interface StringRule {
boolean validate(Editable s);
}
其次,将默认的验证和错误消息放在TextInputLayout中,并使用xml绑定轻松了解验证
<android.support.design.widget.TextInputLayout
android:id="@+id/imageUrlValidation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:validation="@{Rule.NOT_EMPTY_RULE}"
app:errorMsg='@{"Cannot be empty"}'
>
<android.support.design.widget.TextInputEditText
android:id="@+id/input_imageUrl"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Image Url"
android:text="@={feedEntry.imageUrl}" />
</android.support.design.widget.TextInputLayout>
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<data>
<import type="com.example.common.components.TextInputEditTextBindingUtil.Rule" />
<variable
name="feedEntry"
type="com.example.feedentry.repository.bean.FeedEntry" />
</data>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="10dp"
android:orientation="vertical">
<android.support.design.widget.TextInputLayout
android:id="@+id/imageUrlValidation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:validation="@{Rule.NOT_EMPTY_RULE}"
app:errorMsg='@{"Cannot be empty"}'
>
<android.support.design.widget.TextInputEditText
android:id="@+id/input_imageUrl"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Image Url"
android:text="@={feedEntry.imageUrl}" />
</android.support.design.widget.TextInputLayout>
<android.support.design.widget.TextInputLayout
android:id="@+id/titleValidation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:validation="@{Rule.NOT_EMPTY_RULE}"
app:errorMsg='@{"Cannot be empty"}'
>
<android.support.design.widget.TextInputEditText
android:id="@+id/input_title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Title"
android:text="@={feedEntry.title}"
/>
</android.support.design.widget.TextInputLayout>
<android.support.design.widget.TextInputLayout
android:id="@+id/subTitleValidation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:validation="@{Rule.NOT_EMPTY_RULE}"
app:errorMsg='@{"Cannot be empty"}'
>
<android.support.design.widget.TextInputEditText
android:id="@+id/input_subtitle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Subtitle"
android:text="@={feedEntry.subTitle}"
/>
</android.support.design.widget.TextInputLayout>
</LinearLayout>
</layout>
FeedActivity.java
package com.example.common.components;
import android.databinding.BindingAdapter;
import android.support.design.widget.TextInputLayout;
import android.text.Editable;
import android.text.TextUtils;
import android.text.TextWatcher;
/**
* Created by Charles Ng on 7/9/2017.
*/
public class TextInputEditTextBindingUtil {
@BindingAdapter({"app:validation", "app:errorMsg"})
public static void setErrorEnable(TextInputLayout textInputLayout, StringRule stringRule,
final String errorMsg) {
textInputLayout.getEditText().addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
@Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
@Override
public void afterTextChanged(Editable editable) {
textInputLayout
.setErrorEnabled(stringRule.validate(textInputLayout.getEditText().getText()));
if (stringRule.validate(textInputLayout.getEditText().getText())) {
textInputLayout.setError(errorMsg);
} else {
textInputLayout.setError(null);
}
}
});
textInputLayout
.setErrorEnabled(stringRule.validate(textInputLayout.getEditText().getText()));
if (stringRule.validate(textInputLayout.getEditText().getText())) {
textInputLayout.setError(errorMsg);
} else {
textInputLayout.setError(null);
}
}
public static class Rule {
public static StringRule NOT_EMPTY_RULE = s -> TextUtils.isEmpty(s.toString());
public static StringRule EMAIL_RULE = s -> s.toString().length() > 18;
}
public interface StringRule {
boolean validate(Editable s);
}
}
public class FeedActivity extends AppCompatActivity {
private FeedEntryListViewModel viewModel;
@SuppressLint("StaticFieldLeak")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_feed);
viewModel = ViewModelProviders.of(this)
.get(FeedEntryListViewModel.class);
viewModel.init(this);
ViewPager viewPager = findViewById(R.id.viewpager);
setupViewPager(viewPager);
// Set Tabs inside Toolbar
TabLayout tabs = findViewById(R.id.tabs);
tabs.setupWithViewPager(viewPager);
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = findViewById(R.id.fab);
fab.setOnClickListener(view -> {
//insert sample data by button click
final DialogFeedentryBinding dialogFeedEntryBinding = DataBindingUtil
.inflate(LayoutInflater.from(this), R.layout.dialog_feedentry, null, false);
FeedEntry feedEntry = new FeedEntry("", "");
feedEntry.setImageUrl("http://i.imgur.com/DvpvklR.png");
dialogFeedEntryBinding.setFeedEntry(feedEntry);
final Dialog dialog = new AlertDialog.Builder(FeedActivity.this)
.setTitle("Create a new Feed Entry")
.setView(dialogFeedEntryBinding.getRoot())
.setPositiveButton("Submit", null)
.setNegativeButton("Cancel", (dialogInterface, i) -> dialogInterface.dismiss())
.create();
dialog.setOnShowListener(dialogInterface -> {
Button button = ((AlertDialog) dialog).getButton(AlertDialog.BUTTON_POSITIVE);
button.setOnClickListener(view1 -> {
// TODO Do something
//to trigger auto error enable
FeedEntry inputFeedEntry = dialogFeedEntryBinding.getFeedEntry();
Boolean[] validations = new Boolean[]{
dialogFeedEntryBinding.imageUrlValidation.isErrorEnabled(),
dialogFeedEntryBinding.titleValidation.isErrorEnabled(),
dialogFeedEntryBinding.subTitleValidation.isErrorEnabled()
};
boolean isValid = true;
for (Boolean validation : validations) {
if (validation) {
isValid = false;
}
}
if (isValid) {
new AsyncTask<FeedEntry, Void, Void>() {
@Override
protected Void doInBackground(FeedEntry... feedEntries) {
viewModel.insert(feedEntries);
return null;
}
}.execute(inputFeedEntry);
dialogInterface.dismiss();
}
});
});
dialog.show();
});
}
}
公共类FeedActivity扩展了AppCompative活动{
私有FeedEntryListViewModel视图模型;
@SuppressLint(“StaticFieldLeak”)
@凌驾
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_提要);
viewModel=ViewModelProviders.of(本)
.get(FeedEntryListViewModel.class);
init(this);
ViewPager ViewPager=findViewById(R.id.ViewPager);
设置viewPager(viewPager);
//在工具栏内设置选项卡
TabLayout tabs=findviewbyd(R.id.tabs);
选项卡。使用viewPager进行设置(viewPager);
Toolbar Toolbar=findviewbyd(R.id.Toolbar);
设置支持操作栏(工具栏);
FloatingActionButton fab=findViewById(R.id.fab);
fab.setOnClickListener(视图->{
//通过单击按钮插入示例数据
最终对话框FeedEntryBinding DialogFeedentryBinding=DataBindingUtil
.充气(LayoutFlater.from(this),R.layout.dialog\u feedentry,null,false);
FeedEntry FeedEntry=新的FeedEntry(“,”);
feedEntry.setImageUrl(“http://i.imgur.com/DvpvklR.png");
对话框FeedEntryBinding.setFeedEntry(feedEntry);
最终对话框=新建AlertDialog.Builder(FeedActivity.this)
.setTitle(“创建新的提要条目”)
.setView(dialogFeedEntryBinding.getRoot())
.setPositiveButton(“提交”,空)
.setNegativeButton(“取消”,(dialogInterface,i)->dialogInterface.Disease()
.create();
对话框.setOnShowListener(对话框接口->{
按钮按钮=((AlertDialog)对话框).getButton(AlertDialog.Button_正);
按钮。setOnClickListener(视图1->{
//做点什么
//要触发自动错误启用
FeedEntry inputFeedEntry=dialogFeedEntryBinding.getFeedEntry();
布尔[]验证=新布尔[]{
dialogFeedEntryBinding.imageUrlValidation.isErrorEnabled(),
dialogFeedEntryBinding.titleValidation.isErrorEnabled(),
dialogFeedEntryBinding.subTitleValidation.isErrorEnabled()
};
布尔值isValid=true;
for(布尔验证:验证){
如果(验证){
isValid=false;
}
}
如果(有效){
新建异步任务(){
@凌驾
受保护的Void doInBackground(FeedEntry…feedEntries){
viewModel.insert(feedEntries);
返回null;
}
}.执行(inputFeedEntry);
dialogInterface.dismise();
}
});
});
dialog.show();
});
}
}
这样定义xml
<com.google.android.material.textfield.TextInputLayout
android:id="@+id/emailTextInputLayout"
style="@style/myTextInputLayoutStyle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="80dp"
android:layout_marginEnd="16dp"
**app:errorEnabled="true"**
**app:errorText="@{viewModel.emailErrorMessage}"**
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/include">
<com.google.android.material.textfield.TextInputEditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="@string/email"
android:inputType="textEmailAddress"
**android:text="@={viewModel.emailText}" />**
</com.google.android.material.textfield.TextInputLayout>
<Button
android:id="@+id/signInButtonView"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="68dp"
android:layout_marginEnd="16dp"
**android:onClick="@{() -> viewModel.logIn()}"**
android:text="@string/sign_in"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/passwordTextInputLayout" />
假设您在单击按钮后进行验证,所以您的按钮将如下所示
<com.google.android.material.textfield.TextInputLayout
android:id="@+id/emailTextInputLayout"
style="@style/myTextInputLayoutStyle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="80dp"
android:layout_marginEnd="16dp"
**app:errorEnabled="true"**
**app:errorText="@{viewModel.emailErrorMessage}"**
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/include">
<com.google.android.material.textfield.TextInputEditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="@string/email"
android:inputType="textEmailAddress"
**android:text="@={viewModel.emailText}" />**
</com.google.android.material.textfield.TextInputLayout>
<Button
android:id="@+id/signInButtonView"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="68dp"
android:layout_marginEnd="16dp"
**android:onClick="@{() -> viewModel.logIn()}"**
android:text="@string/sign_in"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/passwordTextInputLayout" />
代码很长,所以我在重要的行上添加了双星号Use can read at:。从活动获取绑定,如:MainActivityBinding=DataBindingUtil.setContentView(this,R.layout.main_活动);并通过binding.setError(“您想要的字符串”)来设置值,而不是真正解决问题。我已经知道如何做基本绑定了。可能是个愚蠢的问题,但我应该把这个放在哪里呢?我需要扩展TextInputLayout并将其放在那里吗?谢谢您的指导。显然,
@BindingAdapter
方法没有明确的注册,这让我很恼火。它们基本上可以在代码中的任何位置工作,并且在每个项目中都会位于不同的位置。@MarcinOrlowski您可以演示如何在TextInputLayout中设置errorText吗?以及我需要添加到build.gradle文件中的任何其他内容,除非我不使用数据
class SignInViewModel : ViewModel() {
private val _emailErrorMessage = MutableLiveData("")
val emailText = MutableLiveData("")
val emailErrorMessage: LiveData<String> = _emailErrorMessage
fun logIn() {
if (validateInput()) {
}
}
private fun validateInput(): Boolean {
if (emailText.value?.length!! < 5) {
_emailErrorMessage.value = "no way"
return false
}
_emailErrorMessage.value = ""
return true
}
.
.
binding.lifecycleOwner = this