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。这甚至可能吗?
这就是我想象的工作方式:
<?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>
答案 0 :(得分:33)
在撰写此答案时,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,这有点奇怪,知道errorEnabled
就在那里。但是,通过创建填补缺口并提供缺失实现的Binding Adapter,可以轻松解决这个问题。像这样:
@BindingAdapter("app:errorText")
public static void setErrorMessage(TextInputLayout view, String errorMessage) {
view.setError(errorMessage);
}
请参阅official binding docs,&#34;属性设置器&#34;特别是#34; Custom Setters&#34;。
修改强>
可能是愚蠢的问题,但我应该把它放在哪里?我是否需要扩展
TextInputLayout
并将其放在那里?
它实际上根本不是一个愚蠢的问题,仅仅是因为你无法通过阅读官方文档得到完整的答案。幸运的是,它非常简单:您不需要扩展任何东西 - 只需将方法放在项目中。您可以创建单独的类(即DataBindingAdapters
),或者只是将此方法添加到项目中的任何现有类中 - 这并不重要。只要您使用@BindingAdapter
对此方法进行注释,请确保其为public
和 static
它与哪个类无关。
答案 1 :(得分:2)
我在How to set error on EditText using DataBinding Framwork MVVM上做了一个像我的回答一样的约束。但这一次它使用TextInputLayout作为样本,就像前一个一样。
这个想法的目的:
当然,您可以自己进行验证并使用xml中的<variable>
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以进行准备。
结合
@BindingAdapter({"app:validation", "app:errorMsg"})
public static void setErrorEnable(TextInputLayout textInputLayout, StringRule stringRule,
final String errorMsg) {
}
StringRule
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,在TextInputLayout中放置默认验证和错误消息,以便更容易地知道验证,在xml中绑定
<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>
第三,当单击按钮触发时,您可以使用TextInputLayout中的预定义ID(例如imageUrlValidation)对活动进行最终验证
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();
}
});
完整的代码如下:
<强> dialog_feedentry.xml 强>
<?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>
<强> TextInputEditTextBindingUtil.java 强>
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);
}
}
<强> FeedActivity.java 强>
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();
});
}
}
答案 2 :(得分:0)
这样定义您的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>
然后将这种方法放在任何地方
@BindingAdapter("app:errorText")
fun setErrorText(view: TextInputLayout, errorMessage: String) {
if (errorMessage.isEmpty())
view.error = null
else
view.error = errorMessage;
}
让我们说您将在单击按钮后进行验证,这样您的按钮就会像这样
<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" />
然后在您的视图模型中
您将拥有这些
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
}
.
.
不要忘记在活动或片段中添加它
binding.lifecycleOwner = this
代码很长,所以我在重要行上添加了双星号