我需要能够动态设置EditText的高度属性。我在我的应用程序中使用数据绑定控制其他属性,所以我希望能够使用数据绑定来控制元素的高度。这是我的xml的简化版本:
<?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>
<variable name="loginVM" type="com.testing.stuff.ViewModels.LoginViewModel" />
</data>
<EditText android:inputType="number"
android:id="@+id/txtVerificationCode"
android:layout_height="@{loginVM.compact ? @dimen/verificationHeightCompact : @dimen/verificationHeightFull}"
android:layout_width="match_parent"
android:paddingRight="16dp"
android:paddingLeft="16dp"
android:focusable="true"
android:focusableInTouchMode="true"
android:layout_marginLeft="10dp"
android:alpha="@{loginVM.verificationOpacity}"
android:layout_marginStart="10dp"
android:textAlignment="center"
android:visibility="visible"
android:hint="Enter verificationCode"
android:text="@{loginVM.verificationCode}" />
</layout>
以下是我 View Model 的简化版本:
public class LoginViewModel extends BaseObservable {
public final ObservableField<String> verificationCode;
public final ObservableField<Boolean> compact;
@Bindable
public String getVerificationCode() {
if (this.verificationCode == null) {
return "";
} else {
return this.verificationCode.get();
}
}
public void setVerificationCode(String verificationCode) {
this.verificationCode.set(verificationCode);
invalidateProperties();
}
@Bindable
public Boolean getCompact(){return this.compact.get();}
public void setCompact(Boolean value)
{
this.compact.set(value);
this.invalidateProperties();
}
@BindingAdapter("android:layout_height")
public static void setLayoutHeight(EditText view, float height)
{
ViewGroup.LayoutParams layoutParams = view.getLayoutParams();
layoutParams.height = (int)height;
view.setLayoutParams(layoutParams);
}
public LoginViewModel(Context ctx) {
verificationCode = new ObservableField();
compact = new ObservableField();
}
尺寸在dimens.xml文件中。我正在修改视图模型中的属性。但是,当我启动应用程序时,立即出现以下错误(绑定适配器未在调试中触发)。屏幕上有几个其他元素,但这个特定的元素是我需要在特定操作发生时更改高度的元素:
FATAL EXCEPTION: main
Process: com.testing.stuff, PID: 32752
java.lang.RuntimeException: Unable to start activity
ComponentInfo{com.testing.stuff/com.testing.stuff.Login}:
java.lang.RuntimeException: Binary XML file line #69: You must supply
a layout_height attribute.
Caused by: java.lang.RuntimeException: Binary XML file line #69: You
must supply a layout_height attribute.
在SO上有一些关于这个问题的帖子,但没有明确的答案或者方法不起作用。毫无疑问,这是一种常见的实现。提前感谢您的帮助。
app:width
)将绑定表达式应用于其上,从而调整视图的LayoutParams
。 - CommonsWare