Question

在我的简单应用程序中，我尝试更新ImageView网址以更改应用程序上的图像，我创建了简单的数据绑定类来实现该目的，但无法正常工作，并且没有出现任何错误

我的模型类为User：

class User(baseContext: Context) : BaseObservable() {
    val context:Context = baseContext
    var username: String? = null
    var password: String? = null
    var profilePicUrl: String? = null
        @Bindable
        set(profilePicUrl) {
            field = profilePicUrl
            notifyPropertyChanged(BR.profilePicUrl)
        }

    companion object {
        @JvmStatic
        @BindingAdapter("android:profilePicUrl")
        fun loadImage(view: ImageView, imageUrl: String) {
            if (!imageUrl.isEmpty()) {
                Picasso.get().load(imageUrl).into(view)
            }
        }
    }

    @Bindable
    fun getProfilePicVisibility(): Int {
        return if (profilePicUrl == null || profilePicUrl!!.isEmpty()) View.GONE else View.VISIBLE
    }
}

LoginActivity类：

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    val binding: LoginActivityBinding = DataBindingUtil.setContentView(this, R.layout.login_activity)
    binding.viewModel = ViewModelProviders.of(this, LoginViewModelFactory(this)).get(LoginViewModel::class.java)

    val user = User(baseContext)
    user.username = "my name"
    user.password = "my family"
    user.profilePicUrl = ""

    binding.user = user

    val handlers = ClickHandler(this)
    handlers.user = user
    binding.handlers = handlers
}

然后是ClickHandler类

class ClickHandler(private val context: Context) {
    var user: User? = null

    fun clickOnLoginButton(view: View) {
        user?.profilePicUrl = "https://www.androidhive.info/RxJava/wp-content/uploads/2018/02/1-370x247.jpg"
    }
}

点击按钮后，我希望可以更新ImageView网址，并且可以使用loadImage函数从网址中获取图片并将其附加到其中

我的简化布局：

<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>

        <variable
            name="viewModel"
            type="ir.instacheeta.application.ui.login.viewModel.LoginViewModel" />

        <variable
            name="user"
            type="ir.instacheeta.application.ui.login.model.User" />

        <variable
            name="handlers"
            type="ir.instacheeta.application.ui.login.viewModel.ClickHandler" />
    </data>

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/grey_10">

        ...

                        <Button
                            ...
                            android:onClick="@{handlers::clickOnLoginButton}"
                            ... />

                        ...

            ...

            <com.mikhaellopez.circularimageview.CircularImageView
                ...
                android:profilePicUrl="@{user.profilePicUrl}"
                android:src="@drawable/img_wizard_1"
                android:tint="@color/mdtp_white"
                android:visibility="@{user.profilePicVisibility, default=gone}"
                ... />

        </androidx.constraintlayout.widget.ConstraintLayout>

    </RelativeLayout>
</layout>

Answer 1

您已在处理程序类中声明了用户变量，该变量为null，因此您应该通过clickOnLoginButton方法将XML中的用户对象作为参数传递。

<data>

    <import type="android.view.View" />

    ...
</data>

<Button
...
android:onClick="@{(view) -> handler.clickOnLoginButton(view,user)}"
... />

并更新您的方法

fun clickOnLoginButton(view: View,user:User)

当我单击按钮时，使用数据绑定更改ImageView网址

1 个答案: