相关疑难解决方法(0)

我在使用Integer数据类型实现双向绑定时遇到了一些问题.

public class User {

    private String firstName;
    private String lastName;
    private int age;

    public User() {}

    public void setFirstName(String firstName) {
       this.firstName = firstName;
    }

    public String getFirstName() {
       return this.firstName;
    }

    public void setLastName(String lastName) {
       this.lastName = lastName;
    }

    public String getLastName() {
       return this.lastName;
    }

    public void setAge(int age) {
       this.age = age;
    }

    public int getAge() {
       return this.age;
    }

}

XML:

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android">

    <data class="UserDataBinding">
        <variable
            name="user"
            type="com.databinding.model.User" />
    </data>

    <LinearLayout …

我有这个对象

ObservableInt someNumber;

public ObservableInt getSomeNumber()
{
    return someNumber;
}

public void setSomeNumber(ObservableInt number)
{
    this.someNumber = number;
}

我的AppCompatEditText在xml代码中是这样的:

<android.support.v7.widget.AppCompatEditText
        android:layout_width="0dp"
        android:layout_height="@dimen/agro_item_height"
        android:layout_weight="1"
        android:inputType="numberDecimal"
        android:text="@={String.valueOf(myObject.someNumber)}"
        android:gravity="center_horizontal"/>

我有这个错误:

Error:Execution failed for task ':app:compileDebugJavaWithJavac'.
java.lang.RuntimeException: failure, see logs for details.
cannot generate view binders java.lang.NullPointerException
at android.databinding.tool.expr.MethodCallExpr.generateCode(MethodCallExpr.java:69)
at android.databinding.tool.expr.Expr.toFullCode(Expr.java:745)
at android.databinding.tool.expr.Expr.assertIsInvertible(Expr.java:767)
at android.databinding.tool.BindingTarget.addInverseBinding(BindingTarget.java:68)
at android.databinding.tool.LayoutBinder.<init>(LayoutBinder.java:228)
at android.databinding.tool.DataBinder.<init>(DataBinder.java:52)
at android.databinding.tool.CompilerChef.ensureDataBinder(CompilerChef.java:83)
at android.databinding.tool.CompilerChef.sealModels(CompilerChef.java:168)
at android.databinding.annotationprocessor.ProcessExpressions.writeResourceBundle(ProcessExpressions.java:149)
at android.databinding.annotationprocessor.ProcessExpressions.onHandleStep(ProcessExpressions.java:82)
at android.databinding.annotationprocessor.ProcessDataBinding$ProcessingStep.runStep(ProcessDataBinding.java:154)
at android.databinding.annotationprocessor.ProcessDataBinding$ProcessingStep.access$000(ProcessDataBinding.java:139)
at android.databinding.annotationprocessor.ProcessDataBinding.process(ProcessDataBinding.java:66)
at com.sun.tools.javac.processing.JavacProcessingEnvironment.callProcessor(JavacProcessingEnvironment.java:794)
at com.sun.tools.javac.processing.JavacProcessingEnvironment.discoverAndRunProcs(JavacProcessingEnvironment.java:705)
at com.sun.tools.javac.processing.JavacProcessingEnvironment.access$1800(JavacProcessingEnvironment.java:91)
at com.sun.tools.javac.processing.JavacProcessingEnvironment$Round.run(JavacProcessingEnvironment.java:1035)
at com.sun.tools.javac.processing.JavacProcessingEnvironment.doProcessing(JavacProcessingEnvironment.java:1176) …

将Int值绑定到 aTextView会导致Resources$NotFoundException带有消息“字符串资源 ID #0x2a”（其中0x2a是 的值Int）。为什么会发生这种情况，如何解决？

示例代码： * layout/activity_main.xml：

    <?xml version="1.0" encoding="utf-8"?>
    <layout xmlns:android="http://schemas.android.com/apk/res/android"
            xmlns:tools="http://schemas.android.com/tools">

        <data>
            <variable name="data" type="com.example.Thing" />
        </data>

        <LinearLayout tools:context=".MainActivity">
            <TextView android:text="@{data.x}"/>
        </LinearLayout>
    </layout>

• 东西.kt：

  package com.example
  
  data class Thing(
      var x:Int = 42
  )
  

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• 主活动.kt：

  package com.example
  
  import android.databinding.DataBindingUtil
  import android.os.Bundle
  import android.support.v7.app.AppCompatActivity
  import com.example.databinding.ActivityMainBinding
  
  class MainActivity : AppCompatActivity() {
      override fun onCreate(savedInstanceState: Bundle?) {
          super.onCreate(savedInstanceState)
          var activityMain:ActivityMainBinding = DataBindingUtil.setContentView(this, R.layout.activity_main)
          activityMain.data = Thing()
      }
  }
  

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