数据绑定 - 类型参数 T 具有不兼容的上限：ViewDataBinding 和 SimpleCalculatorActivity

Question

文件名：SimpleCalculatorActivity.java

Xml 文件名：simple_calculator.xml

我收到错误消息 Data Binding Android - Type parameter T has in compatible upper bounds : ViewDataBinding and SimpleCalculatorActivity in line binding = DataBindingUtil.setContentView(this, R.layout.simple_calculator);

我已尝试重命名 xml 文件并将其重命名为原始名称。但对我不起作用。

SimpleCalculatorActivity.java

package com.example.borntoflirt.design1;

import android.databinding.DataBindingUtil;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

import java.text.DecimalFormat;

public class SimpleCalculatorActivity extends AppCompatActivity {

private SimpleCalculatorActivity binding;

// This simple calculator can only perform operations of either addition, subtraction, multiplication or division.
// So we define four static chars to represent these operations

private static final char ADDITION = '+';
private static final char SUBTRACTION = '-';
private static final char MULTIPLICATION = '*';
private static final char DIVISION = '/';

// Set variable for operations

private double digit;
private double total = Double.NaN;
private String CURRENT_ACTION;

private DecimalFormat decimalFormat;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    decimalFormat = new DecimalFormat("#.##########");
    binding = DataBindingUtil.setContentView(this, R.layout.simple_calculator);
}
}

Answer 1

绑定的变量应该是：

SimpleCalculatorBinding binding = DataBindingUtil.setContentView(this, R.layout.simple_calculator);

请关注this post

默认情况下，会根据布局文件的名称生成一个Binding类，将其转换为Pascal大小写，并为其加上“Binding”后缀。上面的布局文件是main_activity.xml，所以生成的类是MainActivityBinding。

例如：

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

   <LinearLayout
       android:orientation="vertical"
       android:layout_width="match_parent"
       android:layout_height="match_parent">
       <TextView android:layout_width="wrap_content"
           android:layout_height="wrap_content"
           android:text="Test"/>
   </LinearLayout>
</layout>