未知属性 onItemSelected/onCheckedChanged [英] Unknown attribute onItemSelected/onCheckedChanged

问题描述

我创建了 SwitchCompat 并添加了 android:onCheckedChanged.一切正常，但 Android Studio 将此属性标记为警告说明.

I created SwitchCompat and added android:onCheckedChanged. everything works fine, but Android Studio marks this attribute as warning with description.

未知属性 android:onCheckedChanged.

Unknown attribute android:onCheckedChanged.

同样的情况是 AppCompatSpinner 和 android:onItemSelected.

The same case is with AppCompatSpinner with android:onItemSelected.

为什么 Android Studio 会显示此警告?我的 Android Studio 版本是 3.5.1

Why Android Studio displaying this warning? My Android Studio version is 3.5.1

带有警告的截图

推荐答案

那是因为 SwitchCompat 实际上没有这样的属性(参见 documentation)，因此您无法在 XML 中分配侦听器.尝试改为实现 onClickListener 或在 XML 之外分配 OnCheckedChanged 侦听器，例如:

That is because SwitchCompat actually does not have such attribute (see documentation), so you can't assign the listener in the XML. Try implementing an onClickListener instead or assign the OnCheckedChanged listener outside of XML, such as:

  final SwitchCompat switchButton = (SwitchCompat) view.findViewById(R.id.switch_button);
  switchButton.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
    @Override
    public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
      //do stuff
    }
  });

也可以通过调用binding.switch_button直接返回SwitchButton，从java代码中的dataBinding对象中获取切换按钮.

You can also get the switch button from the dataBinding object in java code by calling binding.switch_button which returns the SwitchButton directly.

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