Question

我想将Switch置于Action Bar并为Switch OnCheckedChangeListener设置。这是我的代码：的 check_words_menu.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<item
    android:id="@+id/myswitch"
    android:title=""
    app:showAsAction="always"
    android:actionLayout="@layout/switch_action_bar"/>
</menu>

switch_action_bar.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="match_parent">

<Switch
    android:id="@+id/switchForActionBar"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"/>

</RelativeLayout>

和 SomeFragment.java

public class SomeFragment extends Fragment implements CompoundButton.OnCheckedChangeListener {
// ...
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setHasOptionsMenu(true);
}

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    inflater.inflate(R.menu.check_words_menu, menu);
    MenuItem item = menu.findItem(R.id.myswitch);
    item.setActionView(R.layout.switch_action_bar);
    Switch mySwitch = (Switch) item.getActionView();
    mySwitch.setOnCheckedChangeListener(this);
    super.onCreateOptionsMenu(menu, inflater);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    return super.onOptionsItemSelected(item);
}

@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
    // some code
}

运行后我得到ClassCastException：

03-18 13：39：55.750 7206-7206 / com.chubarich.android.translator E / AndroidRuntime：FATAL EXCEPTION：main java.lang.ClassCastException：android.widget.RelativeLayout无法强制转换为android.widget.Switch 在com.chubarich.android.translator.CheckWordsFragment.onCreateOptionsMenu（CheckWordsFragment.java:65）在android.app.FragmentManagerImpl.dispatchCreateOptionsMenu（FragmentManager.java:1871）在android.app.Activity.onCreatePanelMenu（Activity.java:2714）在android.support.v4.app.FragmentActivity.onCreatePanelMenu（FragmentActivity.java:275）在android.support.v7.app.ActionBarActivity.superOnCreatePanelMenu（ActionBarActivity.java:276）在android.support.v7.app.ActionBarActivityDelegate $ 1.onCreatePanelMenu（ActionBarActivityDelegate.java:79）在android.support.v7.app.ActionBarActivityDelegateBase.preparePanel（ActionBarActivityDelegateBase.java:979）在android.support.v7.app.ActionBarActivityDelegateBase.doInvalidatePanelMenu（ActionBarActivityDelegateBase.java:1182）在android.support.v7.app.ActionBarActivityDelegateBase.access $ 100（ActionBarActivityDelegateBase.java:79）在android.support.v7.app.ActionBarActivityDelegateBase $ 1.run（ActionBarActivityDelegateBase.java:115）在android.view.Choreographer $ CallbackRecord.run（Choreographer.java:725）在android.view.Choreographer.doCallbacks（Choreographer.java:555）在android.view.Choreographer.doFrame（Choreographer.java:524）在android.view.Choreographer $ FrameDisplayEventReceiver.run（Choreographer.java:711）在android.os.Handler.handleCallback（Handler.java:615）在android.os.Handler.dispatchMessage（Handler.java:92）在android.os.Looper.loop（Looper.java:137）在android.app.ActivityThread.main（ActivityThread.java:4954） at java.lang.reflect.Method.invokeNative（Native Method）在java.lang.reflect.Method.invoke（Method.java:511）在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:798）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:565）在dalvik.system.NativeStart.main（本地方法）

SomeFragment.java 中的65行是Switch mySwitch = (Switch) item.getActionView();。请告诉我，我的代码出了什么问题？

Answer 1

 Switch mySwitch = (Switch) item.getActionView();

将以上行更改为

View actionView=item.getActionView();
Switch mySwitch = (Switch)actionView.findViewById(R.id.switch_id);

切换操作栏无法正常工作

1 个答案: