布局表达式中可绘制的三元运算符

Question

This is my fragment_setting.xml .

<ToggleButton
    android:layout_width="47dp"
    android:layout_height="27dp"
    android:background="@{settingVm.isNotiOn ? @drawable/btn_on_mid : @drawable/btn_off_mid}"
    android:onClick="@{()->settingVm.changeBtnStatus()}"
    android:text="@string/on"
    android:textOff="on"
    android:textOn="on"
    android:textSize="11sp"
    android:textStyle="bold" />

<ToggleButton
    android:layout_width="47dp"
    android:layout_height="27dp"
    android:background="@{settingVm.isNotiOn ? @drawable/btn_off_mid : @drawable/btn_on_mid}"
    android:onClick="@{()-> settingVm.changeBtnStatus()}"
    android:text="@string/off"
    android:textOff="off"
    android:textOn="off"
    android:textSize="11sp"
    android:textStyle="bold" />

This is my SettingViewModel

class SettingViewModel(handler: SettingHandler) : ViewModel() {
    var handler = handler
    var isNotiOn: Boolean? = true
    var visibility = View.VISIBLE

    init {
        if (BuildConfig.DEBUG) {
            Timber.plant(Timber.DebugTree())
            Timber.d("start")
        }
    }

    fun onBackBtnPressed() {
        Timber.d("onBackBtnPressed()")
        handler.onBackBtnPressed()
    }

    fun showLogoutDialogue() {
        Timber.d("showLogoutDialogue()")
        handler.showLogoutDialogue()
    }

    fun changeBtnStatus(){
        Timber.d("changeBtnStatus()")
        handler.changeBtnStatus()
    }
}

And this is my SettingFragment

...
        val spUtil = SharedPreferenceUtil(activity!!)
        when (spUtil.isNotificationOn) {
            false -> {
                binding!!.settingVm!!.isNotiOn = false
            }
            else -> {
                binding!!.settingVm!!.isNotiOn = true
            }
        }
...
    override fun changeBtnStatus() {
        // TODO: Set real notification setting.

        val spUtil = SharedPreferenceUtil(activity!!)
        when (binding!!.settingVm!!.isNotiOn) {
            true -> {
                binding!!.settingVm!!.isNotiOn = false
                spUtil.isNotificationOn = false
            }
            else -> {
                binding!!.settingVm!!.isNotiOn = true
                spUtil.isNotificationOn = true
            }
        }
    }

What's the problem??? I am not using two way binding and the ternary operator like @={} . But I reckon I should use two way binding because it is not a constant value. And I have two images correctly.

Someone says I should not use is prefix because it might generate getter and setter . So, I even tried removing it and define has prefix or just NotiOn but didn't work.

Answer 1

You can use a MutableLiveData in order to change the status and observe that inside the fragment to get live update and you can change the drawable values according to this LiveData

ViewModel.kt

class GuestViewModel @Inject constructor(val repo: GuestRepository) : ViewModel() {
    val guest = MutableLiveData<Guest>()
    val guestLoading = MutableLiveData<Boolean>()
}

Fragment.kt

@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);
    final TestViewModel viewModel =          ViewModelProviders.of(getActivity()).get(TestViewModel.class);
    viewModel.guestLoading.observe(this, it -> {
         //Do something
    });
}

Answer 2

Please try this code once ## Your XML should be in the code is look like this

<ToggleButton 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:button="@{settingVm.isNotiOn ? @drawable/btn_on_mid : @drawable/btn_off_mid}"/>

and the following java code you can reduce and get the result in proper form. please use this code on fragment class.

val spUtil = SharedPreferenceUtil(activity!!) tbutton.setOnCheckedChangeListener { buttonView, isChecked -> spUtil.isNotificationOn = isChecked binding!!.settingVm!!.isNotiOn = isChecked }

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