Question

我试图通过从ViewModel观察LiveData来更新EditText中的值。

这是我要更新其EditText值的片段：

private var qnaQuestionData: String = "TEST VALUE"

private val communicationViewModel by lazy {
        ViewModelProvider(this).get(
            MyProfileEditSharedViewModel::class.java
        )
    }

override fun onActivityCreated(savedInstanceState: Bundle?) {
        super.onActivityCreated(savedInstanceState)

        communicationViewModel.question.observe(viewLifecycleOwner, Observer {data ->
                data.let { qnaQuestionData = it }
        })

        et_question.setText(qnaQuestionData)

}

这是我的ViewModel：

class MyProfileEditSharedViewModel : ViewModel() {
    val question: MutableLiveData<String> by lazy { MutableLiveData<String>() }
}

当我运行此代码时，我的EditText的值设置为“测试值”，这意味着从未观察到LiveData。我该如何解决？

谢谢！

Answer 1

将通话et_question.setText(qnaQuestionData)移至观察者：

communicationViewModel.question.observe(viewLifecycleOwner, Observer { data ->
    qnaQuestionData = data
    et_question.setText(qnaQuestionData)
})

et_question.setText(qnaQuestionData)

Answer 2

我将您的MyProfileEditSharedViewModel更改为这样

class MyProfileEditSharedViewModel : ViewModel() {
    val question: MutableLiveData<String>  = MutableLiveData()
}

您的片段应该是这样

class someFragment(): Fragment() {

    private var qnaQuestionData: String = "TEST VALUE"
    private val communicationViewModel
        get() = ViewModelProviders.of(activity!!).get(MyProfileEditSharedViewModel::class.java)

    override fun onActivityCreated(savedInstanceState: Bundle?) {
        super.onActivityCreated(savedInstanceState)

        et_question.setText(qnaQuestionData)

        communicationViewModel.question.postValue("This Message will Show") //<------- for testing
        communicationViewModel.question.observe(this, Observer {
            qnaQuestionData = it
            et_question.setText(qnaQuestionData)
        })
    }
}

Answer 3

更改

private val communicationViewModel by lazy {
        ViewModelProvider(requireActivity()).get(
            MyProfileEditSharedViewModel::class.java
        )
    }

到

this

解决了问题。官方文档告诉我将requireActivity()更改为tf.compat.v1.disable_eager_execution() class RLLSTM(): def __init__(self, timestep, ): super(RLLSTM, self).__init__() self.input = tf.compat.v1.placeholder(shape=[None, 4, 5], dtype=tf.float32) self.lstm = tf.contrib.rnn.BasicLSTMCell(4,state_is_tuple=False) # self.cell = tf.contrib.rnn.MultiRNNCell([self.lstm ]*4) self.state_in = self.lstm.zero_state(32, tf.float32) self.x = tf.unstack(self.input, axis=1) for t in self.x: self.output, self.state_in = self.lstm(t, self.state_in) def train(): # tf.compat.v1.reset_default_graph() x = np.zeros(shape=[32, 4,5], dtype=np.float32) init = tf.global_variables_initializer() with tf.compat.v1.Session() as sess: sess.run(init) lstm = RLLSTM(4) # sess.run(tf.global_variables_initializer()) outputs = sess.run([lstm.output, lstm.state_in], feed_dict={lstm.input: x}) print(outputs) if __name__ == '__main__': train()

无法观察LiveData

3 个答案: