无法在android中为微调器设置OnItemClickListener
在自定义的RecyclerView.Adapter<CustomAdapter.ViewHolder>
,我为微调器设置了一个适配器,发现我的微调器的值在选择后没有改变,所以我试图在我的微调器上添加一个OnItemClickListener
:
override fun onBindViewHolder(viewHolder: ViewHolder, position: Int) { // The selectable items of the spinner is dynamically generated from getItems() function val selectableItems: List<String> = getItems() val spinnerAdapter = ArrayAdapter<String>(this.context, androi.R.layout.simple_spinner_item) spinnerAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item) spinnerAdapter.addAll(selectableItems) viewHolder.mySpinner.adapter = spinnerAdapter // the error occurs on the following line: viewHolder.mySpinner.onItemClickListener = AdapterView.OnItemClickListener { adapterView, view, i, l -> adapterView.setSelection(i) } viewHolder.mySpinner.setSelection(origionSelectedPosition) }
编译时,我没有得到任何警告或错误,但是在运行时,我得到了一个RuntimeException,说setOnItemClickListener cannot be used with a spinner
。 这有点奇怪。 我在代码中做错了什么? 还是有人知道为什么我的微调没有改变相应的选择?
Kotlin解决方案的进一步描述:
我曾尝试使用onItemSelectedListener
但未能找到一个合适的方式在kotlin中使用它。 但最后! 以下代码解决了我的问题:
viewHolder.mySpinner.onItemSelectedListener = object : AdapterView.OnItemSelectedListener { override fun onItemSelected(parent: AdapterView<*>, view: View, pos: Int, id: Long) { } override fun onNothingSelected(parent: AdapterView<out Adapter>?) { } }
使用setOnItemSelectedListener
而不是onItemClickListener
。
viewHolder.mySpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { @Override public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { } @Override public void onNothingSelected(AdapterView<?> parent) { } });
在sasikumar的回答之后,我用下面的代码在kotlin中解决了它:
viewHolder.mySpinner.onItemSelectedListener = object : AdapterView.OnItemSelectedListener { override fun onItemSelected(parent: AdapterView<*>, view: View, pos: Int, id: Long) { } override fun onNothingSelected(parent: AdapterView<out Adapter>?) { } }
您可以创建一个非常简单的扩展功能:
文件: Extensions.kt
fun Spinner.setOnItemSelectedListener(listener: AdapterView.OnItemSelectedListener) { onItemSelectedListener = listener }
那么你可以按照你想要的方式来调用它
spinner.setOnItemSelectedListener(object: AdapterView.OnItemSelectedListener { override fun onItemSelected(parent: AdapterView<*>?, view: View?, position: Int, id: Long) { } override fun onNothingSelected(parent: AdapterView<*>?) { } })
与以前的答案类似,但看起来更像原始版本,而不是分配
首先在onCreate函数初始化微调器。
var spinner : Spinner ?= null spinner = findViewById(R.id.spinner) as Spinner
现在添加细节与微调。 这里我使用了字符串资源的数组。
fun addSpinnerData(){ var arr = (resources.getStringArray(R.array.data_list).toMutableList()); adapter = ArrayAdapter<String>( this, android.R.layout.simple_list_item_1, arr) spinner!!.setAdapter(adapter); spinner!!.onItemSelectedListener = object : AdapterView.OnItemSelectedListener{ override fun onItemSelected(p0: AdapterView<*>?, p1: View?, p2: Int, p3: Long) { Toast.makeText(applicationContext," On Click",Toast.LENGTH_SHORT).show(); } override fun onNothingSelected(p0: AdapterView<*>?) { } } }
通过这种方式,你可以实现微调的onItemSelectedListener