当所选项目发生变化时,如何为微调器设置事件侦听器?

基本上我想做的是类似这样的事情:

spinner1.onSelectionChange = handleSelectionChange;

void handleSelectionChange(Object sender){
    //handle event
}

当前回答

spinner.setOnItemSelectedListener(
            new AdapterView.OnItemSelectedListener() {

                @Override
                public void onItemSelected(AdapterView<?> arg0, View arg1,
                        int arg2, long arg3) {

                    // TODO Auto-generated method stub
                }

                @Override
                public void onNothingSelected(AdapterView<?> arg0) {
                    // TODO Auto-generated method stub

                }
                //add some code here
            }
        );

其他回答

找到你的微调器名称和id,然后实现这个方法。

spinnername.setOnItemSelectedListener(new OnItemSelectedListener() {

    @Override
    public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {
        // your code here
    }

    @Override
    public void onNothingSelected(AdapterView<?> parentView) {
        // your code here
    }
});

https://stackoverflow.com/q/1714426/811625

你可以通过一个简单的检查来避免OnItemSelectedListener()被调用:将当前的选择索引存储在一个整数变量中,并在做任何事情之前在onItemSelected(..)中进行检查。

E.g:

Spinner spnLocale;

spnLocale = (Spinner)findViewById(R.id.spnLocale);

int iCurrentSelection = spnLocale.getSelectedItemPosition();

spnLocale.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
    public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) { 
    if (iCurrentSelection != i){
            // Your code here
    }
    iCurrentSelection = i;
    } 

    public void onNothingSelected(AdapterView<?> adapterView) {
        return;
    } 
}); 

当然,iCurrentSelection应该在对象范围内,这样才能工作!

您可以实现AdapterView。Activity中的OnItemSelectedListener类。

然后在onCreate()中使用下面的行

Spinner spin = (Spinner) findViewById(R.id.spinner);
spin.setOnItemSelectedListener(this);

然后重写这两个方法:

public void onItemSelected(AdapterView<?> parent, View v, int position, long id) {
    selection.setText(items[position]);
}

public void onNothingSelected(AdapterView<?> parent) {
    selection.setText("");
}

我知道这个问题解决了很长时间,但我有一个“请选择”字符串在我的字符串数组的顶部。然后,当您编写侦听器时

yourspinner.onItemSelectedListener = object : OnItemSelectedListener {
            override fun onItemSelected(adapterView: AdapterView<*>?, view: View, i: Int, l: Long) {
                yourvalue = yourspinner.getSelectedItem().toString()

                when(yourvalue){
                    "Please Select" -> // DO nothing
                    else -> // Do something
                }
            }

            override fun onNothingSelected(adapterView: AdapterView<*>?) {
                return
            }
        }

当然,您可以扩展when语句以拥有不同的响应或操作。

对于kotlin,您可以使用:

spinner.onItemSelectedListener =  object : AdapterView.OnItemSelectedListener {
    override fun onItemSelected(parent: AdapterView<*>?, view: View?, position: Int, id: Long) {
        
    }

    override fun onNothingSelected(p0: AdapterView<*>?) {
        
    }
}

注意:对于onItemSelected方法的参数,我使用自定义变量名