Android Spinner:获取所选的项目更改事件

Question

如何在所选项目更改时为Spinner设置事件侦听器？

基本上我想要做的是类似于这样的事情:

spinner1.onSelectionChange = handleSelectionChange;

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

Answer 1

以前的一些答案是不正确的.它们适用于其他小部件和视图,但Spinner小部件的文档清楚地指出:

微调器不支持项目单击事件.调用此方法将引发异常.

最好使用OnItemSelectedListener():

spinner.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
    }

});

这适合我.

请注意,在构建视图时也会调用onItemSelected方法,因此您可以考虑将其放在onCreate()方法调用中.

Answer 2

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

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

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

注意:记住一件事.

Spinner OnItemSelectedListener事件将执行两次:

1. Spinner初始化
2. 用户手动选择

尝试使用flag变量来区分这两者.

Answer 3

您可以AdapterView.OnItemSelectedListener在Activity中实现类.

然后使用下面的内容 onCreate()

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

然后覆盖这两个方法:

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

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

Answer 4

/sf/ask/120009851/

您可以通过简单检查来避免调用OnItemSelectedListener():将当前选择索引存储在整数变量中,并在执行任何操作之前检查onItemSelected(..).

例如:

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;
    } 
}); 

因为iCurrentSelection应该在对象范围内工作!

Answer 5

找到您的微调名称并找到ID然后实现此方法.

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
    }
});

Answer 6

spinner-widget的文档说:"一个微调器不支持项目点击事件." 您应该使用"setOnItemSelectedListener"来处理您的问题

Answer 7

您可以在onCreate或onStart中设置OnItemSelectedListener无关紧要-仍将在Activity创建或启动期间分别调用它。
因此我们可以在onCreate中设置它（而不是在onStart中！）。
只需添加一个标志就可以确定首次初始化：

private Spinner mSpinner;
private boolean mSpinnerInitialized;

然后在onCreate（或onCreateView）中：

mSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
                if (!mSpinnerInitialized) {
                    mSpinnerInitialized = true;
                    return;
                }

                // do stuff
            }

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

Answer 8

spinner1.setOnItemSelectedListener(
    new AdapterView.OnItemSelectedListener() {
        //add some code here
    }
);

Answer 9

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称