Question

我的Spinner中实施的Activity存在问题。我相信我认为部分尚不清楚如何寻求完整的解决方案。我有以下Spinner定义代码段：

 spinner = (Spinner) findViewById(R.id.spinner1);
        // Create an ArrayAdapter using the string array and a default spinner layout
        ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,
                R.array.regions, android.R.layout.simple_spinner_item);
        // Specify the layout to use when the list of choices appears
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        // Apply the adapter to the spinner
        spinner.setAdapter(adapter);
        spinner.setOnItemSelectedListener(this);

填充此Spinner的数组位于strings.xml：

<string-array name="regions">
    <item>West</item>
    <item>East</item>
    <item>Asia</item>
    <item>Africa</item>
    <item>Croatia</item>
</string-array>

现在，我执行应用程序时遇到的异常是NullPointerException由onItemSelected实现的Spinner方法。这是方法体：

public void onItemSelected(AdapterView<?> parentView,View v,int position,long id) {
        // TODO Auto-generated method stub
        //Log.d("Position Value: ",(String.valueOf(position).toString()));
        if(position != 0)
        {
            if(spinner.getItemAtPosition(position).toString() != null)
            { 
                filterObject.setRegion(spinner.getItemAtPosition(position).toString());
            }else{
              filterObject.setRegion("Something Wrong!");
            }
        }
    }

如果我删除了第一个检查，即位置！= 0，则应用程序在运行时立即崩溃。一旦我将代码放在这里，应用程序加载正常，当我在Spinner中选择一个元素时，它会立即崩溃。什么可以解决这个问题？

谢谢，

错误日志：

11-30 12:00:47.915: E/AndroidRuntime(19300): FATAL EXCEPTION: main
11-30 12:00:47.915: E/AndroidRuntime(19300): java.lang.NullPointerException
11-30 12:00:47.915: E/AndroidRuntime(19300):    at com.example.sketching.MainActivity.onItemSelected(MainActivity.java:69)
11-30 12:00:47.915: E/AndroidRuntime(19300):    at android.widget.AdapterView.fireOnSelected(AdapterView.java:892)
11-30 12:00:47.915: E/AndroidRuntime(19300):    at android.widget.AdapterView.access$200(AdapterView.java:49)
11-30 12:00:47.915: E/AndroidRuntime(19300):    at android.widget.AdapterView$SelectionNotifier.run(AdapterView.java:860)

Answer 1

不需要这种情况，onCreate()本身Spinner onItemSelected会触发。因此，您需要Initialize filterObject implement OnItemSelectedListener Spinner之前的{{1}}

nullpointerException处理onItemSelected

1 个答案: