Question

我试图在微调器上使用这个适配器，它给出了空指针异常，请给予你值得回应

ArrayAdapter adapter = new ArrayAdapter(this,android.R.layout.simple_spinner_item, R.array.select_action_arrays);

和我的string.xml文件

<string-array name="select_action_arrays">
        <item>alert1</item>
        <item>alert2</item>
        <item>alert3</item>
        <item>alert4</item>
        <item>alert5</item>
    </string-array>

这是完整的代码行

ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, getResources().getStringArray(R.array.select_action_arrays));
        spinnerSelectAction.setAdapter(adapter);
        spinnerSelectAction = (Spinner)findViewById(R.id.spinnerSelectAction);
        spinnerSelectAction.setAdapter(adapter);
        spinnerSelectAction.setOnItemSelectedListener(new OnItemSelectedListener() {
            int count=0;
            @Override
            public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
                if(count >= 1){
                Toast.makeText(getBaseContext(),"inside on item selected ",Toast.LENGTH_SHORT).show();
                }
                count++;
            }
            @Override
            public void onNothingSelected(AdapterView<?> arg0) {}
        });

spinnerSelectAction似乎已初始化

Answer 1

您似乎没有正确初始化适配器。它应该是这样的：

ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
     android.R.layout.simple_spinner_item,
     getResources().getStringArray(R.array.select_action_arrays));

Answer 2

写下面的代码行

ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, getResources().getStringArray(R.array.select_action_arrays));

而不是

ArrayAdapter adapter = new ArrayAdapter(this,android.R.layout.simple_spinner_item, R.array.select_action_arrays);

可能会解决您的问题。

Answer 3

在从视图中检索微调器之前添加到适配器，第一条指令应该是这样的：

spinnerSelectAction = (Spinner)findViewById(R.id.spinnerSelectAction);
spinnerSelectAction.setAdapter(adapter);

微调器适配器中的空指针异常

3 个答案: