java - 从类方法访问 onCreateView() 中声明的变量

Question

如果我有在片段的 onCreateView 中声明的变量；有没有办法可以从 onCreateView 外部访问这些变量？

 public View onCreateView(LayoutInflater viewInflation, ViewGroup container,
            Bundle SavedInstantState) {
        superContext = getActivity().getApplicationContext();
        digitalfragmentview = viewInflation.inflate(
                R.layout.digitalfragment_page, container, false);

        digitalIO0Mode = (Switch) digitalfragmentview
                .findViewById(R.id.digitalio0mode);
        digitalIO1Mode = (Switch) digitalfragmentview
                .findViewById(R.id.digitalio1mode);
        digitalIO2Mode = (Switch) digitalfragmentview
                .findViewById(R.id.digitalio2mode);
        digitalIO3Mode = (Switch) digitalfragmentview
                .findViewById(R.id.digitalio3mode);
        digitalIO4Mode = (Switch) digitalfragmentview
                .findViewById(R.id.digitalio4mode);
        digitalIO5Mode = (Switch) digitalfragmentview
                .findViewById(R.id.digitalio5mode);
        digitalIO6Mode = (Switch) digitalfragmentview
                .findViewById(R.id.digitalio6mode);
        digitalIO7Mode = (Switch) digitalfragmentview
                .findViewById(R.id.digitalio7mode);
        digitalIO8Mode = (Switch) digitalfragmentview
                .findViewById(R.id.digitalio8mode);
        digitalIO9Mode = (Switch) digitalfragmentview
                .findViewById(R.id.digitalio9mode);


        centralDigitalTable = (TableLayout) digitalfragmentview
                .findViewById(R.id.digitalTable);

        Switch[] digitalIOModeSwitchArray = {digitalIO0Mode, digitalIO1Mode,
                digitalIO2Mode, digitalIO3Mode, digitalIO4Mode, digitalIO5Mode,
                digitalIO6Mode, digitalIO7Mode, digitalIO8Mode, digitalIO9Mode};


        return digitalfragmentview;
    }

现在我在类中有这些方法:

   public Switch getIOModeSwitch(int index) {
        return digitalIOModeSwitchArray[index];
    }

    public void getIOModeSwitch(int index, boolean status) {
        digitalIOModeSwitchArray[index].setActivated(status);
    }

但是；他们显然无法访问 digitalIOModeSwitchArray，因为它超出了他们的范围并本地化到 onCreateView 方法。

我尝试将所有变量的启动放在类的 header 之后，但是如果我这样做，数组似乎会填充 null，所以我显然不能这样做。

编辑1:

例如，

如果我这样做 -

public class digitalFragment extends FragmentActivity{
digitalIO0Mode = (Switch) digitalfragmentview
                .findViewById(R.id.digitalio0mode);
        digitalIO1Mode = (Switch) digitalfragmentview
                .findViewById(R.id.digitalio1mode);
        digitalIO2Mode = (Switch) digitalfragmentview
                .findViewById(R.id.digitalio2mode);
        digitalIO3Mode = (Switch) digitalfragmentview
                .findViewById(R.id.digitalio3mode);
        digitalIO4Mode = (Switch) digitalfragmentview
                .findViewById(R.id.digitalio4mode);
        digitalIO5Mode = (Switch) digitalfragmentview
                .findViewById(R.id.digitalio5mode);
        digitalIO6Mode = (Switch) digitalfragmentview
                .findViewById(R.id.digitalio6mode);
        digitalIO7Mode = (Switch) digitalfragmentview
                .findViewById(R.id.digitalio7mode);
        digitalIO8Mode = (Switch) digitalfragmentview
                .findViewById(R.id.digitalio8mode);
        digitalIO9Mode = (Switch) digitalfragmentview
                .findViewById(R.id.digitalio9mode);
Switch[] digitalIOModeSwitchArray = {digitalIO0Mode, digitalIO1Mode,
                digitalIO2Mode, digitalIO3Mode, digitalIO4Mode, digitalIO5Mode,
                digitalIO6Mode, digitalIO7Mode, digitalIO8Mode, digitalIO9Mode};


    public View onCreateView(LayoutInflater viewInflation, ViewGroup container,
            Bundle SavedInstantState) {
        superContext = getActivity().getApplicationContext();
        digitalfragmentview = viewInflation.inflate(
                R.layout.digitalfragment_page, container, false);



        // sets the listener for the mode switches
        for (int i = 0; i < digitalIOModeSwitchArray.length; i++) {
            if (digitalIOModeSwitchArray[i] == null) {
                Log.d(TAG, "Array is null at:" + i);
            }
        }

        return digitalfragmentview;
    }

}

logcat 输出如下所示:

Array is null at: 1
Array is null at: 2
Array is null at: 3
Array is null at: 4
Array is null at: 5
Array is null at: 6
Array is null at: 7
Array is null at: 8
Array is null at: 9

Answer 1

不可以，您不能从声明范围之外访问局部变量。

您必须将它们声明为类中的成员字段。查看官方教程Member Variables .

class Example {

    int field;
    int hello = 2; // initialized to 2
    int there;
    Object[] array = new Object[50]; // array initialized here, all elements null

    Example () {
       there = 2; // can also be initialized in constructor
       // initialize each element of array:
       for (int n = 0; n < array.length; ++ n)
           array[n] = new Object();
    }

    void a () {
       int local;
       local = 1; // ok
       field = 1; // ok
       hello = 1; // ok
       there = 1; // ok
    }

    void b () {
       System.out.println(local); // no 'local' declared here
       System.out.println(field); // ok
       System.out.println(hello); // ok
       System.out.println(there); // ok
    }

}

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