屏幕旋转后多次调用Android微调器onItemSelected [英] Android spinner onItemSelected called multiple times after screen rotation

问题描述

我有一个由三个微调器组成的布局.它们在下拉菜单中提供的选项有所不同.
在我的onCreateView中，我有一种设置微调器的方法.在该方法中，我有类似以下内容:

I have a layout with three spinners. They differ in the option presented in the drop-down.
In my onCreateView I have a method to setup the spinners. Inside that method I have something like this:

  mySpinner = (Spinner) view.findViewById(R.id.my_spinner);
  ArrayAdapter<String> mySpinner =
            new ArrayAdapter<String>(getActivity(), R.layout.background,
                    new ArrayList<String>(Arrays.asList(getResources().getStringArray(R.array.spinner_one_data))));
  mySpinner.setDropDownViewResource(R.layout.spinner_text);
  mySpinner.setAdapter(mySpinner);
  mySpinner.setOnItemSelectedListener(this);

正如我所说，我的其他两个微调器几乎相同，但是选择不同.

As I said, my other two spinners are almost the same but with different options.

我知道onItemSelected在首次设置"中为每个微调器调用一次，因此我有一个标志来防止此问题.使用此标志解决方案，我的微调器正在按预期工作.

I know that onItemSelected is called once for every spinner in a "first setup" so I have a flag to prevent this problem. With this flag solution, my spinners are working as expected.

问题是当我在每个微调器中选择一个选项然后旋转屏幕时.现在，onItemSelected被调用了6次，而不是我期望的3次(我已经设置了一个标志来管理3次调用的这种情况).

The problem is when I select in each spinner an option and then rotate the screen. Now, onItemSelected is called 6 times instead the 3 times that I was expecting (I've set a flag to manage this situation of the 3 times calling).

为什么会发生这种情况，头该怎么办?

Why Is it happening and hoe should I handle this?

推荐答案

我找到了适合我的解决方案.

I've found a solution that is working for me.

我有3个微调器，因此在初始微调器设置中onItemSelected被称为3次.为了避免onItemSelected在初始设置中触发方法，我创建了一个计数器，因此onItemSelected仅相应地触发该方法的计数器值.

I have the 3 spinners so onItemSelected is called 3 times at the initial spinner setup. To avoid onItemSelected from firing a method in the initial setup I've created a counter so onItemSelected only fires the method accordingly the counter value.

我已经意识到，在我的情况下，如果旋转屏幕，会再次触发onItemSelected次3次，再加上每个不在0位置的微调器的时间.

I've realized that in my situation, if a rotated the screen, onItemSelected is fired again the 3 times, plus a time for each spinner that is not in the position 0.

一个例子:

我有3个微调框，用户将其中的2更改为一个可用选项中的一个，然后将其定位为0，因此他最终遇到了这样的情况:

I have the 3 spinners and the user changes 2 of them to one of the available option other then position 0 so he ends up with a situation like this:

First spinner - > Item 2 selected
Second spinner -> Item 0 selected (no changes)
Third spinner -> Item 1 selected

现在，我旋转屏幕，对于初始微调器设置，将触发onItemSelected次3次，对于不在位置0的微调器，将触发2次.

Now, wen I rotate the screen, onItemSelected will be fired 3 times for the initial spinner setup plus 2 times for the spinners that aren't at position 0.

@Override
public void onSaveInstanceState(Bundle outState) {
    int changedSpinners = 0;
    if (spinner1.getSelectedItemPosition() != 0) {
        changedSpinners += 1;
    }
    if (spinner2.getSelectedItemPosition() != 0) {
        changedSpinners += 1;
    }
    if (spinner3.getSelectedItemPosition() != 0) {
        changedSpinners += 1;
    }
    outState.putInt("changedSpinners", changedSpinners);
}

我已将状态保存在onSaveInstanceState中，然后在onCreateView中检查了savedInstanceState != null是否存在，是否从包中提取了changedSpinners并更新了计数器以进行相应操作.

I've saved the state in onSaveInstanceState and then, in onCreateView I checked if savedInstanceState != null and if so, extracted changedSpinners from the bundle and updated my counter to act accordingly.

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