如何运行在一个活动片段​​的测试 [英] How to run tests on an activities fragment

问题描述

我刚刚起步的王氏的JUnit 和我遇到的第一个问题，我应该怎么测试片段？

I am just starting out wih junit and the first issue I'm running into is, how should I test fragments?

被测试的活动有1片段是主要的布局。

The activity being tested has 1 fragment which is the main layout.

@Override
protected void setUp() throws Exception {
    super.setUp();
    Intent intent = new Intent(getInstrumentation().getTargetContext(),
            ActivityWelcome.class);
    startActivity(intent, null, null);

    FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
    mFragmentWelcome = (FragmentWelcome) fragmentManager.findFragmentByTag(FragmentWelcome.TAG);
    if (mFragmentWelcome == null) {

        mFragmentWelcome= FragmentWelcome.newInstance();
        fragmentManager
                .beginTransaction()
                .replace(android.R.id.content, mFragmentWelcome, FragmentWelcome.TAG)
                .commit();
    }
}

我接下来要测试的布局：

I then go on to test the layout:

@SmallTest
public void testLayout() {

    ImageButton buttonImage = (ImageButton) getActivity().findViewById(my.package.R.id.button_invites);
    assertNotNull(buttonImage);
    assertEquals("ImageButton Invite has an invalid drawable"
            , getActivity().getResources().getDrawable(my.package.R.drawable.light_social_invite)
            , buttonImage);
}

错误：

java.lang.NullPointerException
    at my.package.test.ActivityWelcomeUnitTest.testLayout(ActivityWelcomeUnitTest.java:55)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at android.test.InstrumentationTestCase.runMethod(InstrumentationTestCase.java:214)
    at android.test.InstrumentationTestCase.runTest(InstrumentationTestCase.java:199)
    at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:169)
    at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:154)
    at android.test.InstrumentationTestRunner.onStart(InstrumentationTestRunner.java:545)
    at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:1551)

失败的：

ImageButton buttonImage = (ImageButton) mFragmentWelcome.getView().findViewById(my.package.R.id.button_invites);

我不知道为什么片段是空的，我显然不正确地执行此操作，可能会有人请赐教？

I'm not sure why the fragment is null, I am obviously performing this operation incorrectly, could someone please enlighten me?

推荐答案

其实你必须等待UI线程组成的片段的主视图。

Actually you have to wait for the UI thread composes the main view with the fragments.

我有同样的错误，所以我看着Robotium的来源，看看他们是如何处理的。响应是他们使用的等待所需时间的一些方法。

I had the same errors and so I looked at the sources of Robotium to see how they handle that. The response is they use some methods that wait the required time.

有关片段，你可以执行你的说法之前，使用这样的事情：

For fragment you can use something like that before performing your assertions :

protected Fragment waitForFragment(String tag, int timeout) {
        long endTime = SystemClock.uptimeMillis() + timeout;
        while (SystemClock.uptimeMillis() <= endTime) {

            Fragment fragment = getActivity().getSupportFragmentManager().findFragmentByTag(tag);
            if (fragment != null) {
                return fragment;
            }
        }
        return null;
    }

我用5000毫秒的超时，它似乎运作良好。

I use a timeout of 5000ms, it seems to work well.

因此​​，在您code就应该更换

So in your code you should replace

mFragmentWelcome = (FragmentWelcome) fragmentManager.findFragmentByTag(FragmentWelcome.TAG);

按

mFragmentWelcome = (FragmentWelcome) waitForFragment(FragmentWelcome.TAG, 5000);

---

编辑：此响应假定您的JUnit扩展 ActivityInstrumentationTestCase2＆LT; T＆GT;

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