在Espresso测试中使用“hasBackground”

Question

如何使用布局背景的颜色来进行espresso测试？目前可以使用hasBackground()方法：

onView(withId(R.id.backgroundColor)).check(matches(hasBackground(Color.parseColor("#FF55ff77"))));

但是出现了错误:

android.support.test.espresso.base.DefaultFailureHandler$AssertionFailedWithCauseError: '具有drawable ID：-11141257的背景'与所选视图不匹配。

预期结果：具有drawable ID：-11141257的背景。

得到的结果："LinearLayout {id = 2130968576，res-name = backgroundColor，visibility = VISIBLE，width = 996，height = 1088，has-focus = false，has-focusable = false，has-window-focus = true，is-clickable = false，is-enabled = true，is-focused = false，is-focusable = false，is-layout-requested = false，is-selected = false，layout-params = android.widget.LinearLayout $ LayoutParams @ e55f6e7，tag = null，root-is-layout-requested = false，has-input-connection = false，x = 42.0，y = 601.0，child-count = 2} "。

我该如何比较这个？

- Roberto Pinheiro

Answer 1

我正在使用自定义匹配器和 Hamcrest 库来完成它：

Hamcrest 是一个帮助你编写自定义匹配器的库。

public class BackgroundColourMatcher extends TypeSafeMatcher<View> {

    @ColorRes
    private final int mExpectedColourResId;

    private int mColorFromView;

    public BackgroundColourMatcher(@ColorRes int expectedColourResId) {
        super(View.class);
        mExpectedColourResId = expectedColourResId;
    }

    @Override
    protected boolean matchesSafely(View item) {

        if (item.getBackground() == null) {
            return false;
        }
        Resources resources = item.getContext().getResources();
        int colourFromResources = ResourcesCompat.getColor(resources, mExpectedColourResId, null);
        mColorFromView = ((ColorDrawable) item.getBackground()).getColor();
        return mColorFromView == colourFromResources;
    }

    @Override
    public void describeTo(Description description) {
        description.appendText("Color did not match " + mExpectedColourResId + " was " + mColorFromView);
    }
}

您可以为您的匹配器提供以下类似内容：

public class CustomTestMatchers {

    public static Matcher<View> withBackgroundColour(@ColorRes int expectedColor) {
        return new BackgroundColourMatcher(expectedColor);
    }
}

最后在您的测试中：

onView(withId(R.id.my_view)).check(matches(withBackgroundColour(R.color.color_to_check)))

您可以轻松修改BackgroundColourMatcher类，使其直接使用颜色而不是资源。

希望对您有所帮助！

- Yannshu

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如何验证材料按钮的背景色调？因为在这种情况下，背景将始终为空。 - Jimit Patel

Answer 2

另一种方法是直接从视图中检索颜色值：

val bar = activityRule.activity.findViewById<View>(R.id.backgroundColor)
val actualColor = (bar.background as ColorDrawable).color
val expectedColor = Color.parseColor("#FF55ff77")
assertEquals(actualColor, expectedColor)

- Fernando Jascovich