如何計算使用Espresso的RecyclerView物品

Question

使用Espresso和Hamcrest，

如何計算recyclerView中可用的物料編號？

例如：我想檢查5個項目是否顯示在特定的RecyclerView中（如有必要滾動）。

Answer 1

下面的例子ViewAssertion檢查RecyclerView項目計數

public class RecyclerViewItemCountAssertion implements ViewAssertion { 
    private final int expectedCount; 

    public RecyclerViewItemCountAssertion(int expectedCount) { 
    this.expectedCount = expectedCount; 
    } 

    @Override 
    public void check(View view, NoMatchingViewException noViewFoundException) { 
    if (noViewFoundException != null) { 
     throw noViewFoundException; 
    } 

    RecyclerView recyclerView = (RecyclerView) view; 
    RecyclerView.Adapter adapter = recyclerView.getAdapter(); 
    assertThat(adapter.getItemCount(), is(expectedCount)); 
    } 
} 

然後用這個說法

onView(withId(R.id.recyclerView)).check(new RecyclerViewItemCountAssertion(5)); 

我已經開始寫一個庫，它應該使測試更加簡單與咖啡和uiautomator 。這包括RecyclerView操作和斷言的工具。 https://github.com/nenick/espresso-macchiato例如見EspRecyclerView與方法assertItemCountIs（INT）

Answer 2

要完成nenick答案，並提供多一點靈活的解決方案也測試，如果項目COUT是GREATERTHAN，每種不超過...

public class RecyclerViewItemCountAssertion implements ViewAssertion { 

    private final Matcher<Integer> matcher; 

    public RecyclerViewItemCountAssertion(int expectedCount) { 
     this.matcher = is(expectedCount); 
    } 

    public RecyclerViewItemCountAssertion(Matcher<Integer> matcher) { 
     this.matcher = matcher; 
    } 

    @Override 
    public void check(View view, NoMatchingViewException noViewFoundException) { 
     if (noViewFoundException != null) { 
      throw noViewFoundException; 
     } 

     RecyclerView recyclerView = (RecyclerView) view; 
     RecyclerView.Adapter adapter = recyclerView.getAdapter(); 
     assertThat(adapter.getItemCount(), matcher); 
    } 

} 

用法：

onView(withId(R.id.recyclerView)).check(new RecyclerViewItemCountAssertion(5)); 
onView(withId(R.id.recyclerView)).check(new RecyclerViewItemCountAssertion(greaterThan(5)); 
onView(withId(R.id.recyclerView)).check(new RecyclerViewItemCountAssertion(lessThan(5)); 
// ... 

Answer 3

給@Stephane's answer添加一點糖語法。

public class RecyclerViewItemCountAssertion implements ViewAssertion { 
    private final Matcher<Integer> matcher; 

    public static RecyclerViewItemCountAssertion withItemCount(int expectedCount) { 
     return withItemCount(is(expectedCount)); 
    } 

    public static RecyclerViewItemCountAssertion withItemCount(Matcher<Integer> matcher) { 
     return new RecyclerViewItemCountAssertion(matcher); 
    } 

    private RecyclerViewItemCountAssertion(Matcher<Integer> matcher) { 
     this.matcher = matcher; 
    } 

    @Override 
    public void check(View view, NoMatchingViewException noViewFoundException) { 
     if (noViewFoundException != null) { 
      throw noViewFoundException; 
     } 

     RecyclerView recyclerView = (RecyclerView) view; 
     RecyclerView.Adapter adapter = recyclerView.getAdapter(); 
     assertThat(adapter.getItemCount(), matcher); 
    } 
} 

用法：

import static your.package.RecyclerViewItemCountAssertion.withItemCount; 

onView(withId(R.id.recyclerView)).check(withItemCount(5)); 
onView(withId(R.id.recyclerView)).check(withItemCount(greaterThan(5)); 
onView(withId(R.id.recyclerView)).check(withItemCount(lessThan(5)); 
// ... 

Answer 4

我用下面的方法來獲取RecyclerView的計數

public static int getCountFromRecyclerView(@IdRes int RecyclerViewId) { 
int COUNT = 0; 
     Matcher matcher = new TypeSafeMatcher<View>() { 
      @Override 
      protected boolean matchesSafely(View item) { 
       COUNT = ((RecyclerView) item).getAdapter().getItemCount(); 
       return true; 
      } 
      @Override 
      public void describeTo(Description description) { 
      } 
     }; 
     onView(allOf(withId(RecyclerViewId),isDisplayed())).check(matches(matcher)); 
     int result = COUNT; 
      COUNT = 0; 
     return result; 
    } 

用法 -

int itemsCount = getCountFromRecyclerView(R.id.RecyclerViewId); 

然後執行斷言檢查itemsCount與預期的一樣

Answer 5

基於@Sivakumar Kamichetty答案：

1. 變量 '計數' 從內部類中訪問，需要被聲明爲final。
2. 不必要的行：COUNT = 0;
3. 將COUNT變量轉移到一個元素數組。
4. 變量result是不必要的。

不是很好，但工程：

public static int getCountFromRecyclerView(@IdRes int RecyclerViewId) { 
    final int[] COUNT = {0}; 
    Matcher matcher = new TypeSafeMatcher<View>() { 
     @Override 
     protected boolean matchesSafely(View item) { 
      COUNT[0] = ((RecyclerView) item).getAdapter().getItemCount(); 
      return true; 
     } 
     @Override 
     public void describeTo(Description description) {} 
    }; 
    onView(allOf(withId(RecyclerViewId),isDisplayed())).check(matches(matcher)); 
    return COUNT[0]; 
}