replaceText

  /**
   * Returns an action that updates the text attribute of a view. <br>
   * <br>
   * View preconditions:
   *
   * <ul>
   *   <li>must be displayed on screen
   *   <li>must be assignable from EditText
   *       <ul>
   */
  public static ViewAction replaceText(@Nonnull String stringToBeSet) {
    return actionWithAssertions(new ReplaceTextAction(stringToBeSet));
  }

该方法返回一个ViewAction类型对象，通过指定字符串替换控件内容，view有以下几个限制：

• 必须展示在屏幕上，即该视图的visibility不能是gone
• 必须是EditText类型。
  如果该控件的visibility="gone"或者该控件不是EditText类型，则会报错。

typeText

  /**
   * Returns an action that selects the view (by clicking on it) and types the provided string into
   * the view. Appending a \n to the end of the string translates to a ENTER key event. Note: this
   * method performs a tap on the view before typing to force the view into focus, if the view
   * already contains text this tap may place the cursor at an arbitrary position within the text.
   * <br>
   * <br>
   * View preconditions:
   *
   * <ul>
   *   <li>must be displayed on screen
   *   <li>must support input methods
   *       <ul>
   */
  public static ViewAction typeText(String stringToBeTyped) {
      return actionWithAssertions(new TypeTextAction(stringToBeTyped));
  }

该方法返回一个ViewAction类型对象，不过该方法是模拟键盘输入方式输入字符串，所以该方法不能输入汉字，且有以下限制：

• 必须展示在屏幕上
• 必须是可输入类型控件

使用方法

onView(withId(R.id.edit)).perform(ViewActions.typeText("aaa"));//方法一

onView(withId(R.id.edit)).perform(ViewActions.replaceText("测试"));//方法二

方法一

ViewActions.typeText("aaa")最终返回的是一个TypeTextAction类型，perform最终调用的是viewAction.perform(uiController, targetView)方法，该viewAction就是TypeTextAction类型，所以最终会调用TypeTextAction的perform

@Override
  public void perform(UiController uiController, View view) {
    ......
    if (tapToFocus) {
      // Perform a click.
      new GeneralClickAction(Tap.SINGLE, GeneralLocation.CENTER, Press.FINGER)
          .perform(uiController, view);
      uiController.loopMainThreadUntilIdle();
    }
    ......
}

最终会模拟键盘输入的方式输入字符串，而键盘上是不存在中文字符的，所以输入中文字符会报错。

方法二

ViewActions.replaceText("测试")最终返回的是一个ReplaceTextAction类型，perform最终调用的是viewAction.perform(uiController, targetView)方法，该viewAction就是ReplaceTextAction类型，所以最终会调用ReplaceTextAction的perform

  @Override
  public void perform(UiController uiController, View view) {
    ((EditText) view).setText(stringToBeSet);
  }

由上可以看出，目标控件必须是EditText类型。