Uiobject2 of uiautomator2 common classes

        UiAutomator The classes involved are ： UiObject、UiObject2、UiDevice、UiWatcher、BySelector、AccessibilityNodeInfo、Gestures、GestureController、Instrumentation

One 、UiObject and UiObject2

        UiObject2 Representing one UI Control . It is bound to a specific view instance , If the underlying view object is destroyed , It may become obsolete . therefore , If UI Significant changes have taken place , May need to call UiDevice#findObject(BySelector) To get new UiObject2 example .

        UiObject Representing one UI Control . It does not bind directly to the view in any way as an object reference . UiObject Contains help at run time according to {@link UiSelector} Attribute locates the information that matches the view . Once you create a UiObject Example , It can be reused in different views that match selector criteria .

        UiObject yes UI Automator Important classes in the early days of the testing framework ,UiObject2 Is its improved version .

        difference ： Reference article ”UiObject And UiObject2 Trigger UiWatcher Code timing “

        UI Automator Testing frameworks are most commonly used UiObject And UiObject2, The objects generated by these two classes , All represent the controls that meet the specified conditions , When the control is not found , Will trigger UiDevice All registered UiWatcher object , We can do it in UiWatcher In the implementation class of , Write the processing logic when the control is not found , For example, a control is not found , Maybe the pop-up system dialog box blocks the controls we need to find , At this time, it can be in UiWatcher In the implementation class of , Write close this close system popup 、 Or close the business logic code of a business pop-up window .

    UiObject、UiObject2 Trigger UiWatcher The timing of the code is different , Let's spoiler first. They trigger each other UiWatcher The timing of the code

        1、UiObject When executing methods that manipulate controls , Will trigger UiWatcher Code for . For example, call UiObject Of click（） When the method is used , Can trigger UiWatcher Code for , While using UiDevice Of findObject（UiSelector） When looking for controls , It doesn't lead to UiWatcher Code triggering

        2、UiObject2, It is UiDevice Of findObject（BySelector） Method will trigger UiWatcher Code for , That is, when the search control is executed , It will trigger UiWatcher Code for

        We can take a look UiObject2 Source code . So let's see first UiObject2 Which dependent classes are used inside the class ：

        UiDevice： Express UI Operating equipment , It encapsulates the device information 、 Get device controls and device gesture operation functions ;

        BySelector： lookup UiDevice The condition collection object of the control on the device , Through it, you can find the target control on the device ;

        AccessibilityNodeInfo： Accessible node information , All controls visible on the device screen （ Include View And layout ） Can be abstracted into nodes , And nodes can be nested in nodes to form a control tree （ Node tree ）.AccessibilityNodeInfo Contains node information , such as ： Control id, text Width and width 、 Parent node 、 Child node information , Can I click , Check it or not , And encapsulates ui Operation method . All in all UiObject2 Some information about the control properties of the object is from AccessibilityNodeInfo Obtained from . You can UiObject2 Comprehend AccessibilityNodeInfo An agent of

        Gestures： Gesture object ,ui operation , For example, click on 、 Sliding these operations can be abstracted into a gesture ;

        GestureController： Used to perform gestures .

Let's make a concrete analysis UiObject2 Specific source code

1、 Constructors

        You can see ,UiObject2 Is a private function in the package , It means that we can't pass directly new The way to create a UiObject2 object . But through UiDevice#findObject(BySelector) The way to create UiObject2 object . namely UiDevice By finder object BySelector To find qualified UI Control .

/** Package-private constructor. Used by {@link UiDevice#findObject(BySelector)}. */
UiObject2(UiDevice device, BySelector selector, AccessibilityNodeInfo cachedNode) {
    mDevice = device;
    mSelector = selector;
    mCachedNode = cachedNode;
    mGestures = Gestures.getInstance(device);
    mGestureController = GestureController.getInstance(device);
    mDisplayMetrics = mDevice.getInstrumentation().getContext().getResources()
            .getDisplayMetrics();
}

2、getAccessibilityNodeInfo() Get controls Abreast of the times Node information

        First ,UiObject2 The control information represented is saved in mCachedNode Attribute , It's a AccessibilityNodeInfo object .

        1、 In this function, we first judge mCachedNode Whether the object is null, If null It means that this node has been recycled , Throw an exception ;

        2、 And then call getDevice().waitForIdle() Wait for the device to be idle , That is, the current mobile page elements have not changed ;

        3、 call mCachedNode.refresh() To refresh the state of the control to get the latest information on the control , such as textview The text on the control may change , call refreash() Get the latest text after ;

        4、 If refresh() return false, Represents that the control is obsolete , It indicates that the control is no longer in the control tree , This control should be recycled ;

        5、refresh() return false, Then the call is bound in UiObject2 Upper UiWatcher Of checkForCondition() Handle exceptions when the control cannot be found ; etc. checkForCondition() after , Check again mCachedNode Whether there is , If it doesn't exist yet , Direct error reporting ;

        6、refresh() return true, Represents that this control is found in the device control tree , And updated the control information ;

        7、 Go straight back to mCachedNode.

private AccessibilityNodeInfo mCachedNode;


/**
 * Returns an up-to-date {@link AccessibilityNodeInfo} corresponding to the {@link android.view.View} that
 * this object represents.
 */
private AccessibilityNodeInfo getAccessibilityNodeInfo() {
    if (mCachedNode == null) {
        throw new IllegalStateException("This object has already been recycled");
    }

    getDevice().waitForIdle();
    if (!mCachedNode.refresh()) {
        getDevice().runWatchers();

        if (!mCachedNode.refresh()) {
            throw new StaleObjectException();
        }
    }
    return mCachedNode;
}

3、 Get parent control getParent()

        Internal calls are too complicated , Do not understand . Regardless of the , Just get the parent control of the current control .

/** Returns this object's parent, or null if it has no parent. */
public UiObject2 getParent() {
    AccessibilityNodeInfo parent = getAccessibilityNodeInfo().getParent();
    return parent != null ? new UiObject2(getDevice(), mSelector, parent) : null;
}

4、 Get the number of child controls

        First, get the latest information about updating the current control , That's one of them mChildNodeIds Will update .mChildNodeIds yes AccessibilityNodeInfo An array type object in , Save the child node information of the current node .

/** Returns the number of child elements directly under this object. */
public int getChildCount() {
    return getAccessibilityNodeInfo().getChildCount();
}

/**
 * Gets the number of children.
 *
 * @return The child count.
 */
public int getChildCount() {
    return mChildNodeIds == null ? 0 : mChildNodeIds.size();
}

5、 Get the current control internal eligible Of One or all Child controls

/**
 * Searches all elements under this object and returns the first object to match the criteria,
 * or null if no matching objects are found.
 */
public UiObject2 findObject(BySelector selector) {
    AccessibilityNodeInfo node =
            ByMatcher.findMatch(getDevice(), selector, getAccessibilityNodeInfo());
    return node != null ? new UiObject2(getDevice(), selector, node) : null;
}

/** Searches all elements under this object and returns all objects that match the criteria. */
public List<UiObject2> findObjects(BySelector selector) {
    List<UiObject2> ret = new ArrayList<UiObject2>();
    for (AccessibilityNodeInfo node :
            ByMatcher.findMatches(getDevice(), selector, getAccessibilityNodeInfo())) {

        ret.add(new UiObject2(getDevice(), selector, node));
    }

    return ret;
}

6、 Get controls Visible area and Including margins The visible area of

/** Returns the visible bounds of this object in screen coordinates. */
public Rect getVisibleBounds() {
    return getVisibleBounds(getAccessibilityNodeInfo());
}

/** Returns the visible bounds of this object with the margins removed. */
private Rect getVisibleBoundsForGestures() {
    Rect ret = getVisibleBounds();
    ret.left = ret.left + mMarginLeft;
    ret.top = ret.top + mMarginTop;
    ret.right = ret.right - mMarginRight;
    ret.bottom = ret.bottom - mMarginBottom;
    return ret;
}

7、 Get the class name of the control 、 Description information 、 App package name 、 resources id

        You can find , In fact, all this information is stored in UiObject2 The object holds AccessibilityNodeInfo Property object .

/**
 * Returns the class name of the underlying {@link android.view.View} represented by this
 * object.
 */
public String getClassName() {
    CharSequence chars = getAccessibilityNodeInfo().getClassName();
    return chars != null ? chars.toString() : null;
}

/** Returns the content description for this object. */
public String getContentDescription() {
    CharSequence chars = getAccessibilityNodeInfo().getContentDescription();
    return chars != null ? chars.toString() : null;
}

/** Returns the package name of the app that this object belongs to. */
public String getApplicationPackage() {
    CharSequence chars = getAccessibilityNodeInfo().getPackageName();
    return chars != null ? chars.toString() : null;
}

/** Returns the fully qualified resource name for this object's id. */
public String getResourceName() {
    CharSequence chars = getAccessibilityNodeInfo().getViewIdResourceName();
    return chars != null ? chars.toString() : null;
}

8、UI gestures

        You can see the execution on the control UI operation , Need to use GestureController Gesture control object . This object is UiObject2 Is initialized in the constructor of . Concrete UI action , For example, click on 、 Sliding is abstract Gestures class .

How to realize the plan? Write a separate article summary .

/** Clicks on this object. */
public void click() {
    mGestureController.performGesture(mGestures.click(getVisibleCenter()));
}

/** Package-private constructor. Used by {@link UiDevice#findObject(BySelector)}. */
UiObject2(UiDevice device, BySelector selector, AccessibilityNodeInfo cachedNode) {
    mDevice = device;
    mSelector = selector;
    mCachedNode = cachedNode;
    mGestures = Gestures.getInstance(device);
    mGestureController = GestureController.getInstance(device);
    mDisplayMetrics = mDevice.getInstrumentation().getContext().getResources()
            .getDisplayMetrics();
}