Android example source code file (ViewAsserts.java)

This example Android source code file (ViewAsserts.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, child, ui, view, viewasserts

The ViewAsserts.java Android example source code

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.test;

import static junit.framework.Assert.*;

import android.view.View;
import android.view.ViewGroup;

/**
 * Some useful assertions about views.
 */
public class ViewAsserts {

    private ViewAsserts() {}

    /**
     * Assert that view is on the screen.
     * @param origin The root view of the screen.
     * @param view The view.
     */
    static public void assertOnScreen(View origin, View view) {
        int[] xy = new int[2];
        view.getLocationOnScreen(xy);

        int[] xyRoot = new int[2];
        origin.getLocationOnScreen(xyRoot);

        int y = xy[1] - xyRoot[1];

        assertTrue("view should have positive y coordinate on screen",
                y  >= 0);

        assertTrue("view should have y location on screen less than drawing "
                + "height of root view",
                y <= view.getRootView().getHeight());
    }

    /**
     * Assert that view is below the visible screen.
     * @param origin The root view of the screen.
     * @param view The view
     */
    static public void assertOffScreenBelow(View origin, View view) {
        int[] xy = new int[2];
        view.getLocationOnScreen(xy);

        int[] xyRoot = new int[2];
        origin.getLocationOnScreen(xyRoot);

        int y = xy[1] - xyRoot[1];

        assertTrue("view should have y location on screen greater than drawing "
                + "height of origen view (" + y + " is not greater than "
                + origin.getHeight() + ")",
                y > origin.getHeight());
    }

    /**
     * Assert that view is above the visible screen.
     * @param origin Te root view of the screen.
     * @param view The view
     */
    static public void assertOffScreenAbove(View origin, View view) {
        int[] xy = new int[2];
        view.getLocationOnScreen(xy);

        int[] xyRoot = new int[2];
        origin.getLocationOnScreen(xyRoot);

        int y = xy[1] - xyRoot[1];

        assertTrue("view should have y location less than that of origin view",
                y < 0);
    }

    /**
     * Assert that a view has a particular x and y position on the visible screen.
     * @param origin The root view of the screen.
     * @param view The view.
     * @param x The expected x coordinate.
     * @param y The expected y coordinate.
     */
    static public void assertHasScreenCoordinates(View origin, View view, int x, int y) {
        int[] xy = new int[2];
        view.getLocationOnScreen(xy);

        int[] xyRoot = new int[2];
        origin.getLocationOnScreen(xyRoot);

        assertEquals("x coordinate", x, xy[0] - xyRoot[0]);
        assertEquals("y coordinate", y, xy[1] - xyRoot[1]);
    }

    /**
     * Assert that two views are aligned on their baseline, that is that their baselines
     * are on the same y location.
     *
     * @param first The first view
     * @param second The second view
     */
    static public void assertBaselineAligned(View first, View second) {
        int[] xy = new int[2];
        first.getLocationOnScreen(xy);
        int firstTop = xy[1] + first.getBaseline();

        second.getLocationOnScreen(xy);
        int secondTop = xy[1] + second.getBaseline();

        assertEquals("views are not baseline aligned", firstTop, secondTop);
    }

    /**
     * Assert that two views are right aligned, that is that their right edges
     * are on the same x location.
     *
     * @param first The first view
     * @param second The second view
     */
    static public void assertRightAligned(View first, View second) {
        int[] xy = new int[2];
        first.getLocationOnScreen(xy);
        int firstRight = xy[0] + first.getMeasuredWidth();

        second.getLocationOnScreen(xy);
        int secondRight = xy[0] + second.getMeasuredWidth();

        assertEquals("views are not right aligned", firstRight, secondRight);
    }

    /**
     * Assert that two views are right aligned, that is that their right edges
     * are on the same x location, with respect to the specified margin.
     *
     * @param first The first view
     * @param second The second view
     * @param margin The margin between the first view and the second view
     */
    static public void assertRightAligned(View first, View second, int margin) {
        int[] xy = new int[2];
        first.getLocationOnScreen(xy);
        int firstRight = xy[0] + first.getMeasuredWidth();

        second.getLocationOnScreen(xy);
        int secondRight = xy[0] + second.getMeasuredWidth();

        assertEquals("views are not right aligned", Math.abs(firstRight - secondRight), margin);
    }

    /**
     * Assert that two views are left aligned, that is that their left edges
     * are on the same x location.
     *
     * @param first The first view
     * @param second The second view
     */
    static public void assertLeftAligned(View first, View second) {
        int[] xy = new int[2];
        first.getLocationOnScreen(xy);
        int firstLeft = xy[0];

        second.getLocationOnScreen(xy);
        int secondLeft = xy[0];

        assertEquals("views are not left aligned", firstLeft, secondLeft);
    }

    /**
     * Assert that two views are left aligned, that is that their left edges
     * are on the same x location, with respect to the specified margin.
     *
     * @param first The first view
     * @param second The second view
     * @param margin The margin between the first view and the second view
     */
    static public void assertLeftAligned(View first, View second, int margin) {
        int[] xy = new int[2];
        first.getLocationOnScreen(xy);
        int firstLeft = xy[0];

        second.getLocationOnScreen(xy);
        int secondLeft = xy[0];

        assertEquals("views are not left aligned", Math.abs(firstLeft - secondLeft), margin);
    }

    /**
     * Assert that two views are bottom aligned, that is that their bottom edges
     * are on the same y location.
     *
     * @param first The first view
     * @param second The second view
     */
    static public void assertBottomAligned(View first, View second) {
        int[] xy = new int[2];
        first.getLocationOnScreen(xy);
        int firstBottom = xy[1] + first.getMeasuredHeight();

        second.getLocationOnScreen(xy);
        int secondBottom = xy[1] + second.getMeasuredHeight();

        assertEquals("views are not bottom aligned", firstBottom, secondBottom);
    }

    /**
     * Assert that two views are bottom aligned, that is that their bottom edges
     * are on the same y location, with respect to the specified margin.
     *
     * @param first The first view
     * @param second The second view
     * @param margin The margin between the first view and the second view
     */
    static public void assertBottomAligned(View first, View second, int margin) {
        int[] xy = new int[2];
        first.getLocationOnScreen(xy);
        int firstBottom = xy[1] + first.getMeasuredHeight();

        second.getLocationOnScreen(xy);
        int secondBottom = xy[1] + second.getMeasuredHeight();

        assertEquals("views are not bottom aligned", Math.abs(firstBottom - secondBottom), margin);
    }

    /**
     * Assert that two views are top aligned, that is that their top edges
     * are on the same y location.
     *
     * @param first The first view
     * @param second The second view
     */
    static public void assertTopAligned(View first, View second) {
        int[] xy = new int[2];
        first.getLocationOnScreen(xy);
        int firstTop = xy[1];

        second.getLocationOnScreen(xy);
        int secondTop = xy[1];

        assertEquals("views are not top aligned", firstTop, secondTop);
    }

    /**
     * Assert that two views are top aligned, that is that their top edges
     * are on the same y location, with respect to the specified margin.
     *
     * @param first The first view
     * @param second The second view
     * @param margin The margin between the first view and the second view
     */
    static public void assertTopAligned(View first, View second, int margin) {
        int[] xy = new int[2];
        first.getLocationOnScreen(xy);
        int firstTop = xy[1];

        second.getLocationOnScreen(xy);
        int secondTop = xy[1];

        assertEquals("views are not top aligned", Math.abs(firstTop - secondTop), margin);
    }

    /**
     * Assert that the <code>test view is horizontally center aligned
     * with respect to the <code>reference view.
     *
     * @param reference The reference view
     * @param test The view that should be center aligned with the reference view
     */
    static public void assertHorizontalCenterAligned(View reference, View test) {
        int[] xy = new int[2];
        reference.getLocationOnScreen(xy);
        int referenceLeft = xy[0];

        test.getLocationOnScreen(xy);
        int testLeft = xy[0];

        int center = (reference.getMeasuredWidth() - test.getMeasuredWidth()) / 2;
        int delta = testLeft - referenceLeft;

        assertEquals("views are not horizontally center aligned", center, delta);
    }

    /**
     * Assert that the <code>test view is vertically center aligned
     * with respect to the <code>reference view.
     *
     * @param reference The reference view
     * @param test The view that should be center aligned with the reference view
     */
    static public void assertVerticalCenterAligned(View reference, View test) {
        int[] xy = new int[2];
        reference.getLocationOnScreen(xy);
        int referenceTop = xy[1];

        test.getLocationOnScreen(xy);
        int testTop = xy[1];

        int center = (reference.getMeasuredHeight() - test.getMeasuredHeight()) / 2;
        int delta = testTop - referenceTop;

        assertEquals("views are not vertically center aligned", center, delta);
    }

    /**
     * Assert the specified group's integrity. The children count should be >= 0 and each
     * child should be non-null.
     *
     * @param parent The group whose integrity to check
     */
    static public void assertGroupIntegrity(ViewGroup parent) {
        final int count = parent.getChildCount();
        assertTrue("child count should be >= 0", count >= 0);

        for (int i = 0; i < count; i++) {
            assertNotNull("group should not contain null children", parent.getChildAt(i));
            assertSame(parent, parent.getChildAt(i).getParent());
        }
    }

    /**
     * Assert that the specified group contains a specific child once and only once.
     *
     * @param parent The group
     * @param child The child that should belong to group
     */
    static public void assertGroupContains(ViewGroup parent, View child) {
        final int count = parent.getChildCount();
        assertTrue("Child count should be >= 0", count >= 0);

        boolean found = false;
        for (int i = 0; i < count; i++) {
            if (parent.getChildAt(i) == child) {
                if (!found) {
                    found = true;
                } else {
                    assertTrue("child " + child + " is duplicated in parent", false);
                }
            }
        }

        assertTrue("group does not contain " + child, found);
    }

    /**
     * Assert that the specified group does not contain a specific child.
     *
     * @param parent The group
     * @param child The child that should not belong to group
     */
    static public void assertGroupNotContains(ViewGroup parent, View child) {
        final int count = parent.getChildCount();
        assertTrue("Child count should be >= 0", count >= 0);

        for (int i = 0; i < count; i++) {
            if (parent.getChildAt(i) == child) {
                assertTrue("child " + child + " is found in parent", false);
            }
        }
    }
}