退出APP是需要清空所有Activity， 清空的前提是 需要记录已开启的所有 Activity。 在Application.ActivityLifecycleCallbacks的生命周期中调用add和remove操作。
public class ActivityStackHelper { private static LinkedHashMap<Class<?>, Activity> activities = new LinkedHashMap<>(); /** * 保存activity到集合中 * * @param activity */ public static void add(Activity activity) { if (activity == null) { return; } activities.put(activity.getClass(), activity); } /** * 判断指定的activity在map中是否存在 * * @param clazz 指定的activity */ public static boolean isActivityExist(Class clazz) { return clazz != null && get(clazz) != null; } /** * 获取指定clazz的activity * * @param clazz * @param <T> * @return */ public static <T extends Activity> T get(Class<T> clazz) { return (T) activities.get(clazz); } /** * 获取当前集合中的activity * * @return */ public static int getSize() { return activities.size(); } /** * 指定activity是否是activity栈中最底层的activity * * @param activity * @return true，是；false，否 */ public static boolean isLastActivity(Activity activity) { if (activity == null) { return false; } if (activities == null || activities.size() == 0) { return false; } ListIterator<Map.Entry<Class<?>, Activity>> iterator = new ArrayList<>(activities.entrySet()).listIterator(activities.size()); while (iterator.hasPrevious()) { Map.Entry<Class<?>, Activity> next = iterator.previous(); if (next.getKey() == activity.getClass()) { return !iterator.hasPrevious(); } } return false; } /** * 移除集合中的activity * * @param activity */ public static void remove(Activity activity) { if (activity == null) { return; } activities.remove(activity.getClass()); } /** * 清空并finish所有activity */ public static void clearAndFinishActivity() { Set<Map.Entry<Class<?>, Activity>> entries = activities.entrySet(); for (Map.Entry<Class<?>, Activity> entry : entries) { Activity activity = entry.getValue(); if (!activity.isFinishing()) { activity.finish(); } } activities.clear(); } /** * 清空并finish所有activity(除指定activity之外) * * @param clazzs */ public static void clearAndFinishOtherActivity(Class... clazzs) { List<Class> cls = clazzs != null ? Arrays.asList(clazzs) : null; Iterator<Map.Entry<Class<?>, Activity>> iterator = activities.entrySet().iterator(); while (iterator.hasNext()) { Map.Entry<Class<?>, Activity> next = iterator.next(); Class<?> key = next.getKey(); if (cls != null && cls.contains(key)) { continue; } Activity value = next.getValue(); if (!value.isFinishing()) { value.finish(); } iterator.remove(); } } /** * 指定activity是否在运行 * * @param clazz * @param <T> * @return */ public static <T extends Activity> boolean isActivityRunning(Class<T> clazz) { T activity = get(clazz); if (activity == null || activity.isFinishing() || (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1 && activity.isDestroyed())) { return false; } else { return true; } } /** * 获取当前栈顶activity * * @return */ public static Activity getTopActivity() { if (activities == null || activities.size() == 0) { return null; } Iterator<Map.Entry<Class<?>, Activity>> iterator = activities.entrySet().iterator(); Map.Entry<Class<?>, Activity> next = null; while (iterator.hasNext()) { next = iterator.next(); } return next != null ? next.getValue() : null; } /** * 获取次栈顶activity * * @return */ public static Activity getTopSecondActivity() { if (activities == null || activities.size() == 0) { return null; } int size = activities.size(); if (size < 2){ return null; } int index = 1; Iterator<Map.Entry<Class<?>, Activity>> iterator = activities.entrySet().iterator(); Map.Entry<Class<?>, Activity> next = null; while (iterator.hasNext()) { next = iterator.next(); if (index == size - 1){ if (next != null){ LogUtils.i("ActivityStackHelper", "secondActivity" + next.getValue()); return next.getValue(); } } index++; } return null; } /** * 获取除了指定activity之外的栈顶activity * * @param clazz * @return */ public static Activity getTopActivityExclude(Class clazz) { if (activities == null || activities.size() == 0) { return null; } Iterator<Map.Entry<Class<?>, Activity>> iterator = activities.entrySet().iterator(); Map.Entry<Class<?>, Activity> resule = null; while (iterator.hasNext()) { Map.Entry<Class<?>, Activity> next = iterator.next(); if (next.getKey() != clazz) { resule = next; } } return resule != null ? resule.getValue() : null; } }调用使用方法
public class AppActivityLifecycleCallbacks implements Application.ActivityLifecycleCallbacks { @Override public void onActivityCreated(Activity activity, Bundle savedInstanceState) { ActivityStackHelper.add(activity); } @Override public void onActivityDestroyed(Activity activity) { ActivityStackHelper.remove(activity); } }上述工具类用到了LinkedHashMap 是为了保证顺序，其特性详见 https://blog.csdn.net/iblade/article/details/108369770
