一招搞定Android Activity的管理

作者: 一只小松 | 来源:发表于2017-03-13 22:50 被阅读441次

为什么要做activity的管理


在android app的开发过程中,或多或少会涉及到activity的管理。会有这样的业务场景存在,例如:

  • 广播接收器接收到某个动作,需要finish某个指定的activity;
  • 在缺乏activity上下文的地方也需要finish某个指定的activity......

话不多说,上代码。

1. AppManager.java

/**
 * ProjectName:AndroidUtil
 * PackageName: com.standard.util.helper
 * Description:自定义activity的栈管理(栈结构扩展Vector,元素不要求唯一性,可存在多个相同实例)
 * <p>
 * CreateTime: 6/24/2016 12:36
 * Modifier:liminghuang
 * ModifyTime:6/24/2016 12:36
 * Comment:因为第一版本AppManager的使用过程中发现存在问题,所以为了保持api的一致性,采用桥接模式委托AppManagerDelegate类处理
 *
 * @author liminghuang
 */
public final class AppManager {
    /** 是否使用桥接模式 **/
    private boolean isBridge = false;
    /** AppManager管理activity的委托类 **/
    private AppManagerDelegate mDelegate;
    /** 维护activity的栈结构 **/
    private Stack<Activity> mActivityStack;
    private static volatile AppManager sInstance;
    /**
     * 隐藏构造器
     *
     * @param isBridge 是否开启桥接模式
     */
    private AppManager(boolean isBridge) {
        this.isBridge = isBridge;
        mDelegate = AppManagerDelegate.getInstance();
    }
    /**
     * 单例
     *
     * @return 返回AppManager的单例
     */
    public static AppManager getInstance() {
        if (sInstance == null) {
            synchronized (AppManager.class) {
                if (sInstance == null) {
                    sInstance = new AppManager(true);
                }
            }
        }
        return sInstance;
    }
    /**
     * 添加Activity到堆栈
     *
     * @param activity activity实例
     */
    public void addActivity(Activity activity) {
        if (isBridge) {
            mDelegate.addActivity(activity);
        } else {
            if (mActivityStack == null) {
                mActivityStack = new Stack<>();
            }
            mActivityStack.add(activity);
        }
    }
    /**
     * 获取当前Activity(栈中最后一个压入的)
     *
     * @return 当前(栈顶)activity
     */
    public Activity currentActivity() {
        if (isBridge) {
            return mDelegate.currentActivity();
        } else {
            if (mActivityStack != null && !mActivityStack.isEmpty()) {
                return mActivityStack.lastElement();
            }
            return null;
        }
    }
    /**
     * 结束除当前activtiy以外的所有activity
     * 注意:不能使用foreach遍历并发删除,会抛出java.util.ConcurrentModificationException的异常
     *
     * @param activity 不需要结束的activity
     */
    public void finishOtherActivity(Activity activity) {
        if (isBridge) {
            mDelegate.finishOtherActivity(activity);
        } else {
            if (mActivityStack != null) {
                for (Iterator<Activity> it = mActivityStack.iterator(); it.hasNext(); ) {
                    Activity temp = it.next();
                    if (temp != null && temp != activity) {
                        finishActivity(temp);
                    }
                }
            }
        }
    }
    /**
     * 结束除这一类activtiy以外的所有activity
     * 注意:不能使用foreach遍历并发删除,会抛出java.util.ConcurrentModificationException的异常
     *
     * @param cls 不需要结束的activity
     */
    public void finishOtherActivity(Class<?> cls) {
        if (isBridge) {
            mDelegate.finishOtherActivity(cls);
        } else {
            if (mActivityStack != null) {
                for (Iterator<Activity> it = mActivityStack.iterator(); it.hasNext(); ) {
                    Activity activity = it.next();
                    if (!activity.getClass().equals(cls)) {
                        finishActivity(activity);
                    }
                }
            }
        }
    }
    /**
     * 结束当前Activity(堆栈中最后一个压入的)
     */
    public void finishActivity() {
        if (isBridge) {
            mDelegate.finishActivity();
        } else {
            if (mActivityStack != null && !mActivityStack.isEmpty()) {
                Activity activity = mActivityStack.lastElement();
                finishActivity(activity);
            }
        }
    }
    /**
     * 结束指定的Activity
     *
     * @param activity 指定的activity实例
     */
    public void finishActivity(Activity activity) {
        if (isBridge) {
            mDelegate.finishActivity(activity);
        } else {
            if (activity != null) {
                if (mActivityStack != null && mActivityStack.contains(activity)) {// 兼容未使用AppManager管理的实例
                    mActivityStack.remove(activity);
                }
                activity.finish();
            }
        }
    }
    /**
     * 结束指定类名的所有Activity
     *
     * @param cls 指定的类的class
     */
    public void finishActivity(Class<?> cls) {
        if (isBridge) {
            mDelegate.finishActivity(cls);
        } else {
            if (mActivityStack != null) {
                for (Iterator<Activity> it = mActivityStack.iterator(); it.hasNext(); ) {
                    Activity activity = it.next();
                    if (activity.getClass().equals(cls)) {
                        finishActivity(activity);
                    }
                }
            }
        }
    }
    /**
     * 结束所有Activity
     */
    public void finishAllActivity() {
        if (isBridge) {
            mDelegate.finishAllActivity();
        } else {
            if (mActivityStack != null) {
                for (int i = 0, size = mActivityStack.size(); i < size; i++) {
                    if (null != mActivityStack.get(i)) {
                        mActivityStack.get(i).finish();
                    }
                }
                mActivityStack.clear();
            }
        }
    }
    /**
     * 退出应用程序
     */
    public void exitApp() {
        if (isBridge) {
            mDelegate.exitApp();
        } else {
            try {
                finishAllActivity();
                // 退出JVM(java虚拟机),释放所占内存资源,0表示正常退出(非0的都为异常退出)
                System.exit(0);
                // 从操作系统中结束掉当前程序的进程
                android.os.Process.killProcess(android.os.Process.myPid());
            } catch (Exception e) {
                LogUtil.e("Exit exception", e);
            }
        }
    }
}

2. AppManagerDelegate.java

/**
 * ProjectName:AndroidUtil
 * PackageName: com.standard.util.helper
 * Description:自定义activity的栈管理(栈结构扩展Vector,元素不要求唯一性,可存在多个相同实例)
 * <p>
 * CreateTime: 6/24/2016 12:36
 * Modifier:liminghuang
 * ModifyTime:6/24/2016 12:36
 * Comment:
 *
 * @author liminghuang
 */
public final class AppManagerDelegate {
    
    // 使用弱引用是因为存在未使用AppManager的finish方法来释放的activity,但mActivityStack并未断开对其应用导致内存泄露的问题
    private Stack<WeakReference<Activity>> mActivityStack;
    private static volatile AppManagerDelegate sInstance;
    
    private AppManagerDelegate() {
    }
    
    /**
     * 单例
     *
     * @return 返回AppManager的单例
     */
    public static AppManagerDelegate getInstance() {
        if (sInstance == null) {
            synchronized (AppManagerDelegate.class) {
                if (sInstance == null) {
                    sInstance = new AppManagerDelegate();
                }
            }
        }
        return sInstance;
    }
    
    /**
     * 添加Activity到堆栈
     *
     * @param activity activity实例
     */
    public void addActivity(Activity activity) {
        if (mActivityStack == null) {
            mActivityStack = new Stack<>();
        }
        mActivityStack.add(new WeakReference<>(activity));
    }
    /**
     * 检查弱引用是否释放,若释放,则从栈中清理掉该元素
     */
    public void checkWeakReference() {
        if (mActivityStack != null) {
            for (Iterator<WeakReference<Activity>> it = mActivityStack.iterator(); it.hasNext(); ) {
                WeakReference<Activity> activityReference = it.next();
                Activity temp = activityReference.get();
                if (temp == null) {
                    it.remove();// 使用迭代器来进行安全的加锁操作
                }
            }
        }
    }
    
    /**
     * 获取当前Activity(栈中最后一个压入的)
     *
     * @return 当前(栈顶)activity
     */
    public Activity currentActivity() {
        checkWeakReference();
        if (mActivityStack != null && !mActivityStack.isEmpty()) {
            return mActivityStack.lastElement().get();
        }
        return null;
    }
    
    /**
     * 结束除当前activtiy以外的所有activity
     * 注意:不能使用foreach遍历并发删除,会抛出java.util.ConcurrentModificationException的异常
     *
     * @param activtiy 不需要结束的activity
     */
    public void finishOtherActivity(Activity activtiy) {
        if (mActivityStack != null && activtiy != null) {
            for (Iterator<WeakReference<Activity>> it = mActivityStack.iterator(); it.hasNext(); ) {
                WeakReference<Activity> activityReference = it.next();
                Activity temp = activityReference.get();
                if (temp == null) {// 清理掉已经释放的activity
                    it.remove();
                    continue;
                }
                if (temp != activtiy) {
                    it.remove();// 使用迭代器来进行安全的加锁操作
                    temp.finish();
                }
            }
        }
    }
    /**
     * 结束除这一类activtiy以外的所有activity
     *
     * @param cls 指定的某类activity
     */
    public void finishOtherActivity(Class<?> cls) {
        if (mActivityStack != null) {
            for (Iterator<WeakReference<Activity>> it = mActivityStack.iterator(); it.hasNext(); ) {
                WeakReference<Activity> activityReference = it.next();
                Activity activity = activityReference.get();
                if (activity == null) {// 清理掉已经释放的activity
                    it.remove();
                    continue;
                }
                if (!activity.getClass().equals(cls)) {
                    it.remove();// 使用迭代器来进行安全的加锁操作
                    activity.finish();
                }
            }
        }
    }
    
    /**
     * 结束当前Activity(堆栈中最后一个压入的)
     */
    public void finishActivity() {
        Activity activity = currentActivity();
        if (activity != null) {
            finishActivity(activity);
        }
    }
    
    /**
     * 结束指定的Activity
     *
     * @param activity 指定的activity实例
     */
    public void finishActivity(Activity activity) {
        if (activity != null) {
            for (Iterator<WeakReference<Activity>> it = mActivityStack.iterator(); it.hasNext(); ) {
                WeakReference<Activity> activityReference = it.next();
                Activity temp = activityReference.get();
                if (temp == null) {// 清理掉已经释放的activity
                    it.remove();
                    continue;
                }
                if (temp == activity) {
                    it.remove();
                }
            }
            activity.finish();
        }
    }
    
    /**
     * 结束指定类名的所有Activity
     *
     * @param cls 指定的类的class
     */
    public void finishActivity(Class<?> cls) {
        if (mActivityStack != null) {
            for (Iterator<WeakReference<Activity>> it = mActivityStack.iterator(); it.hasNext(); ) {
                WeakReference<Activity> activityReference = it.next();
                Activity activity = activityReference.get();
                if (activity == null) {// 清理掉已经释放的activity
                    it.remove();
                    continue;
                }
                if (activity.getClass().equals(cls)) {
                    it.remove();
                    activity.finish();
                }
            }
        }
    }
    
    /**
     * 结束所有Activity
     */
    public void finishAllActivity() {
        if (mActivityStack != null) {
            for (Iterator<WeakReference<Activity>> it = mActivityStack.iterator(); it.hasNext(); ) {
                WeakReference<Activity> activityReference = it.next();
                Activity activity = activityReference.get();
                if (activity != null) {
                    activity.finish();
                }
            }
            mActivityStack.clear();
        }
    }
    
    /**
     * 退出应用程序
     */
    public void exitApp() {
        try {
            finishAllActivity();
            // 退出JVM(java虚拟机),释放所占内存资源,0表示正常退出(非0的都为异常退出)
            System.exit(0);
            // 从操作系统中结束掉当前程序的进程
            android.os.Process.killProcess(android.os.Process.myPid());
        } catch (Exception e) {
            LogUtil.e("Exit exception", e);
        }
    }
}

如何使用

  • 在BaseActivity#onCreate回调中添加AppManager.getInstance().addActivity(this)
  • 获取当前栈顶activityAppManager.getInstance().currentActivity()
  • 在需要销毁的当前activity的地方调用AppManager.getInstance().finishActivity()
  • 在需要销毁指定类别实例的地方调用AppManager.getInstance().finishActivity(XXX.class)
  • 在需要销毁指定类别除外的其他实例的地方调用AppManager.getInstance().finishOtherActivity(XXX.class)
  • 退出应用调用AppManager.getInstance().exitApp()

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网友评论

  • 山顶蚂蚁:请问能说下第一版没有桥接模式出现的问题么
    山顶蚂蚁:@一只小松 谢谢 我看一下
    一只小松:可以看到AppManagerDelegate#currentActivity 方法体内有一次check的操作,除去已被释放的弱引用

本文标题:一招搞定Android Activity的管理

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