Android 前後臺進程切換判斷

項目有個需求是，應用退到後臺 5 分鐘以後再回到前臺彈出手勢密碼鎖界面提示用戶解鎖，目前已經完成分享一下實現的方法

public class GestureLockManager {

    private DownTimer downTimer;
    private boolean isFromBack;
    private boolean isPop;

    private static GestureLockManager sS;

    private GestureLockManager() {

    }

    static {
        sS = new GestureLockManager();
    }

    public static GestureLockManager getInstance() {
        if (sS == null) {
            sS = new GestureLockManager();
        }
        return sS;
    }

    public void init() {
        //need Android API > 14

        RceApp.getInstance().registerActivityLifecycleCallbacks(new Application.ActivityLifecycleCallbacks() {
            @Override
            public void onActivityCreated(Activity activity, Bundle savedInstanceState) {//進程啓動
                if (activity.getClass().equals(MainActivity.class)) {
                    isFromBack = false;
                    long cacheTime = CacheTask.getInstance().getGestureTime();
                    long currentTime = System.currentTimeMillis();
                    if (cacheTime != 0 && (currentTime - cacheTime) / 60000 > 5 && activity.getIntent() != null && activity.getIntent().getData() != null && "true".equals(activity.getIntent().getData().getQueryParameter("isFromPush"))) {
                        activity.startActivity(new Intent(activity, GestureLoginActivity.class));
                        //如果不是第一次安裝而且殺進程時間間隔大於 5 分鐘 並且 是來的 push 消息
                    }
                }
            }

            @Override
            public void onActivityStarted(Activity activity) {//進程在前臺
                if (!io.rong.common.SystemUtils.isInBackground(activity) && isFromBack && LoginActivity.class != activity.getClass()) {
                    downTimer.stopDown();
                    if (isPop && CacheTask.getInstance().getGestureLock() != null) {
                        activity.startActivity(new Intent(activity, GestureLoginActivity.class));
                    }
                    isPop = false;
                    isFromBack = false;
                }

            }

            @Override
            public void onActivityResumed(Activity activity) {
            }

            @Override
            public void onActivityPaused(Activity activity) {
            }

            @Override
            public void onActivityStopped(Activity activity) {//進程切入後臺
                if (io.rong.common.SystemUtils.isInBackground(activity)) {
                    isFromBack = true;
                    downTimer.startDown(1000 * 60 * 5);
                }

            }

            @Override
            public void onActivitySaveInstanceState(Activity activity, Bundle outState) {
            }

            @Override
            public void onActivityDestroyed(Activity activity) {//進程被殺死
                if (activity.getClass().equals(MainActivity.class)) {
                    CacheTask.getInstance().cacheGestureTime(currentTimeMillis()); //TODO 可能存在殺死進程沒有 cache 當前時間戳的情況
                }
            }
        });

        downTimer = new DownTimer();
        downTimer.setListener(new DownTimer.DownTimerListener() {
            @Override
            public void onFinish() {
                isPop = true;
            }
        });

    }

}

上面是主要實現代碼，建議在 application 類做初始化

 GestureLockManager.getInstance().init();

其中工具類判斷的關鍵代碼

    public static boolean isInBackground(Context context) {
        boolean isInBackground = true;
        ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
        if (Build.VERSION.SDK_INT > Build.VERSION_CODES.KITKAT_WATCH) {
            List<ActivityManager.RunningAppProcessInfo> runningProcesses = am.getRunningAppProcesses();
            if (runningProcesses == null) {
                return false;
            }
            for (ActivityManager.RunningAppProcessInfo processInfo : runningProcesses) {
                //前臺程序
                if (processInfo.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND) {
                    for (String activeProcess : processInfo.pkgList) {
                        if (activeProcess.equals(context.getPackageName())) {
                            return false;
                        }
                    }
                }
            }
        } else {
            List<ActivityManager.RunningTaskInfo> taskInfo = am.getRunningTasks(1);
            ComponentName componentInfo = taskInfo.get(0).topActivity;
            if (componentInfo.getPackageName().equals(context.getPackageName())) {
                isInBackground = false;
            }
        }

        return isInBackground;
    }

最後需要記得這個 API 是需要大於 14 纔可以使用，對 4.0 以下的手機應該是無效的。