public class ActivityCollector {
  private static List<Activity> activityList = new ArrayList<Activity>();
  public static void addActivity(Activity activity){
    activityList.add(activity);
  }
  public static void removeActivity(Activity activity){
    activityList.remove(activity);
  }

  public static void finishAllButLast(){
    Activity activity = activityList.get(activityList.size()-1);
    removeActivity(activity);

    for (Activity activityItem: activityList){
      if (!activityItem.isFinishing()){
        activityItem.finish();
      }
    }

    activityList.clear();
    activityList.add(activity);
  }

  public static void finishAll(){
    for (Activity activity: activityList){
      if (!activity.isFinishing()){
        activity.finish();
      }
    }

    activityList.clear();
  }
}

2）、創(chuàng)建基類BaseActivity，并使所有的activity繼承自該基類。在創(chuàng)建時，添加到活動管理器，銷毀時，從活動管理器中移除。

public class BaseActivity extends Activity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    ActivityCollector.addActivity(this);
  }

  @Override
  protected void onDestroy() {
    super.onDestroy();
    ActivityCollector.removeActivity(this);
  }
}

如果需要銷毀所有activity，只需調(diào)用finishAll()即可

2、操作超時處理

原理：

1）、在activity的stop函數(shù)中，根據(jù)app進程IMPORTANCE_FOREGROUND判斷app在前臺或后臺
2）、在activity的onResume函數(shù)中，做超時檢查。

關(guān)鍵代碼：

abstract public class TimeOutCheckActivity extends BaseActivity {
  private boolean isLeave = false;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    pref = getSharedPreferences(Constant.CONFIG_NAME, Context.MODE_PRIVATE);
  }

  /**
   * 回調(diào)函數(shù)，方便測試
   * @return
  */
  abstract protected String getTag();

  ......省略號......

  /***
   * 當(dāng)用戶使程序恢復(fù)為前臺顯示時執(zhí)行onResume()方法,在其中判斷是否超時.
   */
  @Override
  protected void onResume() {
//    Log.i("Back",getTag() + "，onResume，是否在前臺：" + isOnForeground());
    super.onResume();
    if (isLeave) {
      isLeave = false;
      timeOutCheck();
    }
  }

  @Override 
  protected void onStop() {
    super.onStop();
    if (!isOnForeground()){
      if (!isLeave && isOpenALP()) {
        isLeave = true;
        saveStartTime();
      }
    }
  }

  public void timeOutCheck() {
    long endtime = System.currentTimeMillis();
    if (endtime - getStartTime() >= Constant.TIMEOUT_ALP * 1000) {
      Util.toast(this, "超時了,請重新驗證");
      String alp = pref.getString(Constant.ALP, null);
      if (alp == null || alp == "") {
      } else {
        Intent intent = new Intent(this, UnlockGesturePasswordActivity.class);
        intent.putExtra("pattern", alp);
        intent.putExtra("login",false); //手勢驗證，不進行登錄驗證
        intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
        // 打開新的Activity
        startActivityForResult(intent, Constant.REQ_COMPARE_PATTERN_TIMEOUT_CHECK);
      }
    }
  }

  public void saveStartTime() {
    pref.edit().putLong(Constant.START_TIME, System.currentTimeMillis()).commit();
  }

  public long getStartTime() {
    long startTime = 0;
    try {
      startTime = pref.getLong(Constant.START_TIME, 0);
    }catch (Exception e){
      startTime = 0;
    }
    return startTime;
  }

  /**
   * 程序是否在前端運行,通過枚舉運行的app實現(xiàn)。防止重復(fù)超時檢測多次,保證只有一個activity進入超時檢測
   *當(dāng)用戶按home鍵時，程序進入后端運行，此時會返回false，其他情況引起activity的stop函數(shù)的調(diào)用，會返回true
   * @return
  */
  public boolean isOnForeground() {
    ActivityManager activityManager = (ActivityManager) getApplicationContext().getSystemService(Context.ACTIVITY_SERVICE);
    String packageName = getApplicationContext().getPackageName();

    List<ActivityManager.RunningAppProcessInfo> appProcesses = activityManager.getRunningAppProcesses();
    if (appProcesses == null)
      return false;

    for (ActivityManager.RunningAppProcessInfo appProcess : appProcesses) {
      if (appProcess.processName.equals(packageName)
          && appProcess.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND) { 
        return true;
      }
    }

    return false;
  }
}

補充說明：

可以根據(jù)importance的不同來判斷前臺或后臺，RunningAppProcessInfo 里面的常量IMTANCE就是上面所說的前臺后臺，其實IMOPORTANCE是表示這個app進程的重要性，因為系統(tǒng)回收時候，會根據(jù)IMOPORTANCE來回收進程的。具體可以去看文檔。

public static final int IMPORTANCE_BACKGROUND = 400//后臺 
public static final int IMPORTANCE_EMPTY = 500//空進程 
public static final int IMPORTANCE_FOREGROUND = 100//在屏幕最前端、可獲取到焦點 可理解為Activity生命周期的OnResume(); 
public static final int IMPORTANCE_SERVICE = 300//在服務(wù)中 
public static final int IMPORTANCE_VISIBLE = 200//在屏幕前端、獲取不到焦點可理解為Activity生命周期的OnStart();

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