Android 如何实现弹窗顺序&优先级控制

一般在项目首页中，往往会有多个对话框需要弹出，比如活动弹窗、更新弹窗、评分弹窗等等，而且这些弹窗是有优先级顺序的。这些弹窗一般是通过接口请求后返回结果再显示的，如果只有几个弹窗还好处理，业务逻辑上判断一下先后显示就可以。如果有十几个或者更多，那么处理起来将非常麻烦，而且容易出现问题。

所以封装一个可以按照优先级顺序显示的弹窗功能就非常有必要，首先功能需求如下：

• 按优先级顺序阻塞式显示各种类型弹窗，默认从最高优先级开始显示
• 只有上一个高优先级弹窗显示完或者取消显示，下一个低优先级弹窗才可以显示
• 指定显示某一个弹窗的前提是没有更高优先级的弹窗需要显示
• 在显示一个弹窗之前需要判断是否能够或者需要显示
• 根据优先级去查找指定的弹窗，优先级相当于唯一ID
• 弹窗包括多种类型，Dialog、PopupWindow、Activity等等

接着开始编码去实现功能，先定一个枚举类，罗列出支持的弹窗类型，包括Dialog、PopupWindow、Activity等等。

public enum WindowType {

  DIALOG,
  POUPOWINDOW,
  TOAST,
  SNACKBAR,
  WIDGET,
  ACTIVITY,
  OTHERS

}

然后定义弹窗接口IWindow，它定义了弹窗的基本功能。

/**
* 窗口约定规则
*/
public interface IWindow {

  /**
   * 弹窗展示
   */
  void show(Activity activity);

  /**
   * 弹窗关闭
   */
  void dismiss();

  /**
   * 设置窗口关闭监听
   */
  void setOnWindowDismissListener(OnWindowDismissListener listener);

  /**
   * 设置窗口展示监听
   */
  void setOnWindowShowListener(OnWindowShowListener listener);

}

以及弹窗显示和关闭的监听接口，

/**
* 窗口关闭监听
*/
public interface OnWindowDismissListener {

  /**
   *
   */
  void onDismiss();

}

/**
* 窗口展示监听
*/
public interface OnWindowShowListener {

  void onShow();

}

接下来定义个包裹类WindowWrapper去封装弹窗相关的属性和状态，包括弹窗、优先级、能否显示、窗体类型等等，在处理弹窗显示逻辑时将会用到。

/**
* 窗口参数类
*/
public class WindowWrapper {

  /**
   * 窗口
   */
  private IWindow mWindow;

  /**
   * 优先级，值越大优先级越高
   */
  private int mPriority;

  /**
   * 当前是否处于show状态
   */
  private boolean isShowing;

  /**
   * 是否满足show的条件
   */
  private boolean isCanShow;

  /**
   * 弹窗类型
   */
  private WindowType mWindowType;

  /**
   * 弹窗名称
   */
  private String mWindowName;

  private WindowWrapper(Builder builder) {
    mWindow = builder.window;
    mPriority = builder.priority;
    mWindowType = builder.windowType;
    isCanShow = builder.isCanShow;
    mWindowName = builder.windowName;
  }

  public IWindow getWindow() {
    return mWindow;
  }

  public void setWindow(IWindow window) {
    this.mWindow = window;
  }

  public int getPriority() {
    return mPriority;
  }

  public void setPriority(int priority) {
    this.mPriority = priority;
  }

  public boolean isShowing() {
    return isShowing;
  }

  public void setShowing(boolean showing) {
    isShowing = showing;
  }

  public WindowType getWindowType() {
    return mWindowType;
  }

  public void setWindowType(WindowType mWindowType) {
    this.mWindowType = mWindowType;
  }

  public boolean isCanShow() {
    return isCanShow;
  }

  public void setCanShow(boolean canShow) {
    isCanShow = canShow;
  }

  public String getWindowName() {
    return mWindowName;
  }

  public void setWindowName(String mWindowName) {
    this.mWindowName = mWindowName;
  }

  public static class Builder {

    /**
     * 窗口
     */
    private IWindow window;

    /**
     * 优先级，值越大优先级越高
     */
    private int priority;

    /**
     * 弹窗类型
     */
    private WindowType windowType;

    /**
     * 是否满足show的条件
     */
    private boolean isCanShow;

    /**
     * 弹窗名称
     */
    private String windowName;

    public Builder window(IWindow window) {
      this.window = window;
      return this;
    }

    public Builder priority(int priority) {
      this.priority = priority;
      return this;
    }

    public Builder windowType(WindowType type) {
      this.windowType = type;
      return this;
    }

    public Builder setCanShow(boolean canShow) {
      isCanShow = canShow;
      return this;
    }

    public String getWindowName() {
      return windowName;
    }

    public Builder setWindowName(String windowName) {
      this.windowName = windowName;
      return this;
    }

    public WindowWrapper build() {
      return new WindowWrapper(this);
    }
  }
}

最后通过WindowTaskManager类去统一组织管理弹窗的添加、显示、关闭等逻辑，

public class WindowTaskManager {
  private List<WindowWrapper> mWindows;

  private static WindowTaskManager mDefaultInstance;

  private WindowTaskManager() {
  }

  /**
   * 获取弹窗管理者
   */
  public static WindowTaskManager getInstance() {
    if (mDefaultInstance == null) {
      synchronized (WindowTaskManager.class) {
        if (mDefaultInstance == null) {
          mDefaultInstance = new WindowTaskManager();
        }
      }
    }
    return mDefaultInstance;
  }

  /**
   * 添加弹窗
   *
   * @param windowWrapper 待显示的弹窗
   */
  public synchronized void addWindow(Activity activity, WindowWrapper windowWrapper) {
    if (windowWrapper != null) {
      if (mWindows == null) {
        mWindows = new ArrayList<>();
      }

      if (windowWrapper.getWindow() != null) {
        windowWrapper.getWindow().setOnWindowShowListener(new OnWindowShowListener() {
          @Override
          public void onShow() {
            windowWrapper.setShowing(true);
          }
        });

        windowWrapper.getWindow().setOnWindowDismissListener(new OnWindowDismissListener() {
          @Override
          public void onDismiss() {
            windowWrapper.setShowing(false);
            mWindows.remove(windowWrapper);
            showNext(activity);
          }
        });
      }

      mWindows.add(windowWrapper);
    }
  }

  /**
   * 弹窗满足展示条件
   *
   * @param priority
   */
  public synchronized void enableWindow(Activity activity, int priority, IWindow window) {
    WindowWrapper windowWrapper = getTargetWindow(priority);
    if (windowWrapper != null) {

      if (windowWrapper.getWindow() == null) {
        window.setOnWindowShowListener(new OnWindowShowListener() {
          @Override
          public void onShow() {
            windowWrapper.setShowing(true);
          }
        });

        window.setOnWindowDismissListener(new OnWindowDismissListener() {
          @Override
          public void onDismiss() {
            windowWrapper.setShowing(false);
            mWindows.remove(windowWrapper);
            showNext(activity);
          }
        });
      }

      windowWrapper.setCanShow(true);
      windowWrapper.setWindow(window);
      show(activity, priority);
    }
  }

  /**
   * 移除不需要显示弹窗
   *
   * @param priority
   */
  public synchronized void disableWindow(int priority) {
    WindowWrapper windowWrapper = getTargetWindow(priority);
    if (windowWrapper != null && windowWrapper.getWindow() != null) {
      if (mWindows != null) {
        mWindows.remove(windowWrapper);
      }
    }
  }

  /**
   * 展示弹窗
   * 从优先级最高的Window开始显示
   */
  public synchronized void show(Activity activity) {
    WindowWrapper windowWrapper = getMaxPriorityWindow();
    if (windowWrapper != null && windowWrapper.isCanShow()) {
      IWindow window = windowWrapper.getWindow();
      if (window != null) {
        window.show(activity);
      }
    }
  }

  /**
   * 显示指定的弹窗
   *
   * @param priorities
   */
  public synchronized void show(Activity activity, int priorities) {
    WindowWrapper windowWrapper = getTargetWindow(priorities);
    if (windowWrapper != null && windowWrapper.getWindow() != null) {
      WindowWrapper topShowWindow = getShowingWindow();
      if (topShowWindow == null) {
        int priority = windowWrapper.getPriority();
        WindowWrapper maxPriorityWindow = getMaxPriorityWindow();
        if (maxPriorityWindow != null && windowWrapper.isCanShow() && priority >= maxPriorityWindow.getPriority()) {
          if (windowWrapper.getWindow() != null) {
            windowWrapper.getWindow().show(activity);
          }
        }
      }
    }
  }

  /**
   * 清除弹窗管理者
   */
  public synchronized void clear() {
    if (mWindows != null) {
      for (int i = 0, size = mWindows.size(); i < size; i++) {
        if (mWindows.get(i) != null) {
          IWindow window = mWindows.get(i).getWindow();
          if (window != null) {
            window.dismiss();
          }
        }
      }
      mWindows.clear();
    }
    WindowHelper.getInstance().onDestroy();
  }

  /**
   * 清除弹窗管理者
   *
   * @param dismiss 是否同时dismiss掉弹窗管理者维护的弹窗
   */
  public synchronized void clear(boolean dismiss) {
    if (mWindows != null) {
      if (dismiss) {
        for (int i = 0, size = mWindows.size(); i < size; i++) {
          if (mWindows.get(i) != null) {
            IWindow window = mWindows.get(i).getWindow();
            if (window != null) {
              window.dismiss();
            }
          }
        }
      }
      mWindows.clear();
    }
    WindowHelper.getInstance().onDestroy();
  }

  /**
   * 展示下一个优先级最大的Window
   */
  private synchronized void showNext(Activity activity) {
    WindowWrapper windowWrapper = getMaxPriorityWindow();
    if (windowWrapper != null && windowWrapper.isCanShow()) {
      if (windowWrapper.getWindow() != null) {
        windowWrapper.getWindow().show(activity);
      }
    }
  }

  /**
   * 获取当前栈中优先级最高的Window（优先级相同则返回后添加的弹窗）
   */
  private synchronized WindowWrapper getMaxPriorityWindow() {
    if (mWindows != null) {
      int maxPriority = -1;
      int position = -1;
      for (int i = 0, size = mWindows.size(); i < size; i++) {
        WindowWrapper windowWrapper = mWindows.get(i);
        if (i == 0) {
          position = 0;
          maxPriority = windowWrapper.getPriority();
        } else {
          if (windowWrapper.getPriority() >= maxPriority) {
            position = i;
            maxPriority = windowWrapper.getPriority();
          }
        }
      }
      if (position != -1) {
        return mWindows.get(position);
      } else {
        return null;
      }
    }
    return null;
  }

  private synchronized WindowWrapper getTargetWindow(int priority) {
    if (mWindows != null) {
      for (int i = 0, size = mWindows.size(); i < size; i++) {
        WindowWrapper windowWrapper = mWindows.get(i);
        if (windowWrapper != null && windowWrapper.getPriority() == priority) {
          return windowWrapper;
        }
      }
    }
    return null;
  }

  /**
   * 获取当前处于show状态的弹窗
   */
  private synchronized WindowWrapper getShowingWindow() {
    if (mWindows != null) {
      for (int i = 0, size = mWindows.size(); i < size; i++) {
        WindowWrapper windowWrapper = mWindows.get(i);
        if (windowWrapper != null && windowWrapper.getWindow() != null && windowWrapper.isShowing()) {
          return windowWrapper;
        }
      }
    }
    return null;
  }

}

WindowTaskManager类有三个主要方法：

• addWindow(Activity activity, WindowWrapper windowWrapper)
• enableWindow(Activity activity, int priority, IWindow window)
• disableWindow(int priority)

需要按顺序显示的对话框统一使用addWindow方法添加，这是还未进行网络请求之前就要调用的。作用是告诉WindowTaskManager一共有多少个弹窗需要按顺序显示。当网络请求返回之后，如果需要显示弹窗就调用enableWindow方法去显示，如果不需要显示弹窗就调用disableWindow方法，将这个弹窗从显示队列中移除。

以上就是按顺序显示弹窗的主要逻辑，使用的话窗体先继承IWindow，实现相关方法。然后通过操作WindowTaskManager类就可以了。具体使用方法参见源码。

项目地址：github.com/Geekince/Pr…

彩蛋：

需要在DialogFragment中显示DialogFragment时候，最好不要直接在DialogFragment启动显示，而是在DialogFragment的消失回调中启动显示。因为当前一个DialogFragment消失的时候，getChildFragmentManager可能会失效，应该在外层使用getFragmentManager。

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