package com.hdl.photovoltaic.utils;

import android.app.Activity;
import android.graphics.Rect;
import android.view.View;
import android.view.ViewTreeObserver;
import android.widget.FrameLayout;

/**
 * 键盘状态观察员
 */
public class KeyboardStateObserverUtils {
    private static final String TAG = KeyboardStateObserverUtils.class.getSimpleName();

    public static KeyboardStateObserverUtils getKeyboardStateObserver(Activity activity) {
        return new KeyboardStateObserverUtils(activity);

    }

    private final View mChildOfContent;

    private int usableHeightPrevious;//使用高度

    private OnKeyboardVisibilityListener listener;

    public void setKeyboardVisibilityListener(OnKeyboardVisibilityListener listener) {
        this.listener = listener;

    }

    private KeyboardStateObserverUtils(Activity activity) {
//        activity.getWindow().findViewById(window);
        FrameLayout content = (FrameLayout) activity.findViewById(android.R.id.content);

        mChildOfContent = content.getChildAt(0);

        //获取视图树观察者,添加全局布局监听器
        mChildOfContent.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            public void onGlobalLayout() {
                possiblyResizeChildOfContent();

            }

        });

    }

    /**
     * 重新设置ChildOfContent的大小
     */
    private void possiblyResizeChildOfContent() {
        int usableHeightNow = computeUsableHeight();

        if (usableHeightNow != usableHeightPrevious) {
            //获取整个屏幕的高度
            int usableHeightSansKeyboard = mChildOfContent.getRootView().getHeight();

            int heightDifference = usableHeightSansKeyboard - usableHeightNow;

            if (heightDifference > (usableHeightSansKeyboard / 4)) {
                if (listener != null) {
                    listener.onKeyboardShow(heightDifference);

                }

            } else {
                if (listener != null) {
                    listener.onKeyboardHide(heightDifference);

                }

            }

            usableHeightPrevious = usableHeightNow;

            //Log.d(TAG,"usableHeightNow: " + usableHeightNow + " | usableHeightSansKeyboard:" + usableHeightSansKeyboard + " | heightDifference:" + heightDifference);

        }

    }

    /**
     * 计算可用高度
     *
     * @return 高度
     */
    private int computeUsableHeight() {
        Rect r = new Rect();

        //获取可以显示的区域
        mChildOfContent.getWindowVisibleDisplayFrame(r);

        //Log.d(TAG,"rec bottom>" + r.bottom + " | rec top>" + r.top);
        return (r.bottom - r.top);// 全屏模式下： return r.bottom

    }

    public interface OnKeyboardVisibilityListener {
        void onKeyboardShow(int h);

        void onKeyboardHide(int h);

    }

}