【Android -- Window】PopupWindow 的基本使用

一、前言

Android 中的弹窗基本有两种，一种是 AlertDialog，另一种是 PopupWindow，AlertDialog 的显示位置是固定的，PopWindow 的显示位置是我们可以设置和调整的，因此，像项目中的一些场景如：某个功能的提示说明、点击按钮在按钮上方或者下方弹出菜单、新功能弹窗引导等。

1. 效果图

二、PopupWindow 简单介绍

首先看一下 Google 官方文档对 PopupWindow 的介绍：

This class represents a popup window that can be used to display an arbitrary view. 
The popup window is a floating container that appears on top of the current activity.

大致意思就是：popup window 是一个出现在当前 Activity 顶层的悬浮容器，可以用来展示任意的 View。

1. 构造函数

public PopupWindow(int width, int height)

public PopupWindow(View contentView, int width, int height) 

public PopupWindow(View contentView, int width, int height, boolean focusable) 

2. 设置显示的 View

public void setContentView(View contentView)

3. 设置展示的宽、高

// 设置宽，其实构造函数也是调用的这个方法
public void setWidth(int width)
//设置高
public void setHeight(int height)

4. 设置是否获取焦点

public void setFocusable(boolean focusable)

5. 设置点击 PopupWindow 以外区域是否可以隐藏 PopupWindow

public void setOutsideTouchable(boolean touchable)

6. 隐藏 PopupWindow

public void dismiss()

7. 设置 dissmiss 回调监听

public void setOnDismissListener(OnDismissListener onDismissListener)

8. 显示 PopupWindow

//直接显示在参照View 的左下方
public void showAsDropDown(View anchor)
// 显示在参照View的左下方，可以通过xoff，yOff,来调节x,y方向的偏移
public void showAsDropDown(View anchor, int xoff, int off)

public void showAsDropDown(View anchor, int xoff, int yoff, int gravity)
//显示在指定位置，相对于整个屏幕的window而言，通过gravity调解显示在左、上、右、下、中. x,y调整两个方向的偏移
public void showAtLocation(View parent, int gravity, int x, int y) 

以上就是 PopupWindow 重要的并且常用的 API。

三、封装通用 PopupWindow

由于每次写 PopupWindow 都要写很多重复代码，因此简单的封装了一个 CommonPopWindow. 封装了PopupWindow 的一些常用 API，使用 Builder 模式，就像写 AlertDialog 一样，链式配置。 1. CommonPopWindow 源代码

public class CommonPopupWindow implements PopupWindow.OnDismissListener {
    private static final String TAG = "CustomPopWindow";
    private static final float DEFAULT_ALPHA = 0.7f;
    private Context mContext;
    private int mWidth;
    private int mHeight;
    private boolean mIsFocusable = true;
    private boolean mIsOutside = true;
    private int mResLayoutId = -1;
    private View mContentView;
    private PopupWindow mPopupWindow;
    private int mAnimationStyle = -1;

    private boolean mClippEnable = true;//default is true
    private boolean mIgnoreCheekPress = false;
    private int mInputMode = -1;
    private PopupWindow.OnDismissListener mOnDismissListener;
    private int mSoftInputMode = -1;
    private boolean mTouchable = true;//default is ture
    private View.OnTouchListener mOnTouchListener;

    private Window mWindow;//当前Activity 的窗口
    /**
     * 弹出PopWindow 背景是否变暗，默认不会变暗。
     */
    private boolean mIsBackgroundDark = false;

    private float mBackgroundDrakValue = 0;// 背景变暗的值，0 - 1
    /**
     * 设置是否允许点击 PopupWindow之外的地方，关闭PopupWindow
     */
    private boolean enableOutsideTouchDisMiss = true;// 默认点击pop之外的地方可以关闭

    private CommonPopupWindow(Context context){
        mContext = context;
    }

    public int getWidth() {
        return mWidth;
    }

    public int getHeight() {
        return mHeight;
    }

    /**
     *
     * @param anchor
     * @param xOff
     * @param yOff
     * @return
     */
    public CommonPopupWindow showAsDropDown(View anchor, int xOff, int yOff){
        if(mPopupWindow!=null){
            mPopupWindow.showAsDropDown(anchor,xOff,yOff);
        }
        return this;
    }

    public CommonPopupWindow showAsDropDown(View anchor){
        if(mPopupWindow!=null){
            mPopupWindow.showAsDropDown(anchor);
        }
        return this;
    }

    @RequiresApi(api = Build.VERSION_CODES.KITKAT)
    public CommonPopupWindow showAsDropDown(View anchor, int xOff, int yOff, int gravity){
        if(mPopupWindow!=null){
            mPopupWindow.showAsDropDown(anchor,xOff,yOff,gravity);
        }
        return this;
    }


    /**
     * 相对于父控件的位置（通过设置Gravity.CENTER，下方Gravity.BOTTOM等 ），可以设置具体位置坐标
     * @param parent 父控件
     * @param gravity
     * @param x the popup's x location offset
     * @param y the popup's y location offset
     * @return
     */
    public CommonPopupWindow showAtLocation(View parent, int gravity, int x, int y){
        if(mPopupWindow!=null){
            mPopupWindow.showAtLocation(parent,gravity,x,y);
        }
        return this;
    }

    /**
     * 添加一些属性设置
     * @param popupWindow
     */
    private void apply(PopupWindow popupWindow){
        popupWindow.setClippingEnabled(mClippEnable);
        if(mIgnoreCheekPress){
            popupWindow.setIgnoreCheekPress();
        }
        if(mInputMode!=-1){
            popupWindow.setInputMethodMode(mInputMode);
        }
        if(mSoftInputMode!=-1){
            popupWindow.setSoftInputMode(mSoftInputMode);
        }
        if(mOnDismissListener!=null){
            popupWindow.setOnDismissListener(mOnDismissListener);
        }
        if(mOnTouchListener!=null){
            popupWindow.setTouchInterceptor(mOnTouchListener);
        }
        popupWindow.setTouchable(mTouchable);



    }

    private PopupWindow build(){

        if(mContentView == null){
            mContentView = LayoutInflater.from(mContext).inflate(mResLayoutId,null);
        }

        // 2017.3.17 add
        // 获取当前Activity的window
        Activity activity = (Activity) mContentView.getContext();
        if(activity!=null && mIsBackgroundDark){
            //如果设置的值在0 - 1的范围内，则用设置的值，否则用默认值
            final  float alpha = (mBackgroundDrakValue > 0 && mBackgroundDrakValue