PopupWindow 笔记

简单的调用
背景变暗
一些不同版本导致的小坑

简单调用

// 一个自定义的布局，作为显示的内容
View contentView = LayoutInflater.from(mContext).inflate(R.layout.pop_window, null);
PopupWindow popupWindow = new PopupWindow(contentView,
                LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, true);

popupWindow.setTouchable(true);
popupWindow.setTouchInterceptor(new OnTouchListener() {
  @Override
    public boolean onTouch(View v, MotionEvent event) {

        popupWindow.dismiss();//点击自身关闭

        // 返回 false 表示不拦截 touch 事件，
        // 拦截后 PopupWindow 的 onTouchEvent 不被调用，这样点击外部区域无法 dismiss
        return false;
    }
});
popupWindow.showAsDropDown(view);//将窗口显示在 view 的下面

指定弹出位置的一些方法：

//showAtLocation()显示在指定位置，有两个方法重载：

public void showAtLocation(View parent, int gravity, int x, int y)
public void showAtLocation(IBinder token, int gravity, int x, int y)
 
//showAsDropDown()显示在一个参照物View的周围，有三个方法重载：

public void showAsDropDown(View anchor)
public void showAsDropDown(View anchor, int xoff, int yoff)
public void showAsDropDown(View anchor, int xoff, int yoff, int gravity)

重写 PopupWindow

public popupWindow(Context context){
    this.context = context;
    LayoutInflater inflater = LayoutInflater.from(context);
    rootView = inflater.inflate(R.layout.popup,null);
    setContentView(rootView);

    this.setHeight(ViewGroup.LayoutParams.WRAP_CONTENT);
    this.setWidth(ViewGroup.LayoutParams.MATCH_PARENT);
    this.setFocusable(true);//设置成可获取焦点状态

    //当单击Back键或者其他地方使其消失、需要设置这个属性。
    rootView.setOnTouchListener(this);
    rootView.setOnKeyListener(this);
    rootView.setFocusable(true);
    rootView.setFocusableInTouchMode(true);

    this.setAnimationStyle(R.style.dialog_anim);//设置出现和消失的动画

    //实例化一个ColorDrawable颜色为半透明
    ColorDrawable dw = new ColorDrawable(0xb0000000);
    //设置SelectPicPopupWindow弹出窗体的背景
    this.setBackgroundDrawable(dw);
    //这样设置虽然有半透明的背景，但是出现的方式不太对

}


@Override
public void setOnDismissListener(OnDismissListener onDismissListener) {
    //在弹出框消失时
    super.setOnDismissListener(onDismissListener);
}


//点back键消失
@Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK && this.isShowing()) {
         //如果点击了返回键，而且弹出框已经出现
         this.dismiss();
         return true;
    }
    return false;
}

@Override
public boolean onTouch(View v, MotionEvent event) {
    int height = rootView.findViewById(R.id.popup_linear).getTop();
    // 这个height 是弹出框中的 LinearLayout 在屏幕的位置
    int y = (int) event.getY();
    //获取点击的 y 轴，点击的位置如果在弹出框的上面，是 y < height 
    if (event.getAction() == MotionEvent.ACTION_UP) {
        if (y < height) {
            dismiss();
        }
    }
    return true;
}

调用

LinearLayout linearLayout = (LinearLayout) LayoutInflater.from(getContext())
                .inflate(R.layout.me_layout, null);
popupWindow popupwindow = new popupWindow(getContext());
popupwindow.showAtLocation(linearLayout, Gravity.BOTTOM,0,0);
//这里的 linearLayout 是布局中的最外层的 LinearLayout ，所以这个 pop 出现在最下面

这里的例子没有获取布局中的按钮设置 onClick 事件，
这个是和在其他地方一样的，不表

背景变暗

搜到的很多资料的方法都基本一样，用的最多的就是：

WindowManager.LayoutParams lp = getWindow().getAttributes();  
lp.alpha = 0.7f;  
getWindow().setAttributes(lp);  //让背景变暗
mPopupWindow.setOnDismissListener(new OnDismissListener() {  
 @Override  
    public void onDismiss() {  
        //在关闭 PopupWindow 之后，恢复背景
        WindowManager.LayoutParams lp = getWindow().getAttributes();  
        lp.alpha = 1f;  
        getWindow().setAttributes(lp);  
    }  
});

这个方法有局限性，还有一些是靠添加一个半透明的 View：
动画弹出 PopupWindow 并使背景变暗
还有一些值得参考的：
Android - 利用动画实现背景逐渐变暗

其实如果需要这种效果，还是用 Dialog 会比较简单和理想，
详细见于我的另一篇 Dialog 弹出框笔记

6.0 版本不能 dismiss

简而言之，6.0 版本下的 PopupWindow 需要指定背景，否则点击外部和返回键都不能 dismiss，setOutsideTouchable(true) 无效，

popupWindow.setBackgroundDrawable(new BitmapDrawable());

对比 6.0 之前的版本，发现原因是 preparePopup() 的改动导致：

//6.0 版本下的源码
private void preparePopup(WindowManager.LayoutParams p) {
    if (mContentView == null || mContext == null || mWindowManager == null) {
        throw new IllegalStateException("You must specify a valid content view by "
                + "calling setContentView() before attempting to show the popup.");
    }

    if (mBackground != null) {
        final ViewGroup.LayoutParams layoutParams = mContentView.getLayoutParams();
        int height = ViewGroup.LayoutParams.MATCH_PARENT;
        if (layoutParams != null &&
                layoutParams.height == ViewGroup.LayoutParams.WRAP_CONTENT) {
            height = ViewGroup.LayoutParams.WRAP_CONTENT;
        }

        // when a background is available, we embed the content view
        // within another view that owns the background drawable
        PopupViewContainer popupViewContainer = new PopupViewContainer(mContext);
        PopupViewContainer.LayoutParams listParams = new PopupViewContainer.LayoutParams(
                ViewGroup.LayoutParams.MATCH_PARENT, height
        );
        popupViewContainer.setBackgroundDrawable(mBackground);
        popupViewContainer.addView(mContentView, listParams);

        mPopupView = popupViewContainer;
    } else {
        mPopupView = mContentView;
    }
    mPopupWidth = p.width;
    mPopupHeight = p.height;
}

//6.0 之前的版本
private void preparePopup(WindowManager.LayoutParams p) {
    if (mContentView == null || mContext == null || mWindowManager == null) {
        throw new IllegalStateException("You must specify a valid content view by "
            + "calling setContentView() before attempting to show the popup.");
    }

        // The old decor view may be transitioning out. Make sure it finishes
        // and cleans up before we try to create another one.
    if (mDecorView != null) {
        mDecorView.cancelTransitions();
    }

        // When a background is available, we embed the content view within
        // another view that owns the background drawable.
    if (mBackground != null) {
        mBackgroundView = createBackgroundView(mContentView);
        mBackgroundView.setBackground(mBackground);
    } else {
        mBackgroundView = mContentView;
    }

    mDecorView = createDecorView(mBackgroundView);

        // The background owner should be elevated so that it casts a shadow.
    mBackgroundView.setElevation(mElevation);

        // We may wrap that in another view, so we'll need to manually specify
        // the surface insets.
    p.setSurfaceInsets(mBackgroundView, true /*manual*/, true /*preservePrevious*/);

    mPopupViewInitialLayoutDirectionInherited =
    (mContentView.getRawLayoutDirection() == View.LAYOUT_DIRECTION_INHERIT);
}

两者最大区别在于 6.0 以前不管有没有设置 background 都会创建一个 PopupDecorView，而这个 PopupDecorView 正是负责处理 PopupWindow 的点击事件。
6.0 下 mBackground == null 则不会创建 PopupDecorView，导致不能响应到点击事件。

7.0 下 PopupWindow 跑到了界面的顶部

7.0 下 PopupWindow.update( ) 方法会导致 PopupWindow的位置出现在界面顶部：

public void update() {
    if (!isShowing() || mContentView == null) {
        return;
    }
    ......
    final int newGravity = computeGravity();
    if (newGravity != p.gravity) {
        p.gravity = newGravity;
        update = true;
    }
    ......
}

原因在于 update() 方法中调用的 computeGravity():

private int computeGravity() {
   int gravity = Gravity.START | Gravity.TOP;
   if (mClipToScreen || mClippingEnabled) {
       gravity |= Gravity.DISPLAY_CLIP_VERTICAL;
   }
   return gravity;
}

PopupWindow 笔记

你可能感兴趣的:(PopupWindow 笔记)