21.实现一个点击按钮popwindow 在按钮左边弹出效果，类似于微信那种

//recyclerView适配器里写popwindow

//按钮的点击事件

  holder.mZan.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

        
            
                View view = LayoutInflater.from(context).inflate(R.layout.pop, null);
                window = new PopupWindow(view, 300, ViewGroup.LayoutParams.WRAP_CONTENT );
                mDianZan = view.findViewById(R.id.mDianZan);
                mPinlun = view.findViewById(R.id.mPinlun);
            

//点击小赞
mDianZan.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        
        window.dismiss();
    }
});

            int[] location = new int[2];
            v.getLocationOnScreen(location);
            //popupWindow.setBackgroundDrawable(new ColorDrawable());
            window.setOutsideTouchable(true);
            window.setFocusable(false);
//这个弹出的popwindow的位置位于当前点击事件的左边
            window.showAtLocation(v, Gravity.NO_GRAVITY, location[0]+v.getWidth()-450, location[1]);
        }
    });
}

//popwindow 的xml布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    >

    <LinearLayout
        android:background="@android:color/black"
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="50dp">

        <TextView

            android:id="@+id/mDianZan"
            android:textColor="#FFFFFF"
            android:textSize="20sp"
            android:gravity="center"
            android:textStyle="bold"
            android:text="赞"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="match_parent" />
        <TextView
            android:id="@+id/mPinlun"
            android:textColor="#FFFFFF"
            android:textSize="20sp"
            android:gravity="center"
            android:textStyle="bold"
            android:text="评论"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="match_parent" />
    </LinearLayout>