画饼充饥（畫餅充饑）　

◎ 画饼充饥 huàbǐng-chōngjī

[appease one‘s hunger with depicted cake;draw cakes to allay hunger—feed on illusions] 画个饼子来解饿。本比喻徒有虚名而于实际无好处。后多用来比喻以空想来安慰自己

虽然不曾定个来期,也当画饼充饥,望梅止渴。——明· 冯梦龙《警世通言》