证明:$(1)$∵$AB=CD$
∴$\widehat {AB}=\widehat {AC}$,
即$\widehat {BC}+\widehat {AC}=\widehat {AD}+\widehat {AC}$
∴$\widehat {AD}=\widehat {BC}$
解:$(2)$连接$AC$
∵$\widehat {AD}=\widehat {BC}$
∴$AD=BC$
又∵$CD=AB$,$AC=AC$
∴$△ADC≌△CBA(\mathrm {SSS})$
∴$∠ACD=∠CAB$
∴$AE=CE$