cocosCreator2.2.0以上版本测试过，低版本未测试。适用多种屏幕（大屏，小屏，异形屏等）。
下面附上代码：
start(){
this.resetSize(this.node);
}
/**
* 手机屏幕适配
* @param cav
*/
resetSize(cav) {
let frameSize = cc.view.getFrameSize();
let designSize = cc.view.getDesignResolutionSize();
if (frameSize.width / frameSize.height > designSize.width / designSize.height) {
cav.width = designSize.height * frameSize.width / frameSize.height;
cav.height = designSize.height;
cav.getComponent(cc.Canvas).designResolution = cc.size(cav.width, cav.height);
} else {
cav.width = designSize.width;
cav.height = designSize.width * frameSize.height / frameSize.width;
cav.getComponent(cc.Canvas).designResolution = cc.size(cav.width, cav.height);
}
this.fitScreen(cav, designSize);
}
/**
* 背景适配
* @param canvasnode
* @param designSize
*/
fitScreen(canvasnode, designSize) {
let scaleW = canvasnode.width / designSize.width;
let scaleH = canvasnode.height / designSize.height;
let bgNode = canvasnode.getChildByName('background');
let bgScale = canvasnode.height / bgNode.height;
bgNode.width *= bgScale;
bgNode.height *= bgScale;
if (scaleW > scaleH) {
bgScale = canvasnode.width / bgNode.width;
bgNode.width *= bgScale;
bgNode.height *= bgScale;
}
}