css+transition to make visible and invisible animation

This time I will introduce to you what are the precautions for making visible and invisible animations with css transition. The following is a practical case. Let’s take a look.

Let’s take a look at the renderings first

The probability of a widget with a transition effect like this being used in our actual development is relatively high. However, in the process of developing WeChat mini programs, some friends may find that the transition attribute is not easy to use (explained below), so at this time we will consider using the wx.createAnimation API officially provided by WeChat to create animations.

Next, I will show you how to make the transition attribute easy to use in this need. The following code is

page({
    data: {
        show:false//用于显示或隐藏控件
    },
    chanMask:function(){
        var isShow = this.data.show ? false : true;//如果显示就隐藏，隐藏就显示
        this.setData({
            show:isShow
        })
    }
})

/*index.wxss*/
/*显示前*/
.mask-con{
transition: 1s; 
position: fixed;
width: 100%;
height: 300rpx;
left: 0;
bottom: -300rpx;
 
text-align: center;
line-height: 300rpx;
box-shadow: 0 1px 10px #aaa;
}
/*显示后*/
.mask-con-show{
bottom: 0;
}
<!--index.wxml-->
<view>
<button>点我</button>
<view>
<view>X</view>
慢慢飞起
</view>
</view>

In the above code, we first define a show variable in data. Used for the display state of the mask-con control, this variable is alternately changed in the chanMask function, and then the chanMask function is bound to the click events of the button and close controls. Finally, we decide whether to give the mask-con (our Animation control) Add a class: mask-con-show So here we have implemented a visible and hidden widget with transition, but for some needs this is still too reluctant, such as the situation below:

Many apps or small programs now use this method to close the pop-up window control. The X user clicked it is not enough. After seeing this, smart friends may think of adding another one. A shadow control is under the mask-con and is bound to our chanMask function. In this case, the shadow control and our mask-con may not be in a whole, which is not intuitive enough. For example, the leader wants the shadow to have An effect in which the display color gradually deepens and the hidden color gradually fades. In order to deal with this situation, we adjust the code as follows:

page({
    data: {
        show:false//用于显示或隐藏mask控件
    },
    chanMask:function(){
        var isShow = this.data.show ? false : true;//如果显示就隐藏，隐藏就显示
        this.setData({
            show:isShow
        })
    }
})
/*index.wxss*/
.mask-shadow{
width: 100%;
height: 100%;
 
opacity: 0;
transition: 1s;
}
.mask-shadow-on{
opacity: 0.3;
}
.mask-con{
position: absolute;
width: 100%;
height: 300rpx;
left: 0;
bottom: -300rpx;
 
transition: 1s;
text-align: center;
line-height: 300rpx;
box-shadow: 0 1px 10px #aaa;
}
.mask-con-show{
bottom: 0;
}
 
<!--index.wxml-->
<view>
<button>点我</button>
<view>
<view></view>
<view>
<view>X</view>
慢慢飞起
</view>
</view>
</view>

Here we set two style class names mask-shadow-on and mask-con-show to define the shadow and the effect of the main control mask-con animation (the specific code is determined according to your own needs), it seems that everything is OK, there are no problems, then run a wave first, Emma, ​​Shenma situation ? The shadow and our mask-con are directly displayed without any transition effect. So why does this affect the effect of our program? After some consideration, the blogger found that our transition attribute may be invalid when display is none. , then some friends here may ask, "Blogger, that's wrong. We have clearly set the mask's display to block, why do we still have this problem?"

This is how our mask It takes a while for the control to be fully displayed. However, after our variable show is set to true, our shadow control and main control will immediately add the post-animation style class name. This time is longer than the mask display. The time needs to be faster, so our machine thinks that mask is still in the situation where the display is none

For example: mask is the boss of this whole area. This boss has not finished his performance yet. What do you guys do? The younger brother has already come out to steal the limelight. Where do you want to put the face of being the boss? If not, I have to kill all of you who steal my limelight and see how you behave. This boss doesn't speak much. If you steal his limelight, he won't be happy if you don't perform (user experience), and he won't tell you after the performance. So what should you do if this boss is so difficult to take care of? Some friends are already feeling confused, so what are you waiting for? Pick up the phone in your hand and call the help hotline. . . . . Ah, that’s too far off topic

In fact, the solution is very simple. Yes, the answer is the setTimeout() function. Come on, let’s change the code again:

page({
        data: {
        show:false,//用于显示或隐藏mask控件
        runAM:false//用于动画执行的根据
    },
    chanMask:function(){
        var isShow = this.data.show ? false : true;//如果显示就隐藏，隐藏就显示
        var delay  = isShow ? 30 : 1000;//第一个时间是博主测出来控件显示所需的时间，第二个是动画所需的时间
        if(isShow){
            this.setData({
                show:isShow
            });
        }else{
            this.setData({
                runAM:isShow
            })
        }
        
        setTimeout(function(){
            if(isShow){
                this.setData({
                    runAM:isShow
                });
            }else{
                this.setData({
                    show:isShow
                });
            }
        }, delay);
    }
})
<!--index.wxml-->
<view>
<button>点我</button>
<view>
<view></view>
<view>
<view>X</view>
慢慢飞起
</view>
</view>
</view>

In the above code, We added a new variable runAM to data to use as a certificate for when the animation starts to be executed, and then defined a variable delay for setting the delay in the chanMask function. The code may be a bit convoluted. The blogger will explain it roughly here

The entire process of the program is based on the isShow variable.

When isShow is true, it means that we have to open the mask control, so we first display the mask control, and then delay After 30 milliseconds, add a style class name to the control to be animated

When isShow is false, we first remove the class name of the animation control (after removal, the animation will return to its original form), and then Let the mask hide after a delay of 1000 milliseconds (the time required for animation)

The setting of the first value of delay was measured by the blogger himself. If you are still worried that the control is not displayed, you can It doesn’t matter if you set it to 50 milliseconds or 100 milliseconds. This 0.1 second time difference has little impact on the user experience. If you set it for 1 second and there is no response, I can only say to change your phone

In the end, you will find that during the entire process, the blogger only calls one function to display or hide, and does not create a new function for closing. This writing method is full of style.

This method is also applicable Yu H5

I believe that you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!

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The above is the detailed content of css+transition to make visible and invisible animation. For more information, please follow other related articles on the PHP Chinese website!