How uniapp calls native timer

In Uniapp, we can use Vue.js for cross-platform development, including developing native applications and web applications at the same time. This allows us to write code in JavaScript and run it on multiple platforms without having to write different code for each platform. However, sometimes we need to call the native timer in Uniapp to better interact with the device. This article will introduce how to use Uniapp to call native timers.

What is a native timer?

Native timer refers to the function provided by the operating system for periodically calling specified functions. In some scenarios, we need to perform some specific operations within a fixed time interval. In this case, we can use a timer to achieve this. In web applications, we commonly use JavaScript's built-in setTimeout and setInterval functions, but in native applications, we need to use the timer function provided by the operating system to achieve this.

How to call native timer in Uniapp?

To call the native timer in Uniapp, we need to use the native plug-in function provided by Uniapp. These plug-ins allow us to directly call native functions in Uniapp, including native timers. Let's take the Android platform as an example to introduce how to use native plug-ins to call native timers:

1. In the root directory of the Uniapp project, create a file named "Android" (if you are developing for IOS, create a directory named "IOS").
2. In the Android directory, create a directory named "app" (application package), and create a directory named "src" (source code) within it. Under the "src" directory, create another directory called "main".
3. Create a directory named "java" (Java source code) under the "main" directory, and create a directory named "com.your_company_name.app" (your company name and application package) in it name) directory structure. In the final subdirectory, create a Java class called "TimerPlugin.java".
4. In the TimerPlugin.java class, add the following code:

package com.your_company_name.app;

import android.os.Handler;
import android.os.Looper;
import java.util.Timer;
import java.util.TimerTask;

import io.dcloud.feature.uniapp.bridge.UniJSCallback;
import io.dcloud.feature.uniapp.common.UniModule;

public class TimerPlugin extends UniModule {

    private Timer mTimer;
    private Handler mHandler = new Handler(Looper.getMainLooper());

    public void startTimer(UniJSCallback callback) {
        if (mTimer != null) {
            mTimer.cancel();
            mTimer = null;
        }
        mTimer = new Timer();
        mTimer.scheduleAtFixedRate(new TimerTask() {
            @Override
            public void run() {
                mHandler.post(new Runnable() {
                    @Override
                    public void run() {
                        callback.invoke();
                    }
                });
            }
        }, 0, 1000);
    }

    public void stopTimer() {
        if (mTimer != null) {
            mTimer.cancel();
            mTimer = null;
        }
    }

}

In the above code, we defined a class named "TimerPlugin" and inherited the UniModule class. This class is the base class for the Uniapp plugin. We also define two methods: startTimer and stopTimer. In the startTimer method, we create a new Timer object and register a scheduled task in it. This task will be executed once every second and call the callback function we passed in. The stopTimer method is used to stop scheduled tasks.

5. In the Uniapp project, introduce the plug-in in the page that needs to use the native timer:

<template>
  <view>
  </view>
</template>

<script>
  import { TimerPlugin } from '@/uni_modules/timer-plugin/index.js';

  export default {
    name: 'TimerDemo',
    mounted() {
      TimerPlugin.startTimer(() => {
        console.log('定时器响应');
      });
    },
    destroyed() {
      TimerPlugin.stopTimer();
    }
  }
</script>

The above code introduces the plug-in we just created, and in the mounted life The timer is started during the cycle. When the component is destroyed, we stop the timer.

So far, we have successfully called the native timer in Uniapp and can use it to implement periodic tasks on the Android platform. The same principle also applies to the iOS platform.

Summary

To use Uniapp to call the native timer, you need to use the native plug-in function provided by Uniapp and write the corresponding native code through Java or Swift. Through the above steps, we can easily call the native timer in the Uniapp project and make full use of the device's capabilities to make your application experience smoother and more efficient.

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