1. apply the wake lock tool class AlertWakeLock

After the mobile phone is dormant, the application's calculation, timing and download may be dormant due to the CPU, resulting in the application itself unable to receive the message, data and broadcast in time. To solve the problem caused by CPU sleep, we can use hold lock to keep the CPU from sleeping.
For example, you can use this tool class if you want to collect the temperature of mobile phones all day long.

If the CPU lock is not released, the standby power consumption will be high

2. use

2.0 need to configure permissions

    <uses-permission android:name="android.permission.WAKE_LOCK" />

2.1 lock

    public static void acquireCpuWakeLock(Context context) {
        if (sCpuWakeLock != null) {
            return;
        }

        sCpuWakeLock = createPartialWakeLock(context);
        // Step 3: acquire() obtains the corresponding lock
        sCpuWakeLock.acquire();
    }

2.2 release lock

    public static void releaseCpuLock() {
        if (sCpuWakeLock != null) {
            // Finally: release release
            sCpuWakeLock.release();
            sCpuWakeLock = null;
        }
    }

2.3 complete source code

package com.li.temperature.chart.util;

import android.content.Context;
import android.os.PowerManager;

/*
 Flag Value                 CPU        Screen      Keyboard
 PARTIAL_WAKE_LOCK            On           Off         Off
 SCREEN_DIM_WAKE_LOCK         On           Dim         Off
 SCREEN_BRIGHT_WAKE_LOCK      On           Bright      Off
 FULL_WAKE_LOCK               On           Bright      Bright
 */
public class AlertWakeLock {
    private static final String TAG = "AlertWakeLock";
    private static PowerManager.WakeLock sCpuWakeLock;

    static PowerManager.WakeLock createPartialWakeLock(Context context) {
        // Step 1: get an instance of PowerManager
        PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
        if (null == pm) {
            return null;
        }
        // Step 2: call newWakeLock method in PowerManager to create a WakeLock object
        return pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, TAG);
        // return pm.newWakeLock(PowerManager.FULL_WAKE_LOCK |
        // PowerManager.ACQUIRE_CAUSES_WAKEUP | PowerManager.ON_AFTER_RELEASE,
        // TAG);
    }

    public static void acquireCpuWakeLock(Context context) {
        if (sCpuWakeLock != null) {
            return;
        }

        sCpuWakeLock = createPartialWakeLock(context);
        // Step 3: acquire() obtains the corresponding lock
        sCpuWakeLock.acquire();
    }

    public static void releaseCpuLock() {
        if (sCpuWakeLock != null) {
            // Finally: release release
            sCpuWakeLock.release();
            sCpuWakeLock = null;
        }
    }
}