如何使用 java 获取 android 中的 CPU 温度？

Question

'''

    Process process;
    try {
        process = Runtime.getRuntime().exec("cat sys/class/thermal/thermal_zone0/temp");
          
        process.waitFor();
        BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
        String line = reader.readLine();
        System.out.println("Multan "+ line);
        if(line!=null) {
            float temp = Float.parseFloat(line);
            return temp / 1000.0f;
        }else{
            return 51.0f;
        }
    } catch (Exception e) {
        e.printStackTrace();
        return 0.0f;
    }

'''

I found this solution but it always return 51.0 as line is always null. Someone please help with this. Thanks in advance.

Answer 1

Firstly it's wrong to read a file like this, you don't need to create a new process each time that you want to get the temperature.

Secondly, you may not have the file your are looking for. This is because the /sys/* is a pseudo-filesystem ( sysfs ) created by the system and it's different drivers. It may be very different from a phone to another.

I found a non-exhaustive list of cpu temperature file.

String[] sensorFiles = new String[] {
    "/sys/devices/system/cpu/cpu0/cpufreq/cpu_temp",             
    "/sys/devices/system/cpu/cpu0/cpufreq/FakeShmoo_cpu_temp",    
    "/sys/class/thermal/thermal_zone1/temp",                      
    "/sys/class/i2c-adapter/i2c-4/4-004c/temperature",            
    "/sys/devices/platform/tegra-i2c.3/i2c-4/4-004c/temperature", 
    "/sys/devices/platform/omap/omap_temp_sensor.0/temperature",  
    "/sys/devices/platform/tegra_tmon/temp1_input",               
    "/sys/kernel/debug/tegra_thermal/temp_tj",                   
    "/sys/devices/platform/s5p-tmu/temperature",                  
    "/sys/class/thermal/thermal_zone0/temp",                      
    "/sys/devices/virtual/thermal/thermal_zone0/temp",            
    "/sys/class/hwmon/hwmon0/device/temp1_input",                 
    "/sys/devices/virtual/thermal/thermal_zone1/temp",           
    "/sys/devices/platform/s5p-tmu/curr_temp"
}

You have to try each of them until you get a positive answer.

File correctSensorFile = null;
for (String file : sensorFiles) {
    File f = new File(file);
    if (f.exists()) {
        correctSensorFile = f;
        break;
    }
}

if (correctSensorFile == null)
    throw new RuntimeException("Did not find sensor file to read");

RandomAccessFile reader = new RandomAccessFile(correctSensorFile , "r");
String value = reader.readLine();
reader.close();