Android之查看手机实时电流、电压

就是从文件中读值，由于电流变化太快，显示的是连续读5次的平均值，直接上代码：
public class MainActivity extends Activity {    private boolean mIsStart = true;    private Toast mToast;    private Handler mHandler = new Handler() {        public void handleMessage(android.os.Message msg) {            showToast(getCurrent());            if (mIsStart) {                // 因为Toast.LENGTH_SHORT的默认值是2000                mHandler.sendEmptyMessageDelayed(0, 1900);            }        };    };    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        mHandler.sendEmptyMessage(0);    }    @Override    protected void onDestroy() {        super.onDestroy();        mHandler.removeMessages(0);        mIsStart = false;    }    /**     * 获取当前电流     */    private String getCurrent() {        String result = "null";        try {            Class systemProperties = Class.forName("android.os.SystemProperties");            Method get = systemProperties.getDeclaredMethod("get", String.class);            String platName = (String) get.invoke(null, "ro.hardware");            if (platName.startsWith("mt") || platName.startsWith("MT")) {                String filePath = "/sys/class/power_supply/battery/device/FG_Battery_CurrentConsumption";                // MTK平台该值不区分充放电，都为负数，要想实现充放电电流增加广播监听充电状态即可                result = "当前电流为：" + Math.round(getMeanCurrentVal(filePath, 5, 0) / 10.0f) + "mA";                result += ", 电压为：" + readFile("/sys/class/power_supply/battery/batt_vol", 0) + "mV";            } else if (platName.startsWith("qcom")) {                String filePath ="/sys/class/power_supply/battery/current_now";                int current = Math.round(getMeanCurrentVal(filePath, 5, 0) / 10.0f);                int voltage = readFile("/sys/class/power_supply/battery/voltage_now", 0) / 1000;                // 高通平台该值小于0时电池处于放电状态，大于0时处于充电状态                if (current < 0) {                    result = "充电电流为：" + (-current) + "mA, 电压为：" + voltage + "mV";                } else {                    result = "放电电流为：" + current + "mA, 电压为：" + voltage + "mV";                }            }        } catch (Exception e) {            e.printStackTrace();        }        return result;    }    /**     * 获取平均电流值     * 获取 filePath 文件 totalCount 次数的平均值，每次采样间隔 intervalMs 时间      */    private float getMeanCurrentVal(String filePath, int totalCount, int intervalMs) {        float meanVal = 0.0f;        if (totalCount <= 0) {            return 0.0f;        }        for (int i = 0; i < totalCount; i++) {            try {                float f = Float.valueOf(readFile(filePath, 0));                meanVal += f / totalCount;            } catch (Exception e) {                e.printStackTrace();            }            if (intervalMs <= 0) {                continue;            }            try {                Thread.sleep(intervalMs);            } catch (Exception e) {                e.printStackTrace();            }        }        return meanVal;    }    private int readFile(String path, int defaultValue) {        try {            BufferedReader bufferedReader = new BufferedReader(new FileReader(                    path));            int i = Integer.parseInt(bufferedReader.readLine(), 10);            bufferedReader.close();            return i;        } catch (Exception localException) {        }        return defaultValue;    }    private void showToast(String content) {        if (mToast == null) {            mToast = Toast.makeText(MainActivity.this, content, Toast.LENGTH_SHORT);        } else {            mToast.setText(content);            mToast.setDuration(Toast.LENGTH_SHORT);        }        mToast.show();    }}
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