Androidの加速度センサの値を一定間隔で取得する方法

Androidの加速度センサの値を一定間隔(約200ms)で取得し、CSV形式で値を保存するアプリを作成しているのです。
しかし、取得間隔が一定にならず困っています。
何か良い方法があれば教えていただけないでしょうか。
宜しくお願い致します。

以下、MainActivity.java

java
1public class  MainActivity extends AppCompatActivity implements SensorEventListener {
2    private Sensor accSensor;
3    private TextView mX;
4    private TextView mY;
5    private TextView mZ;
6    private SensorManager mManager;
7    public int button_flag = 0;
8
9    long eventOccuredTimeMilli = -1;
10    long eventOccuredTimeNano = -1;
11
12    //sensorChangedで更新される情報(加速度,ジャイロ)
13
14    ArrayList<String> accX = new ArrayList<String>();
15    ArrayList<String> accY = new ArrayList<String>();
16    ArrayList<String> accZ = new ArrayList<String>();
17
18    ArrayList<String> timeStamp_forAcc = new ArrayList<String>();//UNIX時間
19    ArrayList<String> timeStamp_Time_forAcc = new ArrayList<String>();//時間
20
21    //書き込み用の情報
22    ArrayList<String> accX_w = new ArrayList<String>();
23    ArrayList<String> accY_w = new ArrayList<String>();
24    ArrayList<String> accZ_w = new ArrayList<String>();
25
26    ArrayList<String> timeStamp_forAcc_w = new ArrayList<String>();//UNIX時間
27    ArrayList<String> timeStamp_Time_forAcc_w = new ArrayList<String>();//時間
28
29    //時間(年.月.日_時:分:秒)
30    SimpleDateFormat sdf = new SimpleDateFormat("yy.MM.dd_HH:mm:ss");
31
32    //時間(年.月.日_時:分:秒:ミリ秒)
33    SimpleDateFormat sdf1 = new SimpleDateFormat("yy.MM.dd_HH:mm:ss:SSS");
34
35    //計測開始時間に使用する変数
36    String start_time;
37
38    //ファイル名の確認時に使用
39    String last_fileName;
40
41    String tmp_fileName;//評価対象のファイルを保存するときのやつ
42
43
44
45    public void onAccuracyChanged(Sensor sensor, int n) {
46    }
47
48    @Override
49    protected void onCreate(Bundle savedInstanceState) {
50        super.onCreate(savedInstanceState);
51        setContentView(R.layout.activity_main);
52        mManager = (SensorManager)this.getSystemService(SENSOR_SERVICE);
53        accSensor = this.mManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
54        Button start_btn = (Button) findViewById(R.id.button);
55        Button stop_btn = (Button) findViewById(R.id.button2);
56
57        start_btn.setOnClickListener(new View.OnClickListener() {
58            @Override
59            public void onClick(View v) {
60                sdf.applyPattern("yy.MM.dd_HH:mm:ss");
61                start_time = sdf.format(System.currentTimeMillis());
62
63                button_flag = 1;
64
65                initialize();
66                last_fileName = "";
67            }
68        });
69
70        stop_btn.setOnClickListener(new View.OnClickListener() {
71            @Override
72            public void onClick(View v) {
73                button_flag = 0;
74
75                copy_information();
76                save_route();
77                initialize();
78            }
79        });
80
81        mX = (TextView)this.findViewById(R.id.textView1);
82        mY = (TextView)this.findViewById(R.id.textView2);
83        mZ = (TextView)this.findViewById(R.id.textView3);
84
85
86    }
87
88
89    @Override
90    protected void onPause() {
91        super.onPause();
92        this.mManager.unregisterListener((SensorEventListener)this, this.accSensor);
93    }
94
95    protected void onResume() {
96        super.onResume();
97        this.mManager.registerListener((SensorEventListener) this, this.accSensor, SensorManager.SENSOR_DELAY_NORMAL);
98    }
99
100    public void onSensorChanged(SensorEvent sensorEvent) {
101
102        //UNIX時間
103        if (eventOccuredTimeMilli < 0){
104            eventOccuredTimeMilli = System.currentTimeMillis();
105            eventOccuredTimeNano = sensorEvent.timestamp;
106        }
107
108        long unixtime = eventOccuredTimeMilli
109                + (sensorEvent.timestamp - eventOccuredTimeNano) / 1000000;
110        if (sensorEvent.sensor.getType() ==  Sensor.TYPE_ACCELEROMETER) {
111            if(button_flag==1){
112
113                    Log.d("SENSOR_DATA", "TYPE_ACCELEROMETER1 = " + String.valueOf(sensorEvent.values[0]));
114//                    Log.d("SENSOR_DATA", "TYPE_ACCELEROMETER2 = " + String.valueOf(sensorEvent.values[1]));
115//                    Log.d("SENSOR_DATA", "TYPE_ACCELEROMETER3 = " + String.valueOf(sensorEvent.values[2]));
116
117                    mX.setText("加速度センサーX:" + String.valueOf(sensorEvent.values[0]));
118                    mY.setText("加速度センサーY:" + String.valueOf(sensorEvent.values[1]));
119                    mZ.setText("加速度センサーZ:" + String.valueOf(sensorEvent.values[2]));
120
121                accX.add(String.format("%3.2f", sensorEvent.values[0]));
122                accY.add(String.format("%3.2f", sensorEvent.values[1]));
123                accZ.add(String.format("%3.2f", sensorEvent.values[2]));
124
125
126                timeStamp_forAcc.add(String.valueOf(unixtime));
127                timeStamp_Time_forAcc.add(sdf1.format(unixtime));
128
129            }else{
130                mX.setText("止まっていますX");
131                mY.setText("止まっていますY");
132                mZ.setText("止まっていますZ");
133            }
134        }
135    }
136
137    public void copy_information() {
138
139
140        accX_w = new ArrayList(accX);
141        accY_w = new ArrayList(accY);
142        accZ_w = new ArrayList(accZ);
143
144
145        timeStamp_forAcc_w = new ArrayList(timeStamp_forAcc);
146        timeStamp_Time_forAcc_w = new ArrayList(timeStamp_Time_forAcc);
147
148    }
149
150    //ArrayListを初期化
151    public void initialize() {
152
153        accX.clear();
154        accY.clear();
155        accZ.clear();
156
157
158        timeStamp_forAcc.clear();
159        timeStamp_Time_forAcc.clear();
160
161        eventOccuredTimeMilli = -1;
162        eventOccuredTimeNano = -1;
163    }
164
165    /*書き込み関係*/
166    public void save_route() {
167        String txt_name = "soukoukiroku";
168        String filePath;
169
170        if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
171            filePath = Environment.getExternalStorageDirectory().toString();
172        }else{
173            filePath = Environment.getDataDirectory().toString();
174        }
175
176        File file_route_acc = new File(filePath + "/acc_log/" + txt_name);
177        file_route_acc.getParentFile().mkdir();
178
179        String str;
180        sdf.applyPattern("yy.MM.dd_HH:mm:ss");
181        str = sdf.format(System.currentTimeMillis());
182
183        txt_name = start_time + "-" + str + ".csv";
184
185        //初めての書き込みなら、そのままtxt_nameのファイル名で書き込み。それ以外ならリネーム後書き込み。
186        if(last_fileName != ""){
187            ArrayList<String> list = new ArrayList<String>();
188            list.add("/acc_log/");
189            for(int i=0; i < list.size(); i++){
190                File file = new File( filePath + list.get(i) + last_fileName );
191                if (file.exists()) {
192                    //リネーム
193                    File file2 = new File(filePath + list.get(i) + txt_name);
194                }
195            }
196        }
197        last_fileName = txt_name;
198
199        if(!start_time.equals(str)) {
200
201            tmp_fileName = txt_name;
202
203            // 別スレッドで時間のかかる処理を実行
204            new Thread(new Runnable() {
205                @Override
206
207                public void run() {
208                    //ここではセンサデータを書き込み
209                    writeCSV_route();
210
211                }
212            }).start();
213
214        }
215    }
216
217    //	センサデータ書き込み
218    public void writeCSV_route() {
219
220        String str;
221        String filePath;
222        if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
223            filePath = Environment.getExternalStorageDirectory().toString();
224        }else{
225            filePath = Environment.getDataDirectory().toString();
226        }
227
228        //センサデータを書き込む部分
229
230        //acc書き込み
231        try {
232            BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(filePath + "/acc_log/" + tmp_fileName, true), "UTF-8"));
233            //			 addDebugMessage("acc書きこみ開始 filePath: " + filePath + "/acc/" + tmp_fileName + "  timeStamp.size(): " + timeStamp_forAcc.size());
234            for (int i = 0; i < timeStamp_forAcc_w.size(); i++) {
235                str = timeStamp_forAcc_w.get(i) + "," + timeStamp_Time_forAcc_w.get(i) + "," + accX_w.get(i) + "," + accY_w.get(i) + "," + accZ_w.get(i);
236                bw.write(str);
237                bw.newLine();
238//                   			 Log.d("MainActivity", "writeCSV_route_acc	i: " + i + "	str: " + str + "	filePath: " + filePath + "/acc_test/" + tmp_fileName);
239            }
240            bw.close();
241        }catch (Exception e) {
242        }
243
244
245
246        timeStamp_forAcc_w.clear();
247        timeStamp_Time_forAcc_w.clear();
248
249        accX_w.clear();
250        accY_w.clear();
251        accZ_w.clear();
252
253    }
254
255}