Intentの初期化に失敗する

Android Studio2.2

Intent intent = new Intent(context, BallActivity.class);
startActivity(intent);

画面遷移の上記のようにすることでできますが、intent初期化しようとした時点で（一文目に入るときに）画面がブラックアウトします。エラー文も出ません。BallActivityのonResumeは正しく呼ばれています。LabyrinthView.startSensor();の直前でエラーが起こるので、LabyrinthViewに原因があると思われます。ここで考えられる原因は何があるでしょうか。遷移先のソースコードを以下に載せます。下のアクティビティ以外は普通に起動することができます。マニフェストファイルには遷移先のアクティビティを宣言してあります。

java
1
2//BallActivity.java
3
4import android.content.Context;
5import android.content.Intent;
6import android.os.Bundle;
7import android.support.v7.app.AppCompatActivity;
8import android.view.WindowManager;
9import android.widget.Toast;
10
11public class BallActivity extends AppCompatActivity implements LabyrinthView.EventCallback {
12
13
14    static int clearCounter = 0;
15
16
17    private static final String EXTRA_KEY_STAGE_SEED = "stage_seed";
18
19    int goalCount = 4;
20    int missCount = 0;
21
22    int r = new java.util.Random().nextInt(4000);
23
24    public static Intent newIntent(Context context, int stageSeed) {
25        Intent intent = new Intent(context, BallActivity.class);
26        intent.putExtra(EXTRA_KEY_STAGE_SEED, stageSeed);
27
28        return intent;
29    }
30
31    private int stageSeed;
32
33    private boolean isFinished;
34
35    private LabyrinthView labyrinthView;
36
37
38    @Override
39    protected void onCreate(Bundle savedInstanceState) {
40        super.onCreate(savedInstanceState);
41        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
42
43        //int clearCounter = 0;
44        stageSeed = getIntent().getIntExtra(EXTRA_KEY_STAGE_SEED, 0);
45
46        labyrinthView = new LabyrinthView(this);
47        labyrinthView.setCallback(this);
48        labyrinthView.setStageSeed(stageSeed);
49
50        setContentView(labyrinthView);
51        //setContentView(R.layout.activity_main);
52
53    }
54
55    @Override
56    protected void onResume() {
57        super.onResume();
58
59        labyrinthView.startSensor();
60        //clearCounter += 1;
61
62    }
63
64    @Override
65    protected void onPause() {
66        super.onPause();
67
68        labyrinthView.stopSensor();
69    }
70
71    @Override
72    public void onGoal() {
73
74        if (isFinished) {
75            return;
76        }
77        isFinished = true;
78
79        Map.setClearCounter(Map.getClearCounter()+1);
80
81        Toast.makeText(this, Map.getClearCounter() + "回目のゴール", Toast.LENGTH_SHORT).show();
82
83        labyrinthView.stopSensor();
84
85        Intent intent = newIntent(this, stageSeed + r);
86        startActivity(intent);
87        finish();
88
89    }
90
91    @Override
92    public void onHole() {
93        if (isFinished) {
94            return;
95        }
96        isFinished = true;
97
98        Map.setMissCounter(Map.getMissCounter()+1);
99
100
101
102        Toast.makeText(this, Map.getMissCounter() + "回目のミス", Toast.LENGTH_SHORT).show();
103        //Toast.makeText(this, String.valueOf(Map.getClearCounter()),Toast.LENGTH_LONG).show();
104
105        labyrinthView.stopSensor();
106
107        Intent intent = newIntent(this, stageSeed);
108        startActivity(intent);
109        finish();
110    }
111
112    @Override
113    public void onChange() {
114        if (isFinished) {
115            return;
116        }
117        isFinished = true;
118
119        Toast.makeText(this, "Goal!!", Toast.LENGTH_SHORT).show();
120
121        labyrinthView.stopSensor();
122
123        Intent intent = new Intent(this, StopAlarm.class);
124        startActivity(intent);
125        finish();
126    }
127}
128

java
1//LabyrinthView.java
2
3import android.content.Context;
4import android.graphics.Bitmap;
5import android.graphics.BitmapFactory;
6import android.graphics.Canvas;
7import android.graphics.Color;
8import android.graphics.Paint;
9import android.hardware.Sensor;
10import android.hardware.SensorEvent;
11import android.hardware.SensorEventListener;
12import android.hardware.SensorManager;
13import android.view.SurfaceHolder;
14import android.view.SurfaceView;
15
16import java.util.concurrent.atomic.AtomicBoolean;
17
18public class LabyrinthView extends SurfaceView implements SurfaceHolder.Callback {
19    private static final float ACCEL_WEIGHT = 3f;
20
21    private static final float BALL_SCALE = 0.8f;
22
23    private static final int DRAW_INTERVAL = 1000 / 60;
24    private static final float TEXT_SIZE = 40f;
25
26    private final Paint paint = new Paint();
27    private final Paint textPaint = new Paint();
28
29    private final Bitmap ballBitmap;
30
31    private Ball ball;
32    private Map map;
33
34    interface EventCallback {
35        void onGoal();
36        void onHole();
37        void onChange();
38    }
39
40    private EventCallback eventCallback;
41
42    public void setCallback(EventCallback eventCallback) {
43        this.eventCallback = eventCallback;
44    }
45
46    private int stageSeed;
47
48    public void setStageSeed(int stageSeed) {
49        this.stageSeed = stageSeed;
50    }
51
52    public LabyrinthView(Context context) {
53        super(context);
54
55        textPaint.setColor(Color.WHITE);
56        textPaint.setTextSize(TEXT_SIZE);
57
58        ballBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ball);
59
60        getHolder().addCallback(this);
61    }
62
63
64    private DrawThread drawThread;
65
66    private class DrawThread extends Thread {
67        private final AtomicBoolean isFinished = new AtomicBoolean();
68
69        public void finish() {
70            isFinished.set(true);
71        }
72
73        @Override
74        public void run() {
75            SurfaceHolder holder = getHolder();
76            while (!isFinished.get()) {
77                if (holder.isCreating()) {
78                    continue;
79                }
80                Canvas canvas = holder.lockCanvas();
81                if (canvas == null) {
82                    continue;
83                }
84
85                drawLabyrinth(canvas);
86
87                holder.unlockCanvasAndPost(canvas);
88
89                synchronized (this) {
90                    try {
91                        wait(DRAW_INTERVAL);
92                    } catch (InterruptedException e) {
93                    }
94                }
95            }
96        }
97    }
98
99    public void startDrawThread() {
100        stopDrawThread();
101
102        drawThread = new DrawThread();
103        drawThread.start();
104    }
105
106    public boolean stopDrawThread() {
107        if (drawThread == null) {
108            return false;
109        }
110
111        drawThread.finish();
112        drawThread = null;
113        return true;
114    }
115
116    private static final float ALPHA = 0.8f;
117    private float[] sensorValues;
118
119    private final SensorEventListener sensorEventListener = new SensorEventListener() {
120        @Override
121        public void onSensorChanged(SensorEvent event) {
122            if (sensorValues == null) {
123                sensorValues = new float[3];
124                sensorValues[0] = event.values[0];
125                sensorValues[1] = event.values[1];
126                sensorValues[2] = event.values[2];
127                return;
128            }
129
130            sensorValues[0] = sensorValues[0] * ALPHA + event.values[0] * (1f - ALPHA);
131            sensorValues[1] = sensorValues[1] * ALPHA + event.values[1] * (1f - ALPHA);
132            sensorValues[2] = sensorValues[2] * ALPHA + event.values[2] * (1f - ALPHA);
133
134            if (ball != null) {
135                float xOffset = -sensorValues[0] * ACCEL_WEIGHT;
136                float yOffset = sensorValues[1] * ACCEL_WEIGHT;
137                ball.move(xOffset, yOffset);
138            }
139        }
140
141        @Override
142        public void onAccuracyChanged(Sensor sensor, int accuracy) {
143
144        }
145    };
146
147    public void startSensor() {
148        sensorValues = null;
149
150        SensorManager sensorManager = (SensorManager) getContext().getSystemService(Context.SENSOR_SERVICE);
151        Sensor accelerometer = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
152        sensorManager.registerListener(sensorEventListener, accelerometer, SensorManager.SENSOR_DELAY_GAME);
153    }
154
155    public void stopSensor() {
156        SensorManager sensorManager = (SensorManager) getContext().getSystemService(Context.SENSOR_SERVICE);
157        sensorManager.unregisterListener(sensorEventListener);
158    }
159
160
161    @Override
162    public void surfaceCreated(SurfaceHolder holder) {
163        startDrawThread();
164    }
165
166    @Override
167    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
168    }
169
170    @Override
171    public void surfaceDestroyed(SurfaceHolder holder) {
172        stopDrawThread();
173    }
174
175    public void drawLabyrinth(Canvas canvas) {
176        canvas.drawColor(Color.BLACK);
177
178        int blockSize = ballBitmap.getHeight();
179        if (map == null) {
180            map = new Map(canvas.getWidth(), canvas.getHeight(), blockSize, stageSeed,
181                    eventCallback);
182        }
183        if (ball == null) {
184            ball = new Ball(ballBitmap, map.getStartBlock(), BALL_SCALE, map);
185        }
186
187        map.draw(canvas);
188        ball.draw(canvas);
189
190        if (sensorValues != null) {
191            canvas.drawText("sensor[0] = " + sensorValues[0], 10, 150, textPaint);
192            canvas.drawText("sensor[1] = " + sensorValues[1], 10, 200, textPaint);
193            canvas.drawText("sensor[2] = " + sensorValues[2], 10, 250, textPaint);
194        }
195    }
196
197}
198