Fix some code analysis errors

app/src/main/java/de/hems/trafficsim/MainActivity.java

@@ -97,7 +97,7 @@ public class MainActivity extends AppCompatActivity implements SeekBar.OnSeekBar
         this.track = new Track(defaultNoOfVehicles, defaultTrackLength, defaultBrakeProb,
                 defaultMaxVelocity, defaultDelay, defaultHistoryLength);
         this.viewStack = findViewById(R.id.trackViewStack);
-        this.trackView = new TimeRecordView(this, track);
+        this.trackView = new TimeRecordView(this);
 
         viewStack.addView(this.trackView);
         this.renderer = new Renderer(track, this.trackView.getHolder());
@@ -212,7 +212,7 @@ public class MainActivity extends AppCompatActivity implements SeekBar.OnSeekBar
         this.worker.setStop(true);
         try {
             this.worker.join();
-        } catch (InterruptedException ex) {
+        } catch (InterruptedException ignored) {
         }
         this.worker = null;
     }
@@ -270,7 +270,7 @@ public class MainActivity extends AppCompatActivity implements SeekBar.OnSeekBar
             this.worker.setStop(true);
             try {
                 this.worker.join();
-            } catch (InterruptedException ex) {
+            } catch (InterruptedException ignored) {
             }
         }
 

app/src/main/java/de/hems/trafficsim/Renderer.java

@@ -36,11 +36,11 @@ public class Renderer {
     /**
      * Paint instance of the renderer
      */
-    protected Paint paint;
+    final protected Paint paint;
     /**
      * holder of the surface the renderer draws to
      */
-    protected SurfaceHolder holder;
+    final protected SurfaceHolder holder;
     /**
      * width of the surface to draw to
      */
@@ -137,11 +137,11 @@ public class Renderer {
             canvas = this.holder.lockCanvas();
             synchronized (holder) {
                 int y = 0;
-                int left = 0;
+                int left;
-                int hCompensateStart = 0;
+                int hCompensateStart;
-                int hCompensateEnd = 0;
+                int hCompensateEnd;
-                int vCompensateStart = 0;
+                int vCompensateStart;
-                int vCompensateEnd = 0;
+                int vCompensateEnd;
                 canvas.drawColor(Color.BLACK);
                 for (int curStepIdx = this.track.getVtrList().size()-1; curStepIdx >= 0;
                      curStepIdx--) {

app/src/main/java/de/hems/trafficsim/TimeRecordView.java

@@ -8,7 +8,7 @@ import android.view.ViewGroup;
  * A Surface View which servers as a stage for a renderer.
  */
 public class TimeRecordView extends SurfaceView {
-    public TimeRecordView(Context context, Track track) {
+    public TimeRecordView(Context context) {
         super(context);
         this.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
     }

app/src/main/java/de/hems/trafficsim/Track.java

@@ -13,17 +13,17 @@ public class Track extends Observable {
     /**
      * list a vehicles on the track
      */
-    protected List<Vehicle> vehicles;
+    final protected List<Vehicle> vehicles;
 
     /**
      * list of resulting time records of the simulation
      */
-    protected List<List<VehicleTimeRecord>> vtrList;
+    final protected List<List<VehicleTimeRecord>> vtrList;
 
     /**
      * length of the track
      */
-    protected float trackLength;
+    final protected float trackLength;
 
     /**
      * sum of all vehicle speeds during the simulation, used for average calculation
@@ -39,7 +39,7 @@ public class Track extends Observable {
     /**
      * length of the history kept
      */
-    protected int historyLength;
+    final protected int historyLength;
 
     /**
      * average over all velocities in the simulation
@@ -64,12 +64,12 @@ public class Track extends Observable {
     /**
      * currently configured max velocity for all vehicles
      */
-    protected float maxVelocity;
+    final protected float maxVelocity;
 
     /**
      * currently configured brake probability for all vehicles
      */
-    protected float brakeProb;
+    final protected float brakeProb;
 
     /**
      * counter for executed simulation steps
@@ -79,7 +79,7 @@ public class Track extends Observable {
     /**
      * semaphore protecting the vtrlist
      */
-    protected Semaphore listSemaphore;
+    final protected Semaphore listSemaphore;
 
     /**
      * Constructor for a new Track.
@@ -145,15 +145,6 @@ public class Track extends Observable {
         return delayedAvg;
     }
 
-    /**
-     * Getter for vehicles
-     *
-     * @return vehicles
-     */
-    public List<Vehicle> getVehicles() {
-        return vehicles;
-    }
-
     /**
      * Getter for trackLength
      *
@@ -265,7 +256,7 @@ public class Track extends Observable {
         }
         for(Vehicle v: vehicles){
             v.timeElapse();
-            VehicleTimeRecord vtr = new VehicleTimeRecord(v.id, v.position, v.curVelocity, v.maxVelocity);
+            VehicleTimeRecord vtr = new VehicleTimeRecord(v.position, v.curVelocity, v.maxVelocity);
             records.add(vtr);
         }
         steps++;
@@ -274,7 +265,7 @@ public class Track extends Observable {
         update_avg();
         try {
             Thread.sleep(waitTime);
-        } catch (InterruptedException ex) {
+        } catch (InterruptedException ignored) {
         }
     }
 

app/src/main/java/de/hems/trafficsim/Vehicle.java

@@ -9,7 +9,7 @@ public class Vehicle {
     /**
      * a number to index the vehicle
      */
-    protected int id;
+    final protected int id;
 
     /**
      * current position of the vehicle on the track
@@ -34,7 +34,7 @@ public class Vehicle {
     /**
      * length of the track the vehicle is placed on
      */
-    protected float trackLength;
+    final protected float trackLength;
 
     /**
      * Constructs a new vehicle.

app/src/main/java/de/hems/trafficsim/VehicleTimeRecord.java

@@ -4,25 +4,20 @@ package de.hems.trafficsim;
  * Model class which keeps the previous simulation data for analysis.
  */
 public class VehicleTimeRecord {
-    /**
-     * the id of the vehicle it belongs to
-     */
-    protected int id;
-
     /**
      * the position of the vehicle after the last simulation step
      */
-    protected float position;
+    final protected float position;
 
     /**
      * the velocity of the vehicle during the last simulation step
      */
-    protected float velocity;
+    final protected float velocity;
 
     /**
      * the maximum velocity of the vehicle
      */
-    protected float maxVelocity;
+    final protected float maxVelocity;
 
     public float getMaxVelocity() {
         return maxVelocity;
@@ -39,13 +34,11 @@ public class VehicleTimeRecord {
     /**
      * Construct a new VehicleTimeRecord.
      *
-     * @param id          the id of the vehicle it belongs to
      * @param position    the position of the vehicle after the last simulation step
      * @param velocity    the velocity of the vehicle during the last simulation step
      * @param maxVelocity the maximum velocity of the vehicle
      */
-    public VehicleTimeRecord(int id, float position, float velocity, float maxVelocity) {
+    public VehicleTimeRecord(float position, float velocity, float maxVelocity) {
-        this.id = id;
         this.position = position;
         this.velocity = velocity;
         this.maxVelocity = maxVelocity;

app/src/main/java/de/hems/trafficsim/Worker.java

@@ -9,7 +9,7 @@ public class Worker extends Thread {
     /**
      * the track to simulate
      */
-    protected Track track;
+    protected final Track track;
 
     /**
      * Stop flag, indicating that the worker shall stop
@@ -19,12 +19,12 @@ public class Worker extends Thread {
     /**
      * the MainActivity of the gui
      */
-    protected MainActivity gui;
+    protected final MainActivity gui;
 
     /**
      * the Renderer drawing the Track
      */
-    protected Renderer renderer;
+    protected final Renderer renderer;
 
     /**
      * Amount of simulation steps between two frames in the view. Zero means
@@ -74,7 +74,6 @@ public class Worker extends Thread {
      */
     @Override
     public void run() {
-        Canvas canvas = null;
         int i = 0;
         while (!stop) {
             this.track.timeElapse();

app/src/main/res/layout/activity_main.xml

@@ -382,7 +382,7 @@
                 <Button
                     android:id="@+id/clearButton"
                     style="@style/Widget.AppCompat.Button.Borderless"
-                    android:layout_width="wrap_content"
+                    android:layout_width="0dp"
                     android:layout_height="wrap_content"
                     android:layout_weight="1"
                     android:onClick="onClearButtonClick"