java - 走るたびにタイマーが速くなる

Question

Android用のシンプルな画像ビューアを作っています。スライドショーも実装する必要があります。厄介なバグがあることを除いて、私は一種の完了です。スライドショーを実行すると（ボタンを押すと）動作します。しかし、スライドショーをキャンセルして再度実行すると (同じボタン)、スライドショーの速度が上がります。

EDIT：修正コードを追加し、コードのスライドショー部分のコメントを見て、修正が必要なものを確認してください

   package csc2002.imageviewer;
   //imports

public class MainActivity extends Activity implements OnClickListener {
    static Timer timer = new Timer();
    int arrayIndex = 0;
    int checker=0;
    int start,delay = 1800;
    boolean toggle;


    private static Integer[] imageIds = { //Hard coded array
        R.raw.bulbasaur,R.raw.switch_brain,R.raw.quote,R.raw.victory,R.raw.penguins,R.raw.jellyfish,R.raw.koala};

    private static final int IMAGE_COUNT = imageIds.length;

    @Override
    public void onCreate(Bundle savedInstanceState) { // Called when the app is opened

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button back = (Button)findViewById(R.id.backButton);
        back.setOnClickListener(this);       
        Button next = (Button)findViewById(R.id.nextButton);
        next.setOnClickListener(this);
        Button slideshow = (Button)findViewById(R.id.slideButton);
        slideshow.setOnClickListener(this);
        displayImage();
    }

    // responsible for displaying the image and the name of the image.
    private void displayImage() { // Displays the image on the screen according the the current array index

        ImageView imgView = (ImageView) findViewById(R.id.myimage);             
        imgView.setImageResource(imageIds[arrayIndex]);
        TextView text = (TextView)findViewById(R.id.name);
        text.setText(imageIds[arrayIndex]);
    }

    // This method allows the cycling of images

    public void onClick(View v) {
        if(v.getId()==(R.id.backButton)){ //Back button
            arrayIndex--;

            if(arrayIndex==-1){
                arrayIndex = IMAGE_COUNT-1;
            }
            displayImage();
        }

        else if (v.getId()==(R.id.nextButton)){ //NextButton
            arrayIndex++;
        }
        if(arrayIndex==IMAGE_COUNT){
            arrayIndex = 0;
        }
        displayImage();

        if (v.getId()==R.id.slideButton){ //Slideshow button
            Button slideshow = (Button)findViewById(R.id.slideButton);
            toggle^= true;
            if(toggle==true){
                slideshow.setText("Stop Slideshow");
            }
            else{slideshow.setText("Start Slideshow");}
        }
        // Slideshow functionality

        if(toggle==true){
            //timer=new Timer(); //this was added in the correct solution(This was the main problem).
            timer.scheduleAtFixedRate(new TimerTask() {

                @Override
                public void run() {
                    if(toggle==true){
                        MainActivity.this.runOnUiThread(new Runnable() {
                            public void run() {
                                arrayIndex++;
                                if(arrayIndex==IMAGE_COUNT){
                                    arrayIndex=0;
                                }

                                displayImage();
                            }
                        });
                    }  
                }

            },start,delay);

        }
        else if(toggle==false){
            //timer.cancel(); This was added to correct the solution
        }
    }

    @Override 
    protected void onSaveInstanceState(Bundle outState) { //This saves data when the app is rotated
        outState.putInt("KEY", arrayIndex);
        super.onSaveInstanceState(outState);

    }
    @Override
    protected void onRestoreInstanceState(Bundle save){ //Restores Data after interruption
        super.onRestoreInstanceState(save);
        arrayIndex = save.getInt("KEY");
        displayImage();
    }


}