Java 我的实时壁纸实现中的IndexOutOfBoundsException

方法changeFlowers失败，出现索引越界异常

我是java新手，我正在调用已经实例化的FishOne（Arraylist rederable类）的方法“changeColor（）” 但它失败了，出现了索引越界异常

public void changeFlowers(int i)
{


        FlowerOne f1 = (FlowerOne)(this._fishes.get(i));   // Is this the right way to call ????
        f1.changeColor(this._theme);


}

下面的代码为quantial.java，FishOne.java 提前谢谢你的帮助

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水族馆，

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这取决于完整的逻辑，代码如何是错误安全的。基本上，如果您确定changeFlowers不会在参数i大于ArrayList大小的情况下调用，那么您可以在changeFlowers函数中设置vheck

像

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但最好是使代码从调用该函数的地方安全起来，因为实际问题就在那里以上代码将停止错误，但您还需要更正调用函数的位置。

您如何调用该方法？索引大于_fishesarraylist'大小，请检查i和_fishes.size（）Hi npinti，这是我调用方法f1.changeColor（this.\u主题）的方式；

public class Aquarium {
private AquariumThread _aquariumThread; 
private SurfaceHolder _surfaceHolder;   
private ArrayList<Renderable> _fishes;  
private Bitmap _backgroundImage;
private Context _context;


public void render(){
    Canvas canvas = null;
    try{

        canvas = this._surfaceHolder.lockCanvas(null);
        synchronized (this._surfaceHolder) {
            this.onDraw(canvas);
        }

    }finally{
        if(canvas != null){
            this._surfaceHolder.unlockCanvasAndPost(canvas);
        }
    }   
}


protected void onDraw(Canvas canvas) {
    this.renderBackGround(canvas);
    for (Renderable renderable : this._fishes) {
        renderable.render(canvas);
    }
};

public void initialize(Context context, SurfaceHolder surfaceHolder) {
    this._fishes = new ArrayList<Renderable>();
}



protected void onDraw(Canvas canvas) {
    this.renderBackGround(canvas);
    for (Renderable renderable : this._fishes) {
        renderable.render(canvas);
    }
};


public void start(){
    this._aquariumThread.switchOn();
}


public void stop(){
    boolean retry = true;
    this._aquariumThread.switchOff();
    while (retry) {
        try {
         this._aquariumThread.join();
            retry = false;
        } catch (InterruptedException e) {
            // we will try it again and again...
        }
    }
}


public synchronized void addFishes() {      

Point startPoint1 = new Point(1,300);
this._fishes.add(new fishOne(this._context, this, startPoint1, 90));

Point startPoint2 = new Point(100,300);
this._fishes.add(new fishOne(this._context, this, startPoint2, 90));

Point startPoint3 = new Point(200,300);
this._fishes.add(new fishOne(this._context, this, startPoint3, 90));

}





public void changeFlowers(int i)
{


        FlowerOne f1 = (FlowerOne)(this._fishes.get(i));
        f1.changeColor(this._theme);


}


}

public class fishOne extends Animal {
private static final int TOTAL_FRAMES_IN_SPRITE = 1;
private static final int CLOWN_FISH_FPS = 1; 

int _fishColor;
Bitmap leftBitmap;
Bitmap rightBitmap;


public fishOne(Context context, Aquarium aquarium,  Point startPoint, int speed){       

    super(context, aquarium);   
    this.changeColor(1);
    this.initialize(this.leftBitmap, this.rightBitmap, CLOWN_FISH_FPS, TOTAL_FRAMES_IN_SPRITE, startPoint, speed);

}


public void changeColor(int mfishColor)
{


    switch(mfishColor) {
    case 1:

    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inPurgeable = true;
    this.leftBitmap = BitmapFactory.decodeResource(getContext().getResources(), com.gotit.livewallpaper.fishshd.R.drawable.fish1, options);

    BitmapFactory.Options options1 = new BitmapFactory.Options();
    options1.inPurgeable = true;
    this.rightBitmap = BitmapFactory.decodeResource(getContext().getResources(), com.gotit.livewallpaper.fishshd.R.drawable.fish2, options1);

        break;

    case 2:
    BitmapFactory.Options options2 = new BitmapFactory.Options();
    options2.inPurgeable = true;
    this.leftBitmap = BitmapFactory.decodeResource(getContext().getResources(), com.gotit.livewallpaper.fishshd.R.drawable.redfish1, options2);

    BitmapFactory.Options options3 = new BitmapFactory.Options();
    options3.inPurgeable = true;
    this.rightBitmap = BitmapFactory.decodeResource(getContext().getResources(), com.gotit.livewallpaper.fishshd.R.drawable.redfish2, options3);

        break;
    default:
    }


}


public void render(Canvas canvas){
    super.render(canvas);   
}

}

public void changeFlowers(int i)
{

    if(null!=this._fishes && this._fishes.size()>i){

        FlowerOne f1 = (FlowerOne)(this._fishes.get(i));
        f1.changeColor(this._theme);
}


}