重新启动Activity后功能会发生变化

时间:2011-03-20 03:52:30

标签: java android drag-and-drop collision-detection

我有一个益智游戏,在屏幕上拖动棋子但不能重叠。如果他们尝试重叠,他们的位置会改回到不重叠的位置,并使用invalidate()重新绘制UI。除非在关闭应用程序并重新启动它或更改方向时销毁和重建活动,否则这种方法很有效。

似乎发生的事情是我用于碰撞的位置变量(x,y,right,bottom等)没有重置为在构造函数中初始化它们的方式。碎片与不可见的物体碰撞,与看似随机的位置碰撞,或者不规则地移动。

修复它的唯一方法是手动终止应用程序(如使用任务杀手)或重新安装它。然后它将正常工作,直到第二次创建游戏活动。我究竟做错了什么?有任何想法吗?以下是我在GameView类中的onCreate()中添加片段的方式:

Pieces redtiki = new Pieces(this,0,0,R.drawable.tikired);
...
board.addView(redtiki);

这是我的Pieces课程的一部分:

public class Pieces extends View{

private int x;
private int y;
private int width;
private int height;
private int right;
private int bottom;
private int initialX;
private int initialY;
private Bitmap sizedBitmap;
private Bitmap sourceBitmap;
private int boardSize = 6;
public static ArrayList<Pieces> aPieces = new ArrayList<Pieces>();
//private final Paint mPaint = new Paint();

public Pieces(Context context, int x, int y, int img){
    super(context);
    this.x = x;
    this.y = y;
    sourceBitmap = BitmapFactory.decodeResource(getResources(), img);
    aPieces.add(this);
    initialX=x;
    initialY=y;
}

private void sizePiece(){
    int scaledWidth;
    int scaledHeight;
    int h = sourceBitmap.getHeight();
    int w = sourceBitmap.getWidth();

    if (h>w){
        scaledWidth = 1;
    }else if (w>h){
        scaledWidth = w/h;
    }else{
        scaledWidth = 0;
    }
    if (h>w){
        scaledHeight = h/w;
    }else if (w>h){
        scaledHeight = 1;
    }else{
        scaledHeight = 0;
    }

    int dstWidth = (((((View) getParent()).getWidth())*scaledWidth)/boardSize)-1;//TODO make sure that -1 is necessary for
    int dstHeight = (((((View) getParent()).getHeight())*scaledHeight)/boardSize)-1;//fitting all pieces on the board

    sizedBitmap = Bitmap.createScaledBitmap(sourceBitmap, dstWidth, dstHeight, true);
    width = sizedBitmap.getWidth();
    height = sizedBitmap.getHeight();
    right = x+width;
    bottom = y+height;
}

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    sizePiece();
    canvas.drawBitmap(sizedBitmap, x, y, null);
}

@Override
public boolean onTouchEvent(MotionEvent event){

    float eventX = event.getX();
    float eventY = event.getY();

    switch (event.getAction()) {
    case MotionEvent.ACTION_DOWN:
        //check if touch is on piece
        if (eventX > x && eventX < (x+width) && eventY > y && eventY < (y+height)){
            initialX=x;
            initialY=y;
            break;
        }else{
            return false;
        }
    case MotionEvent.ACTION_MOVE:
        //determine if piece should move horizontally or vertically
        if(width>height){
            for (Pieces piece : aPieces) {
                //if object equals itself in array, skip to next object
                if(piece==this){
                    continue;
                }
                //check if there the possibility for a horizontal collision
                if(this.isAllignedHorizontallyWith(piece)){
                    //check for and handle collisions while moving left
                    if(this.isRightOf(piece)){
                        if(eventX>piece.right+(width/2)){
                            x = (int)(eventX-(width/2)); //move normally
                            /*for(Pieces piece2 : aPieces){
                                if(this.isAllignedHorizontallyWith(piece2)){
                                    if(this.isLeftOf(piece2)){
                                        if(eventX<piece2.x-(width/2)){
                                            x = (int)(eventX-(width/2));
                                            continue;
                                        }else{
                                            x = piece2.x-width-1;
                                        }
                                    }
                                }
                            }*/
                            continue;
                        }else{
                            x = piece.right+1;
                        }
                    }
                    //check for and handle collisions while moving right
                    if(this.isLeftOf(piece)){
                        if(eventX<piece.x-(width/2)){
                            x = (int)(eventX-(width/2));
                            continue;
                        }else{
                            x = piece.x-width-1;
                        }
                    }
                    break;
                }else{
                    x = (int)(eventX-(width/2));
                }
            }
        }
        if(height>width){
            for (Pieces piece : aPieces) {
                //if object equals itself in array, skip to next object
                if(piece==this){
                    continue;
                }
                //check if there the possibility for a vertical collision
                if(this.isAllignedVerticallyWith(piece)){
                    //check for and handle collisions while moving up
                    if(this.isBelow(piece)){
                        if(eventY>piece.bottom+(height/2)){
                            y = (int)(eventY-(height/2)); //move normally
                            continue;
                        }else{
                            y = piece.bottom+1;
                        }
                    }
                    //check for and handle collisions while moving down
                    if(this.isAbove(piece)){
                        if(eventY<piece.y-(height/2)){
                            y = (int)(eventY-(height/2));
                            continue;
                        }else{
                            y = piece.y-height-1;
                        }
                    }
                    break;
                }else{
                    y = (int)(eventY-(height/2));
                }
            }
        }
        invalidate();
        break;

    case MotionEvent.ACTION_UP:
        // end move
        if(this.moves()){
        GameView.counter++;
        }
        initialX=x;
        initialY=y;
        break;
        }
    // parse puzzle
    invalidate();
    return true;
    }

2 个答案:

答案 0 :(得分:1)

在Activity类中,实现OnPause(),OnResume()。

方法

使用上述方法中的日志语句来查看在关闭/打开应用程序期间是否更改了位置/坐标。

调用“OnPause()”时,可以保存各种组件的状态。当调用“OnResume()”(即应用程序到达前台)时,读取已保存的状态并使用您最近读取的坐标绘制视图。

请注意,只有在创建活动时才会调用“OnCreate()”。切换方向不会调用“OnCreate()”

您将找到解释Android API文档的流程图。 http://developer.android.com/reference/android/app/Activity.html

答案 1 :(得分:0)

我刚刚意识到出了什么问题。每次我创建一个新的Pieces对象时,它都会被添加到我的ArrayList aPieces中。因此,每次方向改变,或者我加载了一个新级别,它将加载我的所有新部件并显示它们,但我的旧部件仍然在ArrayList中,因此仍然会检查是否存在冲突。为了解决这个问题,在我加载每个新级别(以及组成该级别的所有部分)之前,我使用Pieces.aPieces.clear();清除列表。现在,它完美无缺。