android– 按下按钮时不调用橡皮擦

概述我有这样的主要类：publicclassMainextendsActivity{Buttonedit,save,eraser,clear;/**Calledwhentheactivityisfirstcreated.*/@OverridepublicvoidonCreate(BundlesavedInstanceState){super.onCreate(savedInstanceState);

我有这样的主要类：

public class Main extends Activity {    button edit,save,eraser,clear;    /** Called when the activity is first created. */    @OverrIDe    public voID onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentVIEw(R.layout.main);        edit = (button) findVIEwByID(R.ID.edit);        save = (button) findVIEwByID(R.ID.save);        clear = (button) findVIEwByID(R.ID.clear);        eraser = (button) findVIEwByID(R.ID.eraser);        eraser.setonClickListener(new OnClickListener() {                @OverrIDe                public voID onClick(VIEw v) {                    GameBoard aa = new GameBoard(Main.this);                    aa.eraser();                    aa.invalIDate();                }        });    }}

我的视图类看起来像这样：

public class GameBoard extends VIEw{    public voID init() {        mPaint = new Paint();        mPaint.setAntiAlias(true);        mPaint.setDither(true);        // mPaint.setcolor(color.BLACK);        mPaint.setcolor(0xFFFF0000);        mPaint.setStyle(Paint.Style.stroke);        mPaint.setstrokeJoin(Paint.Join.ROUND);        mPaint.setstrokeCap(Paint.Cap.ROUND);        mPaint.setstrokeWIDth(12);    }    public Paint mPaint;    public GameBoard(Context context) {        super(context);        init();    }    private Bitmap mBitmap;    private Canvas mCanvas;    private Path mPath;    private Paint mBitmapPaint;    public GameBoard(Context context, AttributeSet aSet) {         super(context, aSet);         init();        mBitmap = Bitmap.createBitmap(800, 1024, Bitmap.Config.ARGB_8888);        mCanvas = new Canvas(mBitmap);        mPath = new Path();        mBitmapPaint = new Paint(Paint.DITHER_FLAG);    }    @OverrIDe    protected voID onSizeChanged(int w, int h, int olDW, int oldh) {        super.onSizeChanged(w, h, olDW, oldh);    }    @OverrIDe    public voID onDraw(Canvas canvas) {        // initialize        // canvas.drawcolor(color.WHITE);        canvas.drawcolor(0xFFAAAAAA);        canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);        canvas.drawPath(mPath, mPaint);    }    private float mX, mY;    private static final float touch_TolERANCE = 4;    private voID touch_start(float x, float y) {        mPath.reset();        mPath.moveto(x, y);        mX = x;        mY = y;    }    private voID touch_move(float x, float y) {        float dx = Math.abs(x - mX);        float dy = Math.abs(y - mY);        if (dx >= touch_TolERANCE || dy >= touch_TolERANCE) {            mPath.quadTo(mX, mY, (x + mX)/2, (y + mY)/2);            mX = x;            mY = y;        }    }    private voID touch_up() {        mPath.lineto(mX, mY);        // commit the path to our offscreen        mCanvas.drawPath(mPath, mPaint);        // kill this so we don't double draw        mPath.reset();    }    @OverrIDe    public boolean ontouchEvent(MotionEvent event) {        float x = event.getX();        float y = event.getY();        switch (event.getAction()) {        case MotionEvent.ACTION_DOWN:            touch_start(x, y);            invalIDate();            break;        case MotionEvent.ACTION_MOVE:            touch_move(x, y);            invalIDate();            break;        case MotionEvent.ACTION_UP:            touch_up();            invalIDate();            break;        }        return true;    }    public voID eraser() {        // Todo auto-generated method stub        Toast.makeText(getContext(), "eraser", Toast.LENGTH_LONG).show();        mPaint.setXfermode(null);        mPaint.setAlpha(0xFF);        mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));        invalIDate();    }}

这是布局：

<com.authorwjf.GameBoard    androID:ID="@+ID/the_canvas"    androID:layout_wIDth="fill_parent"    androID:layout_height="fill_parent" />

当我单击一个按钮时,它不会将mPaint更改为橡皮擦.

谁能帮我？

解决方法:

据我所知,你在onClick中创建的GameBoard永远不会附加到任何东西.

该视图是否属于Activity的布局？

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