Question

我在onCreate中以编程方式创建了Layout：

new Handler().postDelayed(new Runnable() {

        @Override
        public void run() {
            myView = new MyView(SketchActivity.this, layout.getWidth(), layout.getHeight());

            layout2.addView(myView);
            layout2.bringToFront();

        }
    }, 50);

我创建（可变？）位图的视图：

public MyView(Context c, int width, int height) {
        super(c);

        WindowManager wm = (WindowManager) c.getSystemService(Context.WINDOW_SERVICE);
        Display display = wm.getDefaultDisplay();
        int w = display.getWidth(); // deprecated
        int h = display.getHeight();
        setFocusable(true);
        setBackgroundResource(R.drawable.download);

        // setting paint
        mPaint = new Paint();
        mPaint.setAlpha(0);
        mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
        mPaint.setAntiAlias(true);

        // getting image from resources
        Resources r = this.getContext().getResources();

        Bitmap bm = BitmapFactory.decodeResource(getResources(), R.drawable.smoke);

        // converting image bitmap into mutable bitmap

        bitmap = bm.createBitmap(w, h, Config.ARGB_8888);
        mCanvas = new Canvas();
        mCanvas.setBitmap(bitmap); // drawXY will result on that Bitmap
        mCanvas.drawBitmap(bm, 0, 0, null);

    }

我的onDraw功能：

 @Override
    protected void onDraw(Canvas canvas) {
        mCanvas.drawCircle(x, y, r, mPaint);

        canvas.drawBitmap(bitmap, 0, 0, null);

        super.onDraw(canvas);

    }

的onTouchEvent：

@Override
    public boolean onTouchEvent(MotionEvent event) {
        x = (int) event.getX();
        y = (int) event.getY();

        r = 20;
        // Atlast invalidate canvas
        invalidate();

        return true;
    }

没有LogCat错误问题出在myView中。当我创建位图bitmap = bm.createBitmap（w，h，Config.ARGB_8888）;如果我把而不是w，h（屏幕的宽度和高度）一个小数字示例：bitmap = bm.createBitmap（20,20，Config.ARGB_8888）;它创造了一幅小小的画面。但是如果我把w和h放在一起，那么它不是在所有的布局上绘制，而是只绘制一小部分。（即使我尝试：bitmap = bm.createBitmap（800,1080，Config.ARGB_8888）;它仍然只占一小部分，而不是所有的屏幕。我该怎么办？

Answer 1

这解决了它：

public Bitmap getResizedBitmap(Bitmap bm, int newHeight, int newWidth) {
    int width = bm.getWidth();
    int height = bm.getHeight();
    float scaleWidth = ((float) newWidth) / width;
    float scaleHeight = ((float) newHeight) / height;
    // CREATE A MATRIX FOR THE MANIPULATION
    Matrix matrix = new Matrix();
    // RESIZE THE BIT MAP
    matrix.postScale(scaleWidth, scaleHeight);
    // RECREATE THE NEW BITMAP
    Bitmap resizedBitmap = Bitmap.createBitmap(bm, 0, 0, width, height, matrix, false);
    return resizedBitmap;
}

public MyView(Context c, int width, int height) {
        super(c);

        WindowManager wm = (WindowManager) c.getSystemService(Context.WINDOW_SERVICE);
        Display display = wm.getDefaultDisplay();
        int w = display.getWidth(); // deprecated
        int h = display.getHeight();
        setFocusable(true);
        setBackgroundResource(R.drawable.download);

        // setting paint
        mPaint = new Paint();
        mPaint.setAlpha(0);
        mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
        mPaint.setAntiAlias(true);
        mPaint.setMaskFilter(new BlurMaskFilter(8, BlurMaskFilter.Blur.NORMAL));

        // getting image from resources
        Resources r = this.getContext().getResources();

        Bitmap bm = BitmapFactory.decodeResource(getResources(), R.drawable.smoke);
        Bitmap bm2 = getResizedBitmap(bm, h, w);

        // converting image bitmap into mutable bitmap

        bitmap = bm2.createBitmap(w, h, Config.ARGB_8888);
        mCanvas = new Canvas();
        mCanvas.setBitmap(bitmap); // drawXY will result on that Bitmap
        mCanvas.drawBitmap(bm2, 0, 0, null);

    }

Answer 2

看起来您正在回收代码中的Bitmap somwhere。有一个问题。

是的，你应该recycle它，但它总是有点冒险。

修改

看起来你正在吸引Bitmap。如果不是您要执行的操作，则不应手动调用onDraw。当您想重新绘制视图时，请调用invalidate()。

Answer 3

您需要添加Options这样的数据：

Options options = new Options();
options.isMutable = true; // works from api 11

mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.smoke, options);

在布局上绘制位图的问题

3 个答案: