如何减少自动调整文本视图的内存消耗?

时间:2015-03-23 15:46:56

标签: java android textview

我有一个autoresize-textview,它可以满足我的所有需求,但它消耗了大量内存,因为我有很多内存。重新启动我的应用程序会导致内存错误。

什么可能是最耗费内存的元素,是否可以释放一些内存?是否可以回收一些成员(mTextRect,mAvailableSpaceRect,mPaint)?

public class AutoResizeTextview extends TextView
{
    private interface SizeTester
    {
        /**
         * 
         * @param suggestedSize
         *            Size of text to be tested
         * @param availableSpace
         *            available space in which text must fit
         * @return an integer < 0 if after applying {@code suggestedSize} to
         *         text, it takes less space than {@code availableSpace}, > 0
         *         otherwise
         */
        public int onTestSize(int suggestedSize, RectF availableSpace);
    }

    private RectF               mTextRect           = new RectF();

    private RectF               mAvailableSpaceRect;

    private SparseIntArray      mTextCachedSizes;

    private TextPaint           mPaint;

    private float               mMaxTextSize;

    private float               mSpacingMult        = 1.0f;

    private float               mSpacingAdd         = 0.0f;

    private float               mMinTextSize        = 3;

    private int                 mWidthLimit;

    private static final int    NO_LINE_LIMIT       = -1;
    private int                 mMaxLines;

    private boolean             mEnableSizeCache    = true;
    private boolean             mInitiallized;

    public AutoResizeTextview(Context context)
    {
        super(context);
        initialize();
    }

    public AutoResizeTextview(Context context, AttributeSet attrs)
    {
        super(context, attrs);
        initialize();
    }

    public AutoResizeTextview(Context context, AttributeSet attrs, int defStyle)
    {
        super(context, attrs, defStyle);
        initialize();
    }

    private void initialize()
    {
        mPaint = new TextPaint(getPaint());
        mMaxTextSize = getTextSize();
        mAvailableSpaceRect = new RectF();
        mTextCachedSizes = new SparseIntArray();
        if (mMaxLines == 0)
        {
            // no value was assigned during construction
            mMaxLines = NO_LINE_LIMIT;
        }
        mInitiallized = true;
    }

    @Override
    public void setText(final CharSequence text, BufferType type)
    {
        super.setText(text, type);
        adjustTextSize(text.toString());
    }

    @Override
    public void setTextSize(float size)
    {
        mMaxTextSize = size;
        mTextCachedSizes.clear();
        adjustTextSize(getText().toString());
    }

    @Override
    public void setMaxLines(int maxlines)
    {
        super.setMaxLines(maxlines);
        mMaxLines = maxlines;
        reAdjust();
    }

    public int getMaxLines()
    {
        return mMaxLines;
    }

    @Override
    public void setSingleLine()
    {
        super.setSingleLine();
        mMaxLines = 1;
        reAdjust();
    }

    @Override
    public void setSingleLine(boolean singleLine)
    {
        super.setSingleLine(singleLine);
        if (singleLine)
        {
            mMaxLines = 1;
        }
        else
        {
            mMaxLines = NO_LINE_LIMIT;
        }
        reAdjust();
    }

    @Override
    public void setLines(int lines)
    {
        super.setLines(lines);
        mMaxLines = lines;
        reAdjust();
    }

    @Override
    public void setTextSize(int unit, float size)
    {
        Context c = getContext();
        Resources r;

        if (c == null)
            r = Resources.getSystem();
        else
            r = c.getResources();
        mMaxTextSize = TypedValue.applyDimension(unit, size, r.getDisplayMetrics());
        mTextCachedSizes.clear();
        adjustTextSize(getText().toString());
    }

    @Override
    public void setLineSpacing(float add, float mult)
    {
        super.setLineSpacing(add, mult);
        mSpacingMult = mult;
        mSpacingAdd = add;
    }

    /**
     * Set the lower text size limit and invalidate the view
     * 
     * @param minTextSize
     */
    public void setMinTextSize(float minTextSize)
    {
        mMinTextSize = minTextSize;
        reAdjust();
    }

    private void reAdjust()
    {
        adjustTextSize(getText().toString());
    }

    private void adjustTextSize(String string)
    {
        if (!mInitiallized)
        {
            return;
        }
        int startSize = (int) mMinTextSize;
        int heightLimit = getMeasuredHeight() - getCompoundPaddingBottom() - getCompoundPaddingTop();
        mWidthLimit = getMeasuredWidth() - getCompoundPaddingLeft() - getCompoundPaddingRight();
        mAvailableSpaceRect.right = mWidthLimit;
        mAvailableSpaceRect.bottom = heightLimit;
        super.setTextSize(TypedValue.COMPLEX_UNIT_PX, efficientTextSizeSearch(startSize, (int) mMaxTextSize, mSizeTester, mAvailableSpaceRect));
    }

    private final SizeTester    mSizeTester = new SizeTester()
    {
        @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
        @Override
        public int onTestSize(int suggestedSize, RectF availableSPace)
        {
            mPaint.setTextSize(suggestedSize);
            String text = getText().toString();
            boolean singleline = getMaxLines() == 1;
            // if (singleline) {    //my comment-out
            // mTextRect.bottom = mPaint.getFontSpacing();  //my comment-out
            // mTextRect.right = mPaint.measureText(text);  //my comment-out
            // } else { //my comment-out
            StaticLayout layout = new StaticLayout(text, mPaint, mWidthLimit, Alignment.ALIGN_NORMAL, mSpacingMult,
                    mSpacingAdd, true);
            // return early if we have more lines
            if (getMaxLines() != NO_LINE_LIMIT && layout.getLineCount() > getMaxLines())
            {
                return 1;
            }
            mTextRect.bottom = layout.getHeight();
            int maxWidth = -1;
            for (int i = 0; i < layout.getLineCount(); i++)
            {
                if (maxWidth < layout.getLineWidth(i))
                {
                    maxWidth = (int) layout.getLineWidth(i);
                }
            }
            mTextRect.right = maxWidth;
            // }    //my comment-out

            mTextRect.offsetTo(0, 0);
            if (availableSPace.contains(mTextRect))
            {
                // may be too small, don't worry we will find the best match
                return -1;
            }
            else
            {
                // too big
                return 1;
            }
        }
    };

    /**
     * Enables or disables size caching, enabling it will improve performance
     * where you are animating a value inside TextView. This stores the font
     * size against getText().length() Be careful though while enabling it as 0
     * takes more space than 1 on some fonts and so on.
     * 
     * @param enable
     *            enable font size caching
     */
    public void enableSizeCache(boolean enable)
    {
        mEnableSizeCache = enable;
        mTextCachedSizes.clear();
        adjustTextSize(getText().toString());
    }

    private int efficientTextSizeSearch(int start, int end, SizeTester sizeTester, RectF availableSpace)
    {
        if (!mEnableSizeCache)
        {
            return binarySearch(start, end, sizeTester, availableSpace);
        }
        String text = getText().toString();
        int key = text == null ? 0 : text.length();
        int size = mTextCachedSizes.get(key);
        if (size != 0)
        {
            return size;
        }
        size = binarySearch(start, end, sizeTester, availableSpace);
        mTextCachedSizes.put(key, size);
        return size;
    }

    private static int binarySearch(int start, int end, SizeTester sizeTester, RectF availableSpace)
    {
        int lastBest = start;
        int lo = start;
        int hi = end - 1;
        int mid = 0;
        while (lo <= hi)
        {
            mid = (lo + hi) >>> 1;
            int midValCmp = sizeTester.onTestSize(mid, availableSpace);
            if (midValCmp < 0)
            {
                lastBest = lo;
                lo = mid + 1;
            }
            else
                if (midValCmp > 0)
                {
                    hi = mid - 1;
                    lastBest = hi;
                }
                else
                {
                    return mid;
                }
        }
        // make sure to return last best
        // this is what should always be returned
        return lastBest;

    }

    @Override
    protected void onTextChanged(final CharSequence text, final int start, final int before, final int after)
    {
        super.onTextChanged(text, start, before, after);
        reAdjust();
    }

    @Override
    protected void onSizeChanged(int width, int height, int oldwidth, int oldheight)
    {
        mTextCachedSizes.clear();
        super.onSizeChanged(width, height, oldwidth, oldheight);
        if (width != oldwidth || height != oldheight)
        {
            reAdjust();
        }
    }
}
事先提前

0 个答案:

没有答案