TextView图文混排Gif

1.gif解析器

import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;

import java.io.InputStream;
import java.util.Vector;

public class GifDecoder {
    /**
     * File read status: No errors.
     */
    public static final int STATUS_OK = 0;
    /**
     * File read status: Error decoding file (may be partially decoded)
     */
    public static final int STATUS_FORMAT_ERROR = 1;
    /**
     * File read status: Unable to open source.
     */
    public static final int STATUS_OPEN_ERROR = 2;
    /** max decoder pixel stack size */
    protected static final int MAX_STACK_SIZE = 4096;
    protected InputStream in;
    protected int status;
    protected int width; // full image width
    protected int height; // full image height
    protected boolean gctFlag; // global color table used
    protected int gctSize; // size of global color table
    protected int loopCount = 1; // iterations; 0 = repeat forever
    protected int[] gct; // global color table
    protected int[] lct; // local color table
    protected int[] act; // active color table
    protected int bgIndex; // background color index
    protected int bgColor; // background color
    protected int lastBgColor; // previous bg color
    protected int pixelAspect; // pixel aspect ratio
    protected boolean lctFlag; // local color table flag
    protected boolean interlace; // interlace flag
    protected int lctSize; // local color table size
    protected int ix, iy, iw, ih; // current image rectangle
    protected int lrx, lry, lrw, lrh;
    protected Bitmap image; // current frame
    protected Bitmap lastBitmap; // previous frame
    protected byte[] block = new byte[256]; // current data block
    protected int blockSize = 0; // block size last graphic control extension info
    protected int dispose = 0; // 0=no action; 1=leave in place; 2=restore to bg; 3=restore to prev
    protected int lastDispose = 0;
    protected boolean transparency = false; // use transparent color
    protected int delay = 0; // delay in milliseconds
    protected int transIndex; // transparent color index
    // LZW decoder working arrays
    protected short[] prefix;
    protected byte[] suffix;
    protected byte[] pixelStack;
    protected byte[] pixels;
    protected Vector<GifFrame> frames; // frames read from current file
    protected int frameCount;

    private static class GifFrame {
            public GifFrame(Bitmap im, int del) {
                    image = im;
                    delay = del;
            }

            public Bitmap image;
            public int delay;
    }

    /**
     * Gets display duration for specified frame.
     * 
     * @param n
     *          int index of frame
     * @return delay in milliseconds
     */
    public int getDelay(int n) {
            delay = -1;
            if ((n >= 0) && (n < frameCount)) {
                    delay = frames.elementAt(n).delay;
            }
            return delay;
    }

    /**
     * Gets the number of frames read from file.
     * 
     * @return frame count
     */
    public int getFrameCount() {
            return frameCount;
    }

    /**
     * Gets the first (or only) image read.
     * 
     * @return BufferedBitmap containing first frame, or null if none.
     */
    public Bitmap getBitmap() {
            return getFrame(0);
    }

    /**
     * Gets the "Netscape" iteration count, if any. A count of 0 means repeat indefinitiely.
     * 
     * @return iteration count if one was specified, else 1.
     */
    public int getLoopCount() {
            return loopCount;
    }

    /**
     * Creates new frame image from current data (and previous frames as specified by their disposition codes).
     */
    protected void setPixels() {
            // expose destination image's pixels as int array
            int[] dest = new int[width * height];
            // fill in starting image contents based on last image's dispose code
            if (lastDispose > 0) {
                    if (lastDispose == 3) {
                            // use image before last
                            int n = frameCount - 2;
                            if (n > 0) {
                                    lastBitmap = getFrame(n - 1);
                            } else {
                                    lastBitmap = null;
                            }
                    }
                    if (lastBitmap != null) {
                            lastBitmap.getPixels(dest, 0, width, 0, 0, width, height);
                            // copy pixels
                            if (lastDispose == 2) {
                                    // fill last image rect area with background color
                                    int c = 0;
                                    if (!transparency) {
                                            c = lastBgColor;
                                    }
                                    for (int i = 0; i < lrh; i++) {
                                            int n1 = (lry + i) * width + lrx;
                                            int n2 = n1 + lrw;
                                            for (int k = n1; k < n2; k++) {
                                                    dest[k] = c;
                                            }
                                    }
                            }
                    }
            }
            // copy each source line to the appropriate place in the destination
            int pass = 1;
            int inc = 8;
            int iline = 0;
            for (int i = 0; i < ih; i++) {
                    int line = i;
                    if (interlace) {
                            if (iline >= ih) {
                                    pass++;
                                    switch (pass) {
                                    case 2:
                                            iline = 4;
                                            break;
                                    case 3:
                                            iline = 2;
                                            inc = 4;
                                            break;
                                    case 4:
                                            iline = 1;
                                            inc = 2;
                                            break;
                                    default:
                                            break;
                                    }
                            }
                            line = iline;
                            iline += inc;
                    }
                    line += iy;
                    if (line < height) {
                            int k = line * width;
                            int dx = k + ix; // start of line in dest
                            int dlim = dx + iw; // end of dest line
                            if ((k + width) < dlim) {
                                    dlim = k + width; // past dest edge
                            }
                            int sx = i * iw; // start of line in source
                            while (dx < dlim) {
                                    // map color and insert in destination
                                    int index = ((int) pixels[sx++]) & 0xff;
                                    int c = act[index];
                                    if (c != 0) {
                                            dest[dx] = c;
                                    }
                                    dx++;
                            }
                    }
            }
            image = Bitmap.createBitmap(dest, width, height, Config.ARGB_4444);
    }

    /**
     * Gets the image contents of frame n.
     * 
     * @return BufferedBitmap representation of frame, or null if n is invalid.
     */
    public Bitmap getFrame(int n) {
            if (frameCount <= 0)
                    return null;
            n = n % frameCount;
            return ((GifFrame) frames.elementAt(n)).image;
    }

    /**
     * Reads GIF image from stream
     * 
     * @param is
     *          containing GIF file.
     * @return read status code (0 = no errors)
     */
    public int read(InputStream is) {
            init();
            if (is != null) {
                    in = is;
                    readHeader();
                    if (!err()) {
                            readContents();
                            if (frameCount < 0) {
                                    status = STATUS_FORMAT_ERROR;
                            }
                    }
            } else {
                    status = STATUS_OPEN_ERROR;
            }
            try {
                    is.close();
            } catch (Exception e) {
            }
            return status;
    }

    /**
     * Decodes LZW image data into pixel array. Adapted from John Cristy's BitmapMagick.
     */
    protected void decodeBitmapData() {
            int nullCode = -1;
            int npix = iw * ih;
            int available, clear, code_mask, code_size, end_of_information, in_code, old_code, bits, code, count, i, datum, data_size, first, top, bi, pi;
            if ((pixels == null) || (pixels.length < npix)) {
                    pixels = new byte[npix]; // allocate new pixel array
            }
            if (prefix == null) {
                    prefix = new short[MAX_STACK_SIZE];
            }
            if (suffix == null) {
                    suffix = new byte[MAX_STACK_SIZE];
            }
            if (pixelStack == null) {
                    pixelStack = new byte[MAX_STACK_SIZE + 1];
            }
            // Initialize GIF data stream decoder.
            data_size = read();
            clear = 1 << data_size;
            end_of_information = clear + 1;
            available = clear + 2;
            old_code = nullCode;
            code_size = data_size + 1;
            code_mask = (1 << code_size) - 1;
            for (code = 0; code < clear; code++) {
                    prefix[code] = 0; // XXX ArrayIndexOutOfBoundsException
                    suffix[code] = (byte) code;
            }
            // Decode GIF pixel stream.
            datum = bits = count = first = top = pi = bi = 0;
            for (i = 0; i < npix;) {
                    if (top == 0) {
                            if (bits < code_size) {
                                    // Load bytes until there are enough bits for a code.
                                    if (count == 0) {
                                            // Read a new data block.
                                            count = readBlock();
                                            if (count <= 0) {
                                                    break;
                                            }
                                            bi = 0;
                                    }
                                    datum += (((int) block[bi]) & 0xff) << bits;
                                    bits += 8;
                                    bi++;
                                    count--;
                                    continue;
                            }
                            // Get the next code.
                            code = datum & code_mask;
                            datum >>= code_size;
                            bits -= code_size;
                            // Interpret the code
                            if ((code > available) || (code == end_of_information)) {
                                    break;
                            }
                            if (code == clear) {
                                    // Reset decoder.
                                    code_size = data_size + 1;
                                    code_mask = (1 << code_size) - 1;
                                    available = clear + 2;
                                    old_code = nullCode;
                                    continue;
                            }
                            if (old_code == nullCode) {
                                    pixelStack[top++] = suffix[code];
                                    old_code = code;
                                    first = code;
                                    continue;
                            }
                            in_code = code;
                            if (code == available) {
                                    pixelStack[top++] = (byte) first;
                                    code = old_code;
                            }
                            while (code > clear) {
                                    pixelStack[top++] = suffix[code];
                                    code = prefix[code];
                            }
                            first = ((int) suffix[code]) & 0xff;
                            // Add a new string to the string table,
                            if (available >= MAX_STACK_SIZE) {
                                    break;
                            }
                            pixelStack[top++] = (byte) first;
                            prefix[available] = (short) old_code;
                            suffix[available] = (byte) first;
                            available++;
                            if (((available & code_mask) == 0) && (available < MAX_STACK_SIZE)) {
                                    code_size++;
                                    code_mask += available;
                            }
                            old_code = in_code;
                    }
                    // Pop a pixel off the pixel stack.
                    top--;
                    pixels[pi++] = pixelStack[top];
                    i++;
            }
            for (i = pi; i < npix; i++) {
                    pixels[i] = 0; // clear missing pixels
            }
    }

    /**
     * Returns true if an error was encountered during reading/decoding
     */
    protected boolean err() {
            return status != STATUS_OK;
    }

    /**
     * Initializes or re-initializes reader
     */
    protected void init() {
            status = STATUS_OK;
            frameCount = 0;
            frames = new Vector<GifFrame>();
            gct = null;
            lct = null;
    }

    /**
     * Reads a single byte from the input stream.
     */
    protected int read() {
            int curByte = 0;
            try {
                    curByte = in.read();
            } catch (Exception e) {
                    status = STATUS_FORMAT_ERROR;
            }
            return curByte;
    }

    /**
     * Reads next variable length block from input.
     * 
     * @return number of bytes stored in "buffer"
     */
    protected int readBlock() {
            blockSize = read();
            int n = 0;
            if (blockSize > 0) {
                    try {
                            int count = 0;
                            while (n < blockSize) {
                                    count = in.read(block, n, blockSize - n);
                                    if (count == -1) {
                                            break;
                                    }
                                    n += count;
                            }
                    } catch (Exception e) {
                            e.printStackTrace();
                    }
                    if (n < blockSize) {
                            status = STATUS_FORMAT_ERROR;
                    }
            }
            return n;
    }

    /**
     * Reads color table as 256 RGB integer values
     * 
     * @param ncolors
     *          int number of colors to read
     * @return int array containing 256 colors (packed ARGB with full alpha)
     */
    protected int[] readColorTable(int ncolors) {
            int nbytes = 3 * ncolors;
            int[] tab = null;
            byte[] c = new byte[nbytes];
            int n = 0;
            try {
                    n = in.read(c);
            } catch (Exception e) {
                    e.printStackTrace();
            }
            if (n < nbytes) {
                    status = STATUS_FORMAT_ERROR;
            } else {
                    tab = new int[256]; // max size to avoid bounds checks
                    int i = 0;
                    int j = 0;
                    while (i < ncolors) {
                            int r = ((int) c[j++]) & 0xff;
                            int g = ((int) c[j++]) & 0xff;
                            int b = ((int) c[j++]) & 0xff;
                            tab[i++] = 0xff000000 | (r << 16) | (g << 8) | b;
                    }
            }
            return tab;
    }

    /**
     * Main file parser. Reads GIF content blocks.
     */
    protected void readContents() {
            // read GIF file content blocks
            boolean done = false;
            while (!(done || err())) {
                    int code = read();
                    switch (code) {
                    case 0x2C: // image separator
                            readBitmap();
                            break;
                    case 0x21: // extension
                            code = read();
                            switch (code) {
                            case 0xf9: // graphics control extension
                                    readGraphicControlExt();
                                    break;
                            case 0xff: // application extension
                                    readBlock();
                                    String app = "";
                                    for (int i = 0; i < 11; i++) {
                                            app += (char) block[i];
                                    }
                                    if (app.equals("NETSCAPE2.0")) {
                                            readNetscapeExt();
                                    } else {
                                            skip(); // don't care
                                    }
                                    break;
                            case 0xfe:// comment extension
                                    skip();
                                    break;
                            case 0x01:// plain text extension
                                    skip();
                                    break;
                            default: // uninteresting extension
                                    skip();
                            }
                            break;
                    case 0x3b: // terminator
                            done = true;
                            break;
                    case 0x00: // bad byte, but keep going and see what happens break;
                    default:
                            status = STATUS_FORMAT_ERROR;
                    }
            }
    }

    /**
     * Reads Graphics Control Extension values
     */
    protected void readGraphicControlExt() {
            read(); // block size
            int packed = read(); // packed fields
            dispose = (packed & 0x1c) >> 2; // disposal method
            if (dispose == 0) {
                    dispose = 1; // elect to keep old image if discretionary
            }
            transparency = (packed & 1) != 0;
            delay = readShort() * 10; // delay in milliseconds
            transIndex = read(); // transparent color index
            read(); // block terminator
    }

    /**
     * Reads GIF file header information.
     */
    protected void readHeader() {
            String id = "";
            for (int i = 0; i < 6; i++) {
                    id += (char) read();
            }
            if (!id.startsWith("GIF")) {
                    status = STATUS_FORMAT_ERROR;
                    return;
            }
            readLSD();
            if (gctFlag && !err()) {
                    gct = readColorTable(gctSize);
                    bgColor = gct[bgIndex];
            }
    }

    /**
     * Reads next frame image
     */
    protected void readBitmap() {
            ix = readShort(); // (sub)image position & size
            iy = readShort();
            iw = readShort();
            ih = readShort();
            int packed = read();
            lctFlag = (packed & 0x80) != 0; // 1 - local color table flag interlace
            lctSize = (int) Math.pow(2, (packed & 0x07) + 1);
            // 3 - sort flag
            // 4-5 - reserved lctSize = 2 << (packed & 7); // 6-8 - local color
            // table size
            interlace = (packed & 0x40) != 0;
            if (lctFlag) {
                    lct = readColorTable(lctSize); // read table
                    act = lct; // make local table active
            } else {
                    act = gct; // make global table active
                    if (bgIndex == transIndex) {
                            bgColor = 0;
                    }
            }
            int save = 0;
            if (transparency) {
                    save = act[transIndex];
                    act[transIndex] = 0; // set transparent color if specified
            }
            if (act == null) {
                    status = STATUS_FORMAT_ERROR; // no color table defined
            }
            if (err()) {
                    return;
            }
            decodeBitmapData(); // decode pixel data
            skip();
            if (err()) {
                    return;
            }
            frameCount++;
            // create new image to receive frame data
            image = Bitmap.createBitmap(width, height, Config.ARGB_4444);
            setPixels(); // transfer pixel data to image
            frames.addElement(new GifFrame(image, delay)); // add image to frame
            // list
            if (transparency) {
                    act[transIndex] = save;
            }
            resetFrame();
    }

    /**
     * Reads Logical Screen Descriptor
     */
    protected void readLSD() {
            // logical screen size
            width = readShort();
            height = readShort();
            // packed fields
            int packed = read();
            gctFlag = (packed & 0x80) != 0; // 1 : global color table flag
            // 2-4 : color resolution
            // 5 : gct sort flag
            gctSize = 2 << (packed & 7); // 6-8 : gct size
            bgIndex = read(); // background color index
            pixelAspect = read(); // pixel aspect ratio
    }

    /**
     * Reads Netscape extenstion to obtain iteration count
     */
    protected void readNetscapeExt() {
            do {
                    readBlock();
                    if (block[0] == 1) {
                            // loop count sub-block
                            int b1 = ((int) block[1]) & 0xff;
                            int b2 = ((int) block[2]) & 0xff;
                            loopCount = (b2 << 8) | b1;
                    }
            } while ((blockSize > 0) && !err());
    }

    /**
     * Reads next 16-bit value, LSB first
     */
    protected int readShort() {
            // read 16-bit value, LSB first
            return read() | (read() << 8);
    }

    /**
     * Resets frame state for reading next image.
     */
    protected void resetFrame() {
            lastDispose = dispose;
            lrx = ix;
            lry = iy;
            lrw = iw;
            lrh = ih;
            lastBitmap = image;
            lastBgColor = bgColor;
            dispose = 0;
            transparency = false;
            delay = 0;
            lct = null;
    }

    /**
     * Skips variable length blocks up to and including next zero length block.
     */
    protected void skip() {
            do {
                    readBlock();
            } while ((blockSize > 0) && !err());
    }
}

2.AnimatedGifDrawable 动画Drawable

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.drawable.AnimationDrawable;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;

import java.io.InputStream;


/**
 * 
 * @author tracyZhang  https://github.com/TracyZhangLei
 * @since  2014-4-4
 *
 */

public class AnimatedGifDrawable extends AnimationDrawable {

    private final Context context;
    private int mCurrentIndex = 0;
    private UpdateListener mListener;

    public AnimatedGifDrawable(Context context,InputStream source, UpdateListener listener) {
        mListener = listener;
        this.context = context;
        GifDecoder decoder = new GifDecoder();
        decoder.read(source);

        // Iterate through the gif frames, add each as animation frame
        for (int i = 0; i < decoder.getFrameCount(); i++) {
            Bitmap bitmap = decoder.getFrame(i);
            Matrix matrix = new Matrix();
            int width = bitmap.getWidth();
            int height = bitmap.getHeight();
            // 缩放图片的尺寸
            int i1 = dip2px(context, 28);
            float scaleWidth = (float) i1/width;
            float scaleHeight = (float) i1/height;
            matrix.postScale(scaleWidth, scaleHeight);
            Bitmap resizedBitmap = Bitmap.createBitmap(bitmap, 0, 0,
                    width, height, matrix, true);
            BitmapDrawable drawable = new BitmapDrawable(context.getResources(),resizedBitmap);
            // Explicitly set the bounds in order for the frames to display
            drawable.setBounds(0, 0, resizedBitmap.getWidth(), resizedBitmap.getHeight());
            addFrame(drawable, decoder.getDelay(i));
            if (i == 0) {
                // Also set the bounds for this container drawable
                setBounds(0, 0, resizedBitmap.getWidth(), resizedBitmap.getHeight());
            }
        }
    }

    /**
     * Naive method to proceed to next frame. Also notifies listener.
     */
    public void nextFrame() {
        mCurrentIndex = (mCurrentIndex + 1) % getNumberOfFrames();
        if (mListener != null) mListener.update();
    }

    /**
     * Return display duration for current frame
     */
    public int getFrameDuration() {
        return getDuration(mCurrentIndex);
    }

    /**
     * Return drawable for current frame
     */
    public Drawable getDrawable() {
        return getFrame(mCurrentIndex);
    }

    /**
     * Interface to notify listener to update/redraw 
     * Can't figure out how to invalidate the drawable (or span in which it sits) itself to force redraw
     */
    public interface UpdateListener {
        void update();
    }

    /**
     * dip转换px
     *
     * @param context
     * @param dpValue
     * @return float
     */
    public static int dip2px(Context context, float dpValue) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return (int) (dpValue * scale + 0.5f);
    }
}

3.AnimatedImageSpan 将字符串中指定文字转换成图片

import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.os.Handler;
import android.text.style.DynamicDrawableSpan;


/**
 * 
 * @author tracyZhang  https://github.com/TracyZhangLei
 * @since  2014-4-4
 *
 */
public class AnimatedImageSpan extends DynamicDrawableSpan {

    private Drawable mDrawable;

    public AnimatedImageSpan(Drawable d) {
        super();
        mDrawable = d;
        // Use handler for 'ticks' to proceed to next frame 
        final Handler mHandler = new Handler();
        mHandler.post(new Runnable() {
            public void run() {
                ((AnimatedGifDrawable)mDrawable).nextFrame();
                // Set next with a delay depending on the duration for this frame 
                mHandler.postDelayed(this, ((AnimatedGifDrawable)mDrawable).getFrameDuration());
            }
        });
    }

    /*
     * Return current frame from animated drawable. Also acts as replacement for super.getCachedDrawable(),
     * since we can't cache the 'image' of an animated image.
     */
    @Override
    public Drawable getDrawable() {
        return ((AnimatedGifDrawable)mDrawable).getDrawable();
    }

    /*
     * Copy-paste of super.getSize(...) but use getDrawable() to get the image/frame to calculate the size,
     * in stead of the cached drawable.
     */
    @Override
    public int getSize(Paint paint, CharSequence text, int start, int end, Paint.FontMetricsInt fm) {
        Drawable d = getDrawable();
        Rect rect = d.getBounds();

        if (fm != null) {
            fm.ascent = -rect.bottom; 
            fm.descent = 0; 

            fm.top = fm.ascent;
            fm.bottom = 0;
        }

        return rect.right;
    }

    /*
     * Copy-paste of super.draw(...) but use getDrawable() to get the image/frame to draw, in stead of
     * the cached drawable.
     */
    @Override
    public void draw(Canvas canvas, CharSequence text, int start, int end, float x, int top, int y, int bottom, Paint paint) {
        Drawable b = getDrawable();
        canvas.save();

        int transY = bottom - b.getBounds().bottom;
        if (mVerticalAlignment == ALIGN_BASELINE) {
            transY -= paint.getFontMetricsInt().descent;
        }

        canvas.translate(x, transY);
        b.draw(canvas);
        canvas.restore();

    }

}

4.使用方法

 TextView gifTextview = (TextView) findViewById(R.id.gifTextview);
 SpannableStringBuilder stringBuilder = new SpannableStringBuilder();
    AssetManager am = getAssets();
    try {
        InputStream is = am.open("emo/anim_flag_hungary.gif");
        if (is == null) return;
        stringBuilder.append("anim_flag_hungary");
        stringBuilder.append("jkfsdjfksk哈哈");

        WeakReference<AnimatedImageSpan> localImageSpanRef = new WeakReference<>
                (new AnimatedImageSpan(new AnimatedGifDrawable
                        (this, is, new AnimatedGifDrawable.UpdateListener()
                        {
                            @Override
                            public void update() {//update the textview
                                gifTextview.postInvalidate();
                            }
                        })));
        stringBuilder.setSpan(localImageSpanRef.get(), 0, stringBuilder.length()-"anim_flag_hungary".length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
        gifTextview.setGravity(Gravity.CENTER_VERTICAL);
        gifTextview.setText(stringBuilder);
        is.close();
    } catch (IOException e) {
        e.printStackTrace();
    }

如果有不懂的，欢迎随时提问，你的支持是我前进的动力哦！