Android GIF图片的显示

package com.terry.gif;

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

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

//Handler for read & extract Bitmap from *.gif
public class gifOpenHelper {

// to store *.gif data, Bitmap & delay
    class GifFrame {
// to access image & delay w/o interface
public Bitmap image;
public int delay;

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

    }

// to define some error type
public static final int STATUS_OK = 0;
public static final int STATUS_FORMAT_ERROR = 1;
public static final int STATUS_OPEN_ERROR = 2;

protected int status;

protected InputStream in;

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 lastImage; // previous frame
protected int frameindex = 0;

public int getFrameindex() {
return frameindex;
    }

public void setFrameindex(int frameindex) {
this.frameindex = frameindex;
if (frameindex > frames.size() - 1) {
            frameindex = 0;
        }
    }

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

protected static final int MaxStackSize = 4096;
// max decoder pixel stack size

// 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;

// to get its Width / Height
public int getWidth() {
return width;
    }

public int getHeigh() {
return height;
    }

/**
 * 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 = ((GifFrame) frames.elementAt(n)).delay;
        }
return delay;
    }

public int getFrameCount() {
return frameCount;
    }

public Bitmap getImage() {
return getFrame(0);
    }

public int getLoopCount() {
return loopCount;
    }

protected void setPixels() {
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) {
                    lastImage = getFrame(n - 1);
                } else {
                    lastImage = null;
                }
            }
if (lastImage != null) {
                lastImage.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;
                    }
                }
                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.RGB_565);
    }

public Bitmap getFrame(int n) {
        Bitmap im = null;
if ((n >= 0) && (n < frameCount)) {
            im = ((GifFrame) frames.elementAt(n)).image;
        }
return im;
    }

public Bitmap nextBitmap() {
        frameindex++;
if (frameindex > frames.size() - 1) {
            frameindex = 0;
        }
return ((GifFrame) frames.elementAt(frameindex)).image;
    }

public int nextDelay() {
return ((GifFrame) frames.elementAt(frameindex)).delay;
    }

// to read & parse all *.gif stream
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) {
            e.printStackTrace();
        }
return status;
    }

protected void decodeImageData() {
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[MaxStackSize];
        }
if (suffix == null) {
            suffix = new byte[MaxStackSize];
        }
if (pixelStack == null) {
            pixelStack = new byte[MaxStackSize + 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;
            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 >= MaxStackSize) {
break;
                }
                pixelStack[top++] = (byte) first;
                prefix[available] = (short) old_code;
                suffix[available] = (byte) first;
                available++;
if (((available & code_mask) == 0)
                        && (available < MaxStackSize)) {
                    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
        }
    }

protected boolean err() {
return status != STATUS_OK;
    }

// to initia variable
public void init() {
        status = STATUS_OK;
        frameCount = 0;
        frames = new Vector<GifFrame>();
        gct = null;
        lct = null;
    }

protected int read() {
int curByte = 0;
try {
            curByte = in.read();
        } catch (Exception e) {
            status = STATUS_FORMAT_ERROR;
        }
return curByte;
    }

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;
    }

// Global Color Table
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;
    }

// Image Descriptor
protected void readContents() {
// read GIF file content blocks
boolean done = false;
while (!(done || err())) {
int code = read();
switch (code) {
case 0x2C: // image separator
                readImage();
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;
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;
            }
        }
    }

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
    }

// to get Stream - Head
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];
        }
    }

protected void readImage() {
// offset of X
        ix = readShort(); // (sub)image position & size
// offset of Y
        iy = readShort();
// width of bitmap
        iw = readShort();
// height of bitmap
        ih = readShort();

// Local Color Table Flag
int packed = read();
        lctFlag = (packed & 0x80) != 0; // 1 - local color table flag

// Interlace Flag, to array with interwoven if ENABLE, with order
// otherwise
        interlace = (packed & 0x40) != 0; // 2 - interlace flag
// 3 - sort flag
// 4-5 - reserved
        lctSize = 2 << (packed & 7); // 6-8 - local color table size
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;
        }
        decodeImageData(); // decode pixel data
        skip();
if (err()) {
return;
        }
        frameCount++;
// create new image to receive frame data
        image = Bitmap.createBitmap(width, height, Config.RGB_565);
// createImage(width, height);
        setPixels(); // transfer pixel data to image
        frames.addElement(new GifFrame(image, delay)); // add image to frame
// list
if (transparency) {
            act[transIndex] = save;
        }
        resetFrame();
    }

// 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
    }

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());
    }

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

protected void resetFrame() {
        lastDispose = dispose;
        lrx = ix;
        lry = iy;
        lrw = iw;
        lrh = ih;
        lastImage = 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());
    }
}


package com.terry.gif;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;

public class TypegifView extends View implements Runnable {
    gifOpenHelper gHelper;
private boolean isStop = true;
int delta;
    String title;

    Bitmap bmp;

// construct - refer for java
public TypegifView(Context context) {
this(context, null);

    }

// construct - refer for xml
public TypegifView(Context context, AttributeSet attrs) {
super(context, attrs);
//添加属性
        TypedArray ta = context.obtainStyledAttributes(attrs,
                R.styleable.gifView);
int n = ta.getIndexCount();

for (int i = 0; i < n; i++) {
int attr = ta.getIndex(i);

switch (attr) {
case R.styleable.gifView_src:
int id = ta.getResourceId(R.styleable.gifView_src, 0);
                setSrc(id);
break;

case R.styleable.gifView_delay:
int idelta = ta.getInteger(R.styleable.gifView_delay, 1);
                setDelta(idelta);
break;

case R.styleable.gifView_stop:
boolean sp = ta.getBoolean(R.styleable.gifView_stop, false);
if (!sp) {
                    setStop();
                }
break;
            }

        }

        ta.recycle();
    }

/**
 * 设置停止
 *
 * @param stop
 */
public void setStop() {
        isStop = false;
    }

/**
 * 设置启动
 */
public void setStart() {
        isStop = true;

        Thread updateTimer = new Thread(this);
        updateTimer.start();
    }

/**
 * 通过下票设置第几张图片显示
 * @param id
 */
public void setSrc(int id) {

        gHelper = new gifOpenHelper();
        gHelper.read(TypegifView.this.getResources().openRawResource(id));
        bmp = gHelper.getImage();// 得到第一张图片
    }

public void setDelta(int is) {
        delta = is;
    }

// to meaure its Width & Height
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        setMeasuredDimension(measureWidth(widthMeasureSpec),
                measureHeight(heightMeasureSpec));
    }

private int measureWidth(int measureSpec) {
return gHelper.getWidth();
    }

private int measureHeight(int measureSpec) {
return gHelper.getHeigh();
    }

protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
        canvas.drawBitmap(bmp, 0, 0, new Paint());
        bmp = gHelper.nextBitmap();

    }

public void run() {
// TODO Auto-generated method stub
while (isStop) {
try {
this.postInvalidate();
                Thread.sleep(gHelper.nextDelay() / delta);
            } catch (Exception ex) {

            }
        }
    }

}
<main_Activity>
package com.terry.gif;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.ListView;

public class gifActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Button btn = (Button) findViewById(R.id.Button01);
        Button btn2 = (Button) findViewById(R.id.Button02);
final TypegifView view = (TypegifView) findViewById(R.id.gifView1);

        btn.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
                view.setStop();
            }
        });

        btn2.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
                view.setStart();
            }
        });
    }
}