android中自定义view显示gif格式图片

gif解码类,负责把gif解码成一帧一帧的图片数据

public class GifDecoder
{
private int E0;
private int E1[];
private int E2;
private int E6;
private boolean E7;
private int E8[];
private int width;
private int height;
private int ED;
private boolean EE;
private boolean EF;
private int F0[];
private int F1;
private boolean F2;
private int F3;
private long F4;
private int F5;
private static final int F6[] = { 8, 8, 4, 2 };
private static final int F8[] = { 0, 4, 2, 1 };

int curFrame;
int poolsize;
int FA;
byte C2[];
int FB;
int FC;
int FD;

public GifDecoder(byte abyte0[])
{
E0 = -1;
E1 = new int[280];
E2 = -1;
E6 = 0;
E7 = false;
E8 = null;
width = 0;
height = 0;
ED = 0;
EE = false;
EF = false;
F0 = null;
F1 = 0;
F5 = 0;
curFrame = 0;
C2 = abyte0;
poolsize = C2.length;
FA = 0;
}

public boolean moreFrames()
{
return poolsize - FA >= 16;
}

public void nextFrame()
{
curFrame++;
}

public Bitmap decodeImage()
{
return decodeImage(curFrame);
}

public Bitmap decodeImage(int i)
{
if (i <= E0)
{
return null;
}
if (E0 < 0)
{
if (!E3())
{
return null;
}
if (!E4())
{
return null;
}
}
do
{
if (!E9(1))
{
return null;
}
int j = E1[0];
if (j == 59)
{
return null;
}
if (j == 33)
{
if (!E7())
{
return null;
}
}
else if (j == 44)
{
if (!E5())
{
return null;
}
Bitmap image = createImage();
E0++;
if (E0 < i)
{
image = null;
}
else
{
return image;
}
}
}
while (true);
}

public void clear()
{
C2 = null;
E1 = null;
E8 = null;
F0 = null;
}

private Bitmap createImage()
{
int i = width;
int j = height;
int j1 = 0;
int k1 = 0;
int ai[] = new int[4096];
int ai1[] = new int[4096];
int ai2[] = new int[8192];
if (!E9(1))
{
return null;
}
int k = E1[0];
int[] image = new int[width * height];
int ai3[] = E8;
if (EE)
{
ai3 = F0;
}
if (E2 >= 0)
{
ai3[E2] = 0xffffff;
}
int l2 = 1 << k;
int j3 = l2 + 1;
int k2 = k + 1;
int l3 = l2 + 2;
int k3 = -1;
int j4 = -1;
for (int l1 = 0; l1 < l2; l1++)
{
ai1[l1] = l1;
}

int j2 = 0;
E2();
j1 = 0;
label0: for (int i2 = 0; i2 < j; i2++)
{
int i1 = 0;
do
{
if (i1 >= i)
{
break;
}
if (j2 == 0)
{
int i4 = E1(k2);
if (i4 < 0)
{
return Bitmap.createBitmap(image, width, height, Config.RGB_565);
}
if (i4 > l3 || i4 == j3)
{
return Bitmap.createBitmap(image, width, height, Config.RGB_565);
}
if (i4 == l2)
{
k2 = k + 1;
l3 = l2 + 2;
k3 = -1;
continue;
}
if (k3 == -1)
{
ai2[j2++] = ai1[i4];
k3 = i4;
j4 = i4;
continue;
}
int i3 = i4;
if (i4 == l3)
{
ai2[j2++] = j4;
i4 = k3;
}
for (; i4 > l2; i4 = ai[i4])
{
ai2[j2++] = ai1[i4];
}

j4 = ai1[i4];
if (l3 >= 4096)
{
return Bitmap.createBitmap(image, width, height, Config.RGB_565);
}
ai2[j2++] = j4;
ai[l3] = k3;
ai1[l3] = j4;
if (++l3 >= 1 << k2 && l3 < 4096)
{
k2++;
}
k3 = i3;
}
int l = ai2[--j2];
if (l < 0)
{
return Bitmap.createBitmap(image, width, height, Config.RGB_565);
}
if (i1 == 0)
{
FC = 0;
FB = ai3[l];
FD = 0;
}
else if (FB != ai3[l])
{

for (int mm = FD; mm <= FD + FC; mm++)
{
image[j1 * width + mm] = FB;
}
FC = 0;
FB = ai3[l];
FD = i1;
if (i1 == i - 1)
{
image[j1 * width + i1] = ai3[l];
}
}
else
{
FC++;
if (i1 == i - 1)
{
for (int mm = FD; mm <= FD + FC; mm++)
{
image[j1 * width + mm] = FB;
}
}
}
i1++;
}
while (true);
if (EF)
{
j1 += F6[k1];
do
{
if (j1 < j)
{
continue label0;
}
if (++k1 > 3)
{
return Bitmap.createBitmap(image, width, height, Config.RGB_565);
}
j1 = F8[k1];
}
while (true);
}
j1++;
}

return Bitmap.createBitmap(image, width, height, Config.RGB_565);
}

private int E1(int i)
{
while (F5 < i)
{
if (F2)
{
return -1;
}
if (F1 == 0)
{
F1 = E8();
F3 = 0;
if (F1 <= 0)
{
F2 = true;
break;
}
}
F4 += E1[F3] << F5;
F3++;
F5 += 8;
F1--;
}
int j = (int) F4 & (1 << i) - 1;
F4 >>= i;
F5 -= i;
return j;
}

private void E2()
{
F5 = 0;
F1 = 0;
F4 = 0L;
F2 = false;
F3 = -1;
}

private boolean E3()
{
if (!E9(6))
{
return false;
}
return E1[0] == 71 && E1[1] == 73 && E1[2] == 70 && E1[3] == 56 && (E1[4] == 55 || E1[4] == 57) && E1[5] == 97;
}

private boolean E4()
{
if (!E9(7))
{
return false;
}
int i = E1[4];
E6 = 2 << (i & 7);
E7 = EB(i, 128);
E8 = null;
return !E7 || E6(E6, true);
}

private boolean E5()
{
if (!E9(9))
{
return false;
}
width = EA(E1[4], E1[5]);
height = EA(E1[6], E1[7]);
int i = E1[8];
EE = EB(i, 128);
ED = 2 << (i & 7);
EF = EB(i, 64);
F0 = null;
return !EE || E6(ED, false);
}

private boolean E6(int i, boolean flag)
{
int ai[] = new int[i];
for (int j = 0; j < i; j++)
{
if (!E9(3))
{
return false;
}
ai[j] = E1[0] << 16 | E1[1] << 8 | E1[2] | 0xff000000;
}

if (flag)
{
E8 = ai;
}
else
{
F0 = ai;
}
return true;
}

private boolean E7()
{
if (!E9(1))
{
return false;
}
int i = E1[0];
int j = -1;
switch (i)
{
case 249:
j = E8();
if (j < 0)
{
return true;
}
if ((E1[0] & 1) != 0)
{
E2 = E1[3];
}
else
{
E2 = -1;
}
break;
}
do
{
j = E8();
}
while (j > 0);
return true;
}

private int E8()
{
if (!E9(1))
{
return -1;
}
int i = E1[0];
if (i != 0 && !E9(i))
{
return -1;
}
else
{
return i;
}
}

private boolean E9(int i)
{
if (FA + i >= poolsize)
{
return false;
}
for (int j = 0; j < i; j++)
{
int k = C2[FA + j];
if (k < 0)
{
k += 256;
}
E1[j] = k;
}

FA += i;
return true;
}

private static final int EA(int i, int j)
{
return j << 8 | i;
}

private static final boolean EB(int i, int j)
{
return (i & j) == j;
}
}

用GifFrame类表示gif解码后的一帧

public class GifFrame
{
/* 保存gif中所有帧的向量 */
private Vector frames;

/* 当前播放的帧的索引 */
private int index;

public GifFrame()
{
frames = new Vector(1);
index = 0;
}

/* 添加一帧 */
public void addImage(Bitmap image)
{
frames.addElement(image);
}

/* 返回帧数 */
public int size()
{
return frames.size();
}

/* 得到当前帧的图片 */
public Bitmap getImage()
{
if (size() == 0)
{
return null;
}
else
{
return (Bitmap) frames.elementAt(index);
}
}

/* 下一帧 */
public void nextFrame()
{
if (index + 1 < size())
{
index++;
}
else
{
index = 0;
}
}

/* 创建GifFrame */
public static GifFrame CreateGifImage(byte abyte0[])
{
try
{
GifFrame GF = new GifFrame();
Bitmap image = null;
GifDecoder gifdecoder = new GifDecoder(abyte0);
for (; gifdecoder.moreFrames(); gifdecoder.nextFrame())
{
try
{
image = gifdecoder.decodeImage();
if (GF != null && image != null)
{
GF.addImage(image);
}
continue;
}
catch (Exception e)
{
e.printStackTrace();
}
break;
}
gifdecoder.clear();
gifdecoder = null;
return GF;
}
catch (Exception e)
{
e.printStackTrace();
return null;
}
}
}

最后是自定义的显示gif图片的view类

public class GameView extends View implements Runnable
{
Context mContext = null;

/* 声明GifFrame对象 */
GifFrame mGifFrame = null;

public GameView(Context context)
{
super(context);

mContext = context;
/* 解析GIF动画 */
mGifFrame=GifFrame.CreateGifImage(fileConnect(this.getResources().openRawResource(R.drawable.gif1)));
/* 开启线程 */
new Thread(this).start();
}

public void onDraw(Canvas canvas)
{
super.onDraw(canvas);
/* 下一帧 */
mGifFrame.nextFrame();
/* 得到当前帧的图片 */
Bitmap b=mGifFrame.getImage();

/* 绘制当前帧的图片 */
if(b!=null)
canvas.drawBitmap(b,10,10,null);
}

/**
* 线程处理
*/
public void run()
{
while (!Thread.currentThread().isInterrupted())
{
try
{
Thread.sleep(100);
}
catch (InterruptedException e)
{
Thread.currentThread().interrupt();
}
//使用postInvalidate可以直接在线程中更新界面
postInvalidate();
}
}

/* 读取文件 */
public byte[] fileConnect(InputStream is)
{
try
{
ByteArrayOutputStream baos = new ByteArrayOutputStream();
int ch = 0;
while( (ch = is.read()) != -1)
{
baos.write(ch);
}
byte[] datas = baos.toByteArray();
baos.close();
baos = null;
is.close();
is = null;
return datas;
}
catch(Exception e)
{
return null;
}
}
}