Android gif 图片显示

1、自定义一个GIFView，通过Movie 显示动态的gif 图

public class GifView extends View {

    private static final int DEFAULT_MOVIE_VIEW_DURATION = 1000;

    private int mMovieResourceId;
    private Movie movie;

    private long mMovieStart;
    private int mCurrentAnimationTime;


    /**
     * Position for drawing animation frames in the center of the view.
     */
    private float mLeft;
    private float mTop;

    /**
     * Scaling factor to fit the animation within view bounds.
     */
    private float mScale;

    /**
     * Scaled movie frames width and height.
     */
    private int mMeasuredMovieWidth;
    private int mMeasuredMovieHeight;

    private volatile boolean mPaused;
    private boolean mVisible = true;

    private IGifLoadFinishListener mIGifLoadFinishListener;

    public interface IGifLoadFinishListener{
        public void isLoadFinish();
    }

    public GifView(Context context) {
        this(context, null);
    }

    public GifView(Context context, AttributeSet attrs) {
        this(context, attrs, R.styleable.CustomTheme_gifViewStyle);
    }

    public GifView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        setViewAttributes(context, attrs, defStyle);
    }

    @SuppressLint("NewApi")
    private void setViewAttributes(Context context, AttributeSet attrs, int defStyle) {

        /**
         * Starting from HONEYCOMB(Api Level:11) have to turn off HW acceleration to draw
         * Movie on Canvas.
         */
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
            setLayerType(View.LAYER_TYPE_SOFTWARE, null);
        }

        final TypedArray array = context.obtainStyledAttributes(attrs,
                R.styleable.GifView, defStyle, R.style.Widget_GifView);

        //-1 is default value
        mMovieResourceId = array.getResourceId(R.styleable.GifView_gif, -1);
        mPaused = array.getBoolean(R.styleable.GifView_paused, false);

        array.recycle();

        if (mMovieResourceId != -1) {
            movie = Movie.decodeStream(getResources().openRawResource(mMovieResourceId));
        }
    }

    public void setGifResource(int movieResourceId) {
        this.mMovieResourceId = movieResourceId;
        movie = Movie.decodeStream(getResources().openRawResource(mMovieResourceId));
        mMovieStart = android.os.SystemClock.uptimeMillis();
        requestLayout();
    }

    public void setGifResource(String path) {
        movie =   Movie.decodeFile(path);
        mMovieStart = android.os.SystemClock.uptimeMillis();
        requestLayout();
    }

    public int getGifResource() {

        return this.mMovieResourceId;
    }


    public void play() {
        if (this.mPaused) {
            this.mPaused = false;

            /**
             * Calculate new movie start time, so that it resumes from the same
             * frame.
             */
            mMovieStart = android.os.SystemClock.uptimeMillis() - mCurrentAnimationTime;

            invalidate();
        }
    }

    public void pause() {
        if (!this.mPaused) {
            this.mPaused = true;

            invalidate();
        }

    }


    public boolean isPaused() {
        return this.mPaused;
    }

    public boolean isPlaying() {
        return !this.mPaused;
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

        if (movie != null) {
            int movieWidth = movie.width();
            int movieHeight = movie.height();

            /*
             * Calculate horizontal scaling
             */
            float scaleH = 1f;
            int measureModeWidth = MeasureSpec.getMode(widthMeasureSpec);

            if (measureModeWidth != MeasureSpec.UNSPECIFIED) {
                int maximumWidth = MeasureSpec.getSize(widthMeasureSpec);
                if (movieWidth > maximumWidth) {
                    scaleH = (float) movieWidth / (float) maximumWidth;
                }
            }

            /*
             * calculate vertical scaling
             */
            float scaleW = 1f;
            int measureModeHeight = MeasureSpec.getMode(heightMeasureSpec);

            if (measureModeHeight != MeasureSpec.UNSPECIFIED) {
                int maximumHeight = MeasureSpec.getSize(heightMeasureSpec);
                if (movieHeight > maximumHeight) {
                    scaleW = (float) movieHeight / (float) maximumHeight;
                }
            }

            /*
             * calculate overall scale
             */
            mScale = 1f / Math.max(scaleH, scaleW);

            mMeasuredMovieWidth = (int) (movieWidth * mScale);
            mMeasuredMovieHeight = (int) (movieHeight * mScale);

            setMeasuredDimension(mMeasuredMovieWidth, mMeasuredMovieHeight);

        } else {
            /*
             * No movie set, just set minimum available size.
             */
            setMeasuredDimension(getSuggestedMinimumWidth(), getSuggestedMinimumHeight());
        }
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        super.onLayout(changed, l, t, r, b);
        /*
         * Calculate mLeft / mTop for drawing in center
         */
        mLeft = (getWidth() - mMeasuredMovieWidth) / 2f;
        mTop = (getHeight() - mMeasuredMovieHeight) / 2f;

        mVisible = getVisibility() == View.VISIBLE;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        if (movie != null) {
            if (!mPaused) {
                updateAnimationTime();
                //如果只需要要播放一次则加上if  这个条件，如果需要循环播放则，注释 if  条件即可
                if (isFinish()) {
                    mCurrentAnimationTime  = movie.duration();
                    drawMovieFrame(canvas);
                    if (mIGifLoadFinishListener != null){
                        mIGifLoadFinishListener.isLoadFinish();
                    }
                    return;
                }
                drawMovieFrame(canvas);
                invalidateView();
            } else {
                drawMovieFrame(canvas);
            }
        }
    }

    /**
     * Invalidates view only if it is mVisible.
     * 

     * {@link #postInvalidateOnAnimation()} is used for Jelly Bean and higher.
     */
    @SuppressLint("NewApi")
    private void invalidateView() {
        if (mVisible) {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
                postInvalidateOnAnimation();
            } else {
                invalidate();
            }
        }
    }

    /**
     * Calculate current animation time
     */
    private void updateAnimationTime() {
        long now = android.os.SystemClock.uptimeMillis();

        if (mMovieStart == 0) {
            mMovieStart = now;
        }

        int dur = movie.duration();

        if (dur == 0) {
            dur = DEFAULT_MOVIE_VIEW_DURATION;
        }

        mCurrentAnimationTime = (int) ((now - mMovieStart) % dur);
    }

    /**
     * Draw current GIF frame
     */
    private void drawMovieFrame(Canvas canvas) {
        movie.setTime(mCurrentAnimationTime);
        canvas.save(Canvas.MATRIX_SAVE_FLAG);
        canvas.scale(mScale, mScale);
        movie.draw(canvas, mLeft / mScale, mTop / mScale);
        canvas.restore();
    }

    @SuppressLint("NewApi")
    @Override
    public void onScreenStateChanged(int screenState) {
        super.onScreenStateChanged(screenState);
        mVisible = screenState == SCREEN_STATE_ON;
        invalidateView();
    }

    @SuppressLint("NewApi")
    @Override
    protected void onVisibilityChanged(View changedView, int visibility) {
        super.onVisibilityChanged(changedView, visibility);
        mVisible = visibility == View.VISIBLE;
        invalidateView();
    }

    @Override
    protected void onWindowVisibilityChanged(int visibility) {
        super.onWindowVisibilityChanged(visibility);
        mVisible = visibility == View.VISIBLE;
        invalidateView();
    }

   /**
   * 设置gif 加载完成事件监听
   */
    public void setmIGifLoadFinishListener(IGifLoadFinishListener mIGifLoadFinishListener) {
        this.mIGifLoadFinishListener = mIGifLoadFinishListener;
    }

    /**
     * 判断是否播放到最后
     */
    private boolean isFinish(){
        long now = android.os.SystemClock.uptimeMillis();
        return now- mMovieStart >=movie.duration();
    }
}