在Android中全屏显示GIF图片（演示代码）

package cc.duduhuo.gifviewdemo.view; import android.annotation.SuppressLint; import android.content.Context; import android.graphics.Canvas; import android.graphics.Movie; import android.os.Build; import android.os.SystemClock; import android.support.annotation.NonNull; import android.util.AttributeSet; import android.view.View; /** * ======================================================= * 作者：liying - liruoer2008@yeah.net * 日期：2017/8/19 20:09 * 版本：1.0 * 描述：自定义显示Gif图片的View * 备注： * ======================================================= */ public class GifView extends View { private static final int DEFAULT_MOVIE_VIEW_DURATION = 1000; private int mMovieResourceId; private Movie mMovie; 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; public GifView(Context context) { this(context, null); } public GifView(Context context, AttributeSet attrs) { this(context, attrs, 0); } public GifView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); init(); } private void init() { /* * 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); } } public void setGifResource(int movieResourceId) { this.mMovieResourceId = movieResourceId; mMovie = Movie.decodeStream(getResources().openRawResource(mMovieResourceId)); 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 = 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 (mMovie != null) { int movieWidth = mMovie.width(); int movieHeight = mMovie.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 (mMovie != null) { if (!mPaused) { updateAnimationTime(); drawMovieFrame(canvas); invalidateView(); } else { drawMovieFrame(canvas); } } } /** * Invalidates view only if it is mVisible. * <br> * {@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 = mMovie.duration(); if (dur == 0) { dur = DEFAULT_MOVIE_VIEW_DURATION; } mCurrentAnimationTime = (int) ((now - mMovieStart) % dur); } /** * Draw current GIF frame */ private void drawMovieFrame(Canvas canvas) { mMovie.setTime(mCurrentAnimationTime); canvas.save(); canvas.scale(mScale, mScale); mMovie.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(); } /** * get gif width * * @return width */ public int getGifWidth() { return mMovie.width(); } /** * get gif height * * @return height */ public int getGifHeight() { return mMovie.height(); } @SuppressLint("NewApi") @Override protected void onVisibilityChanged(@NonNull 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(); } }