gif图动画在android中还是比较常用的,比如像新浪微博中,有很多gif图片,而且展示非常好,所以我也想弄一个。经过我多方的搜索资料和整理,终于弄出来了,其实github上有很多开源的gif的展示代码,我下载过几个,但是都不是很理想,不是我完全想要的。所以有时候就得自己学会总结,把开源的东西整理成自己的,现在无聊,也正好有朋友需要,所以现在整理了一下,留着以后备用!
废话不多说,直接上图:
在这里主要用的是:android中的android.graphics.Movie 这个类,这是android提供给我们的一个非常方便的工具。
首先,重写控件View,自定义一个展示gif图的GifView,代码如下:
- package net.loonggg.gif.view;
- import net.loonggg.gif.R;
- import android.annotation.SuppressLint;
- import android.content.Context;
- import android.content.res.TypedArray;
- import android.graphics.Canvas;
- import android.graphics.Movie;
- import android.os.Build;
- import android.util.AttributeSet;
- import android.view.View;
- public class GifView extends View {
- /**
- * 默认为1秒
- */
- private static final int DEFAULT_MOVIE_DURATION = 1000;
- private int mMovieResourceId;
- private Movie mMovie;
- private long mMovieStart;
- private int mCurrentAnimationTime = 0;
- private float mLeft;
- private float mTop;
- private float mScale;
- private int mMeasuredMovieWidth;
- private int mMeasuredMovieHeight;
- private boolean mVisible = true;
- private volatile boolean mPaused = false;
- 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) {
- if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
- setLayerType(View.LAYER_TYPE_SOFTWARE, null);
- }
- // 从描述文件中读出gif的值,创建出Movie实例
- final TypedArray array = context.obtainStyledAttributes(attrs,
- R.styleable.GifView, defStyle, R.style.Widget_GifView);
- mMovieResourceId = array.getResourceId(R.styleable.GifView_gif, -1);
- mPaused = array.getBoolean(R.styleable.GifView_paused, false);
- array.recycle();
- if (mMovieResourceId != -1) {
- mMovie = Movie.decodeStream(getResources().openRawResource(
- mMovieResourceId));
- }
- }
- /**
- * 设置gif图资源
- *
- * @param movieResId
- */
- public void setMovieResource(int movieResId) {
- this.mMovieResourceId = movieResId;
- mMovie = Movie.decodeStream(getResources().openRawResource(
- mMovieResourceId));
- requestLayout();
- }
- public void setMovie(Movie movie) {
- this.mMovie = movie;
- requestLayout();
- }
- public Movie getMovie() {
- return mMovie;
- }
- public void setMovieTime(int time) {
- mCurrentAnimationTime = time;
- invalidate();
- }
- /**
- * 设置暂停
- *
- * @param paused
- */
- public void setPaused(boolean paused) {
- this.mPaused = paused;
- if (!paused) {
- mMovieStart = android.os.SystemClock.uptimeMillis()
- - mCurrentAnimationTime;
- }
- invalidate();
- }
- /**
- * 判断gif图是否停止了
- *
- * @return
- */
- public boolean isPaused() {
- return this.mPaused;
- }
- @Override
- protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
- if (mMovie != null) {
- int movieWidth = mMovie.width();
- int movieHeight = mMovie.height();
- int maximumWidth = MeasureSpec.getSize(widthMeasureSpec);
- float scaleW = (float) movieWidth / (float) maximumWidth;
- mScale = 1f / scaleW;
- mMeasuredMovieWidth = maximumWidth;
- mMeasuredMovieHeight = (int) (movieHeight * mScale);
- setMeasuredDimension(mMeasuredMovieWidth, mMeasuredMovieHeight);
- } else {
- setMeasuredDimension(getSuggestedMinimumWidth(),
- getSuggestedMinimumHeight());
- }
- }
- @Override
- protected void onLayout(boolean changed, int l, int t, int r, int b) {
- super.onLayout(changed, l, t, r, b);
- 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);
- }
- }
- }
- @SuppressLint("NewApi")
- private void invalidateView() {
- if (mVisible) {
- if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
- postInvalidateOnAnimation();
- } else {
- invalidate();
- }
- }
- }
- private void updateAnimationTime() {
- long now = android.os.SystemClock.uptimeMillis();
- // 如果第一帧,记录起始时间
- if (mMovieStart == 0) {
- mMovieStart = now;
- }
- // 取出动画的时长
- int dur = mMovie.duration();
- if (dur == 0) {
- dur = DEFAULT_MOVIE_DURATION;
- }
- // 算出需要显示第几帧
- mCurrentAnimationTime = (int) ((now - mMovieStart) % dur);
- }
- private void drawMovieFrame(Canvas canvas) {
- // 设置要显示的帧,绘制即可
- mMovie.setTime(mCurrentAnimationTime);
- canvas.save(Canvas.MATRIX_SAVE_FLAG);
- 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();
- }
- @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();
- }
- }
Movie其实管理着GIF动画中的多个帧,只需要通过 setTime() 一下就可以让它在draw()的时候绘出相应的那帧图像。通过当前时间与duration之间的换算关系,是很容易实现GIF动起来的效果。
其次,在xml布局文件中,把这个view定义进去,代码如下:
- <?xml version="1.0" encoding="utf-8"?>
- <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
- android:layout_width="fill_parent"
- android:layout_height="fill_parent"
- android:orientation="vertical" >
- <net.loonggg.gif.view.GifView
- android:id="@+id/gif1"
- android:layout_width="100dp"
- android:layout_height="100dp"
- android:layout_gravity="center_horizontal"
- android:enabled="false" />
- <net.loonggg.gif.view.GifView
- android:id="@+id/gif2"
- android:layout_width="200dp"
- android:layout_height="200dp"
- android:layout_gravity="center_horizontal"
- android:enabled="false" />
- </LinearLayout>
最后,在MainActivity中的使用,代码如下:
- package net.loonggg.gif;
- import net.loonggg.gif.view.GifView;
- import android.app.Activity;
- import android.os.Bundle;
- public class Gif extends Activity {
- private GifView gif1, gif2;
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.main);
- gif1 = (GifView) findViewById(R.id.gif1);
- // 设置背景gif图片资源
- gif1.setMovieResource(R.raw.kitty);
- gif2 = (GifView) findViewById(R.id.gif2);
- gif2.setMovieResource(R.raw.b);
- // 设置暂停
- // gif2.setPaused(true);
- }
- }
注意:与ImageView和其他View唯一的区别在于我加了一个gif属性。
- <?xml version="1.0" encoding="utf-8"?>
- <resources>
- <declare-styleable name="GifView">
- <attr name="gif" format="reference" />
- <attr name="paused" format="boolean" />
- </declare-styleable>
- <declare-styleable name="CustomTheme">
- <attr name="gifViewStyle" format="reference" />
- </declare-styleable>
- </resources>
这个代码已经非常好了,使用也非常方便,其实不懂代码是什么意思也可以很好的用,只需要懂得我写注释的那几行和Activity里面的那几行代码就可以了!
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