向glide致敬，自己写Gif动图加载框架

用Glide很久了。除了对他膜拜就是膜拜，尤其是它可以实现gif的动态加载，那么我们今天就自己来实现以下如何动态的显示Gif。最后要提一句这个思路呢是从动脑学院得知的。他们是一个很牛逼的培训团体。希望广而告之

上图片

实现功能

• 1，加载本地gif
• 2，加载网络gif

用到技术

• 1，movie类
• 2，canvas类的绘制
• 3，网络下载

都是最简单的方法来实现逼格的效果

实现原理

gif就是一个无声的电影，你把电影的每一帧都会知道imageview上去就不分分钟了么

不就用到了canvas绘制一个gif大小的bigmap。然后在吧bitmap放到imageview里面去。
网络加载图片，就是查找本地是否有该gif，如果没有就先下载然后在从本地导入。

废话不多说直接上代码

package example.com.gifloader;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.widget.ImageView;import example.com.gifloader.core.GifDecoder;public class MainActivity extends AppCompatActivity {    private ImageView imageView;    public static String url = "http://image.haha.mx/2014/02/02/middle/1115779_c221d1fc47b97bb1605cddc9c8aec0a7_1391347675.gif";    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        imageView = (ImageView) findViewById(R.id.iv);        try {            GifDecoder.with(this).load(url).into(imageView);        } catch (Exception e) {            e.printStackTrace();        }    }}

和glide是不是很像就一句话 GifDecoder.with(this).load(url).into(imageView);

package example.com.gifloader.core;import android.content.Context;import android.net.Uri;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.InputStream;/** * Created by wanghao on 16/5/23. * 加载gif */public class GifDecoder {    public static Context context;    public static class Gif {        public static GifDecoder instance = new GifDecoder();    }    public static GifDecoder with(Context c) {        context = c;        return Gif.instance;    }    /**     * load gif file form inputstream     */    public GifDrawer load(InputStream is) {        GifDrawer drawer = new GifDrawer();        drawer.setIs(is);        return drawer;    }    /**     * load gif file form uri     */    public GifDrawer load(Uri uri) {        InputStream is = null;        try {            is = context.getContentResolver().openInputStream(uri);        } catch (FileNotFoundException e) {            e.printStackTrace();        }        return load(is);    }    /**     * load gif file form sdcard     */    public GifDrawer load(File file) {        FileInputStream is = null;        try {            is = new FileInputStream(file);        } catch (FileNotFoundException e) {            e.printStackTrace();        }        return load(is);    }    /**     * load gif file form url     */    public GifDrawer load(String url) {        String name = MD5Utils.string2MD5(url);        System.out.println(name);        FileInputStream is = null;        String path = context.getExternalCacheDir() + File.separator + name;        File file = new File(path);        if (file.exists()) {            try {                is = new FileInputStream(file);                return load(is);            } catch (FileNotFoundException e) {                e.printStackTrace();            }        } else {//           不存在 先下载下来            GifDrawer gifDrawer = new GifDrawer();            GifLoaderTask loadGifTask = new GifLoaderTask(gifDrawer, context);            loadGifTask.execute(url);            return gifDrawer;        }        return load(is);    }}

package example.com.gifloader.core;import android.graphics.Bitmap;import android.graphics.Canvas;import android.graphics.Movie;import android.os.Handler;import android.widget.ImageView;import java.io.InputStream;/** * Created by wanghao on 16/5/23. * gif的绘制 */public class GifDrawer {    private static final String TAG = "GifDrawer";    private InputStream is;    private ImageView imageView;    private Movie movie;    private Bitmap bitmap;    private Canvas canvas;    private Handler handler = new Handler();    private final long delayMills = 16;    private Runnable runnable = new Runnable() {        @Override        public void run() {            draw();            handler.postDelayed(runnable, delayMills);        }    };    private void draw() {        canvas.save();        movie.setTime((int) (System.currentTimeMillis() % movie.duration()));//这个是获取movie的某一帧，我们就不断地循环它        movie.draw(canvas, 0, 0);        imageView.setImageBitmap(bitmap);        canvas.restore();    }    /**     * 传递imagerview,将gif放到gif中去     *     * @param imageView     */    public void into(ImageView imageView) {        this.imageView = imageView;        if (is == null) {            return;        } else if (imageView == null) {            throw new RuntimeException("imagetView can not be null");        } else {//            开始在imageview里面绘制电影            movie = Movie.decodeStream(is);//gif小电影            if (movie == null) {                throw new IllegalArgumentException("Illegal gif file");            }            if (movie.width() <= 0 || movie.height() <= 0) {                return;            }//            需要bitmap            bitmap = Bitmap.createBitmap(movie.width(), movie.height(), Bitmap.Config.RGB_565);            canvas = new Canvas(bitmap);//            准备把canvas的小电影显示在imageview里面            handler.post(runnable);        }    }    public InputStream getIs() {        return is;    }    public void setIs(InputStream is) {        this.is = is;    }    public ImageView getImageView() {        return imageView;    }    public void setImageView(ImageView imageView) {        this.imageView = imageView;    }}

package example.com.gifloader.core;import android.content.Context;import android.os.AsyncTask;import java.io.File;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;/** * Created by wanghao on 16/5/23. */class GifLoaderTask extends AsyncTask<String, Void, String> {    private final Context context;    private String name;    private GifDrawer gifDrawer;    public GifLoaderTask(GifDrawer gifDrawer, Context context) {        this.gifDrawer = gifDrawer;        this.context = context;    }    @Override    protected String doInBackground(String... params) {        try {            System.out.println(params[0]);            name = MD5Utils.string2MD5(params[0]);            System.out.println("--" + name);            InputStream is = HttpLoader.getInputStreanFormUrl(params[0]);            String path = context.getExternalCacheDir() + File.separator + name;            File file = new File(path);            FileOutputStream fops = new FileOutputStream(file);            int len = 0;            byte[] buffer = new byte[1024];            while ((len = is.read(buffer)) != -1) {                fops.write(buffer, 0, len);            }            fops.close();            is.close();        } catch (FileNotFoundException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        }        return params[0];    }    @Override    protected void onPostExecute(String s) {        super.onPostExecute(s);        if (s != null) {            GifDecoder.with(context).load(s).into(gifDrawer.getImageView());        }    }}

如果觉得async很low的可以用其他方法。反正现在下载方法很多。一个意思

代码在github上：https://github.com/wanghao200906/GifLoader

尊重原创：http://blog.csdn.net/wanghao200906/article/details/51483345