Google Glide开源图片加载库使用

1、Android Studio依赖添加

dependencies {
compile 'com.github.bumptech.glide:glide:3.5.2'
compile 'com.android.support:support-v4:22.0.0'
}

Glide需要依赖 Support Library v4。

2、使用

Glide.with(context)//此处不仅可以传Context，还可以传Activity和Fragment，推荐使用后两种，这样可以保持图片加载与其生命周期一致
.load(url)//图片地址，此处可放gif
.placeholder(R.drawable.loading)//占位符，加载时显示的图片，可放gif
.asGif()//只能加载gif文件
.error(R.drawable.failed) //加载失败图片
.crossFade(1000) //添加图片淡入效果， 可设置时长，默认“300ms”
.into(view);

3、Bitmap设置

默认Bitmap格式是RGB_565，占用内存较小，也可自定义修改。

public class GlideConfiguration implements GlideModule {

@Override
public void applyOptions(Context context, GlideBuilder builder) {
// Apply options to the builder here.
builder.setDecodeFormat(DecodeFormat.PREFER_ARGB_8888);
}

@Override
public void registerComponents(Context context, Glide glide) {
// register ModelLoaders here.
}
}

同时在AndroidManifest.xml中将GlideModule定义为meta-data

<meta-data android:name="com.inthecheesefactory.lab.glidepicasso.GlideConfiguration"
android:value="GlideModule"/>

4、缓存

Glide默认开启磁盘缓存和内存缓存，当然也可以对单张图片进行设置特定的缓存策略。 

设置图片不加入到内存缓存

Glide.with(context)
.load(url)
.skipMemoryCache(true)
.into(imageViewInternet);

设置图片不加入到磁盘缓存

Glide.with(context)
.load(url)
.diskCacheStrategy(DiskCacheStrategy.NONE)
.into(imageViewInternet);

Glide支持多种磁盘缓存策略：

DiskCacheStrategy.NONE :不缓存图片 

DiskCacheStrategy.SOURCE :缓存图片源文件 

DiskCacheStrategy.RESULT:缓存修改过的图片 ，默认

DiskCacheStrategy.ALL:缓存所有的图片

Glide会自动获取ImageView的大小，根据view的尺寸加载不同大小的图片存于内存。不过这也导致了Glide每加载一次不同大小的图片都会进行缓存，也就意味着需要进行多次下载。

我们可以通过设置 

diskCacheStrategy(DiskCacheStrategy.ALL)

让Glide既缓存全尺寸又缓存其他尺寸，下次在任何ImageView中加载图片的时候，全尺寸的图片将从缓存中取出，重新调整大小，然后缓存。

缓存清除

Glide自带清除缓存的功能,分别对应

Glide.get(context).clearDiskCache();(清除磁盘缓存)

Glide.get(context).clearMemory();(清除内存缓存)

两个方法.其中clearDiskCache()方法必须运行在子线程,clearMemory()方法必须运行在主线程,这是这两个方法所强制要求的,详见源码.

import android.content.Context;
import android.os.Looper;
import android.text.TextUtils;

import com.bumptech.glide.Glide;
import com.bumptech.glide.load.engine.cache.ExternalCacheDiskCacheFactory;
import com.bumptech.glide.load.engine.cache.InternalCacheDiskCacheFactory;

import java.io.File;
import java.math.BigDecimal;

/**Glide缓存工具类
* Created by Trojx on 2016/10/10 0010.
*/

public class GlideCacheUtil {
private static GlideCacheUtil inst;

public static GlideCacheUtil getInstance() {
if (inst == null) {
inst = new GlideCacheUtil();
}
return inst;
}

/**
* 清除图片磁盘缓存
*/
public void clearImageDiskCache(final Context context) {
try {
if (Looper.myLooper() == Looper.getMainLooper()) {
new Thread(new Runnable() {
@Override
public void run() {
Glide.get(context).clearDiskCache();
// BusUtil.getBus().post(new GlideCacheClearSuccessEvent());
}
}).start();
} else {
Glide.get(context).clearDiskCache();
}
} catch (Exception e) {
e.printStackTrace();
}
}

/**
* 清除图片内存缓存
*/
public void clearImageMemoryCache(Context context) {
try {
if (Looper.myLooper() == Looper.getMainLooper()) { //只能在主线程执行
Glide.get(context).clearMemory();
}
} catch (Exception e) {

4000
e.printStackTrace();
}
}

/**
* 清除图片所有缓存
*/
public void clearImageAllCache(Context context) {
clearImageDiskCache(context);
clearImageMemoryCache(context);
String ImageExternalCatchDir=context.getExternalCacheDir()+ExternalCacheDiskCacheFactory.DEFAULT_DISK_CACHE_DIR;
deleteFolderFile(ImageExternalCatchDir, true);
}

/**
* 获取Glide造成的缓存大小
*
* @return CacheSize
*/
public String getCacheSize(Context context) {
try {
return getFormatSize(getFolderSize(new File(context.getCacheDir() + "/"+InternalCacheDiskCacheFactory.DEFAULT_DISK_CACHE_DIR)));
} catch (Exception e) {
e.printStackTrace();
}
return "";
}

/**
* 获取指定文件夹内所有文件大小的和
*
* @param file file
* @return size
* @throws Exception
*/
private long getFolderSize(File file) throws Exception {
long size = 0;
try {
File[] fileList = file.listFiles();
for (File aFileList : fileList) {
if (aFileList.isDirectory()) {
size = size + getFolderSize(aFileList);
} else {
size = size + aFileList.length();
}
}
} catch (Exception e) {
e.printStackTrace();
}
return size;
}

/**
* 删除指定目录下的文件，这里用于缓存的删除
*
* @param filePath filePath
* @param deleteThisPath deleteThisPath
*/
private void deleteFolderFile(String filePath, boolean deleteThisPath) {
if (!TextUtils.isEmpty(filePath)) {
try {
File file = new File(filePath);
if (file.isDirectory()) {
File files[] = file.listFiles();
for (File file1 : files) {
deleteFolderFile(file1.getAbsolutePath(), true);
}
}
if (deleteThisPath) {
if (!file.isDirectory()) {
file.delete();
} else {
if (file.listFiles().length == 0) {
file.delete();
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
}

/**
* 格式化单位
*
* @param size size
* @return size
*/
private static String getFormatSize(double size) {

double kiloByte = size / 1024;
if (kiloByte < 1) {
return size + "Byte";
}

double megaByte = kiloByte / 1024;
if (megaByte < 1) {
BigDecimal result1 = new BigDecimal(Double.toString(kiloByte));
return result1.setScale(2, BigDecimal.ROUND_HALF_UP).toPlainString() + "KB";
}

double gigaByte = megaByte / 1024;
if (gigaByte < 1) {
BigDecimal result2 = new BigDecimal(Double.toString(megaByte));
return result2.setScale(2, BigDecimal.ROUND_HALF_UP).toPlainString() + "MB";
}

double teraBytes = gigaByte / 1024;
if (teraBytes < 1) {
BigDecimal result3 = new BigDecimal(Double.toString(gigaByte));
return result3.setScale(2, BigDecimal.ROUND_HALF_UP).toPlainString() + "GB";
}
BigDecimal result4 = new BigDecimal(teraBytes);

return result4.setScale(2, BigDecimal.ROUND_HALF_UP).toPlainString() + "TB";
}
}

4、显示圆图

public class GlideCircleTransform extends BitmapTransformation {
public GlideCircleTransform(Context context) {
super(context);
}

@Override
protected Bitmap transform(BitmapPool pool, Bitmap toTransform, int outWidth, int outHeight) {
return circleCrop(pool, toTransform);
}

private static Bitmap circleCrop(BitmapPool pool, Bitmap source) {
if (source == null) return null;
int size = Math.min(source.getWidth(), source.getHeight());
int x = (source.getWidth() - size) / 2;
int y = (source.getHeight() - size) / 2;
// TODO this could be acquired from the pool too
Bitmap squared = Bitmap.createBitmap(source, x, y, size, size);
Bitmap result = pool.get(size, size, Bitmap.Config.ARGB_8888);
if (result == null) {
result = Bitmap.createBitmap(size, size, Bitmap.Config.ARGB_8888);
}
Canvas canvas = new Canvas(result);
Paint paint = new Paint();
paint.setShader(new BitmapShader(squared, BitmapShader.TileMode.CLAMP, BitmapShader.TileMode.CLAMP));
paint.setAntiAlias(true);
float r = size / 2f;
canvas.drawCircle(r, r, r, paint);
return result;
}

@Override
public String getId() {
return getClass().getName();
}
}

Glide.with(mContext)
.load(imageUrl)
.transform(new GlideCircleTransform(mContext))
.into(holder.imageView);

另：在简书上有一系列关于Glide的详细文章，大家可以去学习一下
http://www.jianshu.com/p/7610bdbbad17