Android-okhttp下载图片并保存（刷新图库）

//注意：下载和保存在子线程中进行。
new Thread(new Runnable() {
@Override
public void run() {
final Bitmap bitmap = getPic(url);//下载

onSaveBitmap(bitmap, MainActivity.this);//保存到本地

handler.post(new Runnable() {
@Override
public void run() {
iv4.setImageBitmap(bitmap);//显示图片
}
});
}
}).start();

public Bitmap getPic(String url) {
//获取okHttp对象get请求
try {
OkHttpClient client = new OkHttpClient();
//获取请求对象
Request request = new Request.Builder().url(url).build();
//获取响应体
ResponseBody body = client.newCall(request).execute().body();
//获取流
InputStream in = body.byteStream();
//转化为bitmap
Bitmap bitmap = BitmapFactory.decodeStream(in);

return bitmap;
} catch (IOException e) {
e.printStackTrace();
}
return null;
}

/*
Android保存图片到系统图库：http://blog.csdn.net/xu_fu/article/details/39158747
* */
private void onSaveBitmap(final Bitmap mBitmap, final Context context) {
// 第一步：首先保存图片
//将Bitmap保存图片到指定的路径/sdcard/Boohee/下，文件名以当前系统时间命名,但是这种方法保存的图片没有加入到系统图库中
File appDir = new File(Environment.getExternalStorageDirectory(), "Boohee");

if (!appDir.exists()) {
appDir.mkdir();
}

String fileName = System.currentTimeMillis() + ".jpg";
File file = new File(appDir, fileName);

try {
FileOutputStream fos = new FileOutputStream(file);
mBitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos);
fos.flush();
fos.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}

// 第二步：其次把文件插入到系统图库
try {
MediaStore.Images.Media.insertImage(context.getContentResolver(), file.getAbsolutePath(), fileName, null);
//   /storage/emulated/0/Boohee/1493711988333.jpg
} catch (FileNotFoundException e) {
e.printStackTrace();
}

// 第三步：最后通知图库更新
context.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://" + file)));
//context.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.fromFile(file)));
}

okhttp简单的封装（支持异步）后进行下载并显示图片：

class HttpUtil {
private OkHttpClient client;

public void getImage(String url, Callback callback) {
//单例模式
if (client == null) {
client = new OkHttpClient();
} else {
Request request = new Request.Builder().url(url).build();
//enqueue为OkHttp提供的异步方法
client.newCall(request).enqueue(callback);
}
}
}

new HttpUtil().getImage(url, new Callback() {
@Override
public void onFailure(Request request, IOException e) {

}

@Override
public void onResponse(com.squareup.okhttp.Response response) throws IOException {
byte[] bytes = response.body().bytes();
final Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
//                InputStream inputStream = response.body().byteStream();
//                Bitmap bitmap1 = BitmapFactory.decodeStream(inputStream);
handler.post(new Runnable() {//主线程更新UI
@Override
public void run() {
iv6.setImageBitmap(bitmap);
}
});
}
});