Android实现文件下载

总体思路：下载文件到应用缓存路径，在相册创建文件夹，Copy过去，通知相册刷新。

下载文件到APP缓存路径，这样可避免Android高版本读取本地权限问题，

implementation ’com.squareup.okhttp3:okhttp:3.6.0’implementation ’com.squareup.okio:okio:1.11.0’调用

url：文件url

path：储存的路径

应用缓存路径：getExternalCacheDir().getPath()

DownloadUtil.get().download(url, path, new DownloadUtil.OnDownloadListener() { @Override public void onDownloadSuccess(File file) {//下载成功 handler.sendEmptyMessage(1); } @Override public void onDownloading(int progress) {//进度条handler.sendEmptyMessage(progress); } @Override public void onDownloadFailed() {//下载失败handler.sendEmptyMessage(-1); }});

复制到相册目录

DownloadUtil.createFiles(downLoadFile);

通知相册刷新

DownloadUtil.updateDCIM(this,downloadFile);

工具类

/** * 下载工具类 * martin * 2021.7.21 */public class DownloadUtil { private static final String TAG = DownloadUtil.class.getName(); private static DownloadUtil downloadUtil; private final OkHttpClient okHttpClient; public static DownloadUtil get() {if (downloadUtil == null) { downloadUtil = new DownloadUtil();}return downloadUtil; } private DownloadUtil() {okHttpClient = new OkHttpClient(); } /** * 复制单个文件 * * @param oldPath$Name String 原文件路径+文件名 如：data/user/0/com.test/files/abc.txt * @param newPath$Name String 复制后路径+文件名 如：data/user/0/com.test/cache/abc.txt * @return <code>true</code> if and only if the file was copied; * <code>false</code> otherwise */ public static boolean copyFile(String oldPath$Name, String newPath$Name) {try { File oldFile = new File(oldPath$Name); if (!oldFile.exists()) {Log.e('--Method--', 'copyFile: oldFile not exist.');return false; } else if (!oldFile.isFile()) {Log.e('--Method--', 'copyFile: oldFile not file.');return false; } else if (!oldFile.canRead()) {Log.e('--Method--', 'copyFile: oldFile cannot read.');return false; } /* 如果不需要打log，可以使用下面的语句 if (!oldFile.exists() || !oldFile.isFile() || !oldFile.canRead()) {return false; } */ FileInputStream fileInputStream = new FileInputStream(oldPath$Name); FileOutputStream fileOutputStream = new FileOutputStream(newPath$Name); byte[] buffer = new byte[1024]; int byteRead; while (-1 != (byteRead = fileInputStream.read(buffer))) {fileOutputStream.write(buffer, 0, byteRead); } fileInputStream.close(); fileOutputStream.flush(); fileOutputStream.close(); return true;} catch (Exception e) { e.printStackTrace(); return false;} } /** * 通知相册更新 * * @param context * @param newFile */ public void updateDCIM(Context context, File newFile) {File cameraPath = new File(dcimPath, 'Camera');File imgFile = new File(cameraPath, newFile.getAbsolutePath());if (imgFile.exists()) { Uri uri = Uri.fromFile(imgFile); Intent intent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE); intent.setData(uri); context.sendBroadcast(intent);} } /** * url 下载连接 * saveDir 储存下载文件的SDCard目录 * listener 下载监听 */ public void download(final String url, final String saveDir, final OnDownloadListener listener) {Request request = new Request.Builder().url(url).build();okHttpClient.newCall(request).enqueue(new Callback() { @Override public void onFailure(Call call, IOException e) {// 下载失败listener.onDownloadFailed(); } @Override public void onResponse(Call call, Response response) throws IOException {InputStream is = null;byte[] buf = new byte[2048];int len = 0;FileOutputStream fos = null;// 储存下载文件的目录String savePath = isExistDir(saveDir);try { is = response.body().byteStream(); long total = response.body().contentLength(); File file = new File(savePath, getNameFromUrl(url)); fos = new FileOutputStream(file); long sum = 0; while ((len = is.read(buf)) != -1) {fos.write(buf, 0, len);sum += len;int progress = (int) (sum * 1.0f / total * 100);// 下载中listener.onDownloading(progress); } fos.flush(); // 下载完成 listener.onDownloadSuccess(file);} catch (Exception e) { listener.onDownloadFailed();} finally { try {if (is != null) is.close(); } catch (IOException e) { } try {if (fos != null) fos.close(); } catch (IOException e) { }} }}); } /** * saveDir * 判断下载目录是否存在 */ private static String isExistDir(String saveDir) throws IOException {// 下载位置File downloadFile = new File(saveDir);if (!downloadFile.mkdirs()) { downloadFile.createNewFile();}String savePath = downloadFile.getAbsolutePath();return savePath; } //系统相册路径 static String dcimPath = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM).getAbsolutePath(); /** * 创建文件夹 */ public static void createFiles(File oldFile) {try { File file = new File(isExistDir(dcimPath + '/xxx')); String newPath = file.getPath() + '/' + oldFile.getName(); Log.d('TAG', 'createFiles111: ' + oldFile.getPath() + '--' + newPath); if (copyFile(oldFile.getPath(), newPath)) {Log.d('TAG', 'createFiles222: ' + oldFile.getPath() + '--' + newPath); }} catch (IOException e) { e.printStackTrace();} } /** * url * 从下载连接中解析出文件名 */ @NonNull public static String getNameFromUrl(String url) {return url.substring(url.lastIndexOf('/') + 1); } public interface OnDownloadListener {/** * 下载成功 */void onDownloadSuccess(File file); /** * @param progress 下载进度 */void onDownloading(int progress); /** * 下载失败 */void onDownloadFailed(); }}

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