云炬Android开发笔记 5-8文件下载功能设计与实现
5.文件下载功能设计与实现
【说明】比较复杂；
【增加参数】
【新建downloadhandler】新建下载处理类；
【使用异步的下载方法】
【file工具类】没有讲解，课下编写的
1 package com.flj.latte.util.file;
2
3 import android.content.ContentResolver;
4 import android.content.Context;
5 import android.content.Intent;
6 import android.content.res.AssetManager;
7 import android.database.Cursor;
8 import android.graphics.Bitmap;
9 import android.graphics.Typeface;
10 import android.media.MediaScannerConnection;
11 import android.net.Uri;
12 import android.os.Build;
13 import android.os.Environment;
14 import android.provider.MediaStore;
15 import android.webkit.MimeTypeMap;
16 import android.widget.TextView;
17
18 import com.flj.latte.app.Latte;
19
20 import java.io.BufferedInputStream;
21 import java.io.BufferedOutputStream;
22 import java.io.BufferedReader;
23 import java.io.File;
24 import java.io.FileNotFoundException;
25 import java.io.FileOutputStream;
26 import java.io.IOException;
27 import java.io.InputStream;
28 import java.io.InputStreamReader;
29 import java.text.SimpleDateFormat;
30 import java.util.Date;
31 import java.util.Locale;
32
33
34 public final class FileUtil {
35
36 //格式化的模板
37 private static final String TIME_FORMAT = "_yyyyMMdd_HHmmss";
38
39 private static final String SDCARD_DIR =
40 Environment.getExternalStorageDirectory().getPath();
41
42 //默认本地上传图片目录
43 public static final String UPLOAD_PHOTO_DIR =
44 Environment.getExternalStorageDirectory().getPath() + "/a_upload_photos/";
45
46 //网页缓存地址
47 public static final String WEB_CACHE_DIR =
48 Environment.getExternalStorageDirectory().getPath() + "/app_web_cache/";
49
50 //系统相机目录
51 public static final String CAMERA_PHOTO_DIR =
52 Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM).getPath() + "/Camera/";
53
54 private static String getTimeFormatName(String timeFormatHeader) {
55 final Date date = new Date(System.currentTimeMillis());
56 //必须要加上单引号
57 final SimpleDateFormat dateFormat = new SimpleDateFormat("'" + timeFormatHeader + "'" + TIME_FORMAT, Locale.getDefault());
58 return dateFormat.format(date);
59 }
60
61 /**
62 * @param timeFormatHeader 格式化的头(除去时间部分)
63 * @param extension 后缀名
64 * @return 返回时间格式化后的文件名
65 */
66 public static String getFileNameByTime(String timeFormatHeader, String extension) {
67 return getTimeFormatName(timeFormatHeader) + "." + extension;
68 }
69
70 @SuppressWarnings("ResultOfMethodCallIgnored")
71 private static File createDir(String sdcardDirName) {
72 //拼接成SD卡中完整的dir
73 final String dir = SDCARD_DIR + "/" + sdcardDirName + "/";
74 final File fileDir = new File(dir);
75 if (!fileDir.exists()) {
76 fileDir.mkdirs();
77 }
78 return fileDir;
79 }
80
81 @SuppressWarnings("ResultOfMethodCallIgnored")
82 public static File createFile(String sdcardDirName, String fileName) {
83 return new File(createDir(sdcardDirName), fileName);
84 }
85
86 private static File createFileByTime(String sdcardDirName, String timeFormatHeader, String extension) {
87 final String fileName = getFileNameByTime(timeFormatHeader, extension);
88 return createFile(sdcardDirName, fileName);
89 }
90
91 //获取文件的MIME
92 public static String getMimeType(String filePath) {
93 final String extension = getExtension(filePath);
94 return MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
95 }
96
97 //获取文件的后缀名
98 public static String getExtension(String filePath) {
99 String suffix = "";
100 final File file = new File(filePath);
101 final String name = file.getName();
102 final int idx = name.lastIndexOf('.');
103 if (idx > 0) {
104 suffix = name.substring(idx + 1);
105 }
106 return suffix;
107 }
108
109 /**
110 * 保存Bitmap到SD卡中
111 *
112 * @param dir 目录名,只需要写自己的相对目录名即可
113 * @param compress 压缩比例 100是不压缩,值约小压缩率越高
114 * @return 返回该文件
115 */
116 public static File saveBitmap(Bitmap mBitmap, String dir, int compress) {
117
118 final String sdStatus = Environment.getExternalStorageState();
119 // 检测sd是否可用
120 if (!sdStatus.equals(Environment.MEDIA_MOUNTED)) {
121 return null;
122 }
123 FileOutputStream fos = null;
124 BufferedOutputStream bos = null;
125 File fileName = createFileByTime(dir, "DOWN_LOAD", "jpg");
126 try {
127 fos = new FileOutputStream(fileName);
128 bos = new BufferedOutputStream(fos);
129 mBitmap.compress(Bitmap.CompressFormat.JPEG, compress, bos);// 把数据写入文件
130 } catch (FileNotFoundException e) {
131 e.printStackTrace();
132 } finally {
133 try {
134
135 if (bos != null) {
136 bos.flush();
137 }
138 if (bos != null) {
139 bos.close();
140 }
141 //关闭流
142 if (fos != null) {
143 fos.flush();
144 }
145 if (fos != null) {
146 fos.close();
147 }
148 } catch (IOException e) {
149 e.printStackTrace();
150 }
151 }
152 refreshDCIM();
153
154 return fileName;
155 }
156
157 public static File writeToDisk(InputStream is, String dir, String name) {
158 final File file = FileUtil.createFile(dir, name);
159 BufferedInputStream bis = null;
160 FileOutputStream fos = null;
161 BufferedOutputStream bos = null;
162
163 try {
164 bis = new BufferedInputStream(is);
165 fos = new FileOutputStream(file);
166 bos = new BufferedOutputStream(fos);
167
168 byte data[] = new byte[1024 * 4];
169
170 int count;
171 while ((count = bis.read(data)) != -1) {
172 bos.write(data, 0, count);
173 }
174
175 bos.flush();
176 fos.flush();
177
178
179 } catch (IOException e) {
180 e.printStackTrace();
181 } finally {
182 try {
183 if (bos != null) {
184 bos.close();
185 }
186 if (fos != null) {
187 fos.close();
188 }
189 if (bis != null) {
190 bis.close();
191 }
192 is.close();
193 } catch (IOException e) {
194 e.printStackTrace();
195 }
196 }
197
198 return file;
199 }
200
201 public static File writeToDisk(InputStream is, String dir, String prefix, String extension) {
202 final File file = FileUtil.createFileByTime(dir, prefix, extension);
203 BufferedInputStream bis = null;
204 FileOutputStream fos = null;
205 BufferedOutputStream bos = null;
206
207 try {
208 bis = new BufferedInputStream(is);
209 fos = new FileOutputStream(file);
210 bos = new BufferedOutputStream(fos);
211
212 byte data[] = new byte[1024 * 4];
213
214 int count;
215 while ((count = bis.read(data)) != -1) {
216 bos.write(data, 0, count);
217 }
218
219 bos.flush();
220 fos.flush();
221
222
223 } catch (IOException e) {
224 e.printStackTrace();
225 } finally {
226 try {
227 if (bos != null) {
228 bos.close();
229 }
230 if (fos != null) {
231 fos.close();
232 }
233 if (bis != null) {
234 bis.close();
235 }
236 is.close();
237 } catch (IOException e) {
238 e.printStackTrace();
239 }
240 }
241
242 return file;
243 }
244
245 /**
246 * 通知系统刷新系统相册，使照片展现出来
247 */
248 private static void refreshDCIM() {
249 if (Build.VERSION.SDK_INT >= 19) {
250 //兼容android4.4版本，只扫描存放照片的目录
251 MediaScannerConnection.scanFile(Latte.getApplicationContext(),
252 new String[]{Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM).getPath()},
253 null, null);
254 } else {
255 //扫描整个SD卡来更新系统图库，当文件很多时用户体验不佳，且不适合4.4以上版本
256 Latte.getApplicationContext().sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED, Uri.parse("file://" +
257 Environment.getExternalStorageDirectory())));
258 }
259 }
260
261 /**
262 * 读取raw目录中的文件,并返回为字符串
263 */
264 public static String getRawFile(int id) {
265 final InputStream is = Latte.getApplicationContext().getResources().openRawResource(id);
266 final BufferedInputStream bis = new BufferedInputStream(is);
267 final InputStreamReader isr = new InputStreamReader(bis);
268 final BufferedReader br = new BufferedReader(isr);
269 final StringBuilder stringBuilder = new StringBuilder();
270 String str;
271 try {
272 while ((str = br.readLine()) != null) {
273 stringBuilder.append(str);
274 }
275 } catch (IOException e) {
276 e.printStackTrace();
277 } finally {
278 try {
279 br.close();
280 isr.close();
281 bis.close();
282 is.close();
283 } catch (IOException e) {
284 e.printStackTrace();
285 }
286 }
287 return stringBuilder.toString();
288 }
289
290
291 public static void setIconFont(String path, TextView textView) {
292 final Typeface typeface = Typeface.createFromAsset(Latte.getApplicationContext().getAssets(), path);
293 textView.setTypeface(typeface);
294 }
295
296 /**
297 * 读取assets目录下的文件,并返回字符串
298 */
299 public static String getAssetsFile(String name) {
300 InputStream is = null;
301 BufferedInputStream bis = null;
302 InputStreamReader isr = null;
303 BufferedReader br = null;
304 StringBuilder stringBuilder = null;
305 final AssetManager assetManager = Latte.getApplicationContext().getAssets();
306 try {
307 is = assetManager.open(name);
308 bis = new BufferedInputStream(is);
309 isr = new InputStreamReader(bis);
310 br = new BufferedReader(isr);
311 stringBuilder = new StringBuilder();
312 String str;
313 while ((str = br.readLine()) != null) {
314 stringBuilder.append(str);
315 }
316 } catch (IOException e) {
317 e.printStackTrace();
318 } finally {
319 try {
320 if (br != null) {
321 br.close();
322 }
323 if (isr != null) {
324 isr.close();
325 }
326 if (bis != null) {
327 bis.close();
328 }
329 if (is != null) {
330 is.close();
331 }
332 assetManager.close();
333 } catch (IOException e) {
334 e.printStackTrace();
335 }
336 }
337 if (stringBuilder != null) {
338 return stringBuilder.toString();
339 } else {
340 return null;
341 }
342 }
343
344 public static String getRealFilePath(final Context context, final Uri uri) {
345 if (null == uri) return null;
346 final String scheme = uri.getScheme();
347 String data = null;
348 if (scheme == null)
349 data = uri.getPath();
350 else if (ContentResolver.SCHEME_FILE.equals(scheme)) {
351 data = uri.getPath();
352 } else if (ContentResolver.SCHEME_CONTENT.equals(scheme)) {
353 final Cursor cursor = context.getContentResolver().query(uri, new String[]{MediaStore.Images.ImageColumns.DATA}, null, null, null);
354 if (null != cursor) {
355 if (cursor.moveToFirst()) {
356 final int index = cursor.getColumnIndex(MediaStore.Images.ImageColumns.DATA);
357 if (index > -1) {
358 data = cursor.getString(index);
359 }
360 }
361 cursor.close();
362 }
363 }
364 return data;
365 }
366 }
【保存文件类的封装】
【继续封装com.flj.latte.net.download.DownloadHandler】
【调用的方法】在后面的使用文件下载然后更新应用程序；
【提交代码】