Android通过url下载文件到手机本地
16lz
2021-01-26
文章目录
- 布局
- Activity
- BroadcastReceiver
- 文件工具类
- 图片工具类
- Manifest
- MyApplication
- 这里的demo是一个通过下载地址下载图片文件到手机本地，并在Activity中展示这种图片的例子。
布局
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="center_horizontal" android:orientation="vertical" tools:context="com.example.downFile.MainActivity"> <ImageView android:id="@+id/iv_main" android:layout_width="300dp" android:layout_height="300dp" android:src="@color/colorAccent"/> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="按钮" android:onClick="onClick"/></LinearLayout>Activity
package com.example.downFile;import android.app.DownloadManager;import android.content.Context;import android.content.IntentFilter;import android.net.Uri;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.util.Log;import android.view.View;import android.webkit.MimeTypeMap;import android.widget.ImageView;import com.example.downFile.service.DownLoadReceiver;import java.io.File;public class MainActivity extends AppCompatActivity { private String mTag = getClass().getSimpleName(); private ImageView mIvMain; private String mDownLoadPath = "https://www.baidu.com/img/bd_logo1.png"; private String mFileName = "12.jpg"; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mIvMain = findViewById(R.id.iv_main); } public void onClick(View v) { if (FileUtils.initPictureDir()) { FileUtils.deDuplication(new File(FileUtils.PICTURE_DIR, mFileName)); downPciture(); } else { Log.d(mTag, "目录初始化失败"); } } // 下载 private void downPciture() { // 创建下载任务 DownloadManager.Request request = new DownloadManager.Request(Uri.parse(mDownLoadPath)); // 漫游网络是否可以下载 request.setAllowedOverRoaming(false); // 设置文件类型，可以在下载结束后自动打开该文件 MimeTypeMap mimeTypeMap = MimeTypeMap.getSingleton(); String mimeString = mimeTypeMap.getMimeTypeFromExtension(MimeTypeMap.getFileExtensionFromUrl(mDownLoadPath)); request.setMimeType(mimeString); // 在通知栏中显示，默认就是显示的 request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE); request.setVisibleInDownloadsUi(true); // sdcard的目录下的download文件夹，必须设置 request.setDestinationInExternalPublicDir(TheApplication.getContext().getPackageName() + File.separator + "yunli" + File.separator, mFileName); // request.setDestinationInExternalFilesDir(),也可以自己制定下载路径 // 将下载请求加入下载队列 DownloadManager downloadManager = (DownloadManager) TheApplication.getContext() .getSystemService(Context.DOWNLOAD_SERVICE); // 加入下载队列后会给该任务返回一个long型的id， // 通过该id可以取消任务，重启任务等等 long taskId = downloadManager.enqueue(request); //注册广播接收者，监听下载状态 DownLoadReceiver downLoadReceiver = new DownLoadReceiver(TheApplication.getContext(), downloadManager, taskId, mFileName, mIvMain); registerReceiver(downLoadReceiver, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE)); }}BroadcastReceiver
package com.example.downFile.service;import android.app.DownloadManager;import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;import android.database.Cursor;import android.util.Log;import android.widget.ImageView;import com.example.downFile.FileUtils;import com.example.downFile.LogUtil;import com.example.downFile.ImageUtils;import java.io.File;public class DownLoadReceiver extends BroadcastReceiver { private String mTag = getClass().getSimpleName(); // private NotificationManager nm; // private Intent mIntent; private DownloadManager downloadManager; private long mTaskId; private Context mContext; private String mFileName; private ImageView iv_main; public DownLoadReceiver(Context context, DownloadManager downloadManager, long taskId, String fileName, ImageView iv_main) { this.downloadManager = downloadManager; this.mTaskId = taskId; this.mContext = context; this.mFileName = fileName; this.iv_main = iv_main; } @Override public void onReceive(Context context, Intent intent) { // 检查下载状态 checkDownloadStatus(); } //检查下载状态 private void checkDownloadStatus() { DownloadManager.Query query = new DownloadManager.Query(); query.setFilterById(mTaskId);//筛选下载任务，传入任务ID，可变参数 Cursor c = downloadManager.query(query); if (c.moveToFirst()) { int status = c.getInt(c.getColumnIndex(DownloadManager.COLUMN_STATUS)); switch (status) { case DownloadManager.STATUS_PAUSED: LogUtil.e(mTag, ">>>下载暂停"); case DownloadManager.STATUS_PENDING: LogUtil.e(mTag, ">>>下载延迟"); case DownloadManager.STATUS_RUNNING: LogUtil.e(mTag, ">>>正在下载"); break; case DownloadManager.STATUS_SUCCESSFUL: LogUtil.e(mTag, ">>>下载完成"); File file = new File(FileUtils.PICTURE_DIR, mFileName); Log.d("文件", "存在不：" + file.exists() + "路径" + file.getPath()); ImageUtils.ShowPic2View(mContext, file.getPath(), iv_main); c.close(); // UtilsTools.deleteFile(fileName); //downloadPath = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS).getAbsolutePath() + File.separator + versionName; // installAPK(new File(downloadPath)); break; case DownloadManager.STATUS_FAILED: LogUtil.e(mTag, ">>>下载失败"); break; } } c.close(); }}文件工具类
package com.example.downFile;import android.os.Environment;import android.util.Log;import java.io.File;public class FileUtils { /** * sdcard */ private static final String SD_ROOT = Environment.getExternalStorageDirectory().getPath(); /** * app根目录 */ public static final String PICTURE_DIR = SD_ROOT + File.separator + TheApplication.getContext().getPackageName() + File.separator + "yunli" + File.separator; private FileUtils() { } /** * 是否存在 SDCard * * @return 是否存在 */ public static boolean sdExist() { return Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED); } public static boolean initPictureDir() { if (!sdExist()) { return false; } File picFile = new File(PICTURE_DIR); boolean exists = picFile.exists(); boolean mkdirs = picFile.mkdirs(); return exists || mkdirs; } // 获取文件大小 public static void deDuplication(File file) { if (file.exists()) { Log.d("fileUtil", "存在了：" + file.getPath()); boolean isDelete = file.delete(); Log.d("fileUtil", "删除文件结果：" + isDelete); } else { Log.d("fileUtil", "文件不存在：" + file.getPath()); } }}图片工具类
package com.example.downFile;import android.content.ContentResolver;import android.content.ContentUris;import android.content.Context;import android.database.Cursor;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.net.Uri;import android.os.Environment;import android.provider.MediaStore;import android.text.TextUtils;import android.util.Base64;import android.widget.ImageView;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;/** * 图片相关的工具类 */public class ImageUtils { /** * base64字符串转化成图片 */ public static String GenerateImage(Context context, String imgStr) { //对字节数组字符串进行Base64解码并生成图片 if (imgStr == null) { //图像数据为空 UtilsTools.MsgBox(context, "图片不能为空"); return ""; } try { //Base64解码 byte[] b = Base64Utils.decode(imgStr); for (int i = 0; i < b.length; ++i) { if (b[i] < 0) {//调整异常数据 b[i] += 256; } } // 新生成的jpg图片 // 新图片的文件夹, 如果没有, 就创建 String dirPath = Environment.getExternalStoragePublicDirectory( Environment.DIRECTORY_PICTURES).getAbsolutePath() + "/zdgj/"; File fileDir = new File(dirPath); if (!fileDir.exists()) { fileDir.mkdirs(); } // 文件夹现在存在了, 可以在此文件夹下创建图片了 String imgFilePath = dirPath + System.currentTimeMillis() + ".jpg"; File file = new File(imgFilePath); if (!file.exists()) { file.createNewFile(); } OutputStream out = new FileOutputStream(imgFilePath); out.write(b); out.flush(); out.close(); SharedPrefUtil.putString(context, "facePic", imgFilePath); UtilsTools.MsgBox(context, "图片已保存到本地"); return imgFilePath; } catch (Exception e) { UtilsTools.MsgBox(context, e.getMessage()); return ""; } } /** * 将图片转换成Base64编码的字符串 * * @param path 图片本地路径 * @return base64编码的字符串 */ public static String imageToBase64(String path) { if (TextUtils.isEmpty(path)) { return null; } InputStream is = null; byte[] data; String result = null; try { is = new FileInputStream(path); //创建一个字符流大小的数组。 data = new byte[is.available()]; //写入数组 is.read(data); //用默认的编码格式进行编码 result = Base64.encodeToString(data, Base64.DEFAULT); } catch (IOException e) { e.printStackTrace(); } finally { if (null != is) { try { is.close(); } catch (IOException e) { e.printStackTrace(); } } } return result; } /** * 在ImageView里展示指定路径的图片 * * @param path 本地路径 * @param imageView ImageView */ public static void ShowPic2View(Context context, String path, ImageView imageView) { File localFile = new File(path);// if (!localFile.exists()) {// UtilsTools.MsgBox(context, path + " is null.");// } else { try { FileInputStream localStream; localStream = new FileInputStream(localFile); Bitmap bitmap = BitmapFactory.decodeStream(localStream); imageView.setImageBitmap(bitmap); // if (localStream != null) { localStream.close(); // } } catch (Exception e) { e.printStackTrace(); UtilsTools.MsgBox(context, e.getMessage()); }// } } /** * 删除手机里指定路径的图片 * * @param context Context * @param imgPath 本地路径 */ public static void DeletePicFromMobile(Context context, String imgPath) { try { ContentResolver resolver = context.getContentResolver(); Cursor cursor = MediaStore.Images.Media.query(resolver, MediaStore.Images.Media.EXTERNAL_CONTENT_URI, new String[]{MediaStore.Images.Media._ID}, MediaStore.Images.Media.DATA + "=?", new String[]{imgPath}, null); boolean result; if (cursor.moveToFirst()) { long id = cursor.getLong(0); Uri contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI; Uri uri = ContentUris.withAppendedId(contentUri, id); int count = context.getContentResolver().delete(uri, null, null); result = count == 1; } else { File file = new File(imgPath); result = file.delete(); } if (result) { UtilsTools.MsgBox(context, "删除成功"); } } catch (Exception e) { UtilsTools.MsgBox(context, e.getMessage()); } }}Manifest
<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.downFile"> <!--用于访问网络--> <uses-permission android:name="android.permission.INTERNET"/> <uses-permission android:name="android.permission.CALL_PHONE"/> <!--获取手机唯一标识IMEI--> <uses-permission android:name="android.permission.READ_PHONE_STATE"/> <!--获取运营商信息，用于支持提供运营商信息相关的接口--> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/> <uses-permission android:name="android.permission.VIBRATE"/> <!--用于访问wifi网络信息，wifi信息会用于进行网络定位--> <uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/> <!--这个权限用于获取wifi的获取权限，wifi信息会用来进行网络定位--> <uses-permission android:name="android.permission.CHANGE_WIFI_STATE"/> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> <uses-permission android:name="android.permission.READ_PHONE_STORAE"/> <!-- 用于进行网络定位 --> <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/> <!-- 用于访问GPS定位 --> <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/> <!-- 通讯录权限 --> <uses-permission android:name="android.permission.READ_CONTACTS"/> <uses-permission android:name="android.permission.WRITE_CONTACTS"/> <!-- 相机 --> <uses-permission android:name="android.permission.CAMERA"/> <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/> <uses-permission android:name="android.permission.READ_SETTINGS"/> <application android:name="com.example.downFile.TheApplication" android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:roundIcon="@mipmap/ic_launcher_round" android:supportsRtl="true" android:theme="@style/AppTheme"> <activity android:name="com.example.downFile.MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN"/> <category android:name="android.intent.category.LAUNCHER"/> </intent-filter> </activity> </application></manifest>MyApplication
package com.example.downFile;import android.app.Application;import android.content.Context;import java.lang.ref.WeakReference;public class TheApplication extends Application { private static WeakReference<Context> mContext; @Override public void onCreate() { super.onCreate(); mContext = new WeakReference<>(getApplicationContext()); } /** * 全局获取 Context * * @return ApplicationContext */ public static Context getContext() { return mContext.get(); }}更多相关文章
- android中手势操作图片的平移、缩放、旋转
- Android(安卓)图片处理之图片叠加--Bitmap
- 实现图片浏览，改变透明度的方法
- Android(安卓)JNI/Hardware 加载（二）
- Error generating final archive: Debug Certificate expired on
- android入门学习的网上资料总结
- android UiAutomator利用am命令启动和结束进程
- Android工程Debug证书过期解决方案 -- eclipse
- Android(安卓)Volley使用之二：Volley请求网络图片