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Android学习笔记之数据的Sdcard存储方法及操作sdcard的工具类_sdcard类的方法

作者：笔触狂放9 | 2024-03-26 19:42:49

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sdcard类的方法


（1）文件的目录


（2）各文件的代码：

  1. <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  2.     xmlns:tools="http://schemas.android.com/tools"
  3.     android:layout_width="match_parent"
  4.     android:layout_height="match_parent"
  5.     android:paddingBottom="@dimen/activity_vertical_margin"
  6.     android:paddingLeft="@dimen/activity_horizontal_margin"
  7.     android:paddingRight="@dimen/activity_horizontal_margin"
  8.     android:paddingTop="@dimen/activity_vertical_margin"
  9.     tools:context=".MainActivity" >
  10.  
  11.     <ImageView
  12.         android:id="@+id/imageView1"
  13.         android:layout_width="wrap_content"
  14.         android:layout_height="wrap_content"
  15.         android:layout_alignParentTop="true"
  16.         android:layout_alignRight="@+id/button1"
  17.         android:layout_marginRight="44dp"
  18.         android:layout_marginTop="78dp"
  19.         android:src="@drawable/ic_launcher" />
  20.  
  21.     <Button
  22.         android:id="@+id/button1"
  23.         android:layout_width="wrap_content"
  24.         android:layout_height="wrap_content"
  25.         android:layout_alignParentLeft="true"
  26.         android:layout_below="@+id/imageView1"
  27.         android:layout_marginLeft="96dp"
  28.         android:layout_marginTop="106dp"
  29.         android:text="Button" />
  30.  
  31. </RelativeLayout>


FileService.java也就是操作sdcard的工具类： 

  1. package com.example.data_storage_sdcard.file;
  2.  
  3. import java.io.ByteArrayOutputStream;
  4. import java.io.File;
  5. import java.io.FileInputStream;
  6. import java.io.FileNotFoundException;
  7. import java.io.FileOutputStream;
  8. import java.io.IOException;
  9.  
  10. import android.os.Environment;
  11.  
  12. /**
  13.  * sdcard的存在于上下文无关
  14.  * 
  15.  * @author piaodangdehun
  16.  * 
  17.  */
  18. public class FileService {
  19.  
  20. 	/*
  21. 	 * 存放在sdcard的根目录
  22. 	 */
  23. 	public boolean saveFileToSdcardRoot(String fileName, byte[] data) {
  24. 		boolean flag = false;
  25. 		/*
  26. 		 * 先判断sdcard的状态，是否存在
  27. 		 */
  28. 		String state = Environment.getExternalStorageState();
  29. 		FileOutputStream outputStream = null;
  30. 		File rootFile = Environment.getExternalStorageDirectory(); // 获得sdcard的根路径
  31. 		/*
  32. 		 * 表示sdcard挂载在手机上，并且可以读写
  33. 		 */
  34. 		if (state.equals(Environment.MEDIA_MOUNTED)) {
  35. 			File file = new File(rootFile, fileName);
  36. 			try {
  37. 				outputStream = new FileOutputStream(file);
  38. 				try {
  39. 					outputStream.write(data, 0, data.length);
  40. 					flag = true;
  41. 				} catch (IOException e) {
  42. 					e.printStackTrace();
  43. 				}
  44. 			} catch (FileNotFoundException e) {
  45. 				e.printStackTrace();
  46. 			} finally {
  47. 				if (outputStream != null) {
  48. 					try {
  49. 						outputStream.close();
  50. 					} catch (IOException e) {
  51. 						e.printStackTrace();
  52. 					}
  53. 				}
  54. 			}
  55. 		}
  56. 		return flag;
  57. 	}
  58.  
  59. 	/*
  60. 	 * 存放在sdcard下自定义的目录
  61. 	 */
  62. 	public boolean saveFileToSdcardDir(String fileName, byte[] data) {
  63. 		boolean flag = false;
  64. 		/*
  65. 		 * 先判断sdcard的状态，是否存在
  66. 		 */
  67. 		String state = Environment.getExternalStorageState();
  68. 		FileOutputStream outputStream = null;
  69. 		File rootFile = Environment.getExternalStorageDirectory(); // 获得sdcard的根路径
  70. 		/*
  71. 		 * 表示sdcard挂载在手机上，并且可以读写
  72. 		 */
  73. 		if (state.equals(Environment.MEDIA_MOUNTED)) {
  74. 			File file = new File(rootFile.getAbsoluteFile() + "/txt");
  75. 			if (!file.exists()) {
  76. 				file.mkdirs();
  77. 			}
  78. 			try {
  79. 				outputStream = new FileOutputStream(new File(file, fileName));
  80. 				try {
  81. 					outputStream.write(data, 0, data.length);
  82. 					flag = true;
  83. 				} catch (IOException e) {
  84. 					e.printStackTrace();
  85. 				}
  86. 			} catch (FileNotFoundException e) {
  87. 				e.printStackTrace();
  88. 			} finally {
  89. 				if (outputStream != null) {
  90. 					try {
  91. 						outputStream.close();
  92. 					} catch (IOException e) {
  93. 						e.printStackTrace();
  94. 					}
  95. 				}
  96. 			}
  97. 		}
  98. 		return flag;
  99. 	}
  100.  
  101. 	/*
  102. 	 * 用于读取sdcard的数据
  103. 	 */
  104. 	public String readContextFromSdcard(String fileName) {
  105.  
  106. 		String state = Environment.getExternalStorageState();
  107. 		File rooFile = Environment.getExternalStorageDirectory(); // 获得sdcard的目录
  108.  
  109. 		FileInputStream inputStream = null;// 用于度取数据的流
  110. 		ByteArrayOutputStream outputStream = new ByteArrayOutputStream(); // 用于存放独处的数据
  111.  
  112. 		if (state.equals(Environment.MEDIA_MOUNTED)) {
  113. 			File file = new File(rooFile.getAbsoluteFile() + "/txt/");// 在sdcard目录下创建一个txt目录
  114. 			File file2 = new File(file, fileName);
  115. 			int len = 0;
  116. 			byte[] data = new byte[1024];
  117. 			if (file2.exists()) {
  118. 				try {
  119. 					inputStream = new FileInputStream(file2);
  120. 					try {
  121. 						while ((len = inputStream.read(data)) != -1) {
  122. 							outputStream.write(data, 0, data.length);
  123. 						}
  124. 					} catch (IOException e) {
  125. 						e.printStackTrace();
  126. 					}
  127. 					return new String(outputStream.toByteArray());
  128. 				} catch (FileNotFoundException e) {
  129. 					// TODO Auto-generated catch block
  130. 					e.printStackTrace();
  131. 				} finally {
  132. 					if (outputStream != null) {
  133. 						try {
  134. 							outputStream.close();
  135. 						} catch (IOException e) {
  136. 							e.printStackTrace();
  137. 						}
  138. 					}
  139. 				}
  140. 			}
  141. 		}
  142. 		return null;
  143. 	}
  144.  
  145. 	/**
  146. 	 * 对文件进行分类的保存到固定的文件中去
  147. 	 * 
  148. 	 * @param fileName
  149. 	 * @param data
  150. 	 */
  151. 	public void saveFileToSdcardBySuff(String fileName, byte[] data) {
  152. 		// File file = Environment.getExternalStoragePublicDirectory("");
  153. 		// 保存文件的目录
  154. 		File file = null;
  155. 		if (Environment.getExternalStorageState().equals(
  156. 				Environment.MEDIA_MOUNTED)) {
  157.  
  158. 			/*
  159. 			 * 将不同的文件放入到不同的类别中
  160. 			 */
  161. 			if (fileName.endsWith(".mp3")) {
  162. 				file = Environment
  163. 						.getExternalStoragePublicDirectory(Environment.DIRECTORY_MUSIC);
  164. 			} else if (fileName.endsWith(".jpg") || fileName.endsWith(".png")
  165. 					|| fileName.endsWith(".gif")) {
  166. 				file = Environment
  167. 						.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
  168. 			} else if (fileName.endsWith(".mp4") || fileName.endsWith(".avi")
  169. 					|| fileName.endsWith(".3gp")) {
  170. 				file = Environment
  171. 						.getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES);
  172. 			} else {
  173. 				file = Environment
  174. 						.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
  175. 			}
  176. 			FileOutputStream outputStream = null;
  177. 			try {
  178. 				outputStream = new FileOutputStream(new File(file, fileName));
  179. 				try {
  180. 					outputStream.write(data, 0, data.length);
  181. 				} catch (IOException e) {
  182. 					e.printStackTrace();
  183. 				}
  184. 			} catch (FileNotFoundException e) {
  185. 				e.printStackTrace();
  186. 			} finally {
  187. 				if (outputStream != null) {
  188. 					try {
  189. 						outputStream.close();
  190. 					} catch (IOException e) {
  191. 						e.printStackTrace();
  192. 					}
  193. 				}
  194. 			}
  195. 		}
  196. 	}
  197.  
  198. 	/*
  199. 	 * 删除一个文件
  200. 	 */
  201. 	public boolean deleteFileFromSdcard(String folder, String fileName) {
  202. 		boolean flag = false;
  203. 		File file = Environment.getExternalStorageDirectory();
  204. 		if (Environment.getExternalStorageState().equals(
  205. 				Environment.MEDIA_MOUNTED)) {
  206. 			File exitFile = new File(file.getAbsoluteFile() + "/" + folder);
  207. 			if (exitFile.exists()) {
  208. 				exitFile.delete();
  209. 			}
  210. 		}
  211. 		return flag;
  212. 	}
  213. }

HttpUtils.java访问网络的 

  1. package com.example.data_storage_sdcard.http;
  2.  
  3. import java.io.IOException;
  4.  
  5. import org.apache.http.HttpResponse;
  6. import org.apache.http.client.ClientProtocolException;
  7. import org.apache.http.client.HttpClient;
  8. import org.apache.http.client.methods.HttpPost;
  9. import org.apache.http.impl.client.DefaultHttpClient;
  10. import org.apache.http.util.EntityUtils;
  11.  
  12. public class HttpUtils {
  13. 	/*
  14. 	 * 
  15. 	 */
  16. 	public static byte[] getImage(String path) {
  17. 		byte[] data = null;
  18. 		HttpClient httpClient = new DefaultHttpClient();
  19. 		HttpPost httpPost = new HttpPost(path);
  20. 		try {
  21. 			HttpResponse response = httpClient.execute(httpPost);
  22. 			if (response.getStatusLine().getStatusCode() == 200) {
  23. 				data = EntityUtils.toByteArray(response.getEntity());
  24. 			}
  25. 		} catch (ClientProtocolException e) {
  26. 			e.printStackTrace();
  27. 		} catch (IOException e) {
  28. 			e.printStackTrace();
  29. 		} finally {
  30. 			httpClient.getConnectionManager().shutdown();
  31. 		}
  32.  
  33. 		return data;
  34.  
  35. 	}
  36. }

ImageCache.java将文件放到cache中的：

  1. package com.example.data_storage_sdcard.img;
  2.  
  3. import java.io.File;
  4. import java.io.FileOutputStream;
  5. import java.io.IOException;
  6.  
  7. import android.os.Environment;
  8.  
  9. public class ImageCache {
  10.  
  11. 	public static  String saveImageCache(String fileName, byte[] data) {
  12. 		File file = Environment.getExternalStorageDirectory(); // 根目录
  13. 		FileOutputStream outputStream = null;
  14. 		if (Environment.getExternalStorageState().equals(
  15. 				Environment.MEDIA_MOUNTED)) {
  16. 			try {
  17. 				outputStream = new FileOutputStream(new File(file, fileName));
  18. 				outputStream.write(data, 0, data.length);
  19.  
  20. 				return file.getAbsolutePath() + "/" + fileName;
  21. 			} catch (Exception e) {
  22. 				e.printStackTrace();
  23. 			} finally {
  24. 				if (outputStream != null) {
  25. 					try {
  26. 						outputStream.close();
  27. 					} catch (IOException e) {
  28. 						e.printStackTrace();
  29. 					}
  30. 				}
  31. 			}
  32. 		}
  33. 		return null;
  34. 	}
  35. }

MainActivity.java 

  1. package com.example.data_storage_sdcard;
  2.  
  3. import android.app.Activity;
  4. import android.app.ProgressDialog;
  5. import android.graphics.Bitmap;
  6. import android.graphics.BitmapFactory;
  7. import android.os.AsyncTask;
  8. import android.os.Bundle;
  9. import android.view.Menu;
  10. import android.view.View;
  11. import android.view.View.OnClickListener;
  12. import android.widget.Button;
  13. import android.widget.ImageView;
  14.  
  15. import com.example.data_storage_sdcard.http.HttpUtils;
  16. import com.example.data_storage_sdcard.img.ImageCache;
  17.  
  18. public class MainActivity extends Activity {
  19. 	private Button button;
  20. 	private ImageView imageView;
  21. 	private ProgressDialog progressDialog;
  22.  
  23. 	private String imageName;
  24.  
  25. 	private final String pathString = "http://www.baidu.com/img/bd_logo1.png";
  26.  
  27. 	@Override
  28. 	protected void onCreate(Bundle savedInstanceState) {
  29. 		super.onCreate(savedInstanceState);
  30. 		setContentView(R.layout.activity_main);
  31. 		button = (Button) this.findViewById(R.id.button1);
  32. 		imageView = (ImageView) this.findViewById(R.id.imageView1);
  33.  
  34. 		progressDialog = new ProgressDialog(this);
  35. 		progressDialog.setTitle("下载提示");
  36. 		progressDialog.setMessage("load...");
  37. 		button.setOnClickListener(new OnClickListener() {
  38.  
  39. 			@Override
  40. 			public void onClick(View v) {
  41. 				new MyTask().execute(pathString);
  42. 			}
  43. 		});
  44. 	}
  45.  
  46. 	class MyTask extends AsyncTask<String, Void, byte[]> {
  47.  
  48. 		@Override
  49. 		protected void onPreExecute() {
  50. 			super.onPreExecute();
  51. 			progressDialog.show();
  52. 		}
  53.  
  54. 		@Override
  55. 		protected byte[] doInBackground(String... params) {
  56. 			String name = params[0];
  57. 			imageName = name
  58. 					.substring(name.lastIndexOf("/") + 1, name.length());
  59. 			return HttpUtils.getImage(params[0]);
  60. 		}
  61.  
  62. 		@Override
  63. 		protected void onProgressUpdate(Void... values) {
  64. 			super.onProgressUpdate(values);
  65. 		}
  66.  
  67. 		@Override
  68. 		protected void onPostExecute(byte[] result) {
  69. 			super.onPostExecute(result);
  70. 			if (result != null) {
  71. 				Bitmap bm = BitmapFactory.decodeByteArray(result, 0,
  72. 						result.length);
  73. 				imageView.setImageBitmap(bm);
  74. 				ImageCache.saveImageCache("", result);
  75. 			} else {
  76. 				imageView.setImageResource(R.drawable.ic_launcher);
  77. 			}
  78. 			progressDialog.dismiss();
  79. 		}
  80. 	}
  81.  
  82. 	@Override
  83. 	public boolean onCreateOptionsMenu(Menu menu) {
  84. 		// Inflate the menu; this adds items to the action bar if it is present.
  85. 		getMenuInflater().inflate(R.menu.main, menu);
  86. 		return true;
  87. 	}
  88.  
  89. }

测试类： 

  1. package com.example.data_storage_sdcard;
  2.  
  3. import java.io.FileWriter;
  4.  
  5. import com.example.data_storage_sdcard.file.FileService;
  6.  
  7. import android.nfc.Tag;
  8. import android.test.AndroidTestCase;
  9. import android.util.Log;
  10.  
  11. public class MyTest extends AndroidTestCase {
  12.  
  13. 	public void saveFileToSdcardTest() {
  14. 		FileService fileService = new FileService();
  15.  
  16. 		fileService.saveFileToSdcardRoot("aa.txt",
  17. 				"jkhdsfjkhdskjfhdsjf".getBytes());
  18. 	}
  19.  
  20. 	public void saveFileToSdcardDir() {
  21. 		FileService fileService = new FileService();
  22.  
  23. 		fileService.saveFileToSdcardRoot("aa.txt",
  24. 				"jkhdsfjkhdskjfhdsjf".getBytes());
  25. 	}
  26.  
  27. 	public void readContextFromSdcardTest() {
  28. 		FileService fileService = new FileService();
  29. 		String msg = fileService.readContextFromSdcard("aa.txt");
  30. 		System.err.println("-->" + msg);
  31. 	}
  32.  
  33. 	public void saveFileToSdcardBySuffTest() {
  34. 		FileService fileService = new FileService();
  35. 		fileService.saveFileToSdcardBySuff("aa.avi",
  36. 				"asdfkajsgdhagsdfhdgsf".getBytes());
  37. 	}
  38.  
  39. 	public void delFile() {
  40. 		FileService fileService = new FileService();
  41. 		boolean flag = fileService.deleteFileFromSdcard("txt", "aa.txt");
  42. 	}
  43. }

需要在请单位按中加入访问网络的权限、操作sdcard的权限、测试的权限 

  1. <?xml version="1.0" encoding="utf-8"?>
  2. <manifest xmlns:android="http://schemas.android.com/apk/res/android"
  3.     package="com.example.data_storage_sdcard"
  4.     android:versionCode="1"
  5.     android:versionName="1.0" >
  6.  
  7.     <uses-sdk
  8.         android:minSdkVersion="8"
  9.         android:targetSdkVersion="18" />
  10.  
  11.     <instrumentation
  12.         android:name="android.test.InstrumentationTestRunner"
  13.         android:targetPackage="com.example.data_storage_sdcard" >
  14.     </instrumentation>
  15.     <!-- 添加访问sdcard的权限 -->
  16.     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
  17.     <!-- 添加访问网络的权限 -->
  18.     <uses-permission android:name="android.permission.INTERNET" />
  19.  
  20.     <application
  21.         android:allowBackup="true"
  22.         android:icon="@drawable/ic_launcher"
  23.         android:label="@string/app_name"
  24.         android:theme="@style/AppTheme" >
  25.         <uses-library android:name="android.test.runner" />
  26.  
  27.         <activity
  28.             android:name="com.example.data_storage_sdcard.MainActivity"
  29.             android:label="@string/app_name" >
  30.             <intent-filter>
  31.                 <action android:name="android.intent.action.MAIN" />
  32.  
  33.                 <category android:name="android.intent.category.LAUNCHER" />
  34.             </intent-filter>
  35.         </activity>
  36.  
  37.         <uses-library>
  38.         </uses-library>
  39.     </application>
  40.  
  41. </manifest>




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