Examples of Android file storage and reading functions

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/**
 * File saving and reading function implementation class
 * @author Administrator
 *
 * 2010-6-28 08:15:18 pm
 */
public class FileService {
  public static final String TAG = "FileService";
  private Context context;
  //Get the reference to the incoming context object  public FileService(Context context) {
    = context;
  }
  /**
    * Save the file
    *
    * @param fileName filename
    * @param content file content
    * @throws Exception
    */
  public void save(String fileName, String content) throws Exception {
   // Since the page inputs all text information, when the file name does not end with the .txt suffix, the .txt suffix will be automatically added.   if (!(".txt")) {
    fileName = fileName + ".txt";
   }
   byte[] buf = ("iso8859-1");
   (TAG, new String(buf,"utf-8"));
   fileName = new String(buf,"utf-8");
   (TAG, fileName);
   // Context.MODE_PRIVATE: It is the default operation mode, which means that the file is private data and can only be accessed by the application itself. In this mode, the written content will overwrite the content of the original file. If you want to append the newly written content to the original file.  Context.MODE_APPEND can be used   // Context.MODE_APPEND: The mode will check whether the file exists. If it exists, it will add content to the file, otherwise a new file will be created.   // Context.MODE_WORLD_READABLE and Context.MODE_WORLD_WRITEABLE are used to control whether other applications have permission to read and write the file.   // MODE_WORLD_READABLE: means that the current file can be read by other applications; MODE_WORLD_WRITEABLE: means that the current file can be written by other applications.   // If you want the file to be read and written by other applications, you can pass it in:   // openFileOutput("", Context.MODE_WORLD_READABLE + Context.MODE_WORLD_WRITEABLE);
   FileOutputStream fos = (fileName, context.MODE_PRIVATE);
   (());
   ();
  }
  /**
    * Read file contents
    *
    * @param fileName filename
    * @return File content
    * @throws Exception
    */
  public String read(String fileName) throws Exception {
   // Since the page inputs all text information, when the file name does not end with the .txt suffix, the .txt suffix will be automatically added.   if (!(".txt")) {
    fileName = fileName + ".txt";
   }
   FileInputStream fis = (fileName);
   ByteArrayOutputStream baos = new ByteArrayOutputStream();
   byte[] buf = new byte[1024];
   int len = 0;
   //Put the read data in memory ---ByteArrayOutputStream   while ((len = (buf)) != -1) {
    (buf, 0, len);
   }
   ();
   ();
   //Return the data stored in memory   return ();
  }
}

package ;
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public class TestAndroidActivity extends Activity {
  /** Called when the activity is first created. */
  //Get FileService object  private FileService fileService = new FileService(this);
  //Define the filename input box object in the view  private EditText fileNameText;
  //Define the contentText input box object in the view  private EditText contentText;
  //Define a toast prompt object  private Toast toast;
  @Override
  public void onCreate(Bundle savedInstanceState) {
  (savedInstanceState);
  setContentView();
  //Get object references of two input boxes and two buttons in the view  Button button = (Button)();
  Button read = (Button)();
  fileNameText = (EditText) ();
  contentText = (EditText) ();
  //Add a save event for the save button  (new () {
    @Override
    public void onClick(View v) {
     String fileName = ().toString();
     String content = ().toString();
     //When the file name is empty, prompt the user to have the file name empty and record the log.     if(isEmpty(fileName)) {
      toast = (, .empty_filename, Toast.LENGTH_LONG);
      (RESULT_CANCELED, 0.345f);
      ();
      (, "The file name is empty");
      return;
     }
     //When the file content is empty, the user is prompted to be empty and the log is recorded.     if(isEmpty(content)) {
      toast = (, .empty_content, Toast.LENGTH_LONG);
      (RESULT_CANCELED, 0.345f);
      ();
      (, "The file content is empty");
      return;
     }
     //When the file name and content are not empty, call the save method of fileService     // When the execution is successful, the user is prompted to save successfully and log the log     //When an exception occurs, the user is prompted to fail to save and log     try {
      (fileName, content);
      toast = (, , Toast.LENGTH_LONG);
      (RESULT_CANCELED, 0.345f);
      ();
      (, "The file save successful");
     } catch (Exception e) {
      toast = (, , Toast.LENGTH_LONG);
      (RESULT_CANCELED, 0.345f);
      ();
      (, "The file save failed");
     }
    }
  });
  //Add a read event for the read button  (new () {
    @Override
    public void onClick(View v) {
     //Get the value in the file name input box     String fileName = ().toString();
     //If the file name is empty, the user is prompted to enter the file name and record the log     if(isEmpty(fileName)) {
      toast = (, .empty_filename, Toast.LENGTH_LONG);
      (RESULT_CANCELED, 0.345f);
      ();
      (, "The file name is empty");
      return;
     }
     //Call the read method of fileService and put the read content into the text content input box     //If the execution is successful, the user is prompted to read successfully and the log is recorded.     //If an exception message appears (example: the file does not exist), the user will be prompted to fail to read and log the log.     try {
      ((fileName));
      toast = (, .read_success, Toast.LENGTH_LONG);
      (RESULT_CANCELED, 0.345f);
      ();
      (, "The file read successful");
     } catch (Exception e) {
      toast = (, .read_fail, Toast.LENGTH_LONG);
      (RESULT_CANCELED, 0.345f);
      ();
      (, "The file read failed");
     }
    }
  });
  }
  //Write an isEmpty method to determine whether the string is empty  private boolean isEmpty(String s) {
  if(s == null || "".equals(())) {
   return true;
  }
  return false;
  }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:andro
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  >
  <TextView
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="@string/filename"
  />
  <EditText
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:
  />
  <TextView
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="@string/content"
  />
  <EditText
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:minLines="3"
   android:
  />
  <LinearLayout
  android:orientation="horizontal"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent">
   <Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:
    android:text="@string/save"
   />
   <Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:
    android:text="@string/read"
   />
  </LinearLayout>
</LinearLayout>