Android数据存储内置存储的使用

实现往内置存储中写入文件,读取文件,删除文件:

      核心代码示例如下:

             1)内部存储的写入:

                 方法一:FileOutputStream  fileOutputStream = openFileOutput(String name,int mode);

                 方法二:File file = new File(getFilesDir(), 文件名称);

                             FileOutputStream out = new  FileOutputStream(file);

             2)内部存储的读取:

                 方法一:FileInputStream in = openFileInput(String name);

                 方法二:File file = new File(getFilesDir(), 文件名称);

                            FileInputStream in = newFileInputStream(file);

              3)内部存储的删除:

                            deleteFile();

完整Demo示例如下:

XML布局:

<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:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin" >

    <LinearLayout
        android:paddingLeft="@dimen/activity_horizontal_margin"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal" >

        <EditText
            android:id="@+id/et_name"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:background="@android:drawable/editbox_background"
            android:hint="请输入文件名"
            android:singleLine="true" />

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@android:drawable/edit_text"
            android:onClick="saveFile"
            android:text="保存" />

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@android:drawable/edit_text"
            android:onClick="openFile"
            android:text="打开" />
    LinearLayout>

    <EditText
        android:id="@+id/et_content"
        android:layout_width="fill_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:background="@android:drawable/edit_text"
        android:hint="文件内容" />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@android:drawable/edit_text"
        android:onClick="deleteFile"
        android:text="删除文件" />

LinearLayout>

Java代码:

public class MainActivity extends Activity {
   /**
    * 文件存储的位置:
    * data/data/包名/files/
    */
   private Button save, open, delete;
   private EditText fileName, fileContent;
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      // 初始化控件
      initView();
   }
   // 保存按钮
   public void saveFile(View v) {
      /
      if (TextUtils.isEmpty(fileContent.getText().toString())
                 && TextUtils.isEmpty(fileName.getText().toString())) {
         return;
      }
      try {
         FileOutputStream fileOutputStream = 
               openFileOutput(fileName.getText().toString(), MODE_PRIVATE|MODE_APPEND);
         fileOutputStream.write(fileContent.getText().toString().getBytes());
         fileOutputStream.flush();
         fileOutputStream.close();
         fileName.setText("");
         fileContent.setText("");
         Toast.makeText(MainActivity.this, "保存成功!", Toast.LENGTH_LONG).show();
      } catch (Exception e) {
         // TODO Auto-generated catch block
         e.printStackTrace();
      }
   }
  
   //读取内置存储中的文件
   public void openFile(View view){
      ByteArrayOutputStream outputStream = null;
      try {
         FileInputStream inputStream = new FileInputStream(new File(getFilesDir(),fileName.getText().toString()));      
         outputStream = new ByteArrayOutputStream();
         byte [] buffer = new byte [8*1024];
         int len=0;
         while ((len = inputStream.read(buffer))!=-1) {
             outputStream.write(buffer, 0, len);
             outputStream.flush();
         }       
         String string = new String(outputStream.toByteArray());
         fileContent.setText(string);  
      } catch (Exception e) {
         e.printStackTrace();
      }finally{
         
         if (outputStream != null) {
            try {
               outputStream.close();
            } catch (IOException e) {
               e.printStackTrace();
            }
         }        
      }
   }
   //删除按钮
   public void deleteFile(View view){
      boolean deleteFile = deleteFile(fileName.getText().toString());      
      if (deleteFile) {
         Toast.makeText(this, "删除成功!!", Toast.LENGTH_LONG).show();
      }    
   }  
   private void initView() {
      fileName = (EditText) findViewById(R.id.et_name);
      fileContent = (EditText) findViewById(R.id.et_content);
   }
}