存储卡上读写文本文件
- 文本文件的读写一般借助于 FileOutputStream 和 FileInputStream。
- FileOutputStream用于写文件。 l FileInputStream用于读文
显示效果：
存储的IO设置
FileUtil.java
package com.example.datastorage.util; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.FileReader; import java.io.FileWriter; import java.io.IOException; public class FileUtil { // 把字符串保存到指定路径的文本文件 输出流 public static void saveText(String path, String txt) { BufferedWriter os = null; try { os = new BufferedWriter(new FileWriter(path)); os.write(txt); } catch (Exception e) { e.printStackTrace(); } finally { if (os != null) { try { os.close(); } catch (IOException e) { e.printStackTrace(); } } } } // 从指定路径的文本文件中读取内容字符串 输入流 public static String openText(String path) { BufferedReader is = null; StringBuilder sb = new StringBuilder(); try { is = new BufferedReader(new FileReader(path)); String line = null; // 行读取 while ((line = is.readLine()) != null) { sb.append(line); } } catch (Exception e) { e.printStackTrace(); } finally { if (is != null) { try { is.close(); } catch (IOException e) { e.printStackTrace(); } } } return sb.toString(); } }
FileWriteActivity.java
package com.example.datastorage.util; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.FileReader; import java.io.FileWriter; import java.io.IOException; public class FileUtil { // 把字符串保存到指定路径的文本文件 输出流 public static void saveText(String path, String txt) { BufferedWriter os = null; try { os = new BufferedWriter(new FileWriter(path)); os.write(txt); } catch (Exception e) { e.printStackTrace(); } finally { if (os != null) { try { os.close(); } catch (IOException e) { e.printStackTrace(); } } } } // 从指定路径的文本文件中读取内容字符串 输入流 public static String openText(String path) { BufferedReader is = null; StringBuilder sb = new StringBuilder(); try { is = new BufferedReader(new FileReader(path)); String line = null; // 行读取 while ((line = is.readLine()) != null) { sb.append(line); } } catch (Exception e) { e.printStackTrace(); } finally { if (is != null) { try { is.close(); } catch (IOException e) { e.printStackTrace(); } } } return sb.toString(); } // 把位图数据保存到指定路径的图片文件 public static void saveImage(String path, Bitmap bitmap) { FileOutputStream fos = null; try { fos = new FileOutputStream(path); // 把位图数据压缩到文件输出流中 bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos); } catch (Exception e) { e.printStackTrace(); } finally { if (fos != null) { try { fos.close(); } catch (IOException e) { e.printStackTrace(); } } } } // 从指定路径的图片文件中读取位图数据 public static Bitmap openImage(String path) { Bitmap bitmap = null; FileInputStream fis = null; try { fis = new FileInputStream(path); bitmap = BitmapFactory.decodeStream(fis); } catch (Exception e) { e.printStackTrace(); } finally { if (fis != null) { try { fis.close(); } catch (IOException e) { e.printStackTrace(); } } } return bitmap; } }
布局文件
activity_file_write.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:padding="5dp"> <LinearLayout android:layout_width="match_parent" android:layout_height="40dp" android:orientation="horizontal"> <TextView android:id="@+id/tv_name" android:layout_width="wrap_content" android:layout_height="match_parent" android:gravity="center" android:text="姓名：" android:textColor="@color/black" android:textSize="17sp" /> <EditText android:id="@+id/et_name" android:layout_width="0dp" android:layout_height="match_parent" android:layout_marginTop="3dp" android:layout_marginBottom="3dp" android:layout_weight="1" android:background="@drawable/edittext_select" android:hint="请输入姓名" android:inputType="text" android:maxLength="12" android:textColor="@color/black" android:textSize="17sp" /> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="40dp" android:orientation="horizontal"> <TextView android:id="@+id/tv_age" android:layout_width="wrap_content" android:layout_height="match_parent" android:gravity="center" android:text="年龄：" android:textColor="@color/black" android:textSize="17sp" /> <EditText android:id="@+id/et_age" android:layout_width="0dp" android:layout_height="match_parent" android:layout_marginTop="3dp" android:layout_marginBottom="3dp" android:layout_weight="1" android:background="@drawable/edittext_select" android:hint="请输入年龄" android:inputType="number" android:maxLength="2" android:textColor="@color/black" android:textSize="17sp" /> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="40dp" android:orientation="horizontal"> <TextView android:id="@+id/tv_height" android:layout_width="wrap_content" android:layout_height="match_parent" android:gravity="center" android:text="身高：" android:textColor="@color/black" android:textSize="17sp" /> <EditText android:id="@+id/et_height" android:layout_width="0dp" android:layout_height="match_parent" android:layout_marginTop="3dp" android:layout_marginBottom="3dp" android:layout_weight="1" android:background="@drawable/edittext_select" android:hint="请输入身高" android:inputType="number" android:maxLength="3" android:textColor="@color/black" android:textSize="17sp" /> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="40dp" android:orientation="horizontal"> <TextView android:id="@+id/tv_weight" android:layout_width="wrap_content" android:layout_height="match_parent" android:gravity="center" android:text="体重：" android:textColor="@color/black" android:textSize="17sp" /> <EditText android:id="@+id/et_weight" android:layout_width="0dp" android:layout_height="match_parent" android:layout_marginTop="3dp" android:layout_marginBottom="3dp" android:layout_weight="1" android:background="@drawable/edittext_select" android:hint="请输入体重" android:inputType="numberDecimal" android:maxLength="5" android:textColor="@color/black" android:textSize="17sp" /> </LinearLayout> <CheckBox android:id="@+id/ck_married" android:layout_width="wrap_content" android:layout_height="wrap_content" android:checked="false" android:gravity="center" android:text="已婚" android:textColor="@color/black" android:textSize="17sp" /> <Button android:id="@+id/btn_save" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="保存" android:textColor="@color/black" android:textSize="17sp" /> <Button android:id="@+id/btn_read" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="读取" android:textColor="@color/black" android:textSize="17sp" /> <TextView android:id="@+id/tv_txt" android:layout_width="match_parent" android:layout_height="wrap_content" android:textColor="@color/black" android:textSize="17sp" /> </LinearLayout>
