Android从文件目录中写入和读取图片

要将文件写入储存，首先有在配置文件中去设置权限：

 <span style="white-space:pre"></span><uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>  <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>  <!-- 外部储存可写 -->  <uses-permission android:name="android.permission.READ_CONTACTS"/>

将图片文件写入指定目录：

/* * 访问外部储存私有区域 * 路径为   getExternalFilesDir（）       /mnt/sdcard/Android/data/com.example.call/files * getExternalCacheDir()    /mnt/sdcard/Android/data/com.example.call/cache */public void writeFileToExternalPrivate(){String fileDir = getContext().getExternalFilesDir(Environment.DIRECTORY_MUSIC).getAbsolutePath();Log.v("test", fileDir);String cacheDir = getContext().getExternalCacheDir().getAbsolutePath();File mapFile = new File(cacheDir+File.separator+"map");   //再将图片加载到目录之前先创建Mylog.d("00000000"+mapFile.mkdir());Bitmap bitmap = BitmapFactory.decodeResource(getContext().getResources(), R.drawable.img_person);File file = new File(cacheDir+File.separator+"map","2.png");  //将图片保存到刚创建好的目录下try {FileOutputStream out = new FileOutputStream(file);bitmap.compress(Bitmap.CompressFormat.PNG, 100, out);out.close();} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}Log.v("test", cacheDir);}

从指定目录中读取文件：

<span style="white-space:pre"></span>public void readImgFromFile(){Bitmap bitmap = BitmapFactory.decodeFile(getContext().getExternalCacheDir().getAbsolutePath()+File.separator+"map"+File.separator+"2.png");String cacheDir = getContext().getExternalCacheDir().getAbsolutePath();File file = new File(cacheDir+File.separator+"map","3.png");  //将图片保存到刚创建好的目录下try {FileOutputStream out = new FileOutputStream(file);bitmap.compress(Bitmap.CompressFormat.PNG, 100, out);out.close();} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}

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