add preview image function, add comments

Author: katcom

app/src/main/java/com/katcom/androidFileVault/FileVault.java

@@ -1,18 +1,29 @@
 package com.katcom.androidFileVault;
 
 import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.util.Log;
 
+import java.io.BufferedInputStream;
 import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.UUID;
 
 public class FileVault {
-    public static String sVaultDirectory = "FileVaultOne";
-    private static FileVault sVault;
-    private List<ProtectedFile> mFiles;
+    public static String TAG ="FileVault"; // For debug
+    public static String sVaultDirectory = "FileVaultOne";  // The directory of the vault in the private storage of this app
+    private static FileVault sVault;    // This class is a singleton, only one instance allowed
+    private List<ProtectedFile> mFiles;     // Entries of all files
+    private Context mContext;           // Android context, used to get to the private storage
+
     private FileVault(Context context){
-        // Singleton
+        mContext= context;
         File directory = context.getFilesDir();
         File vaultFolder = new File(directory, sVaultDirectory);
 
@@ -21,7 +32,8 @@ private FileVault(Context context){
         mFiles = new ArrayList<ProtectedFile>();
 
         for(String filename: files){
-            ProtectedFile file = new ProtectedFile(filename,null,UUID.randomUUID());
+            String path = mContext.getFilesDir() + "/" + sVaultDirectory +"/" + filename;
+            ProtectedFile file = new ProtectedFile(filename,path,UUID.randomUUID());
             mFiles.add(file);
         }
     }
@@ -48,4 +60,51 @@ public ProtectedFile getFile(UUID id){
     public String getVaultDirectory(){
         return sVaultDirectory;
     }
+
+    /**
+     *  Get the preview picture of the given file based on its type
+     * @param file
+     * @param sizeX
+     * @param sizeY
+     * @return
+     */
+    public Bitmap getPreview(ProtectedFile file,int sizeX,int sizeY){
+        // Currently all the sample files are pictures, we just need to return the preview of pictures
+           return getPicturePreview(file,sizeX,sizeY);
+    }
+
+    private Bitmap getPicturePreview(ProtectedFile file,int sizeX,int sizeY) {
+        BitmapFactory.Options options = new BitmapFactory.Options();
+        options.inJustDecodeBounds = true;
+        BitmapFactory.decodeFile(file.getFilepath(),options);
+
+        float srcWidth = options.outWidth;
+        float srcHeight = options.outHeight;
+
+        float targetWidth = Utils.dip2px(mContext,sizeX);
+        float targetHeight = Utils.dip2px(mContext,sizeY);
+
+        // Scale the picture
+        int inSampleSize = 1;
+        if(srcHeight > targetHeight || srcHeight > targetHeight){
+            if(srcWidth > targetWidth){
+                inSampleSize = Math.round(srcWidth/targetWidth);
+            }else{
+                inSampleSize = Math.round(srcHeight/targetHeight);
+            }
+        }
+
+        options = new BitmapFactory.Options();
+        options.inSampleSize = inSampleSize;
+
+        return BitmapFactory.decodeFile(file.getFilepath(),options);
+    }
+
+    public void importFile(String filepath){
+        // TODO
+    }
+    public void exportFile(String filename, String sourcePath,String targetPath){
+        // TODO
+    }
+
 }

app/src/main/java/com/katcom/androidFileVault/PreviewMode.java

@@ -3,11 +3,17 @@
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * This class describe different modes of preview. All modes are pre-defined
+ * It shouldn't be instantiated.
+ * The static variables describe the supported modes.
+ * Other class can get the list of all supported mode by calling getModeList() method.
+ */
 public class PreviewMode {
     final public static String FILE_DETAIL = "File Detail";
     final public static String PREVIEW_SMALL = "Preview Small";
     final public static String PREVIEW_MEDIUM = "Preview Medium";
-    final public static String PREVIEW_BIG = "Preview Big";
+    //final public static String PREVIEW_BIG = "Preview Big";
     private static List<String> modes;
 
     private PreviewMode(){}
@@ -16,11 +22,21 @@ private PreviewMode(){}
          modes = new ArrayList<>();
          modes.add(FILE_DETAIL);
          modes.add(PREVIEW_SMALL);
+         modes.add(PREVIEW_MEDIUM);
     }
 
+    /**
+     *
+     * @return The list of all modes.
+     */
     public static List<String> getModeList(){
         return modes;
     }
+
+    /**
+     *
+     * @return The number of the supported modes
+     */
     public static int getModeCount(){
         return modes.size();
     }

app/src/main/java/com/katcom/androidFileVault/ProtectedFile.java

@@ -5,12 +5,25 @@
 public class ProtectedFile {
     private String filename;
     private String filepath;
+    private String type;
+    private UUID id;
+
+    public ProtectedFile(String filename,String filepath,UUID id){
+        this.filename = filename;
+        this.filepath = filepath;
+        this.id = id;
+    }
+
+    public boolean isPicture(){
+        //TODO
+        return false;
+    }
 
+    ////////////////////////// Getter and Setter/////////////////////////////////////
     public UUID getId() {
         return id;
     }
 
-    private UUID id;
     public String getFilename() {
         return filename;
     }
@@ -27,12 +40,14 @@ public void setFilepath(String filepath) {
         this.filepath = filepath;
     }
 
-    private String type;
+    public String getType() {
+        return type;
+    }
 
-    public ProtectedFile(String filename,String filepath,UUID id){
-        this.filename = filename;
-        this.filepath = filepath;
-        this.id = id;
+    public void setType(String type) {
+        this.type = type;
     }
 
+
+
 }

app/src/main/java/com/katcom/androidFileVault/Utils.java

@@ -2,6 +2,7 @@
 
 import android.content.Context;
 import android.content.res.AssetManager;
+import android.graphics.Bitmap;
 import android.util.Log;
 
 import java.io.BufferedInputStream;
@@ -81,4 +82,25 @@ public static void copyFilesFromAsset(Context context,String source,String targe
             }
         }
     }
+
+    /**
+     *  Calculate px (pixel) from dp
+     * @param context
+     * @param dpValue
+     * @return
+     */
+    public static int dip2px(Context context, float dpValue) {
+        final float scale = context.getResources().getDisplayMetrics().density;
+        return (int) (dpValue * scale + 0.5f);
+    }
+
+    /**
+     * Calculate dp from px (pixel)
+     */
+    public static int px2dip(Context context, float pxValue) {
+        final float scale = context.getResources().getDisplayMetrics().density;
+        return (int) (pxValue / scale + 0.5f);
+    }
+
+
 }