src/com/android/camera/ThumbnailController.java

/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.camera;


import android.content.ContentResolver;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.TransitionDrawable;
import android.media.ThumbnailUtil;
import android.net.Uri;
import android.os.ParcelFileDescriptor;
import android.util.Log;
import android.view.ViewGroup.LayoutParams;
import android.widget.ImageView;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

/** A controller shows thumbnail picture on a button. The thumbnail picture
 * corresponds to a URI of the original picture/video. The thumbnail bitmap
 * and the URI can be saved to a file (and later loaded from it).
 * <pre>
 *    public ThumbnailController(ImageView button)
 *    public void setData(Uri uri, Bitmap original)
 *    public void updateDisplayIfNeeded()
 *    public Uri getUri()
 *    public boolean storeData(String filePath)
 *    public boolean loadData(String filePath)
 * </pre>
 */
public class ThumbnailController {

    @SuppressWarnings("unused")
    private static final String TAG = "ThumbnailController";
    private final ContentResolver mContentResolver;
    private Uri mUri;
    private Bitmap mThumb;
    private final ImageView mButton;
    private Drawable[] mThumbs;
    private TransitionDrawable mThumbTransition;
    private boolean mShouldAnimateThumb;
    private final Resources mResources;

    // The "frame" is a drawable we want to put on top of the thumbnail.
    public ThumbnailController(Resources resources,
            ImageView button, ContentResolver contentResolver) {
        mResources = resources;
        mButton = button;
        mContentResolver = contentResolver;
    }

    public void setData(Uri uri, Bitmap original) {
        // Make sure uri and original are consistently both null or both
        // non-null.
        if (uri == null || original == null) {
            uri = null;
            original = null;
        }
        mUri = uri;
        updateThumb(original);
    }

    public Uri getUri() {
        return mUri;
    }

    private static final int BUFSIZE = 4096;

    // Stores the data from the specified file.
    // Returns true for success.
    public boolean storeData(String filePath) {
        if (mUri == null) {
            return false;
        }

        FileOutputStream f = null;
        BufferedOutputStream b = null;
        DataOutputStream d = null;
        try {
            f = new FileOutputStream(filePath);
            b = new BufferedOutputStream(f, BUFSIZE);
            d = new DataOutputStream(b);
            d.writeUTF(mUri.toString());
            mThumb.compress(Bitmap.CompressFormat.PNG, 100, d);
            d.close();
        } catch (IOException e) {
            return false;
        } finally {
            MenuHelper.closeSilently(f);
            MenuHelper.closeSilently(b);
            MenuHelper.closeSilently(d);
        }
        return true;
    }

    // Loads the data from the specified file.
    // Returns true for success.
    public boolean loadData(String filePath) {
        FileInputStream f = null;
        BufferedInputStream b = null;
        DataInputStream d = null;
        try {
            f = new FileInputStream(filePath);
            b = new BufferedInputStream(f, BUFSIZE);
            d = new DataInputStream(b);
            Uri uri = Uri.parse(d.readUTF());
            Bitmap thumb = BitmapFactory.decodeStream(d);
            setData(uri, thumb);
            d.close();
        } catch (IOException e) {
            return false;
        } finally {
            MenuHelper.closeSilently(f);
            MenuHelper.closeSilently(b);
            MenuHelper.closeSilently(d);
        }
        return true;
    }

    public void updateDisplayIfNeeded() {
        if (mUri == null) {
            mButton.setImageDrawable(null);
            return;
        }

        if (mShouldAnimateThumb) {
            mThumbTransition.startTransition(500);
            mShouldAnimateThumb = false;
        }
    }

    private void updateThumb(Bitmap original) {
        if (original == null) {
            mThumb = null;
            mThumbs = null;
            return;
        }

        // Make the mini-thumb size smaller than the button size so that the
        // image corners don't peek out from the rounded corners of the
        // frame_thumb graphic:
        final int PADDING_WIDTH = 2;
        final int PADDING_HEIGHT = 2;
        LayoutParams param = mButton.getLayoutParams();
        final int miniThumbWidth = param.width - 2 * PADDING_WIDTH;
        final int miniThumbHeight = param.height - 2 * PADDING_HEIGHT;
        mThumb = ThumbnailUtil.extractMiniThumb(
                original, miniThumbWidth, miniThumbHeight,
                Util.NO_RECYCLE_INPUT);
        Drawable drawable;
        if (mThumbs == null) {
            mThumbs = new Drawable[2];
            mThumbs[1] = new BitmapDrawable(mResources, mThumb);
            drawable = mThumbs[1];
            mShouldAnimateThumb = false;
        } else {
            mThumbs[0] = mThumbs[1];
            mThumbs[1] = new BitmapDrawable(mResources, mThumb);
            mThumbTransition = new TransitionDrawable(mThumbs);
            drawable = mThumbTransition;
            mShouldAnimateThumb = true;
        }
        mButton.setImageDrawable(drawable);
    }

    public boolean isUriValid() {
        if (mUri == null) {
            return false;
        }
        try {
            ParcelFileDescriptor pfd =
                    mContentResolver.openFileDescriptor(mUri, "r");
            if (pfd == null) {
                Log.e(TAG, "Fail to open URI.");
                return false;
            }
            pfd.close();
        } catch (IOException ex) {
            return false;
        }
        return true;
    }
}