https://source.android.com/ 
/*
 * Copyright (C) 2017 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 android.service.autofill;

import static android.view.autofill.Helper.sDebug;

import android.annotation.DrawableRes;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.annotation.TestApi;
import android.os.Parcel;
import android.os.Parcelable;
import android.text.TextUtils;
import android.util.Log;
import android.view.autofill.AutofillId;
import android.widget.ImageView;
import android.widget.RemoteViews;

import com.android.internal.util.Preconditions;

import java.util.ArrayList;
import java.util.regex.Pattern;


Replaces the content of a child ImageView of a presentation template with the first image that matches a regular expression (regex). 
Typically used to display credit card logos. Example:

  new ImageTransformation.Builder(ccNumberId, Pattern.compile("^4815.*$"),
                                  R.drawable.ic_credit_card_logo1, "Brand 1")
    .addOption(Pattern.compile("^1623.*$"), R.drawable.ic_credit_card_logo2, "Brand 2")
    .addOption(Pattern.compile("^42.*$"), R.drawable.ic_credit_card_logo3, "Brand 3")
    .build();



There is no imposed limit in the number of options, but keep in mind that regexs are
expensive to evaluate, so use the minimum number of regexs and add the most common first
(for example, if this is a tranformation for a credit card logo and the most common credit card
issuers are banks X and Y, add the regexes that resolves these 2 banks first).

/**
 * Replaces the content of a child {@link ImageView} of a
 * {@link RemoteViews presentation template} with the first image that matches a regular expression
 * (regex).
 *
 * <p>Typically used to display credit card logos. Example:
 *
 * <pre class="prettyprint">
 *   new ImageTransformation.Builder(ccNumberId, Pattern.compile("^4815.*$"),
 *                                   R.drawable.ic_credit_card_logo1, "Brand 1")
 *     .addOption(Pattern.compile("^1623.*$"), R.drawable.ic_credit_card_logo2, "Brand 2")
 *     .addOption(Pattern.compile("^42.*$"), R.drawable.ic_credit_card_logo3, "Brand 3")
 *     .build();
 * </pre>
 *
 * <p>There is no imposed limit in the number of options, but keep in mind that regexs are
 * expensive to evaluate, so use the minimum number of regexs and add the most common first
 * (for example, if this is a tranformation for a credit card logo and the most common credit card
 * issuers are banks X and Y, add the regexes that resolves these 2 banks first).
 */
public final class ImageTransformation extends InternalTransformation implements Transformation,
        Parcelable {
    private static final String TAG = "ImageTransformation";

    private final AutofillId mId;
    private final ArrayList<Option> mOptions;

    private ImageTransformation(Builder builder) {
        mId = builder.mId;
        mOptions = builder.mOptions;
    }

    
@hide
/** @hide */
    @TestApi
    @Override
    public void apply(@NonNull ValueFinder finder, @NonNull RemoteViews parentTemplate,
            int childViewId) throws Exception {
        final String value = finder.findByAutofillId(mId);
        if (value == null) {
            Log.w(TAG, "No view for id " + mId);
            return;
        }
        final int size = mOptions.size();
        if (sDebug) {
            Log.d(TAG, size + " multiple options on id " + childViewId + " to compare against");
        }

        for (int i = 0; i < size; i++) {
            final Option option = mOptions.get(i);
            try {
                if (option.pattern.matcher(value).matches()) {
                    Log.d(TAG, "Found match at " + i + ": " + option);
                    parentTemplate.setImageViewResource(childViewId, option.resId);
                    if (option.contentDescription != null) {
                        parentTemplate.setContentDescription(childViewId,
                                option.contentDescription);
                    }
                    return;
                }
            } catch (Exception e) {
                // Do not log full exception to avoid PII leaking
                Log.w(TAG, "Error matching regex #" + i + "(" + option.pattern + ") on id "
                        + option.resId + ": " + e.getClass());
                throw e;

            }
        }
        if (sDebug) Log.d(TAG, "No match for " + value);
    }

    
Builder for ImageTransformation objects. 
/**
     * Builder for {@link ImageTransformation} objects.
     */
    public static class Builder {
        private final AutofillId mId;
        private final ArrayList<Option> mOptions = new ArrayList<>();
        private boolean mDestroyed;

        
Creates a new builder for a autofill id and add a first option.

Params:
  • id – id of the screen field that will be used to evaluate whether the image should
be used.
  • regex – regular expression defining what should be matched to use this image.
  • resId – resource id of the image (in the autofill service's package). The presentation must contain a ImageView child with that id.
Deprecated:use Builder(AutofillId, Pattern, int, CharSequence) instead.
/**
         * Creates a new builder for a autofill id and add a first option.
         *
         * @param id id of the screen field that will be used to evaluate whether the image should
         * be used.
         * @param regex regular expression defining what should be matched to use this image.
         * @param resId resource id of the image (in the autofill service's package). The
         * {@link RemoteViews presentation} must contain a {@link ImageView} child with that id.
         *
         * @deprecated use
         * {@link #ImageTransformation.Builder(AutofillId, Pattern, int, CharSequence)} instead.
         */
        @Deprecated
        public Builder(@NonNull AutofillId id, @NonNull Pattern regex, @DrawableRes int resId) {
            mId = Preconditions.checkNotNull(id);
            addOption(regex, resId);
        }

        
Creates a new builder for a autofill id and add a first option.

Params:
  • id – id of the screen field that will be used to evaluate whether the image should
be used.
  • regex – regular expression defining what should be matched to use this image.
  • resId – resource id of the image (in the autofill service's package). The presentation must contain a ImageView child with that id.
  • contentDescription – content description to be applied in the child view.
/**
         * Creates a new builder for a autofill id and add a first option.
         *
         * @param id id of the screen field that will be used to evaluate whether the image should
         * be used.
         * @param regex regular expression defining what should be matched to use this image.
         * @param resId resource id of the image (in the autofill service's package). The
         * {@link RemoteViews presentation} must contain a {@link ImageView} child with that id.
         * @param contentDescription content description to be applied in the child view.
         */
        public Builder(@NonNull AutofillId id, @NonNull Pattern regex, @DrawableRes int resId,
                @NonNull CharSequence contentDescription) {
            mId = Preconditions.checkNotNull(id);
            addOption(regex, resId, contentDescription);
        }

        
Adds an option to replace the child view with a different image when the regex matches.

Params:
  • regex – regular expression defining what should be matched to use this image.
  • resId – resource id of the image (in the autofill service's package). The presentation must contain a ImageView child with that id.
Returns:this build
Deprecated:use addOption(Pattern, int, CharSequence) instead.
/**
         * Adds an option to replace the child view with a different image when the regex matches.
         *
         * @param regex regular expression defining what should be matched to use this image.
         * @param resId resource id of the image (in the autofill service's package). The
         * {@link RemoteViews presentation} must contain a {@link ImageView} child with that id.
         *
         * @return this build
         *
         * @deprecated use {@link #addOption(Pattern, int, CharSequence)} instead.
         */
        @Deprecated
        public Builder addOption(@NonNull Pattern regex, @DrawableRes int resId) {
            addOptionInternal(regex, resId, null);
            return this;
        }

        
Adds an option to replace the child view with a different image and content description
when the regex matches.

Params:
  • regex – regular expression defining what should be matched to use this image.
  • resId – resource id of the image (in the autofill service's package). The presentation must contain a ImageView child with that id.
  • contentDescription – content description to be applied in the child view.
Returns:this build
/**
         * Adds an option to replace the child view with a different image and content description
         * when the regex matches.
         *
         * @param regex regular expression defining what should be matched to use this image.
         * @param resId resource id of the image (in the autofill service's package). The
         * {@link RemoteViews presentation} must contain a {@link ImageView} child with that id.
         * @param contentDescription content description to be applied in the child view.
         *
         * @return this build
         */
        public Builder addOption(@NonNull Pattern regex, @DrawableRes int resId,
                @NonNull CharSequence contentDescription) {
            addOptionInternal(regex, resId, Preconditions.checkNotNull(contentDescription));
            return this;
        }

        private void addOptionInternal(@NonNull Pattern regex, @DrawableRes int resId,
                @Nullable CharSequence contentDescription) {
            throwIfDestroyed();

            Preconditions.checkNotNull(regex);
            Preconditions.checkArgument(resId != 0);

            mOptions.add(new Option(regex, resId, contentDescription));
        }


        
Creates a new ImageTransformation instance. 
/**
         * Creates a new {@link ImageTransformation} instance.
         */
        public ImageTransformation build() {
            throwIfDestroyed();
            mDestroyed = true;
            return new ImageTransformation(this);
        }

        private void throwIfDestroyed() {
            Preconditions.checkState(!mDestroyed, "Already called build()");
        }
    }

    /////////////////////////////////////
    // Object "contract" methods. //
    /////////////////////////////////////
    @Override
    public String toString() {
        if (!sDebug) return super.toString();

        return "ImageTransformation: [id=" + mId + ", options=" + mOptions + "]";
    }

    /////////////////////////////////////
    // Parcelable "contract" methods. //
    /////////////////////////////////////
    @Override
    public int describeContents() {
        return 0;
    }
    @Override
    public void writeToParcel(Parcel parcel, int flags) {
        parcel.writeParcelable(mId, flags);

        final int size = mOptions.size();
        final Pattern[] patterns = new Pattern[size];
        final int[] resIds = new int[size];
        final CharSequence[] contentDescriptions = new String[size];
        for (int i = 0; i < size; i++) {
            final Option option = mOptions.get(i);
            patterns[i] = option.pattern;
            resIds[i] = option.resId;
            contentDescriptions[i] = option.contentDescription;
        }
        parcel.writeSerializable(patterns);
        parcel.writeIntArray(resIds);
        parcel.writeCharSequenceArray(contentDescriptions);
    }

    public static final Parcelable.Creator<ImageTransformation> CREATOR =
            new Parcelable.Creator<ImageTransformation>() {
        @Override
        public ImageTransformation createFromParcel(Parcel parcel) {
            final AutofillId id = parcel.readParcelable(null);

            final Pattern[] regexs = (Pattern[]) parcel.readSerializable();
            final int[] resIds = parcel.createIntArray();
            final CharSequence[] contentDescriptions = parcel.readCharSequenceArray();

            // Always go through the builder to ensure the data ingested by the system obeys the
            // contract of the builder to avoid attacks using specially crafted parcels.
            final CharSequence contentDescription = contentDescriptions[0];
            final ImageTransformation.Builder builder = (contentDescription != null)
                    ? new ImageTransformation.Builder(id, regexs[0], resIds[0], contentDescription)
                    : new ImageTransformation.Builder(id, regexs[0], resIds[0]);

            final int size = regexs.length;
            for (int i = 1; i < size; i++) {
                if (contentDescriptions[i] != null) {
                    builder.addOption(regexs[i], resIds[i], contentDescriptions[i]);
                } else {
                    builder.addOption(regexs[i], resIds[i]);
                }
            }

            return builder.build();
        }

        @Override
        public ImageTransformation[] newArray(int size) {
            return new ImageTransformation[size];
        }
    };

    private static final class Option {
        public final Pattern pattern;
        public final int resId;
        public final CharSequence contentDescription;

        Option(Pattern pattern, int resId, CharSequence contentDescription) {
            this.pattern = pattern;
            this.resId = resId;
            this.contentDescription = TextUtils.trimNoCopySpans(contentDescription);
        }
    }
}