src/com/android/settings/MasterClear.java

/*
 * Copyright (C) 2008 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.settings;

import com.android.settings.R;

import android.app.Activity;
import android.app.Fragment;
import android.content.Intent;
import android.content.res.Resources;
import android.os.Bundle;
import android.preference.Preference;
import android.preference.PreferenceActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.CheckBox;

/**
 * Confirm and execute a reset of the device to a clean "just out of the box"
 * state.  Multiple confirmations are required: first, a general "are you sure
 * you want to do this?" prompt, followed by a keyguard pattern trace if the user
 * has defined one, followed by a final strongly-worded "THIS WILL ERASE EVERYTHING
 * ON THE PHONE" prompt.  If at any time the phone is allowed to go to sleep, is
 * locked, et cetera, then the confirmation sequence is abandoned.
 *
 * This is the initial screen.
 */
public class MasterClear extends Fragment {

    private static final int KEYGUARD_REQUEST = 55;

    static final String ERASE_EXTERNAL_EXTRA = "erase_sd";

    private View mContentView;
    private Button mInitiateButton;
    private View mExternalStorageContainer;
    private CheckBox mExternalStorage;

    /**
     * Keyguard validation is run using the standard {@link ConfirmLockPattern}
     * component as a subactivity
     * @param request the request code to be returned once confirmation finishes
     * @return true if confirmation launched
     */
    private boolean runKeyguardConfirmation(int request) {
        Resources res = getActivity().getResources();
        return new ChooseLockSettingsHelper(getActivity(), this)
                .launchConfirmationActivity(request,
                        res.getText(R.string.master_clear_gesture_prompt),
                        res.getText(R.string.master_clear_gesture_explanation));
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode != KEYGUARD_REQUEST) {
            return;
        }

        // If the user entered a valid keyguard trace, present the final
        // confirmation prompt; otherwise, go back to the initial state.
        if (resultCode == Activity.RESULT_OK) {
            showFinalConfirmation();
        } else {
            establishInitialState();
        }
    }

    private void showFinalConfirmation() {
        Preference preference = new Preference(getActivity());
        preference.setFragment(MasterClearConfirm.class.getName());
        preference.setTitle(R.string.master_clear_confirm_title);
        preference.getExtras().putBoolean(ERASE_EXTERNAL_EXTRA, mExternalStorage.isChecked());
        ((PreferenceActivity) getActivity()).onPreferenceStartFragment(null, preference);
    }

    /**
     * If the user clicks to begin the reset sequence, we next require a
     * keyguard confirmation if the user has currently enabled one.  If there
     * is no keyguard available, we simply go to the final confirmation prompt.
     */
    private Button.OnClickListener mInitiateListener = new Button.OnClickListener() {

        public void onClick(View v) {
            if (!runKeyguardConfirmation(KEYGUARD_REQUEST)) {
                showFinalConfirmation();
            }
        }
    };

    /**
     * In its initial state, the activity presents a button for the user to
     * click in order to initiate a confirmation sequence.  This method is
     * called from various other points in the code to reset the activity to
     * this base state.
     *
     * <p>Reinflating views from resources is expensive and prevents us from
     * caching widget pointers, so we use a single-inflate pattern:  we lazy-
     * inflate each view, caching all of the widget pointers we'll need at the
     * time, then simply reuse the inflated views directly whenever we need
     * to change contents.
     */
    private void establishInitialState() {
        mInitiateButton = (Button) mContentView.findViewById(R.id.initiate_master_clear);
        mInitiateButton.setOnClickListener(mInitiateListener);
        mExternalStorageContainer = mContentView.findViewById(R.id.erase_external_container);
        mExternalStorage = (CheckBox) mContentView.findViewById(R.id.erase_external);

        mExternalStorageContainer.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                mExternalStorage.toggle();
            }
        });
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        mContentView = inflater.inflate(R.layout.master_clear, null);
        establishInitialState();
        return mContentView;
    }
}