android/app/DialogFragment.java

/*
 * Copyright (C) 2010 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.app;

import android.content.DialogInterface;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.WindowManager;

/**
 * A fragment that displays a dialog window, floating on top of its
 * activity's window.  This fragment contains a Dialog object, which it
 * displays as appropriate based on the fragment's state.  Control of
 * the dialog (deciding when to show, hide, dismiss it) should be done through
 * the API here, not with direct calls on the dialog.
 *
 * <p>Implementations should override this class and implement
 * {@link #onCreateView(LayoutInflater, ViewGroup, Bundle)} to supply the
 * content of the dialog.  Alternatively, they can override
 * {@link #onCreateDialog(Bundle)} to create an entirely custom dialog, such
 * as an AlertDialog, with its own content.
 */
public class DialogFragment extends Fragment
        implements DialogInterface.OnCancelListener, DialogInterface.OnDismissListener {

    /**
     * Style for {@link #DialogFragment(int, int)} constructor: a basic,
     * normal dialog.
     */
    public static final int STYLE_NORMAL = 0;

    /**
     * Style for {@link #DialogFragment(int, int)} constructor: don't include
     * a title area.
     */
    public static final int STYLE_NO_TITLE = 1;

    /**
     * Style for {@link #DialogFragment(int, int)} constructor: don't draw
     * any frame at all; the view hierarchy returned by {@link #onCreateView}
     * is entirely responsible for drawing the dialog.
     */
    public static final int STYLE_NO_FRAME = 2;

    /**
     * Style for {@link #DialogFragment(int, int)} constructor: like
     * {@link #STYLE_NO_FRAME}, but also disables all input to the dialog.
     * The user can not touch it, and its window will not receive input focus.
     */
    public static final int STYLE_NO_INPUT = 3;

    private static final String SAVED_DIALOG_STATE_TAG = "android:savedDialogState";
    private static final String SAVED_STYLE = "android:style";
    private static final String SAVED_THEME = "android:theme";
    private static final String SAVED_CANCELABLE = "android:cancelable";
    private static final String SAVED_BACK_STACK_ID = "android:backStackId";

    int mStyle = STYLE_NORMAL;
    int mTheme = 0;
    boolean mCancelable = true;
    int mBackStackId = -1;

    Dialog mDialog;
    boolean mDestroyed;

    public DialogFragment() {
    }

    /**
     * Call to customize the basic appearance and behavior of the
     * fragment's dialog.  This can be used for some common dialog behaviors,
     * taking care of selecting flags, theme, and other options for you.  The
     * same effect can be achieve by manually setting Dialog and Window
     * attributes yourself.  Calling this after the fragment's Dialog is
     * created will have no effect.
     *
     * @param style Selects a standard style: may be {@link #STYLE_NORMAL},
     * {@link #STYLE_NO_TITLE}, {@link #STYLE_NO_FRAME}, or
     * {@link #STYLE_NO_INPUT}.
     * @param theme Optional custom theme.  If 0, an appropriate theme (based
     * on the style) will be selected for you.
     */
    public void setStyle(int style, int theme) {
        mStyle = style;
        if (mStyle == STYLE_NO_FRAME || mStyle == STYLE_NO_INPUT) {
            mTheme = android.R.style.Theme_Dialog_NoFrame;
        }
        if (theme != 0) {
            mTheme = theme;
        }
    }

    /**
     * Display the dialog, adding the fragment to the given activity.  This
     * is a convenience for explicitly creating a transaction, adding the
     * fragment to it with the given tag, and committing it.  This does
     * <em>not</em> add the transaction to the back stack.  When the fragment
     * is dismissed, a new transaction will be executed to remove it from
     * the activity.
     * @param activity The activity this fragment will be added to.
     * @param tag The tag for this fragment, as per
     * {@link FragmentTransaction#add(Fragment, String) FragmentTransaction.add}.
     */
    public void show(Activity activity, String tag) {
        FragmentTransaction ft = activity.openFragmentTransaction();
        ft.add(this, tag);
        ft.commit();
    }

    /**
     * Display the dialog, adding the fragment to the given activity using
     * an existing transaction and then committing the transaction.
     * @param activity The activity this fragment will be added to.
     * @param transaction An existing transaction in which to add the fragment.
     * @param tag The tag for this fragment, as per
     * {@link FragmentTransaction#add(Fragment, String) FragmentTransaction.add}.
     * @return Returns the identifier of the committed transaction, as per
     * {@link FragmentTransaction#commit() FragmentTransaction.commit()}.
     */
    public int show(Activity activity, FragmentTransaction transaction, String tag) {
        transaction.add(this, tag);
        mBackStackId = transaction.commit();
        return mBackStackId;
    }

    /**
     * Dismiss the fragment and its dialog.  If the fragment was added to the
     * back stack, all back stack state up to and including this entry will
     * be popped.  Otherwise, a new transaction will be committed to remove
     * the fragment.
     */
    public void dismiss() {
        if (mDialog != null) {
            mDialog.dismiss();
        }
        if (mBackStackId >= 0) {
            getActivity().popBackStack(mBackStackId, Activity.POP_BACK_STACK_INCLUSIVE);
            mBackStackId = -1;
        } else {
            FragmentTransaction ft = getActivity().openFragmentTransaction();
            ft.remove(this);
            ft.commit();
        }
    }

    public Dialog getDialog() {
        return mDialog;
    }

    public int getTheme() {
        return mTheme;
    }

    public void setCancelable(boolean cancelable) {
        mCancelable = cancelable;
        if (mDialog != null) mDialog.setCancelable(cancelable);
    }

    public boolean getCancelable() {
        return mCancelable;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (savedInstanceState != null) {
            mStyle = savedInstanceState.getInt(SAVED_STYLE, mStyle);
            mTheme = savedInstanceState.getInt(SAVED_THEME, mTheme);
            mCancelable = savedInstanceState.getBoolean(SAVED_CANCELABLE, mCancelable);
            mBackStackId = savedInstanceState.getInt(SAVED_BACK_STACK_ID, mBackStackId);
        }
    }

    public Dialog onCreateDialog(Bundle savedInstanceState) {
        return new Dialog(getActivity(), getTheme());
    }

    public void onCancel(DialogInterface dialog) {
        if (mBackStackId >= 0) {
            // If this fragment is part of the back stack, then cancelling
            // the dialog means popping off the back stack.
            getActivity().popBackStack(mBackStackId, Activity.POP_BACK_STACK_INCLUSIVE);
            mBackStackId = -1;
        }
    }

    public void onDismiss(DialogInterface dialog) {
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        mDialog = onCreateDialog(savedInstanceState);
        mDestroyed = false;
        switch (mStyle) {
            case STYLE_NO_INPUT:
                mDialog.getWindow().addFlags(
                        WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE |
                        WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE);
                // fall through...
            case STYLE_NO_FRAME:
            case STYLE_NO_TITLE:
                mDialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
        }
        View view = getView();
        if (view != null) {
            if (view.getParent() != null) {
                throw new IllegalStateException("DialogFragment can not be attached to a container view");
            }
            mDialog.setContentView(view);
        }
        mDialog.setOwnerActivity(getActivity());
        mDialog.setCancelable(mCancelable);
        mDialog.setOnCancelListener(this);
        mDialog.setOnDismissListener(this);
        if (savedInstanceState != null) {
            Bundle dialogState = savedInstanceState.getBundle(SAVED_DIALOG_STATE_TAG);
            if (dialogState != null) {
                mDialog.onRestoreInstanceState(dialogState);
            }
        }
    }

    @Override
    public void onStart() {
        super.onStart();
        mDialog.show();
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        if (mDialog != null) {
            Bundle dialogState = mDialog.onSaveInstanceState();
            if (dialogState != null) {
                outState.putBundle(SAVED_DIALOG_STATE_TAG, dialogState);
            }
        }
        outState.putInt(SAVED_STYLE, mStyle);
        outState.putInt(SAVED_THEME, mTheme);
        outState.putBoolean(SAVED_CANCELABLE, mCancelable);
        outState.putInt(SAVED_BACK_STACK_ID, mBackStackId);
    }

    @Override
    public void onStop() {
        super.onStop();
        mDialog.hide();
    }

    /**
     * Detach from list view.
     */
    @Override
    public void onDestroyView() {
        super.onDestroyView();
        mDestroyed = true;
        mDialog.dismiss();
        mDialog = null;
    }
}