Android example source code file (DialogPreference.java)

This example Android source code file (DialogPreference.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, app, attributeset, basesavedstate, bundle, charsequence, content, context, creator, dialog, dialogpreference, drawable, layoutinflater, os, override, parcelable, savedstate, textview, ui, view

The DialogPreference.java Android example source code

/*
 * Copyright (C) 2007 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.preference;


import android.app.AlertDialog;
import android.app.Dialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.SharedPreferences;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.os.Parcel;
import android.os.Parcelable;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.TextView;

/**
 * A base class for {@link Preference} objects that are
 * dialog-based. These preferences will, when clicked, open a dialog showing the
 * actual preference controls.
 * 
 * @attr ref android.R.styleable#DialogPreference_dialogTitle
 * @attr ref android.R.styleable#DialogPreference_dialogMessage
 * @attr ref android.R.styleable#DialogPreference_dialogIcon
 * @attr ref android.R.styleable#DialogPreference_dialogLayout
 * @attr ref android.R.styleable#DialogPreference_positiveButtonText
 * @attr ref android.R.styleable#DialogPreference_negativeButtonText
 */
public abstract class DialogPreference extends Preference implements
        DialogInterface.OnClickListener, DialogInterface.OnDismissListener,
        PreferenceManager.OnActivityDestroyListener {
    private AlertDialog.Builder mBuilder;
    
    private CharSequence mDialogTitle;
    private CharSequence mDialogMessage;
    private Drawable mDialogIcon;
    private CharSequence mPositiveButtonText;
    private CharSequence mNegativeButtonText;
    private int mDialogLayoutResId;

    /** The dialog, if it is showing. */
    private Dialog mDialog;

    /** Which button was clicked. */
    private int mWhichButtonClicked;
    
    public DialogPreference(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        
        TypedArray a = context.obtainStyledAttributes(attrs,
                com.android.internal.R.styleable.DialogPreference, defStyle, 0);
        mDialogTitle = a.getString(com.android.internal.R.styleable.DialogPreference_dialogTitle);
        if (mDialogTitle == null) {
            // Fallback on the regular title of the preference
            // (the one that is seen in the list)
            mDialogTitle = getTitle();
        }
        mDialogMessage = a.getString(com.android.internal.R.styleable.DialogPreference_dialogMessage);
        mDialogIcon = a.getDrawable(com.android.internal.R.styleable.DialogPreference_dialogIcon);
        mPositiveButtonText = a.getString(com.android.internal.R.styleable.DialogPreference_positiveButtonText);
        mNegativeButtonText = a.getString(com.android.internal.R.styleable.DialogPreference_negativeButtonText);
        mDialogLayoutResId = a.getResourceId(com.android.internal.R.styleable.DialogPreference_dialogLayout,
                mDialogLayoutResId);
        a.recycle();
        
    }

    public DialogPreference(Context context, AttributeSet attrs) {
        this(context, attrs, com.android.internal.R.attr.dialogPreferenceStyle);
    }
    
    /**
     * Sets the title of the dialog. This will be shown on subsequent dialogs.
     * 
     * @param dialogTitle The title.
     */
    public void setDialogTitle(CharSequence dialogTitle) {
        mDialogTitle = dialogTitle;
    }

    /**
     * @see #setDialogTitle(CharSequence)
     * @param dialogTitleResId The dialog title as a resource.
     */
    public void setDialogTitle(int dialogTitleResId) {
        setDialogTitle(getContext().getString(dialogTitleResId));
    }
    
    /**
     * Returns the title to be shown on subsequent dialogs.
     * @return The title.
     */
    public CharSequence getDialogTitle() {
        return mDialogTitle;
    }
    
    /**
     * Sets the message of the dialog. This will be shown on subsequent dialogs.
     * <p>
     * This message forms the content View of the dialog and conflicts with
     * list-based dialogs, for example. If setting a custom View on a dialog via
     * {@link #setDialogLayoutResource(int)}, include a text View with ID
     * {@link android.R.id#message} and it will be populated with this message.
     * 
     * @param dialogMessage The message.
     */
    public void setDialogMessage(CharSequence dialogMessage) {
        mDialogMessage = dialogMessage;
    }

    /**
     * @see #setDialogMessage(CharSequence)
     * @param dialogMessageResId The dialog message as a resource.
     */
    public void setDialogMessage(int dialogMessageResId) {
        setDialogMessage(getContext().getString(dialogMessageResId));
    }
    
    /**
     * Returns the message to be shown on subsequent dialogs.
     * @return The message.
     */
    public CharSequence getDialogMessage() {
        return mDialogMessage;
    }
    
    /**
     * Sets the icon of the dialog. This will be shown on subsequent dialogs.
     * 
     * @param dialogIcon The icon, as a {@link Drawable}.
     */
    public void setDialogIcon(Drawable dialogIcon) {
        mDialogIcon = dialogIcon;
    }
    
    /**
     * Sets the icon (resource ID) of the dialog. This will be shown on
     * subsequent dialogs.
     * 
     * @param dialogIconRes The icon, as a resource ID.
     */
    public void setDialogIcon(int dialogIconRes) {
        mDialogIcon = getContext().getResources().getDrawable(dialogIconRes);
    }
    
    /**
     * Returns the icon to be shown on subsequent dialogs.
     * @return The icon, as a {@link Drawable}.
     */
    public Drawable getDialogIcon() {
        return mDialogIcon;
    }
    
    /**
     * Sets the text of the positive button of the dialog. This will be shown on
     * subsequent dialogs.
     * 
     * @param positiveButtonText The text of the positive button.
     */
    public void setPositiveButtonText(CharSequence positiveButtonText) {
        mPositiveButtonText = positiveButtonText;
    }

    /**
     * @see #setPositiveButtonText(CharSequence)
     * @param positiveButtonTextResId The positive button text as a resource.
     */
    public void setPositiveButtonText(int positiveButtonTextResId) {
        setPositiveButtonText(getContext().getString(positiveButtonTextResId));
    }
    
    /**
     * Returns the text of the positive button to be shown on subsequent
     * dialogs.
     * 
     * @return The text of the positive button.
     */
    public CharSequence getPositiveButtonText() {
        return mPositiveButtonText;
    }
    
    /**
     * Sets the text of the negative button of the dialog. This will be shown on
     * subsequent dialogs.
     * 
     * @param negativeButtonText The text of the negative button.
     */
    public void setNegativeButtonText(CharSequence negativeButtonText) {
        mNegativeButtonText = negativeButtonText;
    }
    
    /**
     * @see #setNegativeButtonText(CharSequence)
     * @param negativeButtonTextResId The negative button text as a resource.
     */
    public void setNegativeButtonText(int negativeButtonTextResId) {
        setNegativeButtonText(getContext().getString(negativeButtonTextResId));
    }
    
    /**
     * Returns the text of the negative button to be shown on subsequent
     * dialogs.
     * 
     * @return The text of the negative button.
     */
    public CharSequence getNegativeButtonText() {
        return mNegativeButtonText;
    }
    
    /**
     * Sets the layout resource that is inflated as the {@link View} to be shown
     * as the content View of subsequent dialogs.
     * 
     * @param dialogLayoutResId The layout resource ID to be inflated.
     * @see #setDialogMessage(CharSequence)
     */
    public void setDialogLayoutResource(int dialogLayoutResId) {
        mDialogLayoutResId = dialogLayoutResId;
    }
    
    /**
     * Returns the layout resource that is used as the content View for
     * subsequent dialogs.
     * 
     * @return The layout resource.
     */
    public int getDialogLayoutResource() {
        return mDialogLayoutResId;
    }
    
    /**
     * Prepares the dialog builder to be shown when the preference is clicked.
     * Use this to set custom properties on the dialog.
     * <p>
     * Do not {@link AlertDialog.Builder#create()} or
     * {@link AlertDialog.Builder#show()}.
     */
    protected void onPrepareDialogBuilder(AlertDialog.Builder builder) {
    }
    
    @Override
    protected void onClick() {
        showDialog(null);
    }

    /**
     * Shows the dialog associated with this Preference. This is normally initiated
     * automatically on clicking on the preference. Call this method if you need to
     * show the dialog on some other event.
     * 
     * @param state Optional instance state to restore on the dialog
     */
    protected void showDialog(Bundle state) {
        Context context = getContext();

        mWhichButtonClicked = DialogInterface.BUTTON_NEGATIVE;
        
        mBuilder = new AlertDialog.Builder(context)
            .setTitle(mDialogTitle)
            .setIcon(mDialogIcon)
            .setPositiveButton(mPositiveButtonText, this)
            .setNegativeButton(mNegativeButtonText, this);

        View contentView = onCreateDialogView();
        if (contentView != null) {
            onBindDialogView(contentView);
            mBuilder.setView(contentView);
        } else {
            mBuilder.setMessage(mDialogMessage);
        }
        
        onPrepareDialogBuilder(mBuilder);
        
        getPreferenceManager().registerOnActivityDestroyListener(this);
        
        // Create the dialog
        final Dialog dialog = mDialog = mBuilder.create();
        if (state != null) {
            dialog.onRestoreInstanceState(state);
        }
        if (needInputMethod()) {
            requestInputMethod(dialog);
        }
        dialog.setOnDismissListener(this);
        dialog.show();
    }

    /**
     * Returns whether the preference needs to display a soft input method when the dialog
     * is displayed. Default is false. Subclasses should override this method if they need
     * the soft input method brought up automatically.
     * @hide
     */
    protected boolean needInputMethod() {
        return false;
    }

    /**
     * Sets the required flags on the dialog window to enable input method window to show up.
     */
    private void requestInputMethod(Dialog dialog) {
        Window window = dialog.getWindow();
        window.setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE |
                WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE);
    }

    /**
     * Creates the content view for the dialog (if a custom content view is
     * required). By default, it inflates the dialog layout resource if it is
     * set.
     * 
     * @return The content View for the dialog.
     * @see #setLayoutResource(int)
     */
    protected View onCreateDialogView() {
        if (mDialogLayoutResId == 0) {
            return null;
        }
        
        LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(
                Context.LAYOUT_INFLATER_SERVICE);
        return inflater.inflate(mDialogLayoutResId, null);
    }
    
    /**
     * Binds views in the content View of the dialog to data.
     * <p>
     * Make sure to call through to the superclass implementation.
     * 
     * @param view The content View of the dialog, if it is custom.
     */
    protected void onBindDialogView(View view) {
        View dialogMessageView = view.findViewById(com.android.internal.R.id.message);
        
        if (dialogMessageView != null) {
            final CharSequence message = getDialogMessage();
            int newVisibility = View.GONE;
            
            if (!TextUtils.isEmpty(message)) {
                if (dialogMessageView instanceof TextView) {
                    ((TextView) dialogMessageView).setText(message);
                }
                
                newVisibility = View.VISIBLE;
            }
            
            if (dialogMessageView.getVisibility() != newVisibility) {
                dialogMessageView.setVisibility(newVisibility);
            }
        }
    }
    
    public void onClick(DialogInterface dialog, int which) {
        mWhichButtonClicked = which;
    }
    
    public void onDismiss(DialogInterface dialog) {
        
        getPreferenceManager().unregisterOnActivityDestroyListener(this);
        
        mDialog = null;
        onDialogClosed(mWhichButtonClicked == DialogInterface.BUTTON_POSITIVE);
    }

    /**
     * Called when the dialog is dismissed and should be used to save data to
     * the {@link SharedPreferences}.
     * 
     * @param positiveResult Whether the positive button was clicked (true), or
     *            the negative button was clicked or the dialog was canceled (false).
     */
    protected void onDialogClosed(boolean positiveResult) {
    }

    /**
     * Gets the dialog that is shown by this preference.
     * 
     * @return The dialog, or null if a dialog is not being shown.
     */
    public Dialog getDialog() {
        return mDialog;
    }

    /**
     * {@inheritDoc}
     */
    public void onActivityDestroy() {
        
        if (mDialog == null || !mDialog.isShowing()) {
            return;
        }
        
        mDialog.dismiss();
    }

    @Override
    protected Parcelable onSaveInstanceState() {
        final Parcelable superState = super.onSaveInstanceState();
        if (mDialog == null || !mDialog.isShowing()) {
            return superState;
        }

        final SavedState myState = new SavedState(superState);
        myState.isDialogShowing = true;
        myState.dialogBundle = mDialog.onSaveInstanceState();
        return myState;
    }

    @Override
    protected void onRestoreInstanceState(Parcelable state) {
        if (state == null || !state.getClass().equals(SavedState.class)) {
            // Didn't save state for us in onSaveInstanceState
            super.onRestoreInstanceState(state);
            return;
        }

        SavedState myState = (SavedState) state;
        super.onRestoreInstanceState(myState.getSuperState());
        if (myState.isDialogShowing) {
            showDialog(myState.dialogBundle);
        }
    }

    private static class SavedState extends BaseSavedState {
        boolean isDialogShowing;
        Bundle dialogBundle;
        
        public SavedState(Parcel source) {
            super(source);
            isDialogShowing = source.readInt() == 1;
            dialogBundle = source.readBundle();
        }

        @Override
        public void writeToParcel(Parcel dest, int flags) {
            super.writeToParcel(dest, flags);
            dest.writeInt(isDialogShowing ? 1 : 0);
            dest.writeBundle(dialogBundle);
        }

        public SavedState(Parcelable superState) {
            super(superState);
        }

        public static final Parcelable.Creator<SavedState> CREATOR =
                new Parcelable.Creator<SavedState>() {
            public SavedState createFromParcel(Parcel in) {
                return new SavedState(in);
            }

            public SavedState[] newArray(int size) {
                return new SavedState[size];
            }
        };
    }
    
}