Java tutorial
/* * 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.annotation.CallSuper; import android.annotation.DrawableRes; import android.annotation.Nullable; import android.annotation.StringRes; import android.annotation.UnsupportedAppUsage; 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 { @UnsupportedAppUsage private AlertDialog.Builder mBuilder; @UnsupportedAppUsage private CharSequence mDialogTitle; @UnsupportedAppUsage private CharSequence mDialogMessage; @UnsupportedAppUsage private Drawable mDialogIcon; @UnsupportedAppUsage private CharSequence mPositiveButtonText; @UnsupportedAppUsage private CharSequence mNegativeButtonText; private int mDialogLayoutResId; /** The dialog, if it is showing. */ @UnsupportedAppUsage private Dialog mDialog; /** Which button was clicked. */ @UnsupportedAppUsage private int mWhichButtonClicked; /** Dismiss the dialog on the UI thread, but not inline with handlers */ private final Runnable mDismissRunnable = new Runnable() { @Override public void run() { mDialog.dismiss(); } }; public DialogPreference(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { super(context, attrs, defStyleAttr, defStyleRes); final TypedArray a = context.obtainStyledAttributes(attrs, com.android.internal.R.styleable.DialogPreference, defStyleAttr, defStyleRes); 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, int defStyleAttr) { this(context, attrs, defStyleAttr, 0); } public DialogPreference(Context context, AttributeSet attrs) { this(context, attrs, com.android.internal.R.attr.dialogPreferenceStyle); } public DialogPreference(Context context) { this(context, null); } /** * 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(@DrawableRes int dialogIconRes) { mDialogIcon = getContext().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(@StringRes 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(@StringRes 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() { if (mDialog != null && mDialog.isShowing()) return; 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.setOnShowListener(new DialogInterface.OnShowListener() { @Override public void onShow(DialogInterface dialog) { removeDismissCallbacks(); } }); dialog.setOnDismissListener(this); dialog.show(); } /** * Get the DecorView. * @return the DecorView for the current dialog window, if it exists. * If the window does not exist, null is returned. */ @Nullable private View getDecorView() { if (mDialog != null && mDialog.getWindow() != null) { return mDialog.getWindow().getDecorView(); } return null; } void postDismiss() { removeDismissCallbacks(); View decorView = getDecorView(); if (decorView != null) { // If decorView is null, dialog was already dismissed decorView.post(mDismissRunnable); } } private void removeDismissCallbacks() { View decorView = getDecorView(); if (decorView != null) { decorView.removeCallbacks(mDismissRunnable); } } /** * 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); } /** * 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.from(mBuilder.getContext()); 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. */ @CallSuper 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; } @Override public void onDismiss(DialogInterface dialog) { removeDismissCallbacks(); 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]; } }; } }