Java tutorial
/* * 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.browser; import android.app.Activity; import android.app.Dialog; import android.content.Context; import android.content.res.Resources; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.Handler; import android.text.Spannable; import android.text.SpannableString; import android.text.style.UnderlineSpan; import android.util.Log; import android.view.InflateException; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.Button; import android.widget.ImageView; import android.widget.TextView; import java.io.InputStream; import java.io.IOException; import java.lang.ClassCastException; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; import org.json.JSONException; import org.json.JSONObject; /** * Base dialog class for gears */ class GearsBaseDialog { private static final String TAG = "GearsNativeDialog"; protected Handler mHandler; protected Activity mActivity; protected String mDialogArguments; private Bitmap mIcon; private final int MAX_ICON_SIZE = 64; protected int mChoosenIconSize; // Dialog closing types public static final int CANCEL = 0; public static final int ALWAYS_DENY = 1; public static final int ALLOW = 2; public static final int DENY = 3; public static final int NEW_ICON = 4; public static final int UPDATE_ICON = 5; public static final int REQUEST_ICON = 6; public static final int PAUSE_REQUEST_ICON = 7; public static final int CLEAR_REQUEST_ICON = 8; protected final String LOCAL_DATA_STRING = "localData"; protected final String LOCAL_STORAGE_STRING = "localStorage"; protected final String LOCATION_DATA_STRING = "locationData"; protected String mGearsVersion = "UNDEFINED"; protected boolean mDebug = false; public GearsBaseDialog(Activity activity, Handler handler, String arguments) { mActivity = activity; mHandler = handler; mDialogArguments = arguments; } Resources getResources() { return mActivity.getResources(); } Object getSystemService(String name) { return mActivity.getSystemService(name); } View findViewById(int id) { return mActivity.findViewById(id); } private String getString(int id) { return mActivity.getString(id); } public void setDebug(boolean debug) { mDebug = debug; } public void setGearsVersion(String version) { mGearsVersion = version; } public String closeDialog(int closingType) { return null; } /* * Utility methods for setting up the dialogs elements */ /** * Inflate a given layout in a view (which has to be * a ViewGroup, e.g. LinearLayout). * This is used to share the basic dialog outline among * the different dialog types. */ void inflate(int layout, int viewID) { LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE); View view = findViewById(viewID); if (view != null) { try { ViewGroup viewGroup = (ViewGroup) view; inflater.inflate(layout, viewGroup); } catch (ClassCastException e) { String msg = "exception, the view (" + view + ")"; msg += " is not a ViewGroup"; Log.e(TAG, msg, e); } catch (InflateException e) { Log.e(TAG, "exception while inflating the layout", e); } } else { String msg = "problem, trying to inflate a non-existent view"; msg += " (" + viewID + ")"; Log.e(TAG, msg); } } /** * Button setup. * Set the button's text and its listener. If the text resource's id * is 0, makes the button invisible. */ void setupButton(int buttonRscID, int rscString, View.OnClickListener listener, boolean isLink, boolean requestFocus) { View view = findViewById(buttonRscID); if (view == null) { return; } Button button = (Button) view; if (rscString == 0) { button.setVisibility(View.GONE); } else { CharSequence text = getString(rscString); button.setText(text); button.setOnClickListener(listener); if (isLink) { displayAsLink(button); } if (requestFocus) { button.requestFocus(); } } } /** * Button setup: as the above method, except that 'isLink' and * 'requestFocus' default to false. */ void setupButton(int buttonRsc, int rsc, View.OnClickListener listener) { setupButton(buttonRsc, rsc, listener, false, false); } /** * Utility method to setup the three dialog buttons. */ void setupButtons(int alwaysDenyRsc, int allowRsc, int denyRsc) { setupButton(R.id.button_alwaysdeny, alwaysDenyRsc, new Button.OnClickListener() { public void onClick(View v) { mHandler.sendEmptyMessage(ALWAYS_DENY); } }); setupButton(R.id.button_allow, allowRsc, new Button.OnClickListener() { public void onClick(View v) { mHandler.sendEmptyMessage(ALLOW); } }); setupButton(R.id.button_deny, denyRsc, new Button.OnClickListener() { public void onClick(View v) { mHandler.sendEmptyMessage(DENY); } }); } /** * Display a button as an HTML link. Remove the background, set the * text color to R.color.dialog_link and draw an underline */ void displayAsLink(Button button) { if (button == null) { return; } CharSequence text = button.getText(); button.setBackgroundDrawable(null); int color = getResources().getColor(R.color.dialog_link); button.setTextColor(color); SpannableString str = new SpannableString(text); str.setSpan(new UnderlineSpan(), 0, str.length(), Spannable.SPAN_INCLUSIVE_INCLUSIVE); button.setText(str); button.setFocusable(false); } /** * Utility method to set elements' text indicated in * the dialogs' arguments. */ void setLabel(JSONObject json, String name, int rsc) { try { if (json.has(name)) { String text = json.getString(name); View view = findViewById(rsc); if (view != null && text != null) { TextView textView = (TextView) view; textView.setText(text); textView.setVisibility(View.VISIBLE); } } } catch (JSONException e) { Log.e(TAG, "json exception", e); } } /** * Utility method to hide a view. */ void hideView(View v, int rsc) { if (rsc == 0) { return; } View view; if (v == null) { view = findViewById(rsc); } else { view = v.findViewById(rsc); } if (view != null) { view.setVisibility(View.GONE); } } /** * Utility method to show a view. */ void showView(View v, int rsc) { if (rsc == 0) { return; } View view; if (v == null) { view = findViewById(rsc); } else { view = v.findViewById(rsc); } if (view != null) { view.setVisibility(View.VISIBLE); } } /** * Utility method to set a text. */ void setText(View v, int rsc, CharSequence text) { if (rsc == 0) { return; } View view = v.findViewById(rsc); if (view != null) { TextView textView = (TextView) view; textView.setText(text); textView.setVisibility(View.VISIBLE); } } /** * Utility method to set a text. */ void setText(View v, int rsc, int txtRsc) { if (rsc == 0) { return; } View view = v.findViewById(rsc); if (view != null) { TextView textView = (TextView) view; if (txtRsc == 0) { textView.setVisibility(View.GONE); } else { CharSequence text = getString(txtRsc); textView.setText(text); textView.setVisibility(View.VISIBLE); } } } /** * Utility class to download an icon in the background. * Once done ask the UI thread to update the icon. */ class IconDownload implements Runnable { private String mUrlString; IconDownload(String url) { mUrlString = url; } public void run() { if (mUrlString == null) { return; } try { URL url = new URL(mUrlString); HttpURLConnection connection = (HttpURLConnection) url.openConnection(); connection.setDoInput(true); connection.connect(); int length = connection.getContentLength(); InputStream is = connection.getInputStream(); Bitmap customIcon = BitmapFactory.decodeStream(is); if (customIcon != null) { mIcon = customIcon; mHandler.sendEmptyMessage(UPDATE_ICON); } } catch (ClassCastException e) { Log.e(TAG, "Class cast exception (" + mUrlString + ")", e); } catch (MalformedURLException e) { Log.e(TAG, "Malformed url (" + mUrlString + ") ", e); } catch (IOException e) { Log.e(TAG, "Exception downloading icon (" + mUrlString + ") ", e); } } } /** * Utility method to update the icon. * Called on the UI thread. */ public void updateIcon() { if (mIcon == null) { return; } View view = findViewById(R.id.origin_icon); if (view != null) { ImageView imageView = (ImageView) view; imageView.setMaxHeight(MAX_ICON_SIZE); imageView.setMaxWidth(MAX_ICON_SIZE); imageView.setScaleType(ImageView.ScaleType.FIT_XY); imageView.setImageBitmap(mIcon); imageView.setVisibility(View.VISIBLE); } } /** * Utility method to download an icon from a url and set * it to the GUI element R.id.origin_icon. * It is used both in the shortcut dialog and the * permission dialog. * The actual download is done in the background via * IconDownload; once the icon is downlowded the UI is updated * via updateIcon(). * The icon size is included in the layout with the choosen * size, although not displayed, to limit text reflow once * the icon is received. */ void downloadIcon(String url) { if (url == null) { return; } View view = findViewById(R.id.origin_icon); if (view != null) { view.setMinimumWidth(mChoosenIconSize); view.setMinimumHeight(mChoosenIconSize); view.setVisibility(View.INVISIBLE); } Thread thread = new Thread(new IconDownload(url)); thread.start(); } /** * Utility method that get the dialogMessage * and icon and ask the setupDialog(message,icon) * method to set the values. */ public void setupDialog() { TextView dialogMessage = null; ImageView icon = null; View view = findViewById(R.id.dialog_message); if (view != null) { dialogMessage = (TextView) view; } View iconView = findViewById(R.id.icon); if (iconView != null) { icon = (ImageView) iconView; } if ((dialogMessage != null) && (icon != null)) { setupDialog(dialogMessage, icon); dialogMessage.setVisibility(View.VISIBLE); } } /* * Set the message and icon of the dialog */ public void setupDialog(TextView message, ImageView icon) { message.setText(R.string.unrecognized_dialog_message); icon.setImageResource(R.drawable.ic_dialog_menu_generic); message.setVisibility(View.VISIBLE); } /** * Setup the dialog * By default, just display a simple message. */ public void setup() { setupButtons(0, 0, R.string.default_button); setupDialog(); } /** * Method called when the back button is pressed, * allowing the dialog to intercept the default behaviour. */ public boolean handleBackButton() { return false; } /** * Returns the resource string of the notification displayed * after the dialog. By default, does not return one. */ public int notification() { return 0; } /** * If a secondary dialog (e.g. a confirmation dialog) is created, * GearsNativeDialog will call this method. */ public Dialog onCreateDialog(int id) { // This should be redefined by subclasses as needed. return null; } }