Android example source code file (DigitalClock.java)

This example Android source code file (DigitalClock.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

ampm, android, broadcastreceiver, calendar, content, contentobserver, digitalclock, formatchangeobserver, handler, intentfilter, m12, m24, override, string, text, textview, typeface, ui, util, widget

The DigitalClock.java Android example source code

/*
 * 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.internal.widget;

import com.android.internal.R;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.res.Resources;
import android.database.ContentObserver;
import android.graphics.Typeface;
import android.os.Handler;
import android.provider.Settings;
import android.text.format.DateFormat;
import android.util.AttributeSet;
import android.view.View;
import android.widget.RelativeLayout;
import android.widget.TextView;

import java.text.DateFormatSymbols;
import java.util.Calendar;

/**
 * Displays the time
 */
public class DigitalClock extends RelativeLayout {

    private final static String M12 = "h:mm";
    private final static String M24 = "kk:mm";

    private Calendar mCalendar;
    private String mFormat;
    private TextView mTimeDisplay;
    private AmPm mAmPm;
    private ContentObserver mFormatChangeObserver;
    private boolean mLive = true;
    private boolean mAttached;

    /* called by system on minute ticks */
    private final Handler mHandler = new Handler();
    private final BroadcastReceiver mIntentReceiver = new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {
                if (mLive && intent.getAction().equals(
                            Intent.ACTION_TIMEZONE_CHANGED)) {
                    mCalendar = Calendar.getInstance();
                }
                // Post a runnable to avoid blocking the broadcast.
                mHandler.post(new Runnable() {
                        public void run() {
                            updateTime();
                        }
                });
            }
        };

    static class AmPm {
        private TextView mAmPm;
        private String mAmString, mPmString;

        AmPm(View parent, Typeface tf) {
            mAmPm = (TextView) parent.findViewById(R.id.am_pm);
            if (tf != null) {
                mAmPm.setTypeface(tf);
            }

            String[] ampm = new DateFormatSymbols().getAmPmStrings();
            mAmString = ampm[0];
            mPmString = ampm[1];
        }

        void setShowAmPm(boolean show) {
            mAmPm.setVisibility(show ? View.VISIBLE : View.GONE);
        }

        void setIsMorning(boolean isMorning) {
            mAmPm.setText(isMorning ? mAmString : mPmString);
        }
    }

    private class FormatChangeObserver extends ContentObserver {
        public FormatChangeObserver() {
            super(new Handler());
        }
        @Override
        public void onChange(boolean selfChange) {
            setDateFormat();
            updateTime();
        }
    }

    public DigitalClock(Context context) {
        this(context, null);
    }

    public DigitalClock(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    protected void onFinishInflate() {
        super.onFinishInflate();

        mTimeDisplay = (TextView) findViewById(R.id.timeDisplay);
        mTimeDisplay.setTypeface(Typeface.createFromFile("/system/fonts/Clockopia.ttf"));
        mAmPm = new AmPm(this, Typeface.createFromFile("/system/fonts/DroidSans-Bold.ttf"));
        mCalendar = Calendar.getInstance();

        setDateFormat();
    }

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();

        if (mAttached) return;
        mAttached = true;

        if (mLive) {
            /* monitor time ticks, time changed, timezone */
            IntentFilter filter = new IntentFilter();
            filter.addAction(Intent.ACTION_TIME_TICK);
            filter.addAction(Intent.ACTION_TIME_CHANGED);
            filter.addAction(Intent.ACTION_TIMEZONE_CHANGED);
            mContext.registerReceiver(mIntentReceiver, filter);
        }

        /* monitor 12/24-hour display preference */
        mFormatChangeObserver = new FormatChangeObserver();
        mContext.getContentResolver().registerContentObserver(
                Settings.System.CONTENT_URI, true, mFormatChangeObserver);

        updateTime();
    }

    @Override
    protected void onDetachedFromWindow() {
        super.onDetachedFromWindow();

        if (!mAttached) return;
        mAttached = false;

        if (mLive) {
            mContext.unregisterReceiver(mIntentReceiver);
        }
        mContext.getContentResolver().unregisterContentObserver(
                mFormatChangeObserver);
    }


    void updateTime(Calendar c) {
        mCalendar = c;
        updateTime();
    }

    private void updateTime() {
        if (mLive) {
            mCalendar.setTimeInMillis(System.currentTimeMillis());
        }

        CharSequence newTime = DateFormat.format(mFormat, mCalendar);
        mTimeDisplay.setText(newTime);
        mAmPm.setIsMorning(mCalendar.get(Calendar.AM_PM) == 0);
    }

    private void setDateFormat() {
        mFormat = android.text.format.DateFormat.is24HourFormat(getContext()) 
            ? M24 : M12;
        mAmPm.setShowAmPm(mFormat.equals(M12));
    }

    void setLive(boolean live) {
        mLive = live;
    }
}