Java tutorial
/* * Copyright (C) 2013 Andreas Stuetz <andreas.stuetz@gmail.com> * * 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.arman.efficientqhalgoforch; import android.graphics.Color; import android.graphics.drawable.ColorDrawable; import android.graphics.drawable.Drawable; import android.graphics.drawable.LayerDrawable; import android.graphics.drawable.TransitionDrawable; import android.os.Build; import android.os.Bundle; import android.os.Handler; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentActivity; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentPagerAdapter; import android.support.v4.view.ViewPager; import android.util.TypedValue; import android.view.Menu; import android.view.MenuItem; import android.view.View; import com.astuetz.PagerSlidingTabStrip; public class MainActivity extends FragmentActivity { private final Handler handler = new Handler(); private PagerSlidingTabStrip tabs; private ViewPager pager; private MyPagerAdapter adapter; private Drawable oldBackground = null; private int currentColor = 0xFF3F9FE0; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); tabs = (PagerSlidingTabStrip) findViewById(R.id.tabs); pager = (ViewPager) findViewById(R.id.pager); adapter = new MyPagerAdapter(getSupportFragmentManager()); pager.setAdapter(adapter); final int pageMargin = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 4, getResources().getDisplayMetrics()); pager.setPageMargin(pageMargin); tabs.setViewPager(pager); changeColor(currentColor); } @Override public boolean onCreateOptionsMenu(Menu menu) { getMenuInflater().inflate(R.menu.main, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case R.id.action_contact: QuickContactFragment dialog = new QuickContactFragment(); dialog.show(getSupportFragmentManager(), "QuickContactFragment"); return true; } return super.onOptionsItemSelected(item); } private void changeColor(int newColor) { tabs.setIndicatorColor(newColor); // change ActionBar color just if an ActionBar is available if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) { Drawable colorDrawable = new ColorDrawable(newColor); Drawable bottomDrawable = getResources().getDrawable(R.drawable.actionbar_bottom); LayerDrawable ld = new LayerDrawable(new Drawable[] { colorDrawable, bottomDrawable }); if (oldBackground == null) { if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN_MR1) { ld.setCallback(drawableCallback); } else { getActionBar().setBackgroundDrawable(ld); } } else { TransitionDrawable td = new TransitionDrawable(new Drawable[] { oldBackground, ld }); // workaround for broken ActionBarContainer drawable handling on // pre-API 17 builds // https://github.com/android/platform_frameworks_base/commit/a7cc06d82e45918c37429a59b14545c6a57db4e4 if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN_MR1) { td.setCallback(drawableCallback); } else { getActionBar().setBackgroundDrawable(td); } td.startTransition(200); } oldBackground = ld; // http://stackoverflow.com/questions/11002691/actionbar-setbackgrounddrawable-nulling-background-from-thread-handler getActionBar().setDisplayShowTitleEnabled(false); getActionBar().setDisplayShowTitleEnabled(true); } currentColor = newColor; } public void onColorClicked(View v) { int color = Color.parseColor(v.getTag().toString()); changeColor(color); } @Override protected void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); outState.putInt("currentColor", currentColor); } @Override protected void onRestoreInstanceState(Bundle savedInstanceState) { super.onRestoreInstanceState(savedInstanceState); currentColor = savedInstanceState.getInt("currentColor"); changeColor(currentColor); } private Drawable.Callback drawableCallback = new Drawable.Callback() { @Override public void invalidateDrawable(Drawable who) { getActionBar().setBackgroundDrawable(who); } @Override public void scheduleDrawable(Drawable who, Runnable what, long when) { handler.postAtTime(what, when); } @Override public void unscheduleDrawable(Drawable who, Runnable what) { handler.removeCallbacks(what); } }; public class MyPagerAdapter extends FragmentPagerAdapter { private final String[] TITLES = { "Introduction", "Algorithm", "QuickHull Benchmark", "GrahamScan Benchmark", }; public MyPagerAdapter(FragmentManager fm) { super(fm); } @Override public CharSequence getPageTitle(int position) { return TITLES[position]; } @Override public int getCount() { return TITLES.length; } @Override public Fragment getItem(int position) { return SuperAwesomeCardFragment.newInstance(position); } } }