Java tutorial
/* * This is the source code of Telegram for Android v. 1.3.2. * It is licensed under GNU GPL v. 2 or later. * You should have received a copy of the license in this archive (see LICENSE). * * Copyright Nikolai Kudashov, 2013. */ package spinnersample.lalongooo.com.viewpager; import android.animation.ObjectAnimator; import android.animation.StateListAnimator; import android.app.Activity; import android.content.Intent; import android.content.pm.ActivityInfo; import android.database.DataSetObserver; import android.os.Build; import android.os.Bundle; import android.os.Parcelable; import android.support.v4.view.PagerAdapter; import android.support.v4.view.ViewPager; import android.view.View; import android.view.ViewGroup; import android.view.Window; import android.view.animation.Animation; import android.view.animation.AnimationUtils; import android.widget.ImageView; import android.widget.TextView; import com.viewpagerindicator.CirclePageIndicator; import com.viewpagerindicator.PageIndicator; public class IntroActivity extends Activity { private ViewPager viewPager; private PageIndicator indicator; private ImageView topImage1; private ImageView topImage2; private int lastPage = 0; private boolean startPressed = false; private int[] icons; private int[] messages; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_NO_TITLE); setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT); setContentView(R.layout.intro_layout); icons = new int[] { R.drawable.app_overview_1_buy, R.drawable.app_overview_2_smartphone, R.drawable.app_overview_3_save_money, R.drawable.app_overview_4_coupons }; messages = new int[] { R.string.app_overview_1st_item_text, R.string.app_overview_2nd_item_text, R.string.app_overview_3rd_item_text, R.string.app_overview_4th_item_text }; viewPager = (ViewPager) findViewById(R.id.intro_view_pager); TextView startMessagingButton = (TextView) findViewById(R.id.start_messaging_button); startMessagingButton.setText(getString(R.string.StartMessaging)); if (Build.VERSION.SDK_INT >= 21) { StateListAnimator animator = new StateListAnimator(); animator.addState(new int[] { android.R.attr.state_pressed }, ObjectAnimator.ofFloat(startMessagingButton, "translationZ", AndroidUtilities.dp(2, this), AndroidUtilities.dp(4, this)).setDuration(200)); animator.addState(new int[] {}, ObjectAnimator.ofFloat(startMessagingButton, "translationZ", AndroidUtilities.dp(4, this), AndroidUtilities.dp(2, this)).setDuration(200)); startMessagingButton.setStateListAnimator(animator); } topImage1 = (ImageView) findViewById(R.id.icon_image1); topImage2 = (ImageView) findViewById(R.id.icon_image2); indicator = (CirclePageIndicator) findViewById(R.id.indicator); topImage2.setVisibility(View.GONE); viewPager.setAdapter(new IntroAdapter()); viewPager.setPageMargin(0); viewPager.setOffscreenPageLimit(1); indicator.setViewPager(viewPager); indicator.setOnPageChangeListener(new ViewPager.OnPageChangeListener() { @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { if (lastPage != viewPager.getCurrentItem()) { lastPage = viewPager.getCurrentItem(); final ImageView fadeoutImage; final ImageView fadeinImage; if (topImage1.getVisibility() == View.VISIBLE) { fadeoutImage = topImage1; fadeinImage = topImage2; } else { fadeoutImage = topImage2; fadeinImage = topImage1; } fadeinImage.bringToFront(); fadeinImage.setImageResource(icons[lastPage]); fadeinImage.clearAnimation(); fadeoutImage.clearAnimation(); Animation outAnimation = AnimationUtils.loadAnimation(IntroActivity.this, R.anim.icon_anim_fade_out); outAnimation.setAnimationListener(new Animation.AnimationListener() { @Override public void onAnimationStart(Animation animation) { } @Override public void onAnimationEnd(Animation animation) { fadeoutImage.setVisibility(View.GONE); } @Override public void onAnimationRepeat(Animation animation) { } }); Animation inAnimation = AnimationUtils.loadAnimation(IntroActivity.this, R.anim.icon_anim_fade_in); inAnimation.setAnimationListener(new Animation.AnimationListener() { @Override public void onAnimationStart(Animation animation) { fadeinImage.setVisibility(View.VISIBLE); } @Override public void onAnimationEnd(Animation animation) { } @Override public void onAnimationRepeat(Animation animation) { } }); fadeoutImage.startAnimation(outAnimation); fadeinImage.startAnimation(inAnimation); } } @Override public void onPageSelected(int position) { } @Override public void onPageScrollStateChanged(int state) { } }); startMessagingButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { if (startPressed) { return; } startPressed = true; Intent intent2 = new Intent(IntroActivity.this, ActivityMain.class); startActivity(intent2); finish(); } }); } private class IntroAdapter extends PagerAdapter { @Override public int getCount() { return 4; } @Override public boolean isViewFromObject(View view, Object object) { return view.equals(object); } @Override public Object instantiateItem(ViewGroup container, int position) { View view = View.inflate(container.getContext(), R.layout.intro_view_layout, null); TextView messageTextView = (TextView) view.findViewById(R.id.message_text); container.addView(view, 0); messageTextView .setText(AndroidUtilities.replaceTags(getString(messages[position]), getApplicationContext())); return view; } @Override public void destroyItem(ViewGroup container, int position, Object object) { ((ViewPager) container).removeView((View) object); } } }