Android turns on the fading effect of animation

When we start a program, we can often see different "boot animation", and the ever-changing animation is only the evolution and beautification of four basic animations.

4 android animation effects:

alpha Gradient Transparency Animation Effect scale gradient size scaling animation effect translate screen conversion position movement animation effect rotate screen transfer rotation animation effect

The simplest one is the gradient transparency effect. This one alone can complete the animation effect of fading and fading (the whole welcome page can be used for fading and fading or the first part of the welcome page):

1) Create a new anim folder in res to hold the action files defined by animation:

<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:interpolator="@android:anim/accelerate_interpolator">
    <alpha 
      android:fromAlpha="0.0"
      android:toAlpha="1.0"
      android:duration="2000"/>
    <alpha 
      android:fromAlpha="1.0"
      android:toAlpha="0.0"
      android:startOffset="3000"
      android:duration="3000"/>
  
</set>

fromalpha is the transparency at the beginning, toalpha is the transparency at the end, and duration is the time (in milliseconds).

2) Define the layout file (layout):

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:gravity="center_vertical|center_horizontal"
  android:orientation="vertical" >
 
  <ImageView
    android:id="@+id/welcom_logo"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:src="@drawable/welcome" />
 
</LinearLayout>

There is no difference between here and the past, just mark the pictures that will gradually appear and fade with id.

3) Implementation method (Activity):

public class WelcomeActivity extends Activity implements AnimationListener {
 private ImageView imageView = null;
 private Animation alphaAnimation = null;
 
 @Override
 public void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_welcome);
 imageView = (ImageView) findViewById(R.id.welcom_logo);
 alphaAnimation = AnimationUtils.loadAnimation(this,
  R.anim.welcome_alpha);
 alphaAnimation.setFillEnabled(true);// Start Fill Keep 
 alphaAnimation.setFillAfter(true);// Set the end of the animation 1 The frame is reserved in the view Above 
 imageView.setAnimation(alphaAnimation);
 alphaAnimation.setAnimationListener(this);
 
 }
 
 @Override
 public boolean onCreateOptionsMenu(Menu menu) {
 getMenuInflater().inflate(R.menu.activity_welcome, menu);
 return true;
 }
 
 @Override
 public void onAnimationEnd(Animation animation) {
 // End the welcome page at the end of the animation and jump to the main page 
 Intent intent=new Intent(this,GroupActivity.class);
 startActivity(intent);
 this.finish();
 
 }
 
 @Override
 public void onAnimationRepeat(Animation animation) {
 
 
 }
 
 @Override
 public void onAnimationStart(Animation animation) {
 
 
 }
 public boolean onKeyDown(int KeyCode,KeyEvent event){
 // Mask on Welcome Page BACK Key 
 if(KeyCode==KeyEvent.KEYCODE_BACK){
  return false;
 }
 return false;
 
 }
}

As the name implies, the welcome page is just decorative. 1 flashes without the return key.