Animation animation AlphaAnimation (transparency change)_html/css_WEB-ITnose

Speaking of animation, I think everyone is familiar with it. Next, let’s talk about AlphaAnimation in Animation animation. This is a class that changes the transparency of components. Next we analyze the code.

1. First write the layout file.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">    //这里定义了一个显示图片的组件    <ImageView        android:id="@+id/image"        android:text="@string/hello_world"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:src="@drawable/car_one1"/></RelativeLayout>

2. Next, write the MainActivity.java file.

package com.example.dell.bitmapproject;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.Menu;import android.view.MenuItem;import android.view.View;import android.view.animation.AlphaAnimation;import android.view.animation.AnimationSet;import android.widget.ImageView;public class MainActivity extends AppCompatActivity {    private ImageView image;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        image =(ImageView)findViewById(R.id.image);        image.setOnClickListener(new OnClickListenerImpl());    }    private class OnClickListenerImpl implements View.OnClickListener {        @Override        public void onClick(View v) {            //AnimationSet相当于一个动画的集合，true代表            AnimationSet animationSet = new AnimationSet(true);            //由完全显示-->一半透明            AlphaAnimation alphaAnimation = new AlphaAnimation(1.0f,0.5f);            //3秒完成动画            alphaAnimation.setDuration(3000);            //将AlphaAnimation这个已经设置好的动画添加到 AnimationSet中            animationSet.addAnimation(alphaAnimation);            //启动动画            MainActivity.this.image.startAnimation(animationSet);        }    }}

The role of AnimationSet: In actual programming, we may implement multiple animation effects on the same component. The role of AnimationSet is equivalent to a container holding what we want. To achieve the animation effect, when we want to display the animation effect, we only need to call the startAninmation(AnimationSet animationSet) method.

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