在Android中所有定义好的XML文件都要求保存在res/anim文件夹之中。
准备一张名为picture的图片。
在main.xml中：
<LinearLayout
android:id="@+id/group"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#000000"
android:orientation="vertical"
android:gravity="center_horizontal">
<ImageView
android:id="@+id/mlyw"
android:layout_marginTop="8dp"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:src="@drawable/picture"/>
<Button
android:id="@+id/but"
android:layout_width="100dp"
android:layout_height="40dp"
android:layout_marginTop="80dp"
android:background="#3399ff"
android:textColor="#ffffff"
android:text="开始渐变"/>
</LinearLayout>
在MyAnimationDemo.java中：
package com.li.animation;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.Button;
import android.widget.ImageView;
@SuppressLint({ "ParserError", "ParserError" })
public class MyAnimationDemo extends Activity {
private ImageView mlyw = null;
private Button but = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
super.setContentView(R.layout.main);
this.mlyw = (ImageView)super.findViewById(R.id.mlyw);
this.but = (Button)super.findViewById(R.id.but);
this.but.setOnClickListener(new OnClickListenerImpl());
}
private class OnClickListenerImpl implements OnClickListener{
public void onClick(View v) {
Animation anim = AnimationUtils.loadAnimation(
MyAnimationDemo.this, R.anim.alpha);
MyAnimationDemo.this.mlyw.startAnimation(anim);
}
}
}
在res/anim下新建alpha.xml：
<set xmlns:android="http://schemas.android.com/apk/res/android">
<alpha
android:fromAlpha="1.0"
android:toAlpha="0.0"
android:duration="5000"/>
</set>