ImageSwitcher 图片切换的控件

package com.zhu.testandroid;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup.LayoutParams;
import android.view.animation.AnimationUtils;
import android.widget.Button;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.ViewSwitcher.ViewFactory;

public class MyImageSwitcher extends Activity {
	private ImageSwitcher imageSwitcher;
	private Button btnPrevious;
	private Button btnNext;
	private int foot = 0;
	private int[] imgRes = new int[] { R.drawable.a, R.drawable.b,
			R.drawable.c, R.drawable.d, R.drawable.e, };

	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState); // 生命周期方法
		super.setContentView(R.layout.activity_image_sw); // 设置要使用的布局管理器
		imageSwitcher = (ImageSwitcher) findViewById(R.id.imageSwitcher);
		btnPrevious = (Button) findViewById(R.id.btnPrevious);
		btnNext = (Button) findViewById(R.id.btnNext);

		imageSwitcher.setFactory(new ViewFactory() {// 设置转化工厂

					@Override
					public View makeView() {
						ImageView imageView = new ImageView(
								MyImageSwitcher.this);
						imageView.setBackgroundColor(0xFFFFFFFF);
						imageView.setScaleType(ImageView.ScaleType.CENTER);// 居中显示
						imageView
								.setLayoutParams(new ImageSwitcher.LayoutParams(
										LayoutParams.MATCH_PARENT,
										LayoutParams.MATCH_PARENT));// 定义组件
						return imageView;
					}
				});
		imageSwitcher.setImageResource(imgRes[foot++]);// 初始化时显示，必须放在工厂后面，否则会报NullPointerException
		imageSwitcher.setInAnimation(AnimationUtils.loadAnimation(this,
				android.R.anim.fade_in));// 设置动画
		imageSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this,
				android.R.anim.fade_out));// 设置动画
		btnPrevious.setOnClickListener(new OnClickListener() {

			public void onClick(View v) {
				MyImageSwitcher.this.imageSwitcher
						.setImageResource(imgRes[foot--]);
				MyImageSwitcher.this.checkBtnEnable();

			}
		});
		btnNext.setOnClickListener(new OnClickListener() {

			public void onClick(View v) {
				MyImageSwitcher.this.imageSwitcher
						.setImageResource(imgRes[foot++]);
				MyImageSwitcher.this.checkBtnEnable();

			}
		});

	}

	protected void checkBtnEnable() {// 判断按钮可用状态
		if (this.foot < this.imgRes.length - 1) {
			this.btnNext.setEnabled(true);
		} else {
			this.btnNext.setEnabled(false);
		}
		if (this.foot == 0) {
			this.btnPrevious.setEnabled(false);
		} else {
			this.btnPrevious.setEnabled(true);
		}

	}

}

　　

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <ImageSwitcher
        android:id="@+id/imageSwitcher"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center" />

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal" >

        <Button
            android:id="@+id/btnPrevious"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:enabled="false"
            android:text="上一张" />

        <Button
            android:id="@+id/btnNext"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:enabled="true"
            android:text="下一张" />
    </LinearLayout>

</LinearLayout>