Android应用开发学习之图片切换器

作者：刘昊昱

博客：http://blog.csdn.net/liuhaoyutz

 

如果我们要实现类似Windows的照片查看器切换上一张下一张照片的效果，可以使用图片切换器ImageSwitcher，下面我们来看一个例子，其运行效果如下所示：

先来看主布局文件main.xml，其内容如下：

 

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent"

    android:gravity="center"

    android:orientation="vertical" >



    <ImageSwitcher

		android:id="@+id/imageSwitcher"

		android:layout_width="300px"

		android:layout_height="300px"/>"

    

    <LinearLayout

        android:orientation="horizontal"

        android:gravity="center"

        android:layout_width="match_parent"

        android:layout_height="wrap_content">

        

        <Button 

            android:text="上一张" 

    		android:id="@+id/button1" 

    		android:layout_gravity="center"

    		android:layout_width="wrap_content" 

    		android:layout_height="wrap_content"/>

        <Button 

	    	android:text="下一张" 

    		android:id="@+id/button2" 

    		android:layout_gravity="center"

    		android:layout_width="wrap_content" 

    		android:layout_height="wrap_content"/>            

    </LinearLayout>

    

</LinearLayout>

 

 

下面来看主Activity文件，其内容如下：

 

package com.liuhaoyu;



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 MainActivity extends Activity {

	private int[] imageId = new int[] { R.drawable.img01, R.drawable.img02,

			R.drawable.img03, R.drawable.img04, R.drawable.img05,

			R.drawable.img06, R.drawable.img07, R.drawable.img08};

	private int index = 0;

	private ImageSwitcher imageSwitcher;

	

    /** Called when the activity is first created. */

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

        

        imageSwitcher = (ImageSwitcher) findViewById(R.id.imageSwitcher);

		imageSwitcher.setInAnimation(AnimationUtils.loadAnimation(this,

				android.R.anim.fade_in));

		imageSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this,

				android.R.anim.fade_out));

		imageSwitcher.setFactory(new ViewFactory() {

			@Override

			public View makeView() {

				ImageView imageView = new ImageView(MainActivity.this);

				imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);

				imageView.setLayoutParams(new ImageSwitcher.LayoutParams(

						LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));

				return imageView;

			}

		});

		imageSwitcher.setImageResource(imageId[index]);

		

		Button previous = (Button) findViewById(R.id.button1);

		Button next = (Button) findViewById(R.id.button2);

		previous.setOnClickListener(new OnClickListener() {

			@Override

			public void onClick(View v) {

					if (index > 0) {

						index--;

					} else {

						index = imageId.length - 1;

					}

				imageSwitcher.setImageResource(imageId[index]);

			}

		});

		next.setOnClickListener(new OnClickListener() {

			@Override

			public void onClick(View v) {

				if (index < imageId.length - 1) {

					index++;

				} else {

					index = 0;

				}

				imageSwitcher.setImageResource(imageId[index]);

			}

		});		

    }

}