第37章、图片切换ImageSwitcher&Gallery（从零开始学Android）

　　ImageSwitcher是Android中控制图片展示效果的一个控件，如：幻灯片效果...，颇有感觉啊。做相册一绝。



一、设计界面

　　1、打开“res/layout/activity_main.xml”文件。

　　打开activity_main.xml文件。

　　代码如下：

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

<RelativeLayout 
    xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent"> 
    
    <ImageSwitcher android:id="@+id/switcher"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true" />
    
    <Gallery android:id="@+id/gallery"
        android:background="#55000000"
        android:layout_width="match_parent"
        android:layout_height="60dp"
        android:layout_alignParentBottom="true"
        android:layout_alignParentLeft="true"        
        android:gravity="center_vertical"
        android:spacing="16dp" />

</RelativeLayout>

二、程序文件　

　　打开“src/com.genwoxue.imageswitcher/MainActivity.java”文件。

　　然后输入以下代码：

package com.genwoxue.imageswitcher;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.animation.AnimationUtils;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.Gallery.LayoutParams;
import android.widget.ViewSwitcher.ViewFactory;

public class MainActivity extends Activity implements OnItemSelectedListener, ViewFactory {
	//声明ImageSwitcher、Gallery
	private ImageSwitcher is=null;
	private Gallery gallery=null;

	//定义缩微图
	private Integer[] mThumbIds = { 
			R.drawable.a, 
			R.drawable.b,
			R.drawable.c, 
			R.drawable.d, 
			R.drawable.e};
	//定义图
	private Integer[] mImageIds = { 
			R.drawable.a, 
			R.drawable.b,
			R.drawable.c, 
			R.drawable.d, 
			R.drawable.e};

	@Override
	protected void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);
		requestWindowFeature(Window.FEATURE_NO_TITLE);
		setContentView(R.layout.activity_main);
		
		is = (ImageSwitcher) findViewById(R.id.switcher);
		is.setFactory(this);
		
		//显示效果
		is.setInAnimation(AnimationUtils.loadAnimation(this,android.R.anim.fade_in));
		is.setOutAnimation(AnimationUtils.loadAnimation(this,android.R.anim.fade_out));

		gallery = (Gallery) findViewById(R.id.gallery);
		gallery.setAdapter(new ImageAdapter(this));
		//设置OnItemSelected监听事件
		gallery.setOnItemSelectedListener(this);
	}

	@Override
	public View makeView() {
		ImageView i = new ImageView(this);
		i.setBackgroundColor(0xFF000000);
		i.setScaleType(ImageView.ScaleType.FIT_CENTER);
		i.setLayoutParams(new ImageSwitcher.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
		return i;
	}

	public class ImageAdapter extends BaseAdapter {
		public ImageAdapter(Context c) {
			mContext = c;
		}

		public int getCount() {
			return mThumbIds.length;
		}

		public Object getItem(int position) {
			return position;
		}

		public long getItemId(int position) {
			return position;
		}

		public View getView(int position, View convertView, ViewGroup parent) {
			ImageView i = new ImageView(mContext);
			i.setImageResource(mThumbIds[position]);
			i.setAdjustViewBounds(true);
			i.setLayoutParams(new Gallery.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
			i.setBackgroundResource(R.drawable.e);
			return i;
		}
		private Context mContext;
	}

	@Override
	public void onItemSelected(AdapterView<?> parent, View view, int position,long id) {
		is.setImageResource(mImageIds[position]);
	}

	@Override
	public void onNothingSelected(AdapterView<?> parent) {
	}

}

三、运行效果

　　

　






















扩展：http://android.tgbus.com/Android/tutorial/201108/362438.shtml