【Android】图片切换组件ImageSwitcher的运用

类的继承关系

java.lang.Object
android.view.View
android.view.ViewGroup
android.widget.FrameLayout
android.widget.ViewAnimator
android.widget.ViewSwitcher
android.widget.ImageSwitcher

ImageSwitcher是Android中控制图片展示效果的一个控件，如：幻灯片效果。

公共方法

public void setImageDrawable (Drawable drawable)

绘制图片

public void setImageResource (int resid)

设置图片资源库

public void setImageURI (Uri uri)

设置图片地址

Java类

package com.app.test01;

import com.app.adapter.ImageAdapter;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Gallery;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.Gallery.LayoutParams;
import android.widget.ViewSwitcher.ViewFactory;

public class ImageSwitcherActivity extends Activity{
ImageSwitcher imageSwitcher;
Gallery gallery;
ImageAdapter iAdapter = new ImageAdapter(this);
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_imageswitcher);
imageSwitcher = (ImageSwitcher) findViewById(R.id.imageSwitcher1);
gallery = (Gallery) findViewById(R.id.gallery1);
//设置用来生成将在视图转换器中切换的两个视图的工厂
imageSwitcher.setFactory(new ViewFactory() {
@Override
public View makeView() {
// TODO Auto-generated method stub
ImageView i = new ImageView(ImageSwitcherActivity.this);
// 把图片按比例扩大/缩小到View的宽度，居中显示
i.setScaleType(ImageView.ScaleType.FIT_CENTER);
i.setLayoutParams(new ImageSwitcher.LayoutParams(LayoutParams.MATCH_PARENT,
LayoutParams.MATCH_PARENT));
return i;
}
});

gallery.setAdapter(iAdapter);
gallery.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// TODO Auto-generated method stub
Integer[] iViews = iAdapter.getmImageIds();
imageSwitcher.setImageResource(iViews[position%iViews.length]);
}
});
}
}

适配器ImageAdapter

package com.app.adapter;

import com.app.test01.R;

import android.content.Context;
import android.content.res.TypedArray;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;

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

public int getCount() { /* 重写方法getCount,传回图片数目总数 */
return Integer.MAX_VALUE;
}

public Object getItem(int position) {/* 重写的getItem,传回position */
return position;
}

public long getItemId(int position) {/*重写方法getItemId,传回position */
return position;
}

public View getView(int position, View convertView, ViewGroup parent) {
ImageView i = new ImageView(mContext);
i.setImageResource(mImageIds[position%mImageIds.length]);/* 设定图片给imageView对象 */
i.setLayoutParams(new Gallery.LayoutParams(150,75));
return i;
}

public Integer[] getmImageIds() {
return mImageIds;
}

public void setmImageIds(Integer[] mImageIds) {
this.mImageIds = mImageIds;
}

private Integer[] mImageIds = {
R.drawable.image01,
R.drawable.image02,
R.drawable.image03,
R.drawable.image04,
R.drawable.image05,
R.drawable.image06,
R.drawable.image07,
R.drawable.image08,
R.drawable.image09,
};
}

布局文件

<?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"
android:orientation="vertical" >

<ImageSwitcher
android:id="@+id/imageSwitcher1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true">
</ImageSwitcher>

<Gallery
android:id="@+id/gallery1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:gravity="center_vertical"
android:spacing="16dp"/>

</RelativeLayout>

效果图

附：ImageView的属性scaleType

ImageView的属性android:scaleType，即ImageView.setScaleType(ImageView.ScaleType)。
android:scaleType是控制图片如何resized/moved来匹对ImageView的size。

ImageView.ScaleType / android:scaleType值的意义区别： 

CENTER /center  按图片的原来size居中显示，当图片长/宽超过View的长/宽，则截取图片的居中部分显示
CENTER_CROP / centerCrop  按比例扩大图片的size居中显示，使得图片长(宽)等于或大于View的长(宽)
CENTER_INSIDE / centerInside  将图片的内容完整居中显示，通过按比例缩小或原来的size使得图片长/宽等于或小于View的长/宽
FIT_CENTER / fitCenter  把图片按比例扩大/缩小到View的宽度，居中显示
FIT_END / fitEnd   把图片按比例扩大/缩小到View的宽度，显示在View的下部分位置
FIT_START / fitStart  把图片按比例扩大/缩小到View的宽度，显示在View的上部分位置
FIT_XY / fitXY  把图片不按比例扩大/缩小到View的大小显示
MATRIX / matrix 用矩阵来绘制