初识ImageSwither

imageswitcher继承自viewswitcher，使用ImageSwither只需要两步：

1.为ImageSwither提供一个ViewFactory，该ViewFactory生成的View必须是ImageView.

2.需要切换图片时，只要调用ImageSwither的setImageResource，setImageDrawable，setImageURI方法更换图片即可。

下面是一个gallery，上面是个imageSwither，在gallery里每选择一张图片就会显示到Swither上，并有渐入渐出动画效果。

ImageSwitcher + GridView

 import android.app.Activity;

 import android.os.Bundle;

 import android.view.View;

 import android.view.ViewGroup;

 import android.widget.AdapterView;

 import android.widget.AdapterView.OnItemClickListener;

 import android.widget.BaseAdapter;

 import android.widget.FrameLayout.LayoutParams;

 import android.widget.GridView;

 import android.widget.ImageSwitcher;

 import android.widget.ImageView;

 import android.widget.ViewSwitcher.ViewFactory;

 public class ImageSwitcherTest extends Activity {

     private GridView gridView;

     private ImageSwitcher switcher;

     private int[] mImage = new int[] { R.drawable.p0, R.drawable.p13,

             R.drawable.p16, R.drawable.p2, R.drawable.p4, R.drawable.p8 };

     @Override

     protected void onCreate(Bundle savedInstanceState) {

         // TODO Auto-generated method stub

         super.onCreate(savedInstanceState);

         setContentView(R.layout.layout_imageswitcher);

         switcher = (ImageSwitcher) findViewById(R.id.imageSwitcher2);

         switcher.setFactory(new ViewFactory() {

             @Override

             public View makeView() {

                 // TODO Auto-generated method stub

                 ImageView imageView = new ImageView(ImageSwitcherTest.this);

                 imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);

                 /*imageView.setLayoutParams(new ImageSwitcher.LayoutParams(

                         LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));*/

                 return imageView;

             }

         });

         ImageAdapter adapter = new ImageAdapter();

         gridView = (GridView) findViewById(R.id.gridView2);

         gridView.setAdapter(adapter);

         gridView.setOnItemClickListener(new OnItemClickListener() {

             @Override

             public void onItemClick(AdapterView<?> parent, View view,

                     int position, long id) {

                 // TODO Auto-generated method stub

                 switcher.setImageResource(mImage[position]);

             }

         });

     }

     class ImageAdapter extends BaseAdapter {

         @Override

         public int getCount() {

             // TODO Auto-generated method stub

             return mImage.length;

         }

         @Override

         public Object getItem(int position) {

             // TODO Auto-generated method stub

             return mImage[position];

         }

         @Override

         public long getItemId(int position) {

             // TODO Auto-generated method stub

             return position;

         }

         @Override

         public View getView(int position, View convertView, ViewGroup parent) {

             // TODO Auto-generated method stub

             ImageView imageView = new ImageView(ImageSwitcherTest.this);

             imageView.setImageResource(mImage[position]);

             return imageView;

         }

     }

 }

 <?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" >

     <GridView

         android:id="@+id/gridView2"

         android:layout_width="match_parent"

         android:layout_height="254dp"

         android:numColumns="3"

         android:horizontalSpacing="pt"

         android:verticalSpacing="2pt"

         android:gravity="center"

          >

     </GridView>

     <ImageSwitcher

         android:id="@+id/imageSwitcher2"

         android:layout_width="match_parent"

         android:layout_height="wrap_content"

         android:layout_weight="0.94"

         android:layout_gravity="center_horizontal"

         android:inAnimation="@android:anim/fade_in"

         android:outAnimation="@android:anim/fade_out"

         >

     </ImageSwitcher>

 </LinearLayout>