Android gallery实现选中放大的效果

  最近也在一点点学习，还是老样子，把新学的知识总结一下，方便以后参考用。

现在大多Android入门教程中，都给大家教了gallery的基本用法，浏览图片时大小一样，比较死板。咱们这里稍微加一点点效果：选中放大。

其实也非常简单，就是在适配器中public View getView(int position, View convertView, ViewGroup parent) {}这个抽象方法中做相应处理即可：选中的设置大一点，未选中的设置小一点！

效果实现如下：

 

闲话少说，贴代码：

 

galleryAdapter.java

 

 package com.contacts;

 import android.content.Context;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.animation.Animation;
 import android.view.animation.AnimationUtils;
 import android.widget.BaseAdapter;
 import android.widget.Gallery;
 import android.widget.ImageView;

 public class galleryAdapter extends BaseAdapter{
     Context mContext;
     private int selectItem;
     private int drawable1[]=new int[] {R.drawable.center,R.drawable.left,R.drawable.right};
 public galleryAdapter(Context mContext){
     this.mContext=mContext;
 }
     @Override
     public int getCount() {
         // TODO Auto-generated method stub
         return Integer.MAX_VALUE;          //这里的目的是可以让图片循环浏览
     }

     @Override
     public Object getItem(int position) {
         // TODO Auto-generated method stub
         return position;
     }

     @Override
     public long getItemId(int position) {
         // TODO Auto-generated method stub
         return position;
     }
     public void setSelectItem(int selectItem) {

         if (this.selectItem != selectItem) {
         this.selectItem = selectItem;
         notifyDataSetChanged();
         }
     }


     @Override
     public View getView(int position, View convertView, ViewGroup parent) {
         // TODO Auto-generated method stub
         ImageView imageView=new ImageView(mContext);
         imageView.setImageResource(drawable1[position%drawable1.length]);
 //取余，让图片循环浏览

         if(selectItem==position){
         Animation animation = AnimationUtils.loadAnimation(mContext, R.anim.my_scale_action);    //实现动画效果
         imageView.setLayoutParams(new Gallery.LayoutParams(105,120));
           imageView.startAnimation(animation);  //选中时，这是设置的比较大
                     }
         else{
             imageView.setLayoutParams(new Gallery.LayoutParams(75,90));
 //未选中
         }
         return imageView;
     }

 }

 

ContactsActivity.java

 

 package com.contacts;

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

 public class ContactsActivity extends Activity implements OnItemSelectedListener {
     /** Called when the activity is first created. */
     private galleryAdapter adapter;
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main);
         Gallery gallery=(Gallery)findViewById(R.id.gallery);
         adapter=new galleryAdapter(this);
         gallery.setAdapter(adapter);
        gallery.setSpacing(5);
         gallery.setOnItemSelectedListener(this);
     }
     public void onItemSelected(AdapterView<?> parent, View view, int position,long id) {

         adapter.setSelectItem(position);  //当滑动时，事件响应，调用适配器中的这个方法。


     }
     @Override
     public void onNothingSelected(AdapterView<?> arg0) {//抽象方法，必须实现
         // TODO Auto-generated method stub

     }

 }

 

Main.xml

 

 <?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:orientation="vertical" >

     <Gallery
          android:id="@+id/gallery"
          android:layout_width="fill_parent"
           android:layout_height="wrap_content"
         android:layout_marginTop="30dp"
   />
 </LinearLayout>