Android gallery实现选中放大的效果

╰半夏微凉° 2021-06-10 20:42 376阅读 0赞

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：

![0_13289650650C51.gif][]

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>

还有个动画的配置文件，这里就不贴了，感兴趣的可以下载全部工程。

[点击打开链接][Link 1]

[0_13289650650C51.gif]: /images/20210522/fda338f2fca04a9ea7b7e7af9cc0e885.png
[Link 1]: http://download.csdn.net/detail/pzhtpf/4058268