Gallery与ImageSwitcher结合的简单实现

Gallery控件，即Android中的图片浏览控件。就像一个画廊一样，把图片存储起来，以便浏览查看。

当点击Gallery中的一张图片时，会在ImageSwitcher中显示该图片。首先要做到的时布局设计，其次建立MainActivity.java文件，第一步先获取组件。第二步对Gallery进行数据绑定，创建适配器，绑定数据源和适配器。

然后新建一个ImageAdapter.java文件，继承BaseAdapter抽象类。编写getView()方法。

其中context主要是连接上下文，在创建ImageView时要传一个context。

spacing是图片之间的内间隙。在最外层背景中引用系统样式：<android:backgroud"？android：galleryItemBackground">。

还有一种方法时给每张图片加边框：

1.在values下新建一个item.xml文件，内容如下：

<?xml version="1.0"encoding="utf-8" ?>
<resources>
<declare-styleablename="HelloGallery">
<attrname="android:galleryItemBackground" />
</declare-styleable>
</resources>

2.粗体部分为关键代码：

private class ImageAdapter extends BaseAdapter {
private Context context;
int mGalleryItemBackground;
public ImageAdapter(Context context) {
this.context = context;
TypedArray a = obtainStyledAttributes(R.styleable.HelloGallery);
mGalleryItemBackground = a.getResourceId(
R.styleable.HelloGallery_android_galleryItemBackground, 0);
a.recycle();
}

@Override
public int getCount() {
// TODO Auto-generated method stub
return imagesSmall.length;
}

@Override
public Object getItem(int position) {
return imagesSmall[position];
}

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

@Override
public View getView(int position, View convertView, ViewGroup parent) {
ImageView imageView = new ImageView(
ImageSwitcherGalleryActivity.this);
imageView.setImageResource(imagesSmall[position]);
// imageView.setAdjustViewBounds(true);
imageView.setBackgroundResource(mGalleryItemBackground);
return imageView;
}

}

页面效果显示：

当点击Gallery中的图片时，会在下面的ImageSwitcher中显示该图片。

布局设计：

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >

<Gallery
android:id="@+id/gallery"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:spacing="5dp"   //图片之间的内间隙
android:layout_marginTop="20dp"
android:background="?android:galleryItemBackground" /*设置最外层背景框*//>
<ImageSwitcher
android:id="@+id/switcher"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/gallery"/>

</RelativeLayout>

代码实现：

MainActivity.java

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

public class MainActivity extends Activity {
private Gallery gallery;
private ImageSwitcher switcher;
private int index=0;
private Integer[] imagesID = { R.drawable.car00, R.drawable.car01, R.drawable.car02,
R.drawable.car03, R.drawable.car04, R.drawable.car05,
R.drawable.car06,R.drawable.car07,R.drawable.car08};

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//获取组件
gallery=(Gallery) this.findViewById(R.id.gallery);
switcher=(ImageSwitcher) this.findViewById(R.id.switcher);

//设置ImageSwitcherD对象的数据源
switcher.setFactory(new ViewFactory() {

@Override
public View makeView() {
// TODO Auto-generated method stub
ImageView imageview=new ImageView(MainActivity.this);
return imageview;
}
});
switcher.setImageResource(imagesID[index]);

//对gallery进行数据绑定
gallery.setAdapter(new ImageAdapter(this));
gallery.setOnItemClickListener(new OnItemClickListener() {

@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int position,
long id) {
/*Toast.makeText(MainActivity.this, "你选择了"+(position+1)+"图片",Toast.LENGTH_SHORT ).show();*/
switcher.setImageResource(imagesID[position]);
}
});
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

}

ImageAdapter.java

import android.content.Context;
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;
private Integer[] imageId = {R.drawable.car00, R.drawable.car01, R.drawable.car02,
R.drawable.car03, R.drawable.car04, R.drawable.car05,
R.drawable.car06,R.drawable.car07,R.drawable.car08};

public ImageAdapter(Context c){
mcontext=c;
}

@Override
public int getCount() {
// TODO Auto-generated method stub
return imageId.length;
}

@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;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
ImageView imageview=new ImageView(mcontext);
imageview.setImageResource(imageId[position]);
imageview.setLayoutParams(new Gallery.LayoutParams(120,120));
imageview.setScaleType(ImageView.ScaleType.FIT_CENTER);
return imageview;
}
}