Android实现Gallery相册组件开发

[align=left]Gallery组件主要用于横向显示图像列表，不过按常规做法。Gallery组件只能有限地显示指定的图像。[/align]
[align=left]也就是说，如果为Gallery组件指定了10张图像，那么当Gallery组件显示到第10张时，就不会再继续显示了。这虽然在大多数时候没有什么关系，但在某些情况下，我们希望图像显示到最后一张时再重第1张开始显示，也就是循环显示。要实现这种风格的Gallery组件，就需要对Gallery的Adapter对象进行一番改进。[/align]
[align=left]以下通过Gallery模拟循环显示图像，在单击某一个Gallery组件中的图像时在下方显示一个放大的图像（使用ImageSwitcher组件）。[/align]
[align=left]最终效果图如下：[/align]



[align=left]一、Layout布局文件[/align]
[align=left]A:主界面布局文件[/align]
[align=left] [/align]

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ImageButton android:id="@+id/ibtnHead"

android:layout_height="60px" android:layout_width="60px"
android:src="@drawable/icon" android:scaleType="fitXY"></ImageButton>
</LinearLayout>

[align=left]B:显示Gallery和ImageSwitcher的布局文件[/align]

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<Gallery android:id="@+id/img_gallery"
android:layout_width="fill_parent"

android:layout_height="110px" android:layout_marginTop="2px"
android:layout_alignParentLeft="true"></Gallery>

<ImageSwitcher
android:id="@+id/img_switcher"
android:layout_width="90px" android:layout_height="90px"
android:layout_centerHorizontal="true" android:layout_below="@+id/img_gallery"
></ImageSwitcher>
</RelativeLayout>

[align=left]C:String文件[/align]

<?xml version="1.0" encoding="utf-8"?>
<resources>

<string name="addContact_PleaseChooseImg">请选择图像</string>
</resources>

[align=left]二、设置图片资源[/align]
[align=left]在drawable-hdpi文件夹下放置10个要显示的图片，如下图[/align]
[align=left] [/align]



[align=left]三、主Activity类[/align]
[align=left] [/align]

package cn.moon.contact;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageButton;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.ImageView.ScaleType;
import android.widget.ViewSwitcher.ViewFactory;

publicclass AddContactActivity extends Activity {
ImageButton ibtnImgChoose;
AlertDialog imgChooseDialog;
Gallery gallery;

ImageSwitcher imageSwitcher;
int selectedImage;

privateint[] images = { R.drawable.png0001, R.drawable.png0002,
R.drawable.png0003, R.drawable.png0004, R.drawable.png0005,
R.drawable.png0006, R.drawable.png0007, R.drawable.png0008,
R.drawable.png0009, R.drawable.png0010,
};

publicvoid onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

setContentView(R.layout.addcontact);

System.out.println("AddContact");

ibtnImgChoose = (ImageButton) findViewById(R.id.ibtnHead);

ibtnImgChoose.setOnClickListener(new View.OnClickListener() {
publicvoid onClick(View v) {

initImageChoose();
imgChooseDialog.show();

}
});
}

privatevoid initImageChoose() {

LayoutInflater layoutInflater = LayoutInflater.from(this);
View view = layoutInflater.inflate(R.layout.userheadchoose, null);
gallery = (Gallery) view.findViewById(R.id.img_gallery);
gallery.setAdapter(new imageAdapter(this));

gallery.setSelection(images.length /2);

imageSwitcher = (ImageSwitcher) view.findViewById(R.id.img_switcher);

imageSwitcher.setFactory(new switcherFactory(this));

gallery.setOnItemSelectedListener(new OnItemSelectedListener() {

publicvoid onItemSelected(AdapterView<?> arg0, View arg1,int arg2, long arg3) {

imageSwitcher.setImageResource(images[arg2]);
selectedImage = arg2;

}

publicvoid onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub

}
});

AlertDialog.Builder builder =new AlertDialog.Builder(this);

builder.setTitle("请选择图像");

builder.setPositiveButton("确认", new OnClickListener() {

publicvoid onClick(DialogInterface dialog, int which) {

ibtnImgChoose.setImageResource(images[selectedImage]);
}

});
builder.setNegativeButton("取消", new OnClickListener() {

publicvoid onClick(DialogInterface dialog,
int which) {

}
});
builder.setView(view);
imgChooseDialog = builder.create();

}

class imageAdapter extends BaseAdapter {

private Context context;

public imageAdapter(Context context) {
super();
this.context = context;
}

publicint getCount() {
return images.length;
}

public Object getItem(int arg0) {

// TODO Auto-generated
method stub

returnnull;
}

publiclong getItemId(int position) {
// TODO Auto-generated method
stub

　　return0;
}

public View getView(int position, View convertView, ViewGroup parent) {
ImageView imageView =new ImageView(context);// 构造一个ImageView

imageView.setImageResource(images[position]);// 设置ImageView图片源

　　　　　　imageView.setAdjustViewBounds(true);

　　　　　　imageView.setScaleType(ScaleType.FIT_XY);// 自适应高和宽

　　　　　　imageView.setLayoutParams(new Gallery.LayoutParams(80, 80));// 设置显示图处的大小

　　　　　　imageView.setPadding(10, 5, 10, 5);//
设置四边的距离

return imageView;

}
}

class switcherFactory implements ViewFactory {
private Context context;

public switcherFactory(Context context)
{
super();

this.context = context;
}

public View makeView()
{
ImageView imageView =new ImageView(context);
imageView.setLayoutParams(new ImageSwitcher.LayoutParams(90, 90));
return imageView;
}

}
}

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