Android之Gallery画廊

布局:

<RelativeLayout xmlns:android=""
    xmlns:tools=""
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <ImageSwitcher
        android:id="@+id/switcher"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true" >
    </ImageSwitcher>

    <Gallery
        android:id="@+id/gallery"
        android:layout_width="fill_parent"
        android:layout_height="60dp"
        android:layout_alignParentBottom="true"
        android:layout_alignParentLeft="true"
        android:background="#55000000"
        android:gravity="center_vertical"
        android:spacing="60dp" />

</RelativeLayout>

代码:

package com.example.gallary;

import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.view.Window;
import android.view.animation.AnimationUtils;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.ViewSwitcher.ViewFactory;

public class MainActivity extends Activity
implements OnItemSelectedListener, ViewFactory
{
    private ImageSwitcher mSwitcher;
    private Gallery gll;
    private Integer[] mThumbIds =
    {
            R.drawable.a, R.drawable.b,
            R.drawable.c, R.drawable.d,
            R.drawable.e, R.drawable.f,
            R.drawable.g, R.drawable.h,
            R.drawable.j
    };
    private Integer[] mImageIds =
    {
            R.drawable.a, R.drawable.b,
            R.drawable.c, R.drawable.d,
            R.drawable.e, R.drawable.f,
            R.drawable.g, R.drawable.h,
            R.drawable.j
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_main);

        ///< 图片切换器【在选中某个缩略图时会触发onItemSelected事件，进行资源切换】
        ///< 真正关键的是makeView，这里实现了View的生成
        mSwitcher = (ImageSwitcher)findViewById(R.id.switcher);
        mSwitcher.setFactory(this);
        mSwitcher.setInAnimation(AnimationUtils.loadAnimation(this, android.R.anim.fade_in));
        mSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this, android.R.anim.fade_out));

        ///< 画廊【ImageAdapter为图片适配器，能设置图片资源，然后返回该资源View】
        ///< ImageAdapter作为适配器，承载了显示缩略图和返回缩略图对应的图片资源ID【getItemId】的功能
        gll = (Gallery)findViewById(R.id.gallery);
        gll.setAdapter(new ImageAdapter(this));
        gll.setOnItemSelectedListener(this);
    }

    @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;
    }

    @Override
    public View makeView() {
        // TODO Auto-generated method stub
        ImageView iv = new ImageView(this);

        iv.setBackgroundColor(0xFF000000);

        iv.setScaleType(ImageView.ScaleType.FIT_CENTER);

        iv.setLayoutParams(new ImageSwitcher.LayoutParams(LayoutParams.FILL_PARENT,
                LayoutParams.FILL_PARENT));

        return iv;
    }

    @Override
    public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,
            long arg3) {
        // TODO Auto-generated method stub
        mSwitcher.setImageResource(mImageIds[arg2]);
    }

    @Override
    public void onNothingSelected(AdapterView<?> arg0) {
        // TODO Auto-generated method stub

    }

    public class ImageAdapter extends BaseAdapter
    {
        public ImageAdapter(Context c)
        {
            mContext = c;
        }

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

        @Override
        public Object getItem(int arg0) {
            // TODO Auto-generated method stub
            return arg0;
        }

        @Override
        public long getItemId(int arg0) {
            // TODO Auto-generated method stub
            return arg0;
        }

        @Override
        public View getView(int arg0, View arg1, ViewGroup arg2) {
            // TODO Auto-generated method stub
            ImageView iv = new ImageView(mContext);

            iv.setImageResource(mThumbIds[arg0]);

            iv.setAdjustViewBounds(true);

            iv.setLayoutParams(new Gallery.LayoutParams(LayoutParams.WRAP_CONTENT,
                    LayoutParams.WRAP_CONTENT));

            iv.setBackgroundResource(R.drawable.j);

            return iv;
        }
        private Context mContext;
    }
}