Android编程滑动效果之Gallery+GridView实现图片预览功能(附demo源码下载)

本文实例讲述了Android编程滑动效果之Gallery+GridView实现图片预览功能。分享给大家供大家参考，具体如下：

Android系统自带一个GridView和Gallery两个控件，GridView网格显示，Gallery单个浏览，两者结合起来可以真正实现Gallery浏览图片效果。

本示例通过GridView和Gallery两个控件，模仿实现一个完整的仿Gallery图像集的图片浏览效果。效果图如下：

1、GridView

首先，自定义一个GridImageAdapter图片适配器，用于填充GridView控件的图片

public class GridImageAdapter extends BaseAdapter {
  private Context mContext;
  Drawable btnDrawable;
  public GridImageAdapter(Context context) {
    mContext = context;
    Resources resources = context.getResources();
    btnDrawable = resources.getDrawable(R.drawable.bg);
  }
  @Override
  public int getCount() {
    return ImageSource.mThumbIds.length;
  }
  @Override
  public Object getItem(int position) {
    return position;
  }
  @Override
  public long getItemId(int position) {
    return position;
  }
  @Override
  public View getView(int position, View convertView, ViewGroup parent) {
    ImageViewExt imageView;
    int space;
    if (convertView == null) {
      imageView = new ImageViewExt(mContext);
      if (imageCol == 5) {
        space = dm.heightPixels / imageCol - 6;
        imageView.setLayoutParams(new GridView.LayoutParams(space, space));
      } else {
        space = dm.widthPixels / imageCol - 6;
        imageView.setLayoutParams(new GridView.LayoutParams( space, space));
      }
      imageView.setAdjustViewBounds(true);
      imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);  // 缩放图片使其长和宽一样
       imageView.setPadding(3, 3, 3, 3);
    } else {
      imageView = (ImageViewExt) convertView;
    }
    imageView.setImageResource(ImageSource.mThumbIds[position]);
    return imageView;
  }
}

然后，用GridImageAdapter填充GridView

gridView = (GridView) findViewById(R.id.myGrid);
gridImageAdapter = new GridImageAdapter(this);
gridView.setAdapter(gridImageAdapter);
gridView.setOnItemClickListener(listener); // 设置点击监听事件

最后，设置GridView控件的点击监听事件

AdapterView.OnItemClickListener listener = new AdapterView.OnItemClickListener() {
  @Override
  public void onItemClick(AdapterView<?> arg0, View arg1, int position, long id) {
    Intent intent = new Intent();
    intent.setClass(GridViewActivity.this, GalleryActivity.class);
    intent.putExtra("position", position);
    startActivity(intent);
  }
};

2、Gallery

完成了GridView的图片显示、监听事件后，现在点击图片，会启动一个Activity来显示当前点击的图片，此时显示图片的控件便是Gallery

首先，同GridView一样，自定义一个ImageAdapter图片适配器，用来填充Gallery

public class ImageAdapter extends BaseAdapter {
  private Context mContext;
  private int mPos;
  public ImageAdapter(Context context) {
    mContext = context;
  }
  public void setOwnposition(int ownposition) {
    this.mPos = ownposition;
  }
  public int getOwnposition() {
    return mPos;
  }
  @Override
  public int getCount() {
    return ImageSource.mThumbIds.length;
  }
  @Override
  public Object getItem(int position) {
    mPos=position;
    return position;
  }
  @Override
  public long getItemId(int position) {
    mPos=position;
    return position;
  }
  @Override
  public View getView(int position, View convertView, ViewGroup parent) {
    mPos=position;
    ImageView imageview = new ImageView(mContext);
    imageview.setBackgroundColor(0xFF000000);
    imageview.setScaleType(ImageView.ScaleType.FIT_CENTER);
    imageview.setLayoutParams(new myGallery.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
    imageview.setImageResource(ImageSource.mThumbIds[position]);
    return imageview;
  }
}

然后，用ImageAdapter填充Gallery

myGallery galllery = (myGallery) findViewById(R.id.mygallery);
Intent intent = getIntent();
position = intent.getIntExtra("position", 0); // 获取GridViewActivity传来的图片位置position
ImageAdapter imgAdapter=new ImageAdapter(this);
galllery.setAdapter(imgAdapter); // 设置图片ImageAdapter
galllery.setSelection(position); // 设置当前显示图片
  Animation an= AnimationUtils.loadAnimation(this,R.anim.scale ); // Gallery动画
  galllery.setAnimation(an);

此时，如果细心可以注意到，我们的Gallery也是自己定义的myGallery，具体定义如下：

public class myGallery extends Gallery {
  boolean isFirst = false;
  boolean isLast = false;
  public myGallery(Context context) {
    super(context);
  }
  public myGallery(Context context, AttributeSet paramAttributeSet) {
    super(context, paramAttributeSet);
  }
  /** 是否向左滑动（true - 向左滑动； false - 向右滑动） */
  private boolean isScrollingLeft(MotionEvent e1, MotionEvent e2) {
    return e2.getX() > e1.getX();
  }
  @Override
  public boolean onFling(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
    ImageAdapter ia = (ImageAdapter) this.getAdapter();
    int p = ia.getOwnposition(); // 获取当前图片的position
    int count = ia.getCount(); // 获取全部图片的总数count
    int kEvent;
    if (isScrollingLeft(e1, e2)) {
      if (p == 0 && isFirst) {
        Toast.makeText(this.getContext(), "已是第一页", Toast.LENGTH_SHORT).show();
      } else if (p == 0) {
        isFirst = true;
      } else {
        isLast = false;
      }
      kEvent = KeyEvent.KEYCODE_DPAD_LEFT;
    } else {
      if (p == count - 1 && isLast) {
        Toast.makeText(this.getContext(), "已到最后一页", Toast.LENGTH_SHORT).show();
      } else if (p == count - 1) {
        isLast = true;
      } else {
        isFirst = false;
      }
      kEvent = KeyEvent.KEYCODE_DPAD_RIGHT;
    }
    onKeyDown(kEvent, null);
    return true;
  }
}

GalleryActivity的布局文件gallery.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:gravity="center"
  android:orientation="horizontal"
  android:padding="10dip" >
  <RelativeLayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="#000000"
    android:padding="2dip" >
    <com.homer.gridgallery.myGallery
      android:id="@+id/mygallery"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent"
      android:spacing="16dp" />
  </RelativeLayout>
</LinearLayout>

完整实例代码点击此处本站下载。

更多关于Android相关内容感兴趣的读者可查看本站专题：《Android开发动画技巧汇总》、《Android开发入门与进阶教程》及《Android控件用法总结》。

希望本文所述对大家Android程序设计有所帮助。