Android 照片拖动特效 Android使用Gallery实现照片拖动的特效
snowyeti 人气:0今天要分享一个非常简单的功能:
使用Android原生控件Gallery实现照片拖动的特效
实现思路如下:
- 在布局文件中定义一个Gallery控件
- 由于要显示多张图,为了方便,我直接引用了Android原生的图片资源
- Gallery只是一个控件,为了将图片数据跟控件进行绑定,还需要一个继承BaseAdapter的自定义适配器
源码如下:
1、主activity和自定义内部类ImageAdapter:
import android.app.Activity; import android.content.Context; import android.os.Bundle; import android.util.Log; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.Gallery; import android.widget.ImageView; import com.example.memorydemo.R; public class SimpleGallery extends Activity { private static final String TAG = "SimpleGallery"; @Override protected void onCreate(Bundle onSavedInstance) { super.onCreate(onSavedInstance); setContentView(R.layout.simple_gallery_layout); Gallery gallery = findViewById(R.id.gallery); gallery.setAdapter(new ImageAdapter(this)); } private class ImageAdapter extends BaseAdapter { // 这里我们使用Android原生的资源图标 private int[] imageIds = { android.R.drawable.btn_minus, android.R.drawable.btn_radio, android.R.drawable.ic_lock_idle_low_battery, android.R.drawable.ic_menu_camera }; private Context mContext; public ImageAdapter(Context context) { mContext = context; } @Override public int getCount() { return imageIds.length; } @Override public Object getItem(int position) { return imageIds[position]; } @Override public long getItemId(int position) { return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { ImageView imageView; if (convertView == null) { Log.i(TAG, "convertView is null, create new imageview"); imageView = new ImageView(mContext); } else { Log.i(TAG, "Cast convertView to ImageView"); imageView = (ImageView) convertView; } imageView.setImageResource(imageIds[position]); imageView.setScaleType(ImageView.ScaleType.FIT_XY); // 注意这里要用Gallery.LayoutParams作为布局参数类型,源码中给出了建议(Views given to the Gallery should use // Gallery.LayoutParams s their ayout parameters type) // 由于Android原生图片很小,我将高度设置为 500,方便看效果 imageView.setLayoutParams(new Gallery.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 500)); return imageView; } } }
2、布局文件 simple_gallery_layout.xml如下:
<?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"> <Gallery android:id="@+id/gallery" android:layout_width="match_parent" android:layout_height="match_parent" /> </LinearLayout>
注意:
Gallery控件其实已经被废弃了,建议用 HorizontalScrollView 和 ViewPager 代替,源码中是这么解释的:
@deprecated This widget is no longer supported. Other horizontally scrolling widgets include {@link HorizontalScrollView} and {@link android.support.v4.view.ViewPager} from the support library.
后续会分享 HorizontalScrollView 和 ViewPager这两个控件是如何使用的。
加载全部内容