探索Gallery和ImageSwitcher布局

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:orientation="vertical"
     >
     <Gallery
         android:id="@+id/img_gallery"
         android:layout_width="fill_parent"
         android:layout_height="110px"
         android:layout_marginTop = "100px"
         android:layout_alignParentLeft="true"
         />
     <ImageSwitcher
         android:id="@+id/image_switcher"
         android:layout_width="90px"
         android:layout_height="90px"
         android:layout_alignParentTop="true"
         android:layout_centerHorizontal="true"
         android:layout_alignBottom="@+id/img_gallery"

         ></ImageSwitcher>
 </RelativeLayout>

当把上面Gallery一项属性改成android:layout_marginTop = "0px"，出现下面的效果

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:orientation="vertical"
     >
     <Gallery
         android:id="@+id/img_gallery"
         android:layout_width="fill_parent"
         android:layout_height="110px"
         android:layout_marginTop = "0px"
         android:layout_alignParentLeft="true"
         />
     <ImageSwitcher
         android:id="@+id/image_switcher"
         android:layout_width="90px"
         android:layout_height="90px"

         android:layout_centerHorizontal="true"
         android:layout_alignBottom="@+id/img_gallery"

         ></ImageSwitcher>
 </RelativeLayout>

删掉其中一行

PS： iv.setLayoutParams(new Gallery.LayoutParams(80, 80));  iv.setPadding(15, 10, 15, 10);//setPadding(int left, int top, int right, int bottom)

iv.setLayoutParams(new ImageSwitcher.LayoutParams(90,90));

Gallery中的图像居中显示，单个的图像的实际大小为60*60，虽然代码中指定为80*80，但还需要减去上下Padding，背景画布的高度为110，在xml中指定。

若想整体放大，画布高度调整为300，选中图片大小为160*160，队列图片大小为130*130。且选中图片刚好居中覆盖后面的图片。

75

10

130      160  则Switcher距离最下面的高度应该为 75+10- (160-130)/2 = 70,这个70应该设置为Switcher的layout_marginBottom

10

75

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:orientation="vertical"
     >
     <Gallery
         android:id="@+id/img_gallery"
         android:layout_width="fill_parent"
         android:layout_height="300px"
         android:layout_marginTop = "0px"
         android:layout_alignParentLeft="true"
         />
     <ImageSwitcher
         android:id="@+id/image_switcher"
         android:layout_width="160px"
         android:layout_height="160px"
         android:layout_marginBottom = "70px"
         android:layout_centerHorizontal="true"
         android:layout_alignBottom="@+id/img_gallery"

         ></ImageSwitcher>
 </RelativeLayout>

达到预期效果：

完整控制代码：

package com.hixin.contact;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.AlertDialog.Builder;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.view.Window;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.Gallery.LayoutParams;
import android.widget.HorizontalScrollView;
import android.widget.ImageButton;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.ViewSwitcher.ViewFactory;

public class MainActivity extends Activity {

    ImageButton btn_img;
    AlertDialog  imageChooseDialog;
    Gallery gallery;
    ImageSwitcher is;

    private int[] images ={ R.drawable.image1,R.drawable.image2,R.drawable.image3,
                            R.drawable.image4,R.drawable.image5,R.drawable.image6,
                            R.drawable.image7,R.drawable.image8,R.drawable.image9,
                            R.drawable.image10,R.drawable.image11,R.drawable.image12,
                            R.drawable.image13,R.drawable.image14,R.drawable.image15,
                            R.drawable.image16,R.drawable.image17,R.drawable.image18,
                            R.drawable.image19,R.drawable.image20,R.drawable.image21,
                            R.drawable.image22,R.drawable.image23,R.drawable.image24,
                            R.drawable.image25,R.drawable.image26,R.drawable.image27,
                            R.drawable.image28,R.drawable.image29,R.drawable.image30};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.addnew);
        btn_img = (ImageButton) this.findViewById(R.id.btn_img);
        btn_img.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                initImageChooseDialog();
                imageChooseDialog.show();
            }

        });
    }
    protected void initImageChooseDialog() {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("请选择头像");
        LayoutInflater inflater = LayoutInflater.from(this);
        View view = inflater.inflate(R.layout.imageswitch,null);
        gallery = (Gallery) view.findViewById(R.id.img_gallery);
        gallery.setAdapter(new ImageAdapter(this));
        gallery.setSelection(images.length/2);
        gallery.setOnItemSelectedListener(new OnItemSelectedListener() {

            @Override
            public void onItemSelected(AdapterView<?> parent, View view,
                    int position, long id) {

                is.setImageResource(images[position]);
            }

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

            }

        });
        is = (ImageSwitcher) view.findViewById(R.id.image_switcher);
        is.setFactory(new MyViewFactory(this));
        builder.setView(view);
        imageChooseDialog = builder.create();

    }

    class ImageAdapter extends BaseAdapter {
        private Context context;
        public ImageAdapter(Context context) {
            this.context = context;
        }
        @Override
        public int getCount() {
            // TODO Auto-generated method stub
            return images.length;
        }

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

        @Override
        public long getItemId(int position) {
            // TODO Auto-generated method stub
            return 0;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            // TODO Auto-generated method stub
            ImageView iv = new ImageView(context);
            iv.setImageResource(images[position]);
            iv.setAdjustViewBounds(true);
            iv.setLayoutParams(new Gallery.LayoutParams(150,150));
            iv.setPadding(15, 10, 15, 10);
            return iv;
        }

    }
    class MyViewFactory implements ViewFactory {
        private Context context;
        public MyViewFactory(Context context) {
            this.context = context;
        }
        @Override
        public View makeView() {
            ImageView iv = new ImageView(context);
            iv.setAdjustViewBounds(true);
            iv.setLayoutParams(new ImageSwitcher.LayoutParams(160,160));
            return iv;
        }

    }

}