实现拖动，菜单

 代码：

package com.oyzz.ch3_7;

import android.app.Activity;
import android.app.AlertDialog;
import android.graphics.Color;
import android.os.Bundle;
import android.widget.TextView;

/*欲在Layout里使用Gallery widget，必须引用这些模块*/
import android.content.Context;
import android.content.DialogInterface;
import android.widget.Gallery;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;

public class Ch3_7 extends Activity {
 private TextView mTextView01;

 /** Called when the activity is first created. */
 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);

  mTextView01 = (TextView) findViewById(R.id.myTextView01);
  mTextView01.setText(getString(R.string.str_txt1));
  mTextView01.setTextColor(Color.BLUE);

  ((Gallery) findViewById(R.id.myGallery1)).setAdapter(new ImageAdapter(
    this));
 }

 @Override
 // 重写用来创建菜单
 public boolean onCreateOptionsMenu(Menu menu) {
  menu.add(0, 0, 0, "关于");
  menu.add(0, 1, 1, "菜单");
  menu.add(0, 2, 2, "退出");
  return super.onCreateOptionsMenu(menu);
 }

 @Override
 // 设置菜单的事件
 public boolean onOptionsItemSelected(MenuItem item) {
  super.onOptionsItemSelected(item);
  switch (item.getItemId()) {
  case 0:
   about();
   break;
  case 2:
   exit();
   break; 
  default:
   
   break;
  }
  return true;
 }

 private void about() {
  new AlertDialog.Builder(this).setTitle("关于").setMessage("这是欧阳占柱的范例，呵呵")
    .setPositiveButton("确定", new DialogInterface.OnClickListener() {
     public void onClick(DialogInterface dialog, int which) {

     }
    }).show();
 }

 private void exit() {
  new AlertDialog.Builder(this).setTitle("离开").setMessage("确定要离开吗？")
    .setNegativeButton("确定", new DialogInterface.OnClickListener() {
     public void onClick(DialogInterface dialog, int which) {
      finish();
     }
    }).setPositiveButton("取消",
      new DialogInterface.OnClickListener() {
       public void onClick(DialogInterface dialog,
         int which) {

       }
      }).show();
 }

 public class ImageAdapter extends BaseAdapter {
  /* 类成员 myContext为Context父类 */
  private Context myContext;

  /* 使用android.R.drawable里的图片作为图库来源，类型为整数数组 */
  private int[] myImageIds = { android.R.drawable.btn_minus,
    android.R.drawable.btn_radio,
    android.R.drawable.ic_lock_idle_low_battery,
    android.R.drawable.ic_menu_camera };

  /* 构造器只有一个参数，即要存储的Context */
  public ImageAdapter(Context c) {
   this.myContext = c;
  }

  /* 返回所有已定义的图片总数量 */
  public int getCount() {
   return this.myImageIds.length;
  }

  /* 利用getItem方法，取得目前容器中图像的数组ID */
  public Object getItem(int position) {
   return position;
  }

  public long getItemId(int position) {
   return position;
  }

  /* 取得目前欲显示的图像View，传入数组ID值使之读取与成像 */
  public View getView(int position, View convertView, ViewGroup parent) {
   /* 创建一个ImageView对象 */
   ImageView i = new ImageView(this.myContext);

   i.setImageResource(this.myImageIds[position]);// 设置图像
   i.setScaleType(ImageView.ScaleType.FIT_XY);

   /* 设置这个ImageView对象的宽高，单位为dip */
   i.setLayoutParams(new Gallery.LayoutParams(120, 120));
   return i;
  }

  /* 依据距离中央的位移量 利用getScale返回views的大小(0.0f to 1.0f) */
  public float getScale(boolean focused, int offset) {
   /* Formula: 1 / (2 ^ offset) */
   return Math.max(0, 1.0f / (float) Math.pow(2, Math.abs(offset)));
  }
 }
}

 

main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:background="@drawable/white"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  >
  <TextView
  android:id="@+id/myTextView01"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="@string/hello"
  android:gravity="center_vertical|center_horizontal"
  />
  <Gallery
  android:id="@+id/myGallery1"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:gravity="bottom"
  />
</LinearLayout>

 

strings.xml:

<?xml version="1.0" encoding="utf-8"?>
<resources>
  <string name="hello">Hello World, EX03_15</string>
  <string name="app_name">EX03_15</string><string name="str_txt1">大卫探索Android图示集</string>
 
</resources>

color.xml:

<?xml version="1.0" encoding="utf-8"?>
<resources>
  <drawable name="darkgray">#808080FF</drawable>
  <drawable name="white">#FFFFFFFF</drawable>
</resources>