得知Android小遴选程序第七头（他们定义对话框、Gallery、ImageSwitcher）

效果如下面的：

一共一个activity和两个xml。

******当我们须要使用的组件不在setContentView()设置的布局文件里，那我们就须要使用inflate（）方法来获取。使用view对象调用findViewByid（），作者一开直接调用findViewByid。走了好多弯路，于是写此博文来帮助各位博友，知道了就非常easy了。

*******

MainActivity.java

package com.example.head;

import android.os.Bundle;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageButton;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.ViewSwitcher.ViewFactory;

public class MainActivity extends Activity implements ViewFactory{

	ImageButton imageButton ;
	Gallery gallery;
	ImageSwitcher imageSwitcher;

	int index;

	private final static Integer[] IMAGES = {
		R.drawable.z1,
		R.drawable.z2,
		R.drawable.z3

	};

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

		imageButton = (ImageButton)findViewById(R.id.IB01);

		imageButton.setBackgroundResource(R.drawable.z1);

	}

	public void click(View v){

		LayoutInflater layoutInflater =LayoutInflater.from(MainActivity.this);
		View view = layoutInflater.inflate(R.layout.headchoose, null);
		AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);

		imageSwitcher= (ImageSwitcher)view.findViewById(R.id.IS01);
		 //组件不在activity_main。所以先要使用inflate获得headchoose布局
		//并赋值给view对象。使用view对象，来调用findViewByid（）方法。假设不用view来
		//调用findViewByid（）,找不到会报错。

		gallery =  (Gallery)view.findViewById(R.id.Gall01);

		imageSwitcher.setFactory(MainActivity.this);

		gallery.setAdapter(new ImageAdapter(MainActivity.this));

		gallery.setOnItemClickListener(new OnItemClickListener() {

			@Override
			public void onItemClick(AdapterView<?> arg0, View arg1,
					int position, long arg3) {
				imageSwitcher.setImageResource(IMAGES[position]);
				index = position;

			}
		});

		builder.setTitle("图片选择")
		.setView(view)
		.setPositiveButton("确定", new DialogInterface.OnClickListener() {

			public void onClick(DialogInterface dialog, int which) {
				imageButton.setBackgroundResource(IMAGES[index]);

			}

		});
		builder.show();

	}

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

	/*
	 * ImageAdapter
	 *
	 */

	class ImageAdapter extends BaseAdapter{

		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 position;
		}

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

		@Override
		public View getView(int position, View v, ViewGroup vg) {
			ImageView imageView = new ImageView(context);
			imageView.setImageResource(IMAGES[position]);
			imageView.setLayoutParams(new Gallery.LayoutParams(120, 120));
			imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);

			return imageView;
		}
	}

}

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal" >
    <ImageButton
        android:id="@+id/IB01"
        android:layout_width="70dp"
        android:layout_height="70dp"
        android:onClick="click"/>

    <EditText
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"/>

</LinearLayout>

headchoose.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <Gallery
        android:id="@+id/Gall01"
        android:layout_width="fill_parent"
        android:spacing="10dp"
        android:layout_height="90dp" />

    <ImageSwitcher
        android:id="@+id/IS01"
        android:layout_width="90dp"
        android:layout_height="90dp"
        android:layout_centerHorizontal="true">
    </ImageSwitcher>

</RelativeLayout>

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