阅读《Android 从入门到精通》（24）——切换图片

Posted 2023-01-12 SweetLoverFT

切换图片（ImageSwitcher）

java.lang.Object;
android.view.View;
android.widget.ViewGroup;
android.widget.FrameLayout;
android.widget.ViewAnimator;
android.widget.ImageSwitcher;

ImageSwitcher 提供了显示图片以及图片切换的动画，这一块可以应用于制作动感影集。

ImageSwitcher 类方法

ImageSwitcher 和 Gallery 示例

完整工程：http://download.csdn.net/detail/sweetloveft/9428069

ViewFactory下述工程中主要演示了 ImageSwitcher 和 Gallery 的用法，需要注意的是：ViewFactory.makeView 的实现中，ImageView 所要设置的布局类型是 FrameLayout.LayoutParams，除此之外，其他地方出现要设置的参数均为 Gallery.LayoutParams，否则会导致崩溃！
此外还可以学习下，Window 相关的属性

1.MainActivity.java

package com.sweetlover.activity;

import com.sweetlover.imageswitcher.R;

import android.app.Activity;
import android.content.Context;
import android.graphics.Color;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.animation.AnimationUtils;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.FrameLayout;
import android.widget.Gallery.LayoutParams;
import android.widget.ImageView;
import android.widget.ImageView.ScaleType;
import android.widget.ViewSwitcher.ViewFactory;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageSwitcher;

@SuppressWarnings("deprecation")
public class MainActivity extends Activity implements ViewFactory,
		OnItemSelectedListener 

	public class SelfAdapter extends BaseAdapter 

		private Context context = null;
		
		public SelfAdapter(Context context) 
			super();
			this.context = context;
		

		@Override
		public int getCount() 
			// TODO Auto-generated method stub
			return pic.length;
		

		@Override
		public Object getItem(int position) 
			// TODO Auto-generated method stub
			return pic[position];
		

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

		@Override
		public View getView(int position, View convertView, ViewGroup parent) 
			// TODO Auto-generated method stub
			ImageView imageView = new ImageView(context);
			LayoutParams param = new LayoutParams(WIDTH, HEIGHT);
			imageView.setImageResource(pic[position]);
			imageView.setAdjustViewBounds(true);
			imageView.setLayoutParams(param);
			return imageView;
		
	

	private Gallery gallery = null;
	private SelfAdapter selfAdapter = null;
	private ImageSwitcher imageSwitcher = null;
	private FrameLayout.LayoutParams param = null;
	
	private static final int WIDTH = 480;
	private static final int HEIGHT = 640;
	private static final int BACKGND_COLOR = Color.BLACK;
	private static final int IN_ANIM = android.R.anim.fade_in;
	private static final int OUT_ANIM = android.R.anim.fade_out;
	private static final Integer[] pic =  R.drawable.pic1, R.drawable.pic2,
			R.drawable.pic3 ;

	@Override
	protected void onCreate(Bundle savedInstanceState) 
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		requestWindowFeature(Window.FEATURE_NO_TITLE);
		setContentView(R.layout.activity_main);

		gallery = (Gallery) findViewById(R.id.gallery);
		imageSwitcher = (ImageSwitcher) findViewById(R.id.imageSwitcher);
		selfAdapter = new SelfAdapter(this);
		imageSwitcher.setFactory(this);
		imageSwitcher.setInAnimation(AnimationUtils
				.loadAnimation(this, IN_ANIM));
		imageSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this,
				OUT_ANIM));
		gallery.setAdapter(selfAdapter);
		gallery.setOnItemSelectedListener(this);
	

	@Override
	public void onItemSelected(AdapterView<?> parent, View view, int position,
			long id) 
		// TODO Auto-generated method stub
		imageSwitcher.setImageResource(pic[position]);
	

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

	

	@Override
	public View makeView() 
		// TODO Auto-generated method stub
		ImageView imageView = new ImageView(this);
		param = new FrameLayout.LayoutParams(WIDTH, HEIGHT, Gravity.CENTER);
		imageView.setBackgroundColor(BACKGND_COLOR);
		imageView.setScaleType(ScaleType.CENTER);
		imageView.setLayoutParams(param);
		return imageView;
	

2.activity_main.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" >
    
    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
    
    <ImageSwitcher
        android:id="@+id/imageSwitcher"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true" />
    
    <Gallery
        android:id="@+id/gallery"
        android:background="#660000FF"
        android:layout_width="match_parent"
        android:layout_height="60dp"
        android:layout_alignParentBottom="true"
        android:layout_alignParentLeft="true"
        android:gravity="center_vertical"
        android:spacing="15dp" />
    
</RelativeLayout>

3.AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.sweetlover.imageswitcher"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="19" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity android:name="com.sweetlover.activity.MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
    </application>

</manifest>