Android:实现图片的倒影效果

最新推荐文章于 2021-05-27 11:11:23 发布

zd_1471278687

最新推荐文章于 2021-05-27 11:11:23 发布

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分类专栏： Android 文章标签： android开发图片倒影

本文链接：https://blog.youkuaiyun.com/zd_1471278687/article/details/13998413

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本文介绍如何在Android应用中自定义Gallery控件，实现图片的显示与切换，并为每张图片添加倒影效果。通过创建自定义Gallery类（myGallery），实现了图片的偏转角度和最大缩放值的设定，以及为每个图片添加倒影。同时，通过适配器（ImageAdapter）在Adapter中为Gallery添加图片和倒影。最后，主Activity（Main）配置了Gallery的监听事件，展示了图片的标题和选择效果。

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本文章主要参考来自于：http://blog.youkuaiyun.com/ithomer/article/details/7483169（谢谢IT-Homer的分享！）

本文章根据自己的需要做了点小小的修改，如果想看原版，还是点击上面的连接吧！

1.图片的显示以及切换主要是自定义了一个Gallery

下面是代码myGallery.java：

import android.content.Context;
import android.graphics.Camera;
import android.graphics.Matrix;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.Transformation;
import android.widget.Gallery;
import android.widget.ImageView;

@SuppressWarnings("deprecation")
public class myGallery extends Gallery {

	private Camera mCamera = new Camera();
	private int mMaxRotationAngle = 60;		//图片偏转角度 60
	private int mMaxZoom = -120;
	private int mCoveflowCenter;

	public myGallery(Context context) {
		super(context);
		this.setStaticTransformationsEnabled(true);
	}

	public myGallery(Context context, AttributeSet attrs) {
		super(context, attrs);
		this.setStaticTransformationsEnabled(true);
	}

	public myGallery(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		this.setStaticTransformationsEnabled(true);
	}

	public int getMaxRotationAngle() {
		return mMaxRotationAngle;
	}

	public void setMaxRotationAngle(int maxRotationAngle) {
		mMaxRotationAngle = maxRotationAngle;
	}

	public int getMaxZoom() {
		return mMaxZoom;
	}

	public void setMaxZoom(int maxZoom) {
		mMaxZoom = maxZoom;
	}

	/** 获得Gallery中心到边界的距离*/
	private int getCenterOfCoverflow() {
		return (getWidth() - getPaddingLeft() - getPaddingRight()) / 2 + getPaddingLeft();
	}

	/** 获得View中心位置到边界的距离 */
	private static int getCenterOfView(View view) {
		return view.getLeft() + view.getWidth() / 2;
	}
	
	@Override
	protected void onSizeChanged(int w, int h, int oldw, int oldh) {
		mCoveflowCenter = getCenterOfCoverflow();
		super.onSizeChanged(w, h, oldw, oldh);
	}

	@Override
	protected boolean getChildStaticTransformation(View child, Transformation trans) {
		final int childCenter = getCenterOfView(child);
		final int childWidth = child.getWidth();
		int rotationAngle = 0;

		trans.clear();
		trans.setTransformationType(Transformation.TYPE_BOTH);		// alpha和 matrix都变换

		if (childCenter == mCoveflowCenter) {	//正中间的childView 
			transformImageBitmap((ImageView) child, trans, 0);	
		} else {								//两侧的childView   
			rotationAngle = (int) ( ( (float) (mCoveflowCenter - childCenter) / childWidth ) * mMaxRotationAngle );
			if (Math.abs(rotationAngle) > mMaxRotationAngle) {
				rotationAngle = (rotationAngle < 0) ? -mMaxRotationAngle : mMaxRotationAngle;
			}
			transformImageBitmap((ImageView) child, trans, rotationAngle);
		}

		return true;
	}

	private void transformImageBitmap(ImageView child, Transformation trans, int rotationAngle) {
		mCamera.save();
		
		final Matrix imageMatrix = trans.getMatrix();
		final int imageHeight = child.getLayoutParams().height;
		final int imageWidth = child.getLayoutParams().width;
		final int rotation = Math.abs(rotationAngle);

		//在Z轴上正向移动camera的视角，实际效果为放大图片; 如果在Y轴上移动，则图片上下移动; X轴上对应图片左右移动
		mCamera.translate(0.0f, 0.0f, 200.0f);

		// As the angle of the view gets less, zoom in
		if (rotation < mMaxRotationAngle) {
			float zoomAmount = (float) (mMaxZoom + (rotation * 1.5));
			mCamera.translate(0.0f, 0.0f, zoomAmount);
		}

		mCamera.rotateY(rotationAngle);		//rotationAngle 为正，沿y轴向内旋转； 为负，沿y轴向外旋转
		
		mCamera.getMatrix(imageMatrix);
		imageMatrix.preTranslate(-(imageWidth / 2), -(imageHeight / 2));
		imageMatrix.postTranslate((imageWidth / 2), (imageHeight / 2));
		
		mCamera.restore();
	}
}

2.接下来就是要为图片添加倒影了，用过PhotoShop的都知道添加倒影就是将原有图片倒置，设置渐变式的显示，再将其放在原图片下面就行了，这里的方法也是一样

在为Gallery添加图片的同时，为每个图片添加倒影，需要在Adapter中做

下面就是相关代码 ImageAdapter.java：

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.LinearGradient;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Shader.TileMode;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ImageView.ScaleType;

public class ImageAdapter extends BaseAdapter {
	private ImageView[] mImages; // 存储每个图片的ImageView

	private Context mContext;
	public List<Map<String, Object>> list;

	public Integer[] imgs = { R.drawable.img1, R.drawable.img2,
			R.drawable.img3, R.drawable.img4, R.drawable.img5 };
	public String[] titles = { "孙燕姿", "就是要唱歌", "微笑", "大海", "漂亮"};

	public ImageAdapter(Context c) {
		this.mContext = c;
		list = new ArrayList<Map<String, Object>>();
		for (int i = 0; i < imgs.length; i++) {
			HashMap<String, Object> map = new HashMap<String, Object>();
			map.put("image", imgs[i]);
			list.add(map);
		}
		mImages = new ImageView[list.size()];
	}

	/**
	 * 创建倒影效果
	 */
	@SuppressWarnings("deprecation")
	public boolean createReflectedImages() {
		final int reflectionGap = 4;//原图与倒影之间的间隙
		int index = 0;
		for (Map<String, Object> map : list) {
			Integer id = (Integer) map.get("image");
			Bitmap originalImage = BitmapFactory.decodeResource(
					mContext.getResources(), id); // 获得图片资源
			// 获得图片的长宽
			int width = originalImage.getWidth();
			int height = originalImage.getHeight();

			Matrix matrix = new Matrix();
			matrix.preScale(1, -1); // 实现图片的反转
			Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0,
					height / 2, width, height / 2, matrix, false); // 创建反转后的图片Bitmap对象，图片高是原图的一半
			Bitmap bitmapWithReflection = Bitmap.createBitmap(width,
					(height + height / 2), Config.ARGB_8888); // 创建标准的Bitmap对象，宽和原图一致，高是原图的1.5倍

			Canvas canvas = new Canvas(bitmapWithReflection);
			canvas.drawBitmap(originalImage, 0, 0, null); // 创建画布对象，将原图画于画布，起点是原点位置
			Paint paint = new Paint();
			canvas.drawRect(0, height, width, height + reflectionGap, paint);
			canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null); // 将反转后的图片画到画布中

			paint = new Paint();
			LinearGradient shader = new LinearGradient(0,
					originalImage.getHeight(), 0,
					bitmapWithReflection.getHeight() + reflectionGap,
					0x70ffffff, 0x00ffffff, TileMode.MIRROR);// 创建线性渐变LinearGradient对象
			paint.setShader(shader); // 绘制
			paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));//倒影遮罩效果
			canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()
					+ reflectionGap, paint); // 画布画出反转图片大小区域，然后把渐变效果加到其中，就出现了图片的倒影效果

			ImageView imageView = new ImageView(mContext);
			imageView.setImageBitmap(bitmapWithReflection); // 设置带倒影的Bitmap
			//设置ImageView的大小，可以根据图片大小设置
			// imageView.setLayoutParams(newmyGallery.LayoutParams(width,height));
			imageView.setLayoutParams(new myGallery.LayoutParams(250, 500));//设置ImageView的大小，可根据需要设置固定宽高
			imageView.setScaleType(ScaleType.FIT_CENTER);//将图片按比例缩放
			mImages[index++] = imageView;
		}
		return true;
	}

	@Override
	public int getCount() {
		return imgs.length;
	}

	@Override
	public Object getItem(int position) {
		return mImages[position];
	}

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

	@Override
	public View getView(int position, View convertView, ViewGroup parent) {
		return mImages[position]; // 获得Gallery中对应位置的ImageView
	}

	public float getScale(boolean focused, int offset) {
		return Math.max(0, 1.0f / (float) Math.pow(2, Math.abs(offset)));
	}

}

3.然后在主Activity中进行配置Main.java：

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.TextView;
import android.widget.Toast;

public class Main extends Activity {

	private TextView tvTitle; 	
	private myGallery gallery; 	
	private ImageAdapter adapter;
	
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		initRes();
	}
	
	private void initRes(){      
	    tvTitle = (TextView) findViewById(R.id.tvTitle);      
	    gallery = (myGallery) findViewById(R.id.mygallery);     // 获取自定义的myGallery控件      
	           
	    adapter = new ImageAdapter(this);         
	    adapter.createReflectedImages();    // 创建倒影效果      
	    gallery.setAdapter(adapter);      
	               
	    gallery.setOnItemSelectedListener(new OnItemSelectedListener() {    // 设置选择事件监听      
	        @Override 
	        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {      
	            tvTitle.setText(adapter.titles[position]);      
	        }      
	           
	        @Override 
	        public void onNothingSelected(AdapterView<?> parent) {      
	        }      
	    });      
	           
	    gallery.setOnItemClickListener(new OnItemClickListener() {          // 设置点击事件监听      
	        @Override 
	        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {      
	            Toast.makeText(Main.this, "img " + (position+1) + " selected", Toast.LENGTH_SHORT).show();      
	        }      
	    });      
	}
}

4.最后是页面布局main.xml：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
    <TextView
        android:id="@+id/tvTitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:textSize="16sp" />

    <com.homer.reflect.myGallery
        android:id="@+id/mygallery"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_centerVertical="true" />

</RelativeLayout>

5.大功告成啦！看看效果：