android設置圖片為圓角

大家好,這一節給大家分享的是Android中幾種圖像特效處理的小技巧,比如圓角,倒影,還有就是圖片縮放,Drawable轉化為Bitmap,Bitmap轉化為Drawable等等.

廢話少說了,直接講解今天的實例,本例主要是先獲取壁紙(getWallpaper()),然后對當前壁紙的一些特效處理.大家按步驟一步一步來:

第一步:新建一個Android工程命名為ImageDemo,工程結構如下:

第二步:新建一個.java文件,命名為ImageUtil.java,在里面定義一些圖片處理方法,代碼如下:

    package com.android.tutor;

    import android.graphics.Bitmap;

    import android.graphics.Canvas;

    import android.graphics.LinearGradient;

    import android.graphics.Matrix;

    import android.graphics.Paint;

    import android.graphics.PixelFormat;

    import android.graphics.PorterDuffXfermode;

    import android.graphics.Rect;

    import android.graphics.RectF;

    import android.graphics.Bitmap.Config;

    import android.graphics.PorterDuff.Mode;

    import android.graphics.Shader.TileMode;

    import android.graphics.drawable.Drawable;

    public class ImageUtil {


    //放大縮小圖片  
    public static Bitmap zoomBitmap(Bitmap bitmap,int w,int h){  
        int width = bitmap.getWidth();  
        int height = bitmap.getHeight();  
        Matrix matrix = new Matrix();  
        float scaleWidht = ((float)w / width);  
        float scaleHeight = ((float)h / height);  
        matrix.postScale(scaleWidht, scaleHeight);  
        Bitmap newbmp = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);  
        return newbmp;  
    }  
    //將Drawable轉化為Bitmap  
     public static Bitmap drawableToBitmap(Drawable drawable){  
            int width = drawable.getIntrinsicWidth();  
            int height = drawable.getIntrinsicHeight();  
            Bitmap bitmap = Bitmap.createBitmap(width, height,  
                    drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888  
                            : Bitmap.Config.RGB_565);  
            Canvas canvas = new Canvas(bitmap);  
            drawable.setBounds(0,0,width,height);  
            drawable.draw(canvas);  
            return bitmap;  

        }  

     //獲得圓角圖片的方法  
    public static Bitmap getRoundedCornerBitmap(Bitmap bitmap,float roundPx){  

        Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap  
                .getHeight(), Config.ARGB_8888);  
        Canvas canvas = new Canvas(output);  

        final int color = 0xff424242;  
        final Paint paint = new Paint();  
        final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());  
        final RectF rectF = new RectF(rect);  

        paint.setAntiAlias(true);  
        canvas.drawARGB(0, 0, 0, 0);  
        paint.setColor(color);  
        canvas.drawRoundRect(rectF, roundPx, roundPx, paint);  

        paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));  
        canvas.drawBitmap(bitmap, rect, rect, paint);  

        return output;  
    }  
    //獲得帶倒影的圖片方法  
    public static Bitmap createReflectionImageWithOrigin(Bitmap bitmap){  
        final int reflectionGap = 4;  
        int width = bitmap.getWidth();  
        int height = bitmap.getHeight();  

        Matrix matrix = new Matrix();  
        matrix.preScale(1, -1);  

        Bitmap reflectionImage = Bitmap.createBitmap(bitmap,   
                0, height/2, width, height/2, matrix, false);  

        Bitmap bitmapWithReflection = Bitmap.createBitmap(width, (height + height/2), Config.ARGB_8888);  

        Canvas canvas = new Canvas(bitmapWithReflection);  
        canvas.drawBitmap(bitmap, 0, 0, null);  
        Paint deafalutPaint = new Paint();  
        canvas.drawRect(0, height,width,height + reflectionGap,  
                deafalutPaint);  

        canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);  

        Paint paint = new Paint();  
        LinearGradient shader = new LinearGradient(0,  
                bitmap.getHeight(), 0, bitmapWithReflection.getHeight()  
                + reflectionGap, 0x70ffffff, 0x00ffffff, TileMode.CLAMP);  
        paint.setShader(shader);  
        // Set the Transfer mode to be porter duff and destination in  
        paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));  
        // Draw a rectangle using the paint with our linear gradient  
        canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()  
                + reflectionGap, paint);  

        return bitmapWithReflection;  
    }  

}  </pre><br />

第三步:修改main.xml布局文件,主要放了兩個ImageView控件,代碼如下: 

    <?xml version="1.0" encoding="utf-8"?>  
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
        android:orientation="vertical"  
        android:layout_width="fill_parent"  
        android:layout_height="fill_parent"  
        >  
        <ImageView   
            android:id="@+id/image01"   
            android:layout_width="wrap_content"   
            android:layout_height="wrap_content"   
            android:padding="10px"  
            />  
        <ImageView  
            android:id="@+id/image02"  
            android:layout_width="wrap_content"   
            android:layout_height="wrap_content"   
            android:padding="10px"  
        />  
    </LinearLayout>  


第四步:修改主核心程序,ImageDemo.java,代碼如下: 
    package com.android.tutor;

    import android.app.Activity;

    import android.graphics.Bitmap;

    import android.graphics.drawable.Drawable;

    import android.os.Bundle;

    import android.widget.ImageView;

    public class Imagedemo extends Activity {

        private ImageView mImageView01,mImageView02;


    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
        setupViews();  
    }  

    private void setupViews(){  
        mImageView01 = (ImageView)findViewById(R.id.image01);  
        mImageView02 = (ImageView)findViewById(R.id.image02);  

        //獲取壁紙返回值是Drawable  
        Drawable drawable = getWallpaper();  
        //將Drawable轉化為Bitmap  
        Bitmap bitmap = ImageUtil.drawableToBitmap(drawable);  
        //縮放圖片  
        Bitmap zoomBitmap = ImageUtil.zoomBitmap(bitmap, 100, 100);  
        //獲取圓角圖片  
        Bitmap roundBitmap = ImageUtil.getRoundedCornerBitmap(zoomBitmap, 10.0f);  
        //獲取倒影圖片  
        Bitmap reflectBitmap = ImageUtil.createReflectionImageWithOrigin(zoomBitmap);  
        //這里可以讓Bitmap再轉化為Drawable  
//      Drawable roundDrawable = new BitmapDrawable(roundBitmap);         
//      Drawable reflectDrawable = new BitmapDrawable(reflectBitmap);         
//      mImageView01.setBackgroundDrawable(roundDrawable);  
//      mImageView02.setBackgroundDrawable(reflectDrawable);  

        mImageView01.setImageBitmap(roundBitmap);  
        mImageView02.setImageBitmap(reflectBitmap);  
    }  


}  </pre><br />