和你一起終身學習，這里是程序員Android

經(jīng)典好文推薦，通過閱讀本文，您將收獲以下知識點:

一、ImageView 的繼承關(guān)系
二、ImageView 常用方法
三、ImageView 背景 間距屬性設(shè)置
四、使用Bitmap 類型動態(tài)設(shè)置ImageView 資源
五、ImageView 圖片倒影實現(xiàn)
六、ImageView 圖片縮放實現(xiàn)
七、ImageView 圓角圖片實現(xiàn)
八、Bitmap 與Drawable 轉(zhuǎn)換工具類

一、ImageView 的繼承關(guān)系

ImageView的繼承關(guān)系 如下：

java.lang.Object   
       ? android.view.View      
                 ? android.widget.ImageView

二、ImageView 常用方法

ImageView主要用于顯示圖像資源，Bitmap或Drawable資源，同時也常用于圖片渲染調(diào)色，圖片縮放剪裁等。

以下XML代碼段是使用ImageView顯示圖像資源的常見示例：

1. 在xml使用ImageView?控件

 <LinearLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent">
     <ImageView
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:src="@mipmap/ic_launcher"
         />
 LinearLayout>
 

三、 ImageView 背景 間距屬性設(shè)置

1. 在xml使用ImageView控件

    <ImageView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/grey"
        android:padding="5dp" 
        android:src="@drawable/ic_launcher" />

2. 實現(xiàn)效果如下：

padding background 屬性設(shè)置

四、 使用Bitmap 類型動態(tài)設(shè)置ImageView 資源

1. 在xml?使用ImageView控件

<ImageView
        android:id="@+id/img_1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="5dp" />

2.java?類實現(xiàn)

        // 1.從資源中獲取Bitmap
        ImageView mImageView1 = (ImageView) findViewById(R.id.img_1);
        DrawableUtils.UseBitmap(this, mImageView1, R.drawable.gril);

3.DrawableUtils類方法實現(xiàn)

    // 1.從資源中獲取Bitmap
    public static void UseBitmap(Context context, ImageView imageView, int drawableId) {

        Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(),
                drawableId);
        imageView.setImageBitmap(bitmap);

    }

4. 實現(xiàn)效果如下：

bitmap 類型的圖片

五、ImageView 圖片倒影實現(xiàn)

1. 在xml使用ImageView?控件

    <ImageView
        android:id="@+id/img_4"
        android:layout_width="match_parent"
        android:layout_height="200dp"
        android:background="@color/grey"
        android:padding="5dp" />

2.?java代碼 實現(xiàn)效果

        // 4.倒影圖片
        ImageView mImageView4 = (ImageView) findViewById(R.id.img_4);
        mImageView4.setImageBitmap(DrawableUtils.CreateReflectionImageWithOrigin(
                DrawableUtils.DrawableToBitmap(getResources().getDrawable(
                        R.drawable.img1))));

3.?DrawableUtils?工具類的方法實現(xiàn)

    // 5. Drawable----> Bitmap
    public static Bitmap DrawableToBitmap(Drawable drawable) {

        // 獲取 drawable 長寬
        int width = drawable.getIntrinsicWidth();
        int heigh = drawable.getIntrinsicHeight();

        drawable.setBounds(0, 0, width, heigh);

        // 獲取drawable的顏色格式
        Bitmap.Config config = drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
                : Bitmap.Config.RGB_565;
        // 創(chuàng)建bitmap
        Bitmap bitmap = Bitmap.createBitmap(width, heigh, config);
        // 創(chuàng)建bitmap畫布
        Canvas canvas = new Canvas(bitmap);
        // 將drawable 內(nèi)容畫到畫布中
        drawable.draw(canvas);
        return bitmap;
    }

4. 實現(xiàn)效果如下：

ImageView 倒影功能實現(xiàn)

六、ImageView 圖片縮放實現(xiàn)

1. 在xml使用ImageView?控件

    <ImageView
        android:id="@+id/img_2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="5dp" />

2.?java代碼 實現(xiàn)效果

        // 2. 圖片縮放
        ImageView mImageView2 = (ImageView) findViewById(R.id.img_2);
        mImageView2.setImageDrawable(DrawableUtils.ZoomDrawable(getResources().getDrawable(R.drawable.img1),
                240, 200));

3.?DrawableUtils?工具類方法實現(xiàn)

    // 9. drawable進行縮放 ---> bitmap 然后比對bitmap進行縮放
    public static Drawable ZoomDrawable(Drawable drawable, int w, int h) {
        int width = drawable.getIntrinsicWidth();
        int height = drawable.getIntrinsicHeight();
        // 調(diào)用5 中 drawable轉(zhuǎn)換成bitmap
        Bitmap oldbmp = DrawableToBitmap(drawable);

        // 創(chuàng)建操作圖片用的Matrix對象
        Matrix matrix = new Matrix();
        // 計算縮放比例
        float sx = ((float) w / width);
        float sy = ((float) h / height);
        // 設(shè)置縮放比例
        matrix.postScale(sx, sy);
        // 建立新的bitmap，其內(nèi)容是對原bitmap的縮放后的圖
        Bitmap newbmp = Bitmap.createBitmap(oldbmp, 0, 0, width, height,
                matrix, true);
        return new BitmapDrawable(newbmp);
    }

4. 實現(xiàn)效果如下：

Imageview 縮放

七、ImageView 圓角圖片 實現(xiàn)

1. 在xml使用ImageView?控件

    <ImageView
        android:id="@+id/img_3"
        android:layout_width="match_parent"
        android:layout_height="150dp"
        android:background="@color/grey"
        android:padding="5dp" />

2.java代碼 實現(xiàn)效果

        // 3. 圓角圖片
        ImageView mImageView3 = (ImageView) findViewById(R.id.img_3);
        mImageView3.setImageBitmap(DrawableUtils.SetRoundCornerBitmap(
                DrawableUtils.DrawableToBitmap(getResources().getDrawable(
                        R.drawable.img1)), 60));

3.?DrawableUtils工具類方法實現(xiàn)

    // 6.圓角圖片
    public static Bitmap SetRoundCornerBitmap(Bitmap bitmap, float roundPx) {
        int width = bitmap.getWidth();
        int heigh = bitmap.getHeight();
        // 創(chuàng)建輸出bitmap對象
        Bitmap outmap = Bitmap.createBitmap(width, heigh,
                Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(outmap);
        final int color = 0xff424242;
        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, width, heigh);
        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(PorterDuff.Mode.SRC_IN));
        canvas.drawBitmap(bitmap, rect, rect, paint);

        return outmap;
    }

4. 實現(xiàn)效果如下：

圓角圖片實現(xiàn)

八、Bitmap與Drawable?轉(zhuǎn)換工具類

Bitmap與Drawable?轉(zhuǎn)換常用工具類源代碼如下：

public class DrawableUtils {

    // 1.從資源中獲取Bitmap
    public static void UseBitmap(Context context, ImageView imageView, int drawableId) {

        Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(),
                drawableId);
        imageView.setImageBitmap(bitmap);

    }

    // 2.Bitmap ---> byte[]
    public byte[] BitmapToBytes(Bitmap bitmap) {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);
        return baos.toByteArray();
    }

    // 3.byte[] ---->bitmap
    public Bitmap BytesToBitmap(byte[] b) {
        if (b.length != 0) {
            return BitmapFactory.decodeByteArray(b, 0, b.length);
        } else {
            return null;
        }
    }

    // 4.Bitmap 縮放方法
    public static Bitmap ZoomBitmap(Bitmap bitmap, int width, int heigh) {
        int w = bitmap.getWidth();
        int h = bitmap.getHeight();
        Matrix matrix = new Matrix();
        float scalewidth = (float) width / w;
        float scaleheigh = (float) heigh / h;
        matrix.postScale(scalewidth, scaleheigh);
        Bitmap newBmp = Bitmap.createBitmap(bitmap, 0, 0, w, h, matrix, true);
        return newBmp;

    }

    // 5. Drawable----> Bitmap
    public static Bitmap DrawableToBitmap(Drawable drawable) {

        // 獲取 drawable 長寬
        int width = drawable.getIntrinsicWidth();
        int heigh = drawable.getIntrinsicHeight();

        drawable.setBounds(0, 0, width, heigh);

        // 獲取drawable的顏色格式
        Bitmap.Config config = drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
                : Bitmap.Config.RGB_565;
        // 創(chuàng)建bitmap
        Bitmap bitmap = Bitmap.createBitmap(width, heigh, config);
        // 創(chuàng)建bitmap畫布
        Canvas canvas = new Canvas(bitmap);
        // 將drawable 內(nèi)容畫到畫布中
        drawable.draw(canvas);
        return bitmap;
    }

    // 6.圓角圖片
    public static Bitmap SetRoundCornerBitmap(Bitmap bitmap, float roundPx) {
        int width = bitmap.getWidth();
        int heigh = bitmap.getHeight();
        // 創(chuàng)建輸出bitmap對象
        Bitmap outmap = Bitmap.createBitmap(width, heigh,
                Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(outmap);
        final int color = 0xff424242;
        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, width, heigh);
        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(PorterDuff.Mode.SRC_IN));
        canvas.drawBitmap(bitmap, rect, rect, paint);

        return outmap;
    }

    // 7.獲取帶倒影的圖片
    public static Bitmap CreateReflectionImageWithOrigin(Bitmap bitmap) {

        final int reflectionGapLine = 4;
        int w = bitmap.getWidth();
        int h = bitmap.getHeight();
        Matrix matrix = new Matrix();
        matrix.preScale(1, -1);

        Bitmap reflectionImage = Bitmap.createBitmap(bitmap, 0, h / 2, w,
                h / 2, matrix, false);

        Bitmap bitmapWithReflection = Bitmap.createBitmap(w, (h + h / 2),
                Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmapWithReflection);
        canvas.drawBitmap(bitmap, 0, 0, null);
        Paint deafalutPaint = new Paint();
        canvas.drawRect(0, h, w, h + reflectionGapLine, deafalutPaint);

        canvas.drawBitmap(reflectionImage, 0, h + reflectionGapLine, null);

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

    // 8. bitmap ---Drawable
    public static Drawable BitmapToDrawable(Bitmap bitmap, Context context) {
        BitmapDrawable drawbale = new BitmapDrawable(context.getResources(),
                bitmap);
        return drawbale;
    }

    // 9. drawable進行縮放 ---> bitmap 然后比對bitmap進行縮放
    public static Drawable ZoomDrawable(Drawable drawable, int w, int h) {
        int width = drawable.getIntrinsicWidth();
        int height = drawable.getIntrinsicHeight();
        // 調(diào)用5 中 drawable轉(zhuǎn)換成bitmap
        Bitmap oldbmp = DrawableToBitmap(drawable);

        // 創(chuàng)建操作圖片用的Matrix對象
        Matrix matrix = new Matrix();
        // 計算縮放比例
        float sx = ((float) w / width);
        float sy = ((float) h / height);
        // 設(shè)置縮放比例
        matrix.postScale(sx, sy);
        // 建立新的bitmap，其內(nèi)容是對原bitmap的縮放后的圖
        Bitmap newbmp = Bitmap.createBitmap(oldbmp, 0, 0, width, height,
                matrix, true);
        return new BitmapDrawable(newbmp);
    }

}

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