android 方式實現imageview圓角
阿新 • • 發佈：2018-11-14
- 自定義imageview
public class RoundImageView extends ImageView { /** * 圖片的型別，圓形or圓角 */ private int type; public static final int TYPE_CIRCLE = 0; public static final int TYPE_ROUND = 1; /** * 圓角大小的預設值 */ private static final int BODER_RADIUS_DEFAULT = 10; /** * 圓角的大小 */ private int mBorderRadius; /** * 繪圖的Paint */ private Paint mBitmapPaint; /** * 圓角的半徑 */ private int mRadius; /** * 3x3 矩陣，主要用於縮小放大 */ private Matrix mMatrix; /** * 渲染影象，使用影象為繪製圖形著色 */ private BitmapShader mBitmapShader; /** * view的寬度 */ private int mWidth; private RectF mRoundRect; /** * 建構函式:獲取自定義屬性 */ public RoundImageView(Context context, AttributeSet attrs) { super(context, attrs); mMatrix = new Matrix(); mBitmapPaint = new Paint(); mBitmapPaint.setAntiAlias(true); TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.RoundImageView); mBorderRadius = a.getDimensionPixelSize( R.styleable.RoundImageView_borderRadius, (int) TypedValue .applyDimension(TypedValue.COMPLEX_UNIT_DIP, BODER_RADIUS_DEFAULT, getResources() .getDisplayMetrics()));// 預設為10dp type = a.getInt(R.styleable.RoundImageView_type, TYPE_CIRCLE);// 預設為Circle a.recycle(); } /** * 關於view的寬高:主要用於當設定型別為圓形時，我們強制讓view的寬和高一致 */ @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { Log.e("TAG", "onMeasure"); super.onMeasure(widthMeasureSpec, heightMeasureSpec); /** * 如果型別是圓形，則強制改變view的寬高一致，以小值為準;如果是圓角則不用管寬高問題 */ if (type == TYPE_CIRCLE) { mWidth = Math.min(getMeasuredWidth(), getMeasuredHeight()); mRadius = mWidth / 2; setMeasuredDimension(mWidth, mWidth); } } /** * 1. 設定BitmapShader * 2. 繪製 */ @Override protected void onDraw(Canvas canvas) { if (getDrawable() == null) { return; } setUpShader(); if (type == TYPE_ROUND) { canvas.drawRoundRect(mRoundRect, mBorderRadius, mBorderRadius, mBitmapPaint); } else { canvas.drawCircle(mRadius, mRadius, mRadius, mBitmapPaint); // drawSomeThing(canvas); } } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { super.onSizeChanged(w, h, oldw, oldh); // 圓角圖片的範圍 if (type == TYPE_ROUND) mRoundRect = new RectF(0, 0, getWidth(), getHeight()); } /** * 初始化BitmapShader//給paint附加一個具有某種魔力(縮放)的shader * 1. drawable轉化為我們的bitmap * 2. 設定shader 的mode * 3. 設定scale: 因為最終縮放完成的圖片一定要大於我們的view的區域 * 4. scale設定給matrix * 5. matrix設定給shader * 6. shader設定給paint */ private void setUpShader() { Drawable drawable = getDrawable(); if (drawable == null) { return; } Bitmap bmp = drawableToBitamp(drawable); // 將bmp作為著色器，就是在指定區域內繪製bmp;此構造方法用的是拉伸mode: clamp mBitmapShader = new BitmapShader(bmp, CLAMP, CLAMP); float scale = 1.0f; if (type == TYPE_CIRCLE) { // 拿到bitmap寬或高的小值//我們需要畫正方形 int bSize = Math.min(bmp.getWidth(), bmp.getHeight()); scale = mWidth * 1.0f / bSize; } else if (type == TYPE_ROUND) { // 如果圖片的寬或者高與view的寬高不匹配，計算出需要縮放的比例；縮放後的圖片的寬高，一定要大於我們view的寬高；所以我們這裡取大值；//view的寬度/bitmap的寬度=縮放倍數 scale = Math.max(getWidth() * 1.0f / bmp.getWidth(), getHeight() * 1.0f / bmp.getHeight()); } // shader的變換矩陣，我們這裡主要用於放大或者縮小 mMatrix.setScale(scale, scale); // 設定變換矩陣 mBitmapShader.setLocalMatrix(mMatrix); // 先給paint設定shader;然後畫筆會有所不同哦,例如 mBitmapPaint.setShader(mBitmapShader); } /** * drawable轉bitmap * * @param drawable * @return */ private Bitmap drawableToBitamp(Drawable drawable) { if (drawable instanceof BitmapDrawable) { BitmapDrawable bd = (BitmapDrawable) drawable; return bd.getBitmap(); } //以下為drawable轉bitmap的通用方法 int w = drawable.getIntrinsicWidth(); int h = drawable.getIntrinsicHeight(); Bitmap bitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888); Canvas canvas = new Canvas(bitmap); drawable.setBounds(0, 0, w, h); drawable.draw(canvas); return bitmap; } /** * 新增一個方法 * bitmap轉drawable */ private Drawable bitmapToDrawable(Bitmap bitmap) { Drawable drawable = new BitmapDrawable(null, bitmap); return drawable; } //狀態儲存與恢復 private static final String STATE_INSTANCE = "state_instance"; private static final String STATE_TYPE = "state_type"; private static final String STATE_BORDER_RADIUS = "state_border_radius"; @Override protected Parcelable onSaveInstanceState() { Bundle bundle = new Bundle(); bundle.putParcelable(STATE_INSTANCE, super.onSaveInstanceState()); bundle.putInt(STATE_TYPE, type); bundle.putInt(STATE_BORDER_RADIUS, mBorderRadius); return bundle; } @Override protected void onRestoreInstanceState(Parcelable state) { if (state instanceof Bundle) { Bundle bundle = (Bundle) state; super.onRestoreInstanceState(((Bundle) state) .getParcelable(STATE_INSTANCE)); this.type = bundle.getInt(STATE_TYPE); this.mBorderRadius = bundle.getInt(STATE_BORDER_RADIUS); } else { super.onRestoreInstanceState(state); } } /** * 動態修改圓角大小 * */ public void setBorderRadius(int borderRadius) { int pxVal = dp2px(borderRadius); if (this.mBorderRadius != pxVal) { this.mBorderRadius = pxVal; invalidate(); } } /** * 動態設定type * */ public void setType(int type) { if (this.type != type) { this.type = type; if (this.type != TYPE_ROUND && this.type != TYPE_CIRCLE) { this.type = TYPE_CIRCLE; } requestLayout(); } } private int dp2px(int dpVal) { return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dpVal, getResources().getDisplayMetrics()); }
- 自定義控制元件屬性
<!--圓角圖片設計--> <attr name="borderRadius" format="dimension" /> <attr name="type"> <enum name="circle" value="0" /> <enum name="round" value="1" /> </attr> <declare-styleable name="RoundImageView"> <attr name="borderRadius" /> <attr name="type" /> </declare-styleable>
- 使用方式
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<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:id="@+id/relative_reconmmend" android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="horizontal"> <RoundImageView android:id="@+id/iv_grid_img" android:layout_width="120dp" android:layout_height="120dp" android:scaleType="fitXY" android:src="@drawable/icon_no_pic_long" app:borderRadius="5dp" app:type="round" /> </RelativeLayout>
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按照正常的例項化,就可以了成功了,優點就是沒有記憶體溢位了
參考文章鴻洋顯示效果和鴻洋的一樣,不在顯示了