绘制带边框的正方形的图片

package com.example.k.shoppingapp.Other; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.PorterDuff; import android.graphics.PorterDuffXfermode; import android.util.AttributeSet; import android.view.View; import com.example.k.shoppingapp.R; import com.example.k.shoppingapp.Util.Adaptation; /** * Created by k on 2016/8/14. */ public class SquareBlockView extends View { int mHeight = 0,mWidth = 0; public Bitmap bitmap = null; Context context; public SquareBlockView(Context context, AttributeSet attrs) { super(context, attrs); bitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.ok); this.context = context; } public SquareBlockView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); int f = measuredWidth(widthMeasureSpec); int g = measuredHeight(heightMeasureSpec); setMeasuredDimension(f, g); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); int min = Math.min(mWidth, mHeight); /** * 长度如果不一致，按小的值进行压缩 * Adaptation.dp2px(context,1)进行适配 */ bitmap = Bitmap.createScaledBitmap(bitmap, min-Adaptation.dp2px(context,1), min-Adaptation.dp2px(context,1), false); canvas.drawBitmap(createCircleImage(bitmap, min), 0, 0, null); } //************************************************************************************************ private int measuredWidth(int widthMeasureSpec) { int Mode = MeasureSpec.getMode(widthMeasureSpec); int Size = MeasureSpec.getSize(widthMeasureSpec); if (Mode == MeasureSpec.EXACTLY) { mWidth = Size; } else { //由图片决定大小 int value = getPaddingLeft()+getPaddingRight()+bitmap.getWidth(); if (Mode == MeasureSpec.AT_MOST) { //由图片和Padding决定宽度，但是不能超过View的宽 mWidth = Math.min(value,Size); } } return mWidth; } //********************************************************************************************** private int measuredHeight(int heightMeasureSpec) { int Mode = MeasureSpec.getMode(heightMeasureSpec); int Size = MeasureSpec.getSize(heightMeasureSpec); if (Mode == MeasureSpec.EXACTLY) { mHeight = Size; } else { //由图片决定高度 int intvalur1 = getPaddingTop()+getPaddingBottom()+bitmap.getHeight(); if (Mode == MeasureSpec.AT_MOST) { //由图片和Padding决定大小，但是不能超过View的高 mHeight = Math.min(intvalur1,Size); } } return mHeight; } private Bitmap createCircleImage(Bitmap source, int min) { final Paint paint = new Paint(); paint.setAntiAlias(true); //设置画矩形的笔的颜色 paint.setColor(Color.parseColor("#0C0C0C")); //设置画矩形的笔为实心笔 paint.setStyle(Paint.Style.FILL); Bitmap bitmap = Bitmap.createBitmap(min, min, Bitmap.Config.ARGB_8888); //canvas上的操作都会应在bitmap上 Canvas canvas = new Canvas(bitmap); //画一个矩形 canvas.drawRect(0,0,min,min,paint); //设置为重叠模式，下面的将被上面的挡住一些部分或者全部 paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_OVER)); /** * 绘制图片 * Adaptation.dp2px(context,1)/2 等于0.5dp */ canvas.drawBitmap(source, Adaptation.dp2px(context,1)/2, Adaptation.dp2px(context,1)/2, paint); return bitmap; } }

适配类：

package com.example.k.shoppingapp.Util; import android.content.Context; /** * Created by k on 2016/8/14. */ public class Adaptation { public static int dp2px(Context context,float dp) { final float scale = context.getResources().getDisplayMetrics().density; return (int) (dp * scale + 0.5f); } //sp转px public static int sp2px(Context context,float sp) { final float scale = context.getResources().getDisplayMetrics().scaledDensity; return (int) (sp * scale + 0.5f); } } 使用方法：（布局文件）

<com.example.k.shoppingapp.Other.SquareBlockView android:id="@+id/sss" android:layout_margin="7dp" android:layout_width="45dp" android:layout_height="45dp" /> 代码：

squareBlockView = (SquareBlockView)findViewById(R.id.sss); squareBlockView.bitmap = BitmapFactory.decodeResource(getResources(),R.drawable.jin); squareBlockView.postInvalidate();