自定义控件之圆形头像CircleImageView

一  啥也不说了 先看效果吧  

二 目的  今天项目有个需求  需要使用圆形图像并带边框  我就先思考了一下 思路  使用      shape 做背景  或者 自定义View 继承ImageView 去实现 然后就 尝试 shape发现不能    实现这个效果 然后就决定 使用自定义View 当然 由于本人水平有限  所以从网上找到一 个实现方式。

三 那先让我们来回顾一下 自定义控件的步骤吧。

    1 为什么要自定义控件。

          a 特定的显示风格

             系统提供的控件或没有提供控件来显示我们app统一的风格，我们需要自定义控件。

          b 处理特有的用户交互

              比如一些特定的操作，移动，删除，变色。

          c 优化我们的布局

              比如在ListView中可以通过自定义控件 实现复杂的自定义布局，减少渲染的次数。

          d 分装

              将一种特定的效果 封装起来  在以后的项目中可以反复使用

      2 如何自定义View

           a 自定义属性的声明与获取。

            b 测量onMeasure

            c 布局onLayout

            d onDraw

            e onTouchEvent

            f  onInterceptTouchEvent(ViewGroup)处理交互拦截事件

            g 状态的恢复与保存

四  上代码吧

            1 java代码  继承ImageView 的类

                   

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.RectF;
import android.graphics.Shader;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.TransitionDrawable;
import android.net.Uri;
import android.util.AttributeSet;
import android.widget.ImageView;

import com.xuhj.library.R;


/**
 * 圆形控件
 */
public class CircleImageView extends ImageView {
	

    private static final ScaleType SCALE_TYPE = ScaleType.CENTER_CROP;

    private static final Bitmap.Config BITMAP_CONFIG = Bitmap.Config.ARGB_8888;
    private static final int COLORDRAWABLE_DIMENSION = 1;

    private static final int DEFAULT_BORDER_WIDTH = 0;
    private static final int DEFAULT_BORDER_COLOR = Color.BLACK;

    private final RectF mDrawableRect = new RectF();
    private final RectF mBorderRect = new RectF();

    private final Matrix mShaderMatrix = new Matrix();
    private final Paint mBitmapPaint = new Paint();
    private final Paint mBorderPaint = new Paint();

    private int mBorderColor = DEFAULT_BORDER_COLOR;
    private int mBorderWidth = DEFAULT_BORDER_WIDTH;

    private Bitmap mBitmap;
    private BitmapShader mBitmapShader;
    private int mBitmapWidth;
    private int mBitmapHeight;

    private float mDrawableRadius;
    private float mBorderRadius;

    private boolean mReady;
    private boolean mSetupPending;

    public CircleImageView(Context context) {
        super(context);

        init();
    }

    public CircleImageView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public CircleImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        TypedArray a = context.obtainStyledAttributes(attrs,
                R.styleable.CircleImageView, defStyle, 0);

        mBorderWidth = a.getDimensionPixelSize(
                R.styleable.CircleImageView_border_width, DEFAULT_BORDER_WIDTH);
        mBorderColor = a.getColor(R.styleable.CircleImageView_border_color,
                DEFAULT_BORDER_COLOR);

        a.recycle();

        init();
    }

    private void init() {
        super.setScaleType(SCALE_TYPE);
        mReady = true;

        if (mSetupPending) {
            setup();
            mSetupPending = false;
        }
    }

    @Override
    public ScaleType getScaleType() {
        return SCALE_TYPE;
    }

    @Override
    public void setScaleType(ScaleType scaleType) {
        if (scaleType != SCALE_TYPE) {
            throw new IllegalArgumentException(String.format(
                    "ScaleType %s not supported.", scaleType));
        }
    }

    @Override
    protected void onDraw(Canvas canvas) {
        if (getDrawable() == null) {
            return;
        }
        canvas.drawCircle(getWidth() / 2, getHeight() / 2, mDrawableRadius,
                mBitmapPaint);
        if (mBorderWidth != 0) {
            canvas.drawCircle(getWidth() / 2, getHeight() / 2, mBorderRadius,
                    mBorderPaint);
        }
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        setup();
    }

    public int getBorderColor() {
        return mBorderColor;
    }

    public void setBorderColor(int borderColor) {
        if (borderColor == mBorderColor) {
            return;
        }

        mBorderColor = borderColor;
        mBorderPaint.setColor(mBorderColor);
        invalidate();
    }

    public int getBorderWidth() {
        return mBorderWidth;
    }

    public void setBorderWidth(int borderWidth) {
        if (borderWidth == mBorderWidth) {
            return;
        }

        mBorderWidth = borderWidth;
        setup();
    }

    @Override
    public void setImageBitmap(Bitmap bm) {
        super.setImageBitmap(bm);
        mBitmap = bm;
        setup();
    }

    @Override
    public void setImageDrawable(Drawable drawable) {
        super.setImageDrawable(drawable);
        mBitmap = getBitmapFromDrawable(drawable);
        setup();
    }

    @Override
    public void setImageResource(int resId) {
        super.setImageResource(resId);
        mBitmap = getBitmapFromDrawable(getDrawable());
        setup();
    }

    @Override
    public void setImageURI(Uri uri) {
        super.setImageURI(uri);
        mBitmap = getBitmapFromDrawable(getDrawable());
        setup();
    }

    private Bitmap getBitmapFromDrawable(Drawable drawable) {
        if (drawable == null) {
            return null;
        }

        if (drawable instanceof BitmapDrawable) {
            return ((BitmapDrawable) drawable).getBitmap();
        }

        try {
            Bitmap bitmap;

            if (drawable instanceof ColorDrawable) {
                bitmap = Bitmap.createBitmap(COLORDRAWABLE_DIMENSION,
                        COLORDRAWABLE_DIMENSION, BITMAP_CONFIG);
            } else if (drawable instanceof TransitionDrawable) {
                Drawable drawable_temp = ((TransitionDrawable) drawable).getDrawable(1);
                if (drawable_temp instanceof BitmapDrawable) {
                    return ((BitmapDrawable) drawable_temp).getBitmap();
                } else if (drawable_temp instanceof ColorDrawable) {
                    bitmap = Bitmap.createBitmap(COLORDRAWABLE_DIMENSION,
                            COLORDRAWABLE_DIMENSION, BITMAP_CONFIG);
                } else {
                    bitmap = Bitmap.createBitmap(drawable_temp.getIntrinsicWidth(),
                            drawable_temp.getIntrinsicHeight(), BITMAP_CONFIG);
                }
            } else {
                bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(),
                        drawable.getIntrinsicHeight(), BITMAP_CONFIG);
            }

            Canvas canvas = new Canvas(bitmap);
            drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
            drawable.draw(canvas);
            return bitmap;
        } catch (OutOfMemoryError e) {
            return null;
        } catch (IllegalArgumentException e) {
            return null;
            // TODO: handle exception
        }
    }

    private void setup() {
        if (!mReady) {
            mSetupPending = true;
            return;
        }

        if (mBitmap == null) {
            return;
        }

        mBitmapShader = new BitmapShader(mBitmap, Shader.TileMode.CLAMP,
                Shader.TileMode.CLAMP);

        mBitmapPaint.setAntiAlias(true);
        mBitmapPaint.setShader(mBitmapShader);

        mBorderPaint.setStyle(Paint.Style.STROKE);
        mBorderPaint.setAntiAlias(true);
        mBorderPaint.setColor(mBorderColor);
        mBorderPaint.setStrokeWidth(mBorderWidth);

        mBitmapHeight = mBitmap.getHeight();
        mBitmapWidth = mBitmap.getWidth();

        mBorderRect.set(0, 0, getWidth(), getHeight());
        mBorderRadius = Math.min((mBorderRect.height() - mBorderWidth) / 2,
                (mBorderRect.width() - mBorderWidth) / 2);

        mDrawableRect.set(mBorderWidth, mBorderWidth, mBorderRect.width()
                - mBorderWidth, mBorderRect.height() - mBorderWidth);
        mDrawableRadius = Math.min(mDrawableRect.height() / 2,
                mDrawableRect.width() / 2);

        updateShaderMatrix();
        invalidate();
    }

    private void updateShaderMatrix() {
        float scale;
        float dx = 0;
        float dy = 0;

        mShaderMatrix.set(null);

        if (mBitmapWidth * mDrawableRect.height() > mDrawableRect.width()
                * mBitmapHeight) {
            scale = mDrawableRect.height() / (float) mBitmapHeight;
            dx = (mDrawableRect.width() - mBitmapWidth * scale) * 0.5f;
        } else {
            scale = mDrawableRect.width() / (float) mBitmapWidth;
            dy = (mDrawableRect.height() - mBitmapHeight * scale) * 0.5f;
        }

        mShaderMatrix.setScale(scale, scale);
        mShaderMatrix.postTranslate((int) (dx + 0.5f) + mBorderWidth,
                (int) (dy + 0.5f) + mBorderWidth);

        mBitmapShader.setLocalMatrix(mShaderMatrix);
    }

}

            2 xml代码  自定义属性

五 如何使用

         1  将java代码拷贝到 你的项目包下

         2  将xml代码拷贝到你的res目录  value 文件夹 的 attrs 文件中 

         3  在布局中引用java类  如果 需要带边框的效果   需要定义 命名空间  然后使用自定义属性