自定义控件之圆形头像CircleImageView

最新推荐文章于 2021-05-29 08:21:29 发布

杰克庹庹

最新推荐文章于 2021-05-29 08:21:29 发布

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分类专栏： Android—UI 文章标签：安卓自定义控件圆形头像

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本文介绍了一种自定义Android ImageView的方法，使其能够显示圆形图片并带有边框。通过继承ImageView类并利用BitmapShader进行绘制，实现了特定的需求。文章还提供了详细的代码示例及使用说明。

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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

</pre><pre name="code" class="java">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

<declare-styleable name="CircleImageView">
        <attr name="border_width" format="dimension" />
        <attr name="border_color" format="color" />
    </declare-styleable>