Question

我想创建一个半圆/圆形图像视图。下面是我用来创建圆形图像视图但我无法创建半圆形图像（半圆）的代码

package com.example.dynamicviews;

import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Shader;
import android.graphics.drawable.BitmapDrawable;
import android.util.AttributeSet;
import android.widget.ImageView;

/**
 * Customized Imageview with Rounded Border and Shadow
 * @author Rahul Gupta <rahulg@exzeo.com>
 * @since 2014-01-01
 */
public class RoundedImageView extends ImageView
{
    private int borderWidth = 2;
    private int viewWidth;
    private int viewHeight;
    private Bitmap image;
    private Paint paint;
    private Paint paintBorder;
    private BitmapShader shader;

    public RoundedImageView(Context context)
    {
        super(context);
        setup();
    }

    public RoundedImageView(Context context, AttributeSet attrs)
    {
        super(context, attrs);
        setup();
    }

    public RoundedImageView(Context context, AttributeSet attrs, int defStyle)
    {
        super(context, attrs, defStyle);
        setup();
    }

    /**
     * Custom Class to round imageview with color
     * @param context Context of the activity
     * @param borderColor Border color to be set
     */
    @SuppressLint("NewApi")
    public RoundedImageView(Context context, String borderColor) {
        super(context);
         // init paint
        paint = new Paint();
        paint.setAntiAlias(true);
        paintBorder = new Paint();
        setBorderColor(Color.WHITE);
        paintBorder.setAntiAlias(true);
        this.setLayerType(LAYER_TYPE_SOFTWARE, paintBorder);
        paintBorder.setShadowLayer(3.0f, 0.0f,1.0f, Color.parseColor(borderColor));
    }

    @SuppressLint("NewApi")
    private void setup()
    {
        // init paint
        paint = new Paint();
        paint.setAntiAlias(true);
        paintBorder = new Paint();
        setBorderColor(Color.WHITE);
        paintBorder.setAntiAlias(true);
        this.setLayerType(LAYER_TYPE_SOFTWARE, paintBorder);
        paintBorder.setShadowLayer(3.0f, 0.0f,1.0f, Color.BLACK);
        loadBitmap();
    }

    public void setBorderWidth(int borderWidth)
    {
        this.borderWidth = borderWidth;
        this.invalidate();
    }

    public void setBorderColor(int borderColor)
    {
        if (paintBorder != null)
            paintBorder.setColor(borderColor);

        this.invalidate();
    }

    private void loadBitmap()
    {
        BitmapDrawable bitmapDrawable = (BitmapDrawable) this.getDrawable();

        if (bitmapDrawable != null)
            image = bitmapDrawable.getBitmap();
    }

    @SuppressLint("DrawAllocation")
    @Override
    public void onDraw(Canvas canvas)
    {
        // load the bitmap

        // init shader
        if (image != null)
        {
            shader = new BitmapShader(Bitmap.createScaledBitmap(image, canvas.getWidth(), canvas.getHeight(), false), Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
            paint.setShader(shader);
            int circleCenter = viewWidth / 2;

            // circleCenter is the x or y of the view's center
            // radius is the radius in pixels of the cirle to be drawn
            // paint contains the shader that will texture the shape
            canvas.drawCircle(circleCenter + borderWidth, circleCenter + borderWidth, circleCenter + borderWidth - 4.0f, paintBorder);
            canvas.drawCircle(circleCenter + borderWidth, circleCenter + borderWidth, circleCenter - 4.0f, paint);
        }
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
    {
        int width = measureWidth(widthMeasureSpec);
        int height = measureHeight(heightMeasureSpec, widthMeasureSpec);

        viewWidth = width - (borderWidth * 2);
        viewHeight = height - (borderWidth * 2);

        setMeasuredDimension(width, height);
    }

    private int measureWidth(int measureSpec)
    {
        int result = 0;
        int specMode = MeasureSpec.getMode(measureSpec);
        int specSize = MeasureSpec.getSize(measureSpec);

        if (specMode == MeasureSpec.EXACTLY)
        {
            // We were told how big to be
            result = specSize;
        }
        else
        {
            // Measure the text
            result = viewWidth;
        }

        return result;
    }

    private int measureHeight(int measureSpecHeight, int measureSpecWidth)
    {
        int result = 0;
        int specMode = MeasureSpec.getMode(measureSpecHeight);
        int specSize = MeasureSpec.getSize(measureSpecHeight);

        if (specMode == MeasureSpec.EXACTLY)
        {
            // We were told how big to be
            result = specSize;
        }
        else
        {
            // Measure the text (beware: ascent is a negative number)
            result = viewHeight;
        }

        return (result + 2);
    }
}

以下是截图： - enter image description here

所需的结果如下所示： - 两个imageview的左半圆和右半圆，其间有图像资源： -

enter image description here

Answer 1

我的一个项目我有相同的半圈和内部需要显示一些图像，所以我只使用简单的技巧，我只创建一个半圆图像并设置为图像视图的src，然后我将另一个图像设置为背景。你也可以有一些技巧，比如创建简单的框架布局并将一些半圆图像设置为背景，并在框架布局的侧面使用一些图像视图，并将一些其他图像设置为该图像视图。我希望这可能会给你一些实现任务的基本想法。祝你好运:)

Answer 2

我在javascript项目中做的是将div放入圆角，半径等于宽度/高度的一半。对于半圆，你可以做一个h x w的矩形，其中h = 2 * w。左上角和左下角半径r将是r = w。

答案的链接，说明如何在Android中进行圆角： round corners

我知道它不完整，但它提出了一个主意。创造力就是通过不同的方式来解决独特的问题。希望它有所帮助！

Answer 3

试试这个

<shape xmlns:android="http//schemas.android.com/apk/res/android"
   android:shape="semicircle">
<solid android:background="@drawable/yourimage" />
<size android:width="60dp"
    android:height="40dp" />
</shape>

然后在你的班级id = shape中说出

Shape shape = (Shape) findViewById(R.id.shape);
shape.split(10dp , center);

如何在Android中创建半圆形图像视图

3 个答案: