Question

我需要使用此类在ImageView周围绘制一个红色边框：

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.widget.ImageView;

public class RoundedImageView extends ImageView {

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

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

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

protected void onDraw(Canvas canvas) {
    float radius = 45.0f;
    Paint bp= new Paint();
    bp.setAntiAlias(true);
    canvas.drawARGB(0, 0, 0, 0);
    bp.setColor(Color.RED);
    bp.setStrokeWidth(16);


    Path clipPath = new Path();
    RectF rect = new RectF(0, 0, this.getWidth(), this.getHeight());
    clipPath.addRoundRect(rect, radius, radius, Path.Direction.CW);
    canvas.drawRoundRect(rect, radius, radius, bp);
    canvas.clipPath(clipPath);

    super.onDraw(canvas);
}
}

但它似乎并没有画出边界？我不知道自己做错了什么？

任何人都可以帮忙吗？

由于

Answer 1

好的，这就是我最终做的事情：

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.widget.ImageView;

public class RoundedImageView extends ImageView {

private static final int PADDING = 8;
private static final float STROKE_WIDTH = 16f;

private Paint mBorderPaint;

public RoundedImageView(Context context) {
    this(context, null);
}

public RoundedImageView(Context context, AttributeSet attrs) {
    this(context, attrs, 0);
    setPadding(PADDING, PADDING, PADDING, PADDING);
}

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

private void initBorderPaint() {
    mBorderPaint = new Paint();
    mBorderPaint.setAntiAlias(true);
    mBorderPaint.setStyle(Paint.Style.STROKE);
    mBorderPaint.setColor(Color.WHITE);
    mBorderPaint.setStrokeWidth(STROKE_WIDTH);
}

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    canvas.drawRect(PADDING, PADDING, getWidth() - PADDING, getHeight() - PADDING, mBorderPaint);
}
}

它没有按照要求给出圆角，但并非真正必要。这只会在图像周围创建一个边框。

Answer 2

在drawable文件夹中创建一个命名border.xml的xml并添加以下代码：

  <?xml version="1.0" encoding="utf-8"?>
   <shape xmlns:android="http://schemas.android.com/apk/res/android" 
    android:shape="rectangle">
   <solid android:color="@android:color/transparent" />
 <stroke android:width="0.7dip" android:color="#808080"/>
 </shape>

现在将此添加到您的框架布局中，并将您的imageview放在框架布局中，您就完成了。

<FrameLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:background="@drawable/border"
android:padding="3dp" >

<ImageView
    android:id="@+id/image"
    android:layout_width="100dp"
    android:layout_height="110dp"
  android:layout_margin="1dp"     />
</FrameLayout>

希望它有所帮助。谢谢:)）

Answer 3

在drawable文件夹中创建一个命名为border.xml的xml，并添加以下代码：

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="oval">
<size android:height="100dp" android:width="100dp"/>
<solid android:color="@android:color/transparent" />
<stroke android:width="5dip" android:color="#f2db2f"/>
</shape>

在您的布局中添加以下内容：

<FrameLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:foregroundGravity="center|top"
android:foreground="@drawable/border"
android:layout_weight="4">
<ImageView
android:id="@+id/dog"
android:scaleType="centerCrop"
android:src="@drawable/gears"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</FrameLayout>

如何在圆形imageview周围绘制边框？

3 个答案: