自定义布局控件-圆形RelativeLayout

一、创建自定义类

package com.test.circularlayout;

import android.content.Context;

import android.content.res.TypedArray;

import android.graphics.Canvas;

import android.graphics.Paint;

import android.util.AttributeSet;

import android.widget.RelativeLayout;

public class CircleRelativeLayout extends RelativeLayout {

    private int color;

    private int[] colors;

    private int alpha;

    public CircleRelativeLayout(Context context) {

        super(context);

    }

    public CircleRelativeLayout(Context context, AttributeSet attrs) {

        super(context,attrs);

        init(context,attrs);

        setWillNotDraw(false);

    }

    private void init(Context context, AttributeSet attrs) {

        TypedArray array = context.obtainStyledAttributes(attrs,

                R.styleable.CircleRelativeLayoutLayout);

        color = array.getColor(R.styleable.CircleRelativeLayoutLayout_background_color,0X0000000);

        alpha = array.getInteger(R.styleable.CircleRelativeLayoutLayout_background_alpha,100);

        setColors();

        array.recycle();

    }

    @Override

    protected void onDraw(Canvas canvas) { //构建圆形

        int width = getMeasuredWidth();

        Paint mPaint = new Paint();

        mPaint.setARGB(alpha,colors[0],colors[1],colors[2]);

        mPaint.setAntiAlias(true);

        float cirX = width / 2;

        float cirY = width / 2;

        float radius = width / 2;

        canvas.drawCircle(cirX, cirY, radius, mPaint);

        super.onDraw(canvas);

    }

    public void setColor(int color) { //设置背景色

        this.color = color;

        setColors();

        invalidate();

    }

    public void setAlhpa(int alhpa) { //设置透明度

        this.alpha = alhpa;

        invalidate();

    }

    public void setColors() {

        int red = (color & 0xff0000) >> 16;

        int green = (color & 0x00ff00) >> 8;

        int blue = (color & 0x0000ff);

        this.colors = new int[]{red,green,blue};

    }

}

二、添加自定义属性 values/attr.xml

<?xml version="1.0" encoding="utf-8"?>

<resources>

    <declare-styleable name="CircleRelativeLayoutLayout">

        <attr name="background_color" format="color" />

        <attr name="background_alpha" format="integer" />

    </declare-styleable>

</resources>

三、布局文件引用

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    xmlns:circle="http://schemas.android.com/apk/res-auto"

    android:id="@+id/activity_main"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    tools:context="com.test.circularlayout.MainActivity">

    <com.test.circularlayout.CircleRelativeLayout

        android:layout_margin="5dp"

        android:layout_width="100dp"

        android:layout_height="100dp">

        <TextView

            android:textColor="#ffffff"

            android:text="默认的颜色"

            android:layout_centerInParent="true"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content" />

    </com.test.circularlayout.CircleRelativeLayout>

    <com.test.circularlayout.CircleRelativeLayout

        circle:background_color="#3838e4"

        circle:background_alpha="100"

        android:layout_marginLeft="110dp"

        android:layout_marginTop="5dp"

        android:layout_width="90dp"

        android:layout_height="90dp">

        <TextView

            android:textColor="#ffffff"

            android:text="自定义"

            android:layout_centerInParent="true"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content" />

    </com.test.circularlayout.CircleRelativeLayout>

    <com.test.circularlayout.CircleRelativeLayout

        android:id="@+id/crlayout"

        android:layout_marginLeft="210dp"

        android:layout_marginTop="5dp"

        android:layout_width="80dp"

        android:layout_height="80dp">

        <TextView

            android:textColor="#ffffff"

            android:text="代码设置"

            android:layout_centerInParent="true"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content" />

    </com.test.circularlayout.CircleRelativeLayout>

</RelativeLayout>

四、获取和设置控件

public class MainActivity extends Activity {

    CircleRelativeLayout crlayout;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        crlayout = (CircleRelativeLayout) findViewById(R.id.crlayout);

        crlayout.setColor(getResources().getColor(R.color.colorAccent));

        crlayout.setAlhpa(160);

    }

}