Android--view自定义--彩虹桥

一：自定义属性
在values文件夹下，打开attrs.xml，其实这个文件名称可以是任意的，写在这里更规范一点，表示里面放的全是view的属性<注意format类型>

<resources>
    <declare-styleable name="rainbow">
        <attr name="rainbow_hspace" format="dimension">attr>
        <attr name="rainbow_wspace" format="dimension">attr>
        <attr name="rainbow_color" format="color">attr>
    declare-styleable>
resources>

二：继承自View

package com.tool.keyproject;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;

public class KeyView extends View {
    int barColor = Color.parseColor("#1E88E5");
    int hSpace = 50;
    int vSpace = 100;
    int space = 20;
    float delta = 10f;

    private Paint paint;

    float startX = 0;

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

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

    public KeyView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.rainbow, 0, 0);
        hSpace = typedArray.getDimensionPixelSize(R.styleable.rainbow_rainbow_hspace, hSpace);
        vSpace = typedArray.getDimensionPixelOffset(R.styleable.rainbow_rainbow_wspace, vSpace);
        barColor = typedArray.getColor(R.styleable.rainbow_rainbow_color, barColor);

        paint = new Paint();
        paint.setColor(barColor);
        paint.setAntiAlias(true);
        paint.setStrokeWidth(space);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        float sw = this.getMeasuredWidth();
        if (startX >= sw + (hSpace + space) - (sw % (hSpace + space))) {
            startX = 0;
        } else {
            startX += delta;
        }
        float start = startX;

        while (start < sw) {
            canvas.drawLine(start, 5, start + hSpace, 5, paint);
            start += (hSpace + space);
        }
        start = startX - space - hSpace;

        while (start >= -hSpace) {
            canvas.drawLine(start, 5, start + hSpace, 5, paint);
            start -= (hSpace + space);
        }
        invalidate();
    }
}

三：布局文件引用

<com.tool.keyproject.KeyView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:rainbow_color="@android:color/holo_blue_bright"
    app:rainbow_hspace="80dp"
    app:rainbow_wspace="10dp"
    >com.tool.keyproject.KeyView>