定義

Builder模式可以將一個(gè)類的構(gòu)建和表示進(jìn)行分離

NavigationBar實(shí)踐

1.目的效果

 new DefaultNavigation.Builder(this)
                .setTitle("所有圖片")
                .setLeftOnClickListener(this)
                .create();

2.分析

navigation.png

3.代碼(從項(xiàng)目中抽取)

/**
 * 項(xiàng)目名稱：joke
 * 類描述：
 * 創(chuàng)建人：woochen123
 * 創(chuàng)建時(shí)間：2017/5/17 23:41
 */
public class DefaultNavigation extends AbsNavigationBar<DefaultNavigation.Builder.NavigationParams> {
    public DefaultNavigation(Builder.NavigationParams params) {
        super(params);
    }

    @Override
    public int bindLayoutId() {
        return R.layout.default_navigation;
    }

    @Override
    public void applyView() {
        // 給我們的導(dǎo)航條綁定資源
        setImageResource(R.id.iv_left, getParams().leftIconRes);
        setImageResource(R.id.iv_right, getParams().rightIconRes);
        setImageResource(R.id.iv_right_icon, getParams().textRightIconRes);
        setText(R.id.tv_title, getParams().title);
        setText(R.id.left_tv, getParams().leftTv);
        setText(R.id.tv_right, getParams().rightTv);
        setBackgroundColor(R.id.title_bar, getParams().bgColor);
        setOnClickListener(R.id.iv_left, getParams().leftOnClickListener);
        setOnClickListener(R.id.tv_right, getParams().rightOnClickListener);
    }


    /**
     * 設(shè)置背景
     * @param title_bar
     * @param bgColor
     */
    private void setBackgroundColor(int title_bar, int bgColor) {
        ViewGroup view = findViewById(title_bar);
        if (view != null) {
            view.setBackgroundColor(bgColor);
        }
    }

    public static class Builder extends AbsNavigationBar.Builder {
        public NavigationParams params;

        public Builder(Context context, ViewGroup parent) {
            super(context, parent);
            params = new NavigationParams(context,parent);
        }

        public Builder(Context context) {
            super(context,null);
            params = new NavigationParams(context,null);
        }


        public Builder setTitle(String title) {
            params.title = title;
            return this;
        }

        public Builder setRight(String right) {
            params.rightTv = right;
            return this;
        }

        public Builder setLeft(String left) {
            params.leftTv = left;
            return this;
        }

        public Builder setLeftIcon(int iconRes) {
            params.leftIconRes = iconRes;
            return this;
        }


        public Builder setRightIcon(int iconRes) {
            params.rightIconRes = iconRes;
            return this;
        }

        public Builder setTitleBackgroundColor(int bgColor) {
            params.bgColor = bgColor;
            return this;
        }

        public Builder setLeftOnClickListener(View.OnClickListener onClickListener) {
            params.leftOnClickListener = onClickListener;
            return this;
        }

        public Builder setRightOnClickListener(View.OnClickListener onClickListener) {
            params.rightOnClickListener = onClickListener;
            return this;
        }

        @Override
        public <T extends AbsNavigationBar> T create() {
            DefaultNavigation defaultNavigation = new DefaultNavigation(params);
            return (T) defaultNavigation;
        }

        public static class NavigationParams extends AbsNavigationBar.Builder.NavigationParams {
            //標(biāo)題
            public String title;
            //左邊圖片資源
            public int leftIconRes;
            //右邊圖片資源
            public int rightIconRes;
            //左邊的點(diǎn)擊事件
            public View.OnClickListener leftOnClickListener;
            //右邊的點(diǎn)擊事件
            public View.OnClickListener rightOnClickListener;
            public String leftTv;
            public String rightTv;
            public int bgColor;

            public NavigationParams(Context context, ViewGroup parent) {
                super(context, parent);
            }
        }

    }
}

4.總結(jié)

1.目標(biāo)類的實(shí)例化操作實(shí)際上交給了Builder對(duì)象來完成，目標(biāo)對(duì)象只暴露很少的api給開發(fā)者來調(diào)用（將目標(biāo)類的構(gòu)建抽離出來，將只有在目標(biāo)類被實(shí)例化的時(shí)候才能配置或者只能配置一次的各項(xiàng)參數(shù)隱藏起來）

5.優(yōu)點(diǎn)

1.有利于擴(kuò)展（builder對(duì)象是獨(dú)立的，可以很方便的進(jìn)行api的增加和修改，而不會(huì)影響目標(biāo)類的過多改動(dòng)）