安卓通用标题栏工具类的封装

    标题栏中可能会有几个TextView或者ImageView控件，在每个需要使用的页面中引入很繁琐，Builder构造器模式，一个一个方法的组装，最后拼接成一个完整的对象，如AlertDialog就使用了这种模式。AlertDialog构造器模式的简单演示：

    new AlertDialog.Builder(activity)

    .setTitle("")

    .setPositiveButton("",null)

    .show();

    下面我们参考这个实现标题栏的构造器，代码如下

public class TitleBuilder {

private View viewTitle;

private TextView tvTitle;

private ImageView ivLeft;

private ImageView ivRight;

private TextView tvLeft;

private TextView tvRight;

public TitleBuilder(Activity context) {

viewTitle = context.findViewById(R.id.rl_titlebar);

tvTitle = (TextView) viewTitle.findViewById(R.id.titlebar_tv);

ivLeft = (ImageView) viewTitle.findViewById(R.id.titlebar_iv_left);

ivRight = (ImageView) viewTitle.findViewById(R.id.titlebar_iv_right);

tvLeft = (TextView) viewTitle.findViewById(R.id.titlebar_tv_left);

tvRight = (TextView) viewTitle.findViewById(R.id.titlebar_tv_right);

}

public TitleBuilder(View context) {

viewTitle = context.findViewById(R.id.rl_titlebar);

tvTitle = (TextView) viewTitle.findViewById(R.id.titlebar_tv);

ivLeft = (ImageView) viewTitle.findViewById(R.id.titlebar_iv_left);

ivRight = (ImageView) viewTitle.findViewById(R.id.titlebar_iv_right);

tvLeft = (TextView) viewTitle.findViewById(R.id.titlebar_tv_left);

tvRight = (TextView) viewTitle.findViewById(R.id.titlebar_tv_right);

}

// title

public TitleBuilder setTitleBgRes(int resid) {

viewTitle.setBackgroundResource(resid);

return this;

}

public TitleBuilder setTitleText(String text) {

tvTitle.setVisibility(TextUtils.isEmpty(text) ? View.GONE

: View.VISIBLE);

tvTitle.setText(text);

return this;

}

// left

public TitleBuilder setLeftImage(int resId) {

ivLeft.setVisibility(resId > 0 ? View.VISIBLE : View.GONE);

ivLeft.setImageResource(resId);

return this;

}

public TitleBuilder setLeftText(String text) {

tvLeft.setVisibility(TextUtils.isEmpty(text) ? View.GONE : View.VISIBLE);

tvLeft.setText(text);

return this;

}

public TitleBuilder setLeftOnClickListener(OnClickListener listener) {

if (ivLeft.getVisibility() == View.VISIBLE) {

ivLeft.setOnClickListener(listener);

} else if (tvLeft.getVisibility() == View.VISIBLE) {

tvLeft.setOnClickListener(listener);

}

return this;

}

// right

public TitleBuilder setRightImage(int resId) {

ivRight.setVisibility(resId > 0 ? View.VISIBLE : View.GONE);

ivRight.setImageResource(resId);

return this;

}

public TitleBuilder setRightText(String text) {

tvRight.setVisibility(TextUtils.isEmpty(text) ? View.GONE

: View.VISIBLE);

tvRight.setText(text);

return this;

}

public TitleBuilder setRightOnClickListener(OnClickListener listener) {

if (ivRight.getVisibility() == View.VISIBLE) {

ivRight.setOnClickListener(listener);

} else if (tvRight.getVisibility() == View.VISIBLE) {

tvRight.setOnClickListener(listener);

}

return this;

}

public View build() {

return viewTitle;

}

}

标题栏的布局就是中间一个title，左右两侧各有一个TextView和ImageView，如果ImageView的ID大于0，则表示这个控件被引用，显示为visible,否则为gone,同理TextView则用TextUtils.isEmpty()来进行判断，返回的是类对象，就可以直接用方法点方法的形式来进行引用，无需使用对象来调用方法。标题栏工具类的封装就完成了，下面来演示下怎么

使用

    new TitleBuilder(view)

.setTitleText("首页")

.setLeftText("LEFT")

.setLeftOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

ToastUtils.showToast(activity, "left onclick", Toast.LENGTH_SHORT);

}

});

return view;

演示效果如下图所示：

以后我们就不需要再去每个页面findViewById得到标题栏的控件，重复的代码都可以省略了。