自定义toast

tv = new TextView(getApplicationContext());
		// 这个context的生命周期长
		toast = new Toast(getApplicationContext());
		// 高亮显示
		SpannableString ss = new SpannableString("我是谁");
		ss.setSpan(new ForegroundColorSpan(Color.MAGENTA), 1, 2, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
		tv.setText(ss);
		toast.setView(tv);
		toast.show();