枚举

枚举用法：

1.okhttp

package okhttp3;

import java.io.IOException;

public enum Protocol
{
HTTP_1_0, HTTP_1_1, SPDY_3, HTTP_2;

private final String protocol;

public static Protocol get(String protocol)
throws IOException
{
if (protocol.equals(HTTP_1_0.protocol)) return HTTP_1_0;
if (protocol.equals(HTTP_1_1.protocol)) return HTTP_1_1;
if (protocol.equals(HTTP_2.protocol)) return HTTP_2;
if (protocol.equals(SPDY_3.protocol)) return SPDY_3;
throw new IOException("Unexpected protocol: " + protocol);
}

public String toString()
{
return this.protocol;
}
}

2.oschina

package net.oschina.app.ui;

import net.oschina.app.R;
import net.oschina.app.fragment.ExploreFragment;
import net.oschina.app.fragment.MyInformationFragment;
import net.oschina.app.viewpagerfragment.NewsViewPagerFragment;
import net.oschina.app.viewpagerfragment.TweetsViewPagerFragment;

public enum MainTab {

NEWS(0, R.string.main_tab_name_news, R.drawable.tab_icon_new,
NewsViewPagerFragment.class),

TWEET(1, R.string.main_tab_name_tweet, R.drawable.tab_icon_tweet,
TweetsViewPagerFragment.class),

QUICK(2, R.string.main_tab_name_quick, R.drawable.tab_icon_new,
null),

EXPLORE(3, R.string.main_tab_name_explore, R.drawable.tab_icon_explore,
ExploreFragment.class),

ME(4, R.string.main_tab_name_my, R.drawable.tab_icon_me,
MyInformationFragment.class);

private int idx;
private int resName;
private int resIcon;
private Class<?> clz;

private MainTab(int idx, int resName, int resIcon, Class<?> clz) {
this.idx = idx;
this.resName = resName;
this.resIcon = resIcon;
this.clz = clz;
}

public int getIdx() {
return idx;
}

public void setIdx(int idx) {
this.idx = idx;
}

public int getResName() {
return resName;
}

public void setResName(int resName) {
this.resName = resName;
}

public int getResIcon() {
return resIcon;
}

public void setResIcon(int resIcon) {
this.resIcon = resIcon;
}

public Class<?> getClz() {
return clz;
}

public void setClz(Class<?> clz) {
this.clz = clz;
}
}

private void initTabs() {
MainTab[] tabs = MainTab.values();
final int size = tabs.length;
for (int i = 0; i < size; i++) {
MainTab mainTab = tabs[i];
TabSpec tab = mTabHost.newTabSpec(getString(mainTab.getResName()));
View indicator = LayoutInflater.from(getApplicationContext())
.inflate(R.layout.tab_indicator, null);
TextView title = (TextView) indicator.findViewById(R.id.tab_title);
Drawable drawable = this.getResources().getDrawable(
mainTab.getResIcon());
title.setCompoundDrawablesWithIntrinsicBounds(null, drawable, null,
null);
if (i == 2) {
indicator.setVisibility(View.INVISIBLE);
mTabHost.setNoTabChangedTag(getString(mainTab.getResName()));
}
title.setText(getString(mainTab.getResName()));
tab.setIndicator(indicator);
tab.setContent(new TabContentFactory() {

@Override
public View createTabContent(String tag) {
return new View(MainActivity.this);
}
});
mTabHost.addTab(tab, mainTab.getClz(), null);

if (mainTab.equals(MainTab.ME)) {
View cn = indicator.findViewById(R.id.tab_mes);
mBvNotice = new BadgeView(MainActivity.this, cn);
mBvNotice.setBadgePosition(BadgeView.POSITION_TOP_RIGHT);
mBvNotice.setTextSize(TypedValue.COMPLEX_UNIT_SP, 10);
mBvNotice.setBackgroundResource(R.drawable.notification_bg);
mBvNotice.setGravity(Gravity.CENTER);
}
mTabHost.getTabWidget().getChildAt(i).setOnTouchListener(this);
}
}

枚举很像c里面的结构体，小巧。可以保存信息。保存tabhost的模板信息。

枚举可以替代以前在接口里面定义的常量字符串。不用public static final了。

枚举可以switch。