原文:http://blog.csdn.net/fwwdn/article/details/7550822
本文利用ContextMenu(上下文菜单),Chronometer实现简单计数器。
Main.xml:
- <?xml version="1.0" encoding="utf-8"?>
- <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
- android:orientation="vertical"
- android:layout_width= "fill_parent"
- android:layout_height = "fill_parent"
- android:gravity = "center_horizontal"
- >
- <Chronometer
- android:id ="@+id/chronometer"
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:format="%s"
- android:textSize="80px"
- android:textColor="#00FF00"
- />
- </LinearLayout >
/layout/menu/context_menu.xml
- <?xml version="1.0" encoding="utf-8"?>
- <menu xmlns:android="http://schemas.android.com/apk/res/android">
- <item android:id="@+id/timer_start" android:title=" 开始计时 " />
- <item android:id="@+id/timer_stop" android:title=" 终止计时 " />
- <item android:id="@+id/timer_reset" android:title=" 清零 " />
- </menu>
主Activity:
- public class MainActivity extends Activity {
- private Chronometer timer;
- @Override
- public void onCreate(Bundle savedInstanceState)
- {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.main);
- // 获得计时器对象
- timer = (Chronometer)this.findViewById(R.id.chronometer);
- //长按计时器时,出现上下文菜单
- this.registerForContextMenu(timer);
- }
- //创建上下文菜单
- @Override
- public void onCreateContextMenu(ContextMenu menu, View v,
- ContextMenuInfo menuInfo)
- {
- super.onCreateContextMenu(menu, v, menuInfo);
- // ContextMenu的Item不支持Icon,所以不用再资源文件中,为它们设定图标
- if (v.getId() == R.id.chronometer)
- {
- //加载xml菜单布局文件
- this.getMenuInflater().inflate(R.menu.context_menu, menu);
- // 设定头部图标
- menu.setHeaderIcon(R.drawable.icon);
- // 设定头部标题
- menu.setHeaderTitle(" 计时器控制选项 ");
- }
- }
- //选择菜单项后的响应
- @Override
- public boolean onContextItemSelected(MenuItem item)
- {
- switch (item.getItemId())
- {
- case R.id.timer_start:
- // 将计时器清零
- timer.setBase(SystemClock.elapsedRealtime());
- //开始计时
- timer.start();
- break;
- case R.id.timer_stop:
- //停止计时
- timer.stop();
- break;
- case R.id.timer_reset:
- //将计时器清零
- timer.setBase(SystemClock.elapsedRealtime());
- break;
- }
- return super.onContextItemSelected(item);
- }
- }
运行结果如图所示:
长按计时器弹出上下文菜单选择开始计时: