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=" 開始計時 " />
<item android:id="@+id/timer_stop" android:title=" 終止計時 " />
<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);
// 獲得計時器對象
timer = (Chronometer)this.findViewById(R.id.chronometer);
//長按計時器時,出現上下文菜單
this.registerForContextMenu(timer);
}
//創建上下文菜單
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo)
{
super.onCreateContextMenu(menu, v, menuInfo);
// ContextMenu的Item不支持Icon,所以不用再資源文件中,爲它們設定圖標
if (v.getId() == R.id.chronometer)
{
//加載xml菜單佈局文件
this.getMenuInflater().inflate(R.menu.context_menu, menu);
// 設定頭部圖標
menu.setHeaderIcon(R.drawable.icon);
// 設定頭部標題
menu.setHeaderTitle(" 計時器控制選項 ");
}
}
//選擇菜單項後的響應
@Override
public boolean onContextItemSelected(MenuItem item)
{
switch (item.getItemId())
{
case R.id.timer_start:
// 將計時器清零
timer.setBase(SystemClock.elapsedRealtime());
//開始計時
timer.start();
break;
case R.id.timer_stop:
//停止計時
timer.stop();
break;
case R.id.timer_reset:
//將計時器清零
timer.setBase(SystemClock.elapsedRealtime());
break;
}
return super.onContextItemSelected(item);
}
}
運行結果如圖所示:
長按計時器彈出上下文菜單選擇開始計時: