節錄自：
http://developer.android.com/reference/android/widget/Button.html
http://blog.chinatimes.com/tomsun/archive/2010/11/09/560824.html
Represents a push-button widget. Push-buttons can be pressed, or clicked, by the user to perform an action.
A typical use of a push-button in an activity would be the following:
public class MyActivity extends Activity {
protected void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.content_layout_id);
final Button button = (Button) findViewById(R.id.button_id);
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Perform action on click
}
});
}
}
However, instead of applying an
OnClickListener to the button in your activity, you can assign a method to your button in the XML layout, using the
android:onClick attribute. For example:
<Button
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:text="@string/self_destruct"
android:onClick="selfDestruct" />
Now, when a user clicks the button, the Android system calls the activity's selfDestruct(View) method. In order for this to work, the method must be public and accept a View as its only parameter. For example:
public void selfDestruct(View view) {
// Kabloey
}
The
View passed into the method is a reference to the widget that was clicked.
新的方法：
當手機用戶按下按鈕時，便會直接呼叫該按鈕的方法，並執行method 裡頭的程式運算動作。如此一來，就可免除了”OnClick”監聽器的使用。
因為，該對應之方法是獨立撰寫於”onCreate(Bundle)”覆寫方法之外，而非寫在”onCreate(Bundle)”覆寫方法裡頭。所以，當”onCreate(Bundle)”覆寫方法被載入時，Android系統並不會將它馬上載入Activity生命週期的運作當中。
不過，此法有個缺點，那就是Android 1.1(API Level 2)與Android 1.5(API Level 3)並不支援。
且宣告的method務必使用public。
