我正在玩UI事件处理,我找到了一些我无法从
Android Dev找到解释的东西：我有一个ImageView和一个TextView,每当我触摸ImageView时,TextView都会显示一条消息.但以下代码不起作用：
public class ShowSomething extends Activity {
private LinearLayout ll;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
LinearLayout ll = (LinearLayout)findViewById(R.id.linearLayout);
final TextView textview = (TextView)findViewById(R.id.textview);
MyImageView image = new MyImageView(this,textview);
image.setImageResource(R.drawable.icon);
ll.addView(image,48,48);
}
}
和MyImageView.java
public class MyImageView extends ImageView implements OnTouchListener{
private TextView textview;
public MyImageView(Context context,TextView textview) {
super(context);
this.textview = textview;
}
@Override
public boolean onTouch(View v,MotionEvent event) {
textview.setText("Event captured !");
return true;
}
}
main.xml中
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/linearLayout" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <TextView android:id="@+id/textview" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="Holder" /> </LinearLayout>
但是当我像这样在MyImageView上附加一个OnTouchListener时,它确实有效：
文件ShowSomething.java
public class ShowSomething extends Activity {
private LinearLayout ll;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
LinearLayout ll = (LinearLayout)findViewById(R.id.linearLayout);
final TextView textview = (TextView)findViewById(R.id.textview);
MyImageView image = new MyImageView(this,textview);
image.setImageResource(R.drawable.icon);
image.setOnTouchListener(new OnTouchListener() {
@Override
public boolean onTouch(View v,MotionEvent event) {
textview.setText("Event captured!");
return false;
}
});
ll.addView(image,48);
}
}
并提交MyImageView.java文件
public class MyImageView extends ImageView {
private TextView textview;
public MyImageView(Context context,TextView textview) {
super(context);
this.textview = textview;
}
}
但据我所知,2实现是相同的(实现事件监听器) – 我是否误解了什么？
