java, android 自訂Listener Interface

android系統中實現了 onClickListener，onTouchListener 等介面。但如果要使應用響應自訂輸入事件，則要實現自訂的 Listener Interface。

這篇文章中給出了很好的例子，我這裡把它貼過來。

MyActivity.java

public class MyActivity extends Activity implements InternetManager.Listener {    private TextView mText;    private InternetManager mInetMgr;    /* called just like onCreate at some point in time */     public void onStateChange(boolean state) {        if (state) {            mText.setText("on");        } else {            mText.setText("off");        }    }    public void onCreate() {        mInetMgr = new InternetManager();        mInetMgr.registerListener(this);        mInetMgr.doYourWork();    }}

InternetManager.java

public class InternetManager {    // all the listener stuff below    public interface Listener {        public void onStateChange(boolean state);    }    private Listener mListener = null;    public void registerListener (Listener listener) {        mListener = listener;    }    // -----------------------------    // the part that this class does    private boolean isInternetOn = false;    public void doYourWork() {        // do things here        // at some point        isInternetOn = true;        // now notify if someone is interested.        if (mListener != null)            mListener.onStateChange(isInternetOn);    }}