Template模式在Android中的使用

template模式主要是将不变化的方法放在父类中，再声明一个抽象方法，子类通过实现该抽象方法，达到封装变化的作用.

其实android也大量的使用template模式，比如view：

、

下面用代码示例：

public class TemplateActivity extends Activity implements OnClickListener ,OnFocusChangeListener{
    public static final String TITLE = "title";

    @Override
    public void setTitle(int titleId) {
        super.setTitle(titleId);
    }

    private MyButton mButton;
    private MyView  mView;


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.entry);
        findComponent();
        setOnClickListener();
        setOnFocusChangeListener();

    }

    private void setOnClickListener() {
        mButton.setOnClickListener(this);
        mView.setOnClickListener(this);
    }

    
    private void setOnFocusChangeListener() {
        mButton.setOnFocusChangeListener(this);
        mView.setOnFocusChangeListener(this);
    }
    
    private void findComponent() {
        mButton = (MyButton) this.findViewById(R.id.btn);
        mView=(MyView) this.findViewById(R.id.view);

    }

    @Override
    public void onClick(View v) {
        int id = v.getId();
        switch (id) {
        case R.id.btn:
            DebugLog.log("btn onclick");
            break;
        case R.id.view:
            DebugLog.log("view onclick");
            break;
        default:
            break;
        }

    }

    @Override
    public void onFocusChange(View v, boolean hasFocus) {
        int id = v.getId();
        switch (id) {
        case R.id.btn:
            DebugLog.log("btn onFocusChange");
            break;
        case R.id.view:
            DebugLog.log("view onFocusChange");
            break;
        default:
            break;
        }
        
    }

}

public class DebugLog {
    public final static boolean DEBUG = true;

    public static void log(String message) {
        if (DEBUG) {
            String fullClassName = Thread.currentThread().getStackTrace()[3].getClassName();
            String className = fullClassName.substring(fullClassName.lastIndexOf(".") + 1);
            String methodName = Thread.currentThread().getStackTrace()[3].getMethodName();
            int lineNumber = Thread.currentThread().getStackTrace()[3].getLineNumber();

            Log.d(className + "." + methodName + "():" + lineNumber, message);
        }
    }
    
    
    public static void printThreadId(String message) {
        if (DEBUG) {
            Log.d(message, String.valueOf(Thread.currentThread().getId()));
        }
    }

    public static void log(String tag, String message) {
        if (DEBUG) {
            String methodName = Thread.currentThread().getStackTrace()[3].getMethodName();
            int lineNumber = Thread.currentThread().getStackTrace()[3].getLineNumber();

            Log.d(tag + "." + methodName + "():" + lineNumber, message);
        }
    }

    public static void printTrace(String message) {
        if (DEBUG) {
            printIllegalArgumentException("", message);
        }
    }

    public static String getStackTrace(Throwable throwable) {
        Writer writer = new StringWriter();
        PrintWriter printWriter = new PrintWriter(writer);
        throwable.printStackTrace(printWriter);
        return writer.toString();
    }

    public static void printIllegalArgumentException(String tag, String arg) {
        if (DEBUG) {
            final Throwable throwable = new IllegalArgumentException(arg);
            Log.w(tag, arg, throwable);
        }
    }

}



public class MyView extends View {

	public MyView(Context context, AttributeSet attrs) {
		super(context, attrs);
		// TODO Auto-generated constructor stub
	}

	@Override
	protected void onDraw(Canvas canvas) {
		Paint paint = new Paint();
		paint.setARGB(255, 255, 0, 0);
		canvas.drawCircle(100, 100, 100, paint);
		super.onDraw(canvas);
	}

	public MyView(Context context) {
		super(context);
	}

}

public class MyButton extends Button {

	public MyButton(Context context) {
		super(context);
	}

	@Override
	protected void onDraw(Canvas canvas) {
		Paint paint = new Paint();
		paint.setARGB(255, 255, 0, 0);
		canvas.drawCircle(100, 100, 100, paint);
		super.onDraw(canvas);
	}

	public MyButton(Context context, AttributeSet attrs) {
		super(context, attrs);
	}

}
<?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"  
    >  
     
<com.fp.app.view.MyButton android:id="@+id/btn"   
    android:layout_width="fill_parent"   
    android:layout_height="wrap_content"   
    android:text="click me my button" />  
<com.fp.app.view.MyView android:id="@+id/view"   
    android:layout_width="fill_parent"   
    android:layout_height="wrap_content"   
    android:text=" click me  my view" />  
</LinearLayout>