先上圖

LEDView效果如圖所示。

之前看到一篇部落格使用兩個TextView實現了該效果，於是我想用自定義控制元件的方式實現一個LEDView，使用時即可直接使用該控制元件。

採用組合控制元件的方式，將兩個TextView疊放在一起，再使用digital-7.ttf字型來顯示資料，從而達到LED的效果。程式碼如下：

LEDView.class

package ione.zy.demo;

import java.io.File;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;

import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.AssetManager;
import android.graphics.Typeface;
import android.os.Handler;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.TextView;

public class LEDView extends LinearLayout {

	private TextView timeView;
	private TextView bgView;
	private static final String FONT_DIGITAL_7 = "fonts" + File.separator
			+ "digital-7.ttf";

	private static final String DATE_FORMAT = "%02d:%02d:%02d";
	private static final int REFRESH_DELAY = 500;

	private final Handler mHandler = new Handler();
	private final Runnable mTimeRefresher = new Runnable() {

		@Override
		public void run() {
			Calendar calendar = Calendar.getInstance(TimeZone
					.getTimeZone("GMT+8"));
			final Date d = new Date();
			calendar.setTime(d);

			timeView.setText(String.format(DATE_FORMAT,
					calendar.get(Calendar.HOUR), calendar.get(Calendar.MINUTE),
					calendar.get(Calendar.SECOND)));
			mHandler.postDelayed(this, REFRESH_DELAY);
		}
	};

	@SuppressLint("NewApi")
	public LEDView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		init(context);
	}

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

	public LEDView(Context context) {
		super(context);
		init(context);
	}

	private void init(Context context) {
		LayoutInflater layoutInflater = LayoutInflater.from(context);

		View view = layoutInflater.inflate(R.layout.ledview, this);
		timeView = (TextView) view.findViewById(R.id.ledview_clock_time);
		bgView = (TextView) view.findViewById(R.id.ledview_clock_bg);
		AssetManager assets = context.getAssets();
		final Typeface font = Typeface.createFromAsset(assets, FONT_DIGITAL_7);
		timeView.setTypeface(font);// 設定字型
		bgView.setTypeface(font);// 設定字型

	}

	public void start() {
		mHandler.post(mTimeRefresher);
	}

	public void stop() {
		mHandler.removeCallbacks(mTimeRefresher);
	}
}
 

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
      <TextView  
        android:id ="@+id/ledview_clock_time"  
        android:layout_width ="wrap_content"  
        android:layout_height ="wrap_content"  
        android:layout_centerInParent="true"
        android:shadowColor ="#00ff00"  
        android:shadowDx ="0"  
        android:shadowDy ="0"  
        android:shadowRadius ="10"  
        android:textColor ="#00ff00"  
        android:textSize ="80sp" />  
        
    <TextView
        android:id ="@+id/ledview_clock_bg"   
        android:layout_width="wrap_content"  
        android:layout_height="wrap_content"  
        android:layout_centerInParent="true"
        android:layout_gravity="center"  
        android:text="@string/default_time"  
        android:textColor="#3300ff00"  
        android:textSize="80sp" /> 
</RelativeLayout>
 

package ione.zy.demo;

import android.os.Build;
import android.os.Bundle;
import android.view.Menu;
import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.app.ActionBar;
import android.app.Activity;

@TargetApi(Build.VERSION_CODES.HONEYCOMB)
public class LEDActivity extends Activity {

	private LEDView ledView;

	@SuppressLint("NewApi")
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_led);
		ledView = (LEDView) findViewById(R.id.ledview);
		
		  ActionBar actionBar = getActionBar();  
		  actionBar.setDisplayHomeAsUpEnabled(true); 
	}

	@Override
	protected void onResume() {
		super.onResume();
		ledView.start();
	}

	@Override
	protected void onStop() {
		super.onStop();
		ledView.stop();
	}
	
	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		getMenuInflater().inflate(R.menu.activity_led, menu);
		return true;
	}

}
 

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".LEDActivity"
    android:background="@color/black" >

   <ione.zy.demo.LEDView 
        android:id="@+id/ledview"
        android:layout_width="wrap_content"  
        android:layout_height="wrap_content"  
        android:layout_centerInParent="true"
        android:layout_gravity="center"  />  

</RelativeLayout>