Framework-zz-24-code-bb

 在Android平台上来实践上述范例的架构，兹建立Android开发项目(Project)如下：

  

4.  代码范例：Framework部分

// IPlugin.java接口

package Framework; 

public interface IPlugin{

     boolean execute(int code, int arg);

}

 

// Plugin.java类

package Framework;

public abstract class Plugin implements IPlugin{

         @Override public boolean execute(int code, int arg) {

                return onExecute(code, arg);

        }

        protected abstract boolean onExecute(int code, int arg);

} 

 

5. 代码范例：App部分 

// UC2_Stub.java类

package Service;

import Framework.Plugin; 

public abstract class UC2_Stub extends Plugin {

    private int curr_music;

        @Override

        protected boolean onExecute(int code, int arg) {

                if(code == 0)                     play(curr_music);   //播放目前音樂

                else if(code == 1)               stop();            //停止播放音樂

                else if(code == 2)               curr_music = arg;   //設定目前音樂

                return false;

        }

        public abstract void play(int arg);

        public abstract void stop();

} 

// UC2_Plugin.java类

package Service;

import android.content.Context;

import android.media.MediaPlayer;

import android.util.Log; 

public class UC2_Plugin extends UC2_Stub{

        private MediaPlayer mPlayer = null;

        private Context ctx;       

        public UC2_Plugin(Context context){  ctx = context;     }

        @Override public void play(int arg) {

                if(mPlayer != null) return;

                mPlayer = MediaPlayer.create(ctx, arg);

                try {

              mPlayer.start();

                } catch (Exception e) { Log.e("StartPlay", "error: " + e.getMessage(), e);        }

        }

        @Override public void stop() {

                if (mPlayer != null) {

                   mPlayer.stop();

                        mPlayer.release();

                        mPlayer = null;

                }

 }} 

 

// MainActivity.java类

package com.example.cx02;

import Framework.IPlugin;

import Service.UC2_Plugin;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.LinearLayout;

 

public class MainActivity extends Activity implements OnClickListener {

    private Button btn, btn2, btn3, btn4;

    private IPlugin ip; 

    public void onCreate(Bundle icicle) {

                super.onCreate(icicle);

                LinearLayout layout = new LinearLayout(this);

                layout.setOrientation(LinearLayout.VERTICAL);

                btn = new Button(this);    btn.setId(101);

                btn.setBackgroundResource(R.drawable.leaf);

                btn.setText("music_01");  btn.setOnClickListener(this);

                LinearLayout.LayoutParams param =

                    new LinearLayout.LayoutParams(250, 100);

                param.topMargin = 10;    param.leftMargin = 10;

                layout.addView(btn, param);

                btn2 = new Button(this);   btn2.setId(102);

                btn2.setBackgroundResource(R.drawable.leaf2);

                btn2.setText("music_02");  btn2.setOnClickListener(this);

                layout.addView(btn2, param);

                btn3 = new Button(this);   btn3.setId(103);

                btn3.setBackgroundResource(R.drawable.heart);

                btn3.setText("stop");      btn3.setOnClickListener(this);

                layout.addView(btn3, param);

                btn4 = new Button(this);      btn4.setId(104);

                btn4.setBackgroundResource(R.drawable.heart);

                btn4.setText("exit");         btn4.setOnClickListener(this);

                layout.addView(btn4, param);

                setContentView(layout);

                //-------------------------------

                ip = new UC2_Plugin(this);

                }

           public void onClick(View v) {

                switch(v.getId()){

                     case 101: set_music(R.raw.jp_song); break;

                     case 102: set_music(R.raw.test_cbr); break;

                     case 103: stop(); break;

                     case 104: stop(); finish(); break;

                    }

         }

         public void play(){   ip.execute(0, -1);   }

         public void stop(){   ip.execute(1, -1);  }

         public void set_music(int song_id) { stop();  ip.execute(2, song_id);  play(); }

    }

}