Android面授班一单元机试答案

一、现场得分题:1、配置java环境变量，cmd下输入javac得到相关指令得分。

（5’）参考答案：Step1 安装JDK,并记录其安装目录Step1 鼠标右键单击我的电脑->属性（win7->高级系统设置）打开系统属性面板Step2 选中高级选项卡->环境变量Step3 在系统环境变量中增加JA V A_HOME其值为JDK的安装目录Step4 在修改系统环境变量中的path在其前端添加%JA V A_HOME%\bin;Step5 在系统环境变量中增加classpath其值为%JA V A_HOME%\jre\lib\rt.jar;.;2、用记事本编写HelloWorld.java编译运行后可在cmd下输出HelloWorld.（5’）参考答案：step1:创建HelloWorld.java文件并编写如下内容：public class HelloWorld{public static void main(String[]args){System.out.println(“HelloWorld”);}}step2:打开cmd->javac HelloWorld.javastep3: java HelloWorld3、在cmd下创建、编译、运行android项目，在模拟器上输出HelloAndroid（10’）step1 分别将sdk下的tools,platform-tools及ant下的bin目录配至系统环境变量的path中step2 cmd->android list targets 得到android2.2的编号step3 android create project --target <target-id> --name MyFirstApp --path <path-to-workspace>/MyFirstApp --activity MainActivity --package com.example.myfirstappstep3 进入项目的根目录执行ant debugstep4 adb install bin/MyFirstApp-debug.apk二、单元项目核心功能题：1、使用MediaPlayer播放raw/a.mp3文件。

(5’)参考答案：public class MainActivity extends Activity{@Overridepublic void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);MediaPlayer.create(this, R.raw.a).start();}}2、使用MediaPlayer播放sdcard下的a.mp3文件(5’)参考答案：public class MainActivity extends Activity{@Overridepublic void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);MediaPlayer player=new MediaPlayer();try{player.setDataSource(“mnt/sdcard/a.mp3”);player.prepare();player.start();}catch(Exception e){}}}3、使用SeekBar控制MediaPlayer的播放进度，SeekBar可实时显示MediaPlayer的进度得分。

(15’)参考答案：part1: main.xml<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="/apk/res/android"android:layout_width="fill_parent"android:layout_height="fill_parent"android:orientation="vertical" ><SeekBarandroid:id="@+id/seek"android:layout_width="fill_parent"android:layout_height="wrap_content"/></LinearLayout>part2:MainActivity.javapublic class TestTestActivity extends Activity {/** Called when the activity is first created. */MediaPlayer player=new MediaPlayer();SeekBar seek;@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(yout.main);seek=(SeekBar)findViewById(R.id.seek);try{player.setDataSource("mnt/sdcard/a.mp3");player.prepare();player.start();seek.setMax(player.getDuration());}catch(Exception e){}new Thread(){@Overridepublic void run(){while(player.isPlaying()){seek.setProgress(player.getCurrentPosition());}}}.start();seek.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {@Overridepublic void onStopTrackingTouch(SeekBar seekBar) {}@Overridepublic void onStartTrackingTouch(SeekBar seekBar) {}@Overridepublic void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {if(fromUser)player.seekTo(progress);}});}}4、使用SurfaceView+MediaPlayer播放sdcard下ywsy.3gp要求用SeekBar控制并实时显示播放进度，有画面，SeekBar 功能完整得分(15’)参考答案：part1 main.xml<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="/apk/res/android"android:layout_width="fill_parent"android:layout_height="fill_parent"android:orientation="vertical" ><SeekBarandroid:id="@+id/seek"android:layout_width="fill_parent"android:layout_height="wrap_content"/><SurfaceViewandroid:id="@+id/sf"android:layout_width="fill_parent"android:layout_height="fill_parent"/></LinearLayout>part2: MainActivity.javapublic class TestTestActivity extends Activity implements SurfaceHolder.Callback{/** Called when the activity is first created. */MediaPlayer player=new MediaPlayer();SurfaceV iew sf;SurfaceHolder sh;SeekBar seek;@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(yout.main);seek=(SeekBar)findViewById(R.id.seek);sf=(SurfaceView)findViewById(R.id.sf);sh=sf.getHolder();sh.addCallback(this);sh.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);seek.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {@Overridepublic void onStopTrackingTouch(SeekBar seekBar) {}@Overridepublic void onStartTrackingTouch(SeekBar seekBar) {}@Overridepublic void onProgressChanged(SeekBar seekBar, int progress,boolean fromUser) {// TODO Auto-generated method stubif(fromUser)player.seekTo(progress);}});}@Overridepublic void surfaceChanged(SurfaceHolder holder, int format, int width,int height) {}@Overridepublic void surfaceCreated(SurfaceHolder holder) {try{player.setDataSource("mnt/sdcard/a.mp3");player.prepare();player.start();player.setDisplay(sh);seek.setMax(player.getDuration());}catch(Exception e){}new Thread(){@Overridepublic void run(){while(player.isPlaying()){seek.setProgress(player.getCurrentPosition());}}}.start();}@Overridepublic void surfaceDestroyed(SurfaceHolder holder) {}}5、使用ImageView实现图片放大缩小旋转，要求缩小时图片居中，放大时可以通过滚动看到图片全景得分。