22_Android中的本地音乐播放器和网络音乐播放器的编写，本地视频播放器和网络视频播放器，照相机案例，偷拍案例实现

1 编写以下案例：

当点击了”播放”之后，在手机上的/mnt/sdcard2/natural.mp3就会播放。

2 编写布局文件activity_main.xml

<LinearLayout 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"     android:orientation="vertical"     tools:context=".MainActivity" >       <EditText         android:id="@+id/et_path"         android:layout_width="fill_parent"         android:layout_height="wrap_content"         android:hint="请输入要播放文件的路径" />       <LinearLayout         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:orientation="horizontal" >           <Button             android:id="@+id/bt_play"             android:onClick="play"             android:layout_width="0dip"             android:layout_height="wrap_content"             android:layout_weight="1"             android:text="播放" />         <Button               android:id="@+id/bt_pause"             android:onClick="pause"             android:layout_width="0dip"             android:layout_height="wrap_content"             android:layout_weight="1"             android:text="暂停" />         <Button               android:id="@+id/bt_stop"             android:onClick="stop"             android:layout_width="0dip"             android:layout_height="wrap_content"             android:layout_weight="1"             android:text="停止" />         <Button               android:id="@+id/bt_replay"             android:onClick="replay"             android:layout_width="0dip"             android:layout_height="wrap_content"             android:layout_weight="1"             android:text="重播" />     </LinearLayout>   </LinearLayout>

3 编写MainActivity

package com.itheima.musicplayer;   import java.io.File; import java.io.IOException;   import android.app.Activity; import android.media.AudioManager; import android.media.MediaPlayer; import android.media.MediaPlayer.OnCompletionListener; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.Toast;   public class MainActivity extends Activity {     private EditText et_path;         private MediaPlayer mediaPlayer;         private Button bt_play,bt_pause,bt_stop,bt_replay;       @Override     protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        et_path = (EditText) findViewById(R.id.et_path);        bt_play = (Button) findViewById(R.id.bt_play);        bt_pause = (Button) findViewById(R.id.bt_pause);        bt_stop = (Button) findViewById(R.id.bt_stop);        bt_replay = (Button) findViewById(R.id.bt_replay);     }     /**      * 播放      * @param view      */     public void play(View view) {        String filepath = et_path.getText().toString().trim();        File file = new File(filepath);        if(file.exists()){            try {               mediaPlayer = new MediaPlayer();               mediaPlayer.setDataSource(filepath);//设置播放的数据源。                mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);               mediaPlayer.prepare();//准备开始播放 播放的逻辑是c代码在新的线程里面执行。               mediaPlayer.start();               bt_play.setEnabled(false);               mediaPlayer.setOnCompletionListener(new OnCompletionListener() {                   @Override                   public void onCompletion(MediaPlayer mp) {                      bt_play.setEnabled(true);                   }               });            } catch (Exception e) {               e.printStackTrace();               Toast.makeText(this, "播放失败", 0).show();            }        }else{            Toast.makeText(this, "文件不存在，请检查文件的路径", 0).show();        }     }     /**      * 暂停      * @param view      */     public void pause(View view) {        if("继续".equals(bt_pause.getText().toString())){            mediaPlayer.start();            bt_pause.setText("暂停");            return;        }        if(mediaPlayer!=null&&mediaPlayer.isPlaying()){            //这里表示的是暂停功能            mediaPlayer.pause();            bt_pause.setText("继续");        }     }         /**      * 停止      * @param view      */     public void stop(View view) {        if(mediaPlayer!=null&&mediaPlayer.isPlaying()){            //通过stop方法停止播放音乐            mediaPlayer.stop();            mediaPlayer.release();            mediaPlayer = null;        }        bt_pause.setText("暂停");        bt_play.setEnabled(true);     }     /**      * 重播      * @param view      */     public void replay(View view) {        if(mediaPlayer!=null&&mediaPlayer.isPlaying()){            //通过seekTo方法指定到某个位置播放音乐            mediaPlayer.seekTo(0);        }else{            play(view);        }        bt_pause.setText("暂停");     } }

如果想播放网络上的音乐，需要把上面的play代码改成：

/**      * 播放      *      * @param view      */     public void play(View view) {        String filepath = et_path.getText().toString().trim();        // http://        if (filepath.startsWith("http://")) {            try {               mediaPlayer = new MediaPlayer();               mediaPlayer.setDataSource(filepath);// 设置播放的数据源。                mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);               // mediaPlayer.prepare();//同步的准备方法。               mediaPlayer.prepareAsync();// 异步的准备               mediaPlayer.setOnPreparedListener(new OnPreparedListener() {                   @Override                   public void onPrepared(MediaPlayer mp) {                      mediaPlayer.start();                      bt_play.setEnabled(false);                   }               });               mediaPlayer.setOnCompletionListener(new OnCompletionListener() {                   @Override                   public void onCompletion(MediaPlayer mp) {                      bt_play.setEnabled(true);                   }               });            } catch (Exception e) {               e.printStackTrace();               Toast.makeText(this, "播放失败", 0).show();            }         } else {            Toast.makeText(this, "请检查文件的路径", 0).show();        }     }

==============================================================================

1. 视频播放器，实现”播放”、“暂停”、”停止”、“重播”。案例截图如下：

2. 

1. 播放布局文件

<LinearLayout 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"     android:orientation="vertical"     tools:context=".MainActivity" >       <EditText         android:id="@+id/et_path"         android:layout_width="fill_parent"         android:layout_height="wrap_content"         android:hint="请输入要播放文件的路径" />       <SeekBar         android:id="@+id/seekBar1"         android:layout_width="match_parent"         android:layout_height="wrap_content" />       <LinearLayout         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:orientation="horizontal" >           <Button             android:id="@+id/bt_play"             android:layout_width="0dip"             android:layout_height="wrap_content"             android:layout_weight="1"             android:onClick="play"             android:text="播放" />           <Button             android:id="@+id/bt_pause"             android:layout_width="0dip"             android:layout_height="wrap_content"             android:layout_weight="1"             android:onClick="pause"             android:text="暂停" />           <Button             android:id="@+id/bt_stop"             android:layout_width="0dip"             android:layout_height="wrap_content"             android:layout_weight="1"             android:onClick="stop"             android:text="停止" />           <Button             android:id="@+id/bt_replay"             android:layout_width="0dip"             android:layout_height="wrap_content"             android:layout_weight="1"             android:onClick="replay"             android:text="重播" />     </LinearLayout>       <SurfaceView         android:id="@+id/sv"         android:layout_width="fill_parent"         android:layout_height="fill_parent" />   </LinearLayout>

1. 编写MainActivity，代码如下：

package com.itheima.musicplayer;   import java.io.File; import java.io.IOException; import java.util.Timer; import java.util.TimerTask;   import android.app.Activity; import android.media.AudioManager; import android.media.MediaPlayer; import android.media.MediaPlayer.OnCompletionListener; import android.os.Bundle; import android.view.SurfaceHolder; import android.view.SurfaceHolder.Callback; import android.view.SurfaceView; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.SeekBar; import android.widget.SeekBar.OnSeekBarChangeListener; import android.widget.Toast;   public class MainActivity extends Activity {     private EditText et_path;     private MediaPlayer mediaPlayer;         private Button bt_play,bt_pause,bt_stop,bt_replay;         private SurfaceView sv;     private SurfaceHolder holder;         private int position;     private String filepath;       private SeekBar seekBar1;         private Timer timer;     private TimerTask task;         @Override     protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        et_path = (EditText) findViewById(R.id.et_path);        bt_play = (Button) findViewById(R.id.bt_play);        bt_pause = (Button) findViewById(R.id.bt_pause);        bt_stop = (Button) findViewById(R.id.bt_stop);        bt_replay = (Button) findViewById(R.id.bt_replay);               seekBar1 = (SeekBar) findViewById(R.id.seekBar1);        seekBar1.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {                       @Override            public void onStopTrackingTouch(SeekBar seekBar) {               int postion = seekBar.getProgress();               mediaPlayer.seekTo(postion);            }                       @Override            public void onStartTrackingTouch(SeekBar seekBar) {                          }                       @Override            public void onProgressChanged(SeekBar seekBar, int progress,                   boolean fromUser) {                          }        });               //得到surfaceview        sv = (SurfaceView) findViewById(R.id.sv);        //得到显示界面内容的容器        holder = sv.getHolder();        //在低版本模拟器上运行记得加上下面的参数。不自己维护双缓冲区，而是等待多媒体播放框架主动的推送数据。        holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);        holder.addCallback(new Callback() {                       @Override            public void surfaceDestroyed(SurfaceHolder holder) {               System.out.println("destoryed");               if(mediaPlayer!=null&&mediaPlayer.isPlaying()){                   position = mediaPlayer.getCurrentPosition();                   mediaPlayer.stop();                   mediaPlayer.release();                   mediaPlayer = null;                   timer.cancel();                   task.cancel();                   timer = null;                   task = null;               }            }                       @Override            public void surfaceCreated(SurfaceHolder holder) {               System.out.println("created");               if(position>0){//记录的有播放进度。                   try {                      mediaPlayer = new MediaPlayer();                      mediaPlayer.setDataSource(filepath);//设置播放的数据源。                       mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);                      mediaPlayer.setDisplay(holder);                      mediaPlayer.prepare();//准备开始播放 播放的逻辑是c代码在新的线程里面执行。                      mediaPlayer.start();                      mediaPlayer.seekTo(position);                      bt_play.setEnabled(false);                      mediaPlayer.setOnCompletionListener(new OnCompletionListener() {                          @Override                          public void onCompletion(MediaPlayer mp) {                             bt_play.setEnabled(true);                          }                      });                      int max = mediaPlayer.getDuration();                      seekBar1.setMax(max);                      timer = new Timer();                      task = new TimerTask() {                          @Override                          public void run() {                              seekBar1.setProgress(mediaPlayer.getCurrentPosition());                          }                      };                      timer.schedule(task, 0, 500);                   } catch (IOException e) {                      e.printStackTrace();                   }               }            }                       @Override            public void surfaceChanged(SurfaceHolder holder, int format, int width,                   int height) {               System.out.println("changed");            }        });     }         /**      * 播放      * @param view      */     public void play(View view) {        filepath = et_path.getText().toString().trim();        File file = new File(filepath);        if(file.exists()){            try {               mediaPlayer = new MediaPlayer();               mediaPlayer.setDataSource(filepath);//设置播放的数据源。                mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);               mediaPlayer.setDisplay(holder);               mediaPlayer.prepare();//准备开始播放 播放的逻辑是c代码在新的线程里面执行。               mediaPlayer.start();               //设置拖动进度条的最大值               int max = mediaPlayer.getDuration();               seekBar1.setMax(max);               timer = new Timer();               task = new TimerTask() {                   @Override                   public void run() {                       seekBar1.setProgress(mediaPlayer.getCurrentPosition());                   }               };               timer.schedule(task, 0, 500);                             bt_play.setEnabled(false);               mediaPlayer.setOnCompletionListener(new OnCompletionListener() {                   @Override                   public void onCompletion(MediaPlayer mp) {                      bt_play.setEnabled(true);                   }               });            } catch (Exception e) {               e.printStackTrace();               Toast.makeText(this, "播放失败", 0).show();            }        }else{            Toast.makeText(this, "文件不存在，请检查文件的路径", 0).show();        }     }     /**      * 暂停      * @param view      */     public void pause(View view) {        if("继续".equals(bt_pause.getText().toString())){            mediaPlayer.start();            bt_pause.setText("暂停");            return;        }        if(mediaPlayer!=null&&mediaPlayer.isPlaying()){            mediaPlayer.pause();            bt_pause.setText("继续");        }     }         /**      * 停止      * @param view      */     public void stop(View view) {        if(mediaPlayer!=null&&mediaPlayer.isPlaying()){            mediaPlayer.stop();            mediaPlayer.release();            mediaPlayer = null;        }        bt_pause.setText("暂停");        bt_play.setEnabled(true);     }         /**      * 重播      * @param view      */     public void replay(View view) {        if(mediaPlayer!=null&&mediaPlayer.isPlaying()){            mediaPlayer.seekTo(0);        }else{            play(view);        }        bt_pause.setText("暂停");     } }

 

网络视频播放器，编写布局文件

<LinearLayout 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"     android:orientation="vertical"     tools:context=".MainActivity" >       <EditText         android:id="@+id/et_path"         android:layout_width="fill_parent"         android:layout_height="wrap_content"         android:hint="请输入要播放文件的路径"/>       <LinearLayout         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:orientation="horizontal" >           <Button             android:id="@+id/bt_play"             android:layout_width="0dip"             android:layout_height="wrap_content"             android:layout_weight="1"             android:onClick="play"             android:text="播放" />           <Button             android:id="@+id/bt_pause"             android:layout_width="0dip"             android:layout_height="wrap_content"             android:layout_weight="1"             android:onClick="pause"             android:text="暂停" />           <Button             android:id="@+id/bt_stop"             android:layout_width="0dip"             android:layout_height="wrap_content"             android:layout_weight="1"             android:onClick="stop"             android:text="停止" />           <Button             android:id="@+id/bt_replay"             android:layout_width="0dip"             android:layout_height="wrap_content"             android:layout_weight="1"             android:onClick="replay"             android:text="重播" />     </LinearLayout>       <SurfaceView         android:id="@+id/sv"         android:layout_width="fill_parent"         android:layout_height="fill_parent" />   </LinearLayout>

编写MainActivity

package com.itheima.musicplayer;   import java.io.File; import java.io.IOException;   import android.app.Activity; import android.media.AudioManager; import android.media.MediaPlayer; import android.media.MediaPlayer.OnCompletionListener; import android.os.Bundle; import android.view.SurfaceHolder; import android.view.SurfaceHolder.Callback; import android.view.SurfaceView; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.Toast;   public class MainActivity extends Activity {     private EditText et_path;         private MediaPlayer mediaPlayer;         private Button bt_play,bt_pause,bt_stop,bt_replay;         private SurfaceView sv;     private SurfaceHolder holder;         private int position;     private String filepath;       @Override     protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        et_path = (EditText) findViewById(R.id.et_path);        bt_play = (Button) findViewById(R.id.bt_play);        bt_pause = (Button) findViewById(R.id.bt_pause);        bt_stop = (Button) findViewById(R.id.bt_stop);        bt_replay = (Button) findViewById(R.id.bt_replay);        //得到surfaceview        sv = (SurfaceView) findViewById(R.id.sv);        //得到显示界面内容的容器        holder = sv.getHolder();        //在低版本模拟器上运行记得加上下面的参数。不自己维护双缓冲区，而是等待多媒体播放框架主动的推送数据。        holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);        holder.addCallback(new Callback() {                       @Override            public void surfaceDestroyed(SurfaceHolder holder) {               System.out.println("destoryed");               if(mediaPlayer!=null&&mediaPlayer.isPlaying()){                   position = mediaPlayer.getCurrentPosition();                   mediaPlayer.stop();                   mediaPlayer.release();                   mediaPlayer = null;               }            }                       @Override            public void surfaceCreated(SurfaceHolder holder) {               System.out.println("created");               if(position>0){//记录的有播放进度。                   try {                      mediaPlayer = new MediaPlayer();                      mediaPlayer.setDataSource(filepath);//设置播放的数据源。                       mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);                      mediaPlayer.setDisplay(holder);                      mediaPlayer.prepare();//准备开始播放 播放的逻辑是c代码在新的线程里面执行。                      mediaPlayer.start();                      mediaPlayer.seekTo(position);                      bt_play.setEnabled(false);                      mediaPlayer.setOnCompletionListener(new OnCompletionListener() {                          @Override                          public void onCompletion(MediaPlayer mp) {                             bt_play.setEnabled(true);                          }                      });                   } catch (IOException e) {                      e.printStackTrace();                   }               }            }                       @Override            public void surfaceChanged(SurfaceHolder holder, int format, int width,                   int height) {               System.out.println("changed");            }        });            }     /**      * 播放      * @param view      */     public void play(View view) {        filepath = et_path.getText().toString().trim();        //File file = new File(filepath);        if(filepath.startsWith("http://")){            try {               mediaPlayer = new MediaPlayer();                mediaPlayer.setDataSource(filepath);//设置播放的数据源。                mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);               mediaPlayer.setDisplay(holder);               mediaPlayer.prepare();//准备开始播放 播放的逻辑是c代码在新的线程里面执行。               mediaPlayer.start();               bt_play.setEnabled(false);               mediaPlayer.setOnCompletionListener(new OnCompletionListener() {                   @Override                   public void onCompletion(MediaPlayer mp) {                      bt_play.setEnabled(true);                   }               });            } catch (Exception e) {               e.printStackTrace();               Toast.makeText(this, "播放失败", 0).show();            }        }else{            Toast.makeText(this, "文件不存在，请检查文件的路径", 0).show();        }     }     /**      * 暂停      * @param view      */     public void pause(View view) {        if("继续".equals(bt_pause.getText().toString())){            mediaPlayer.start();            bt_pause.setText("暂停");            return;        }        if(mediaPlayer!=null&&mediaPlayer.isPlaying()){            mediaPlayer.pause();            bt_pause.setText("继续");        }     }     /**      * 停止      * @param view      */     public void stop(View view) {        if(mediaPlayer!=null&&mediaPlayer.isPlaying()){            mediaPlayer.stop();            mediaPlayer.release();            mediaPlayer = null;        }        bt_pause.setText("暂停");        bt_play.setEnabled(true);     }     /**      * 重播      * @param view      */     public void replay(View view) {        if(mediaPlayer!=null&&mediaPlayer.isPlaying()){            mediaPlayer.seekTo(0);        }else{            play(view);        }        bt_pause.setText("暂停");     }   }

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android"     package="com.itheima.musicplayer"     android:versionCode="1"     android:versionName="1.0" >       <uses-sdk         android:minSdkVersion="8"         android:targetSdkVersion="19" />     <!-- 注意如果涉及到网络的都要添加上下面的一句 -->     <uses-permission android:name="android.permission.INTERNET"/>       <application         android:allowBackup="true"         android:icon="@drawable/ic_launcher"         android:label="@string/app_name"         android:theme="@style/AppTheme" >         <activity             android:name="com.itheima.musicplayer.MainActivity"             android:label="@string/app_name" >             <intent-filter>                 <action android:name="android.intent.action.MAIN" />                   <category android:name="android.intent.category.LAUNCHER" />             </intent-filter>         </activity>     </application>   </manifest>

 

照相机引用，如果想使用模拟器进行拍照，需要制定模拟器的一个设置，设置如下图：

编写以下案例，当点击”拍照”之后弹出权限提示框。

1 编写布局文件activity_main.xml，代码如下：

<LinearLayout 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"     android:orientation="vertical"     tools:context=".MainActivity" >       <Button         android:onClick="click"         android:layout_width="fill_parent"         android:layout_height="wrap_content"         android:text="拍照" />         <ImageView         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:id="@+id/iv"/>     </LinearLayout>

1 MainActivity的代码如下：

package com.itheima.camera;   import java.io.File;   import android.app.Activity; import android.content.Intent; import android.net.Uri; import android.os.Bundle; import android.os.Environment; import android.provider.MediaStore; import android.util.Log; import android.view.View; import android.widget.ImageView;   /**  * 拍照的实例代码  * @author toto  */ public class MainActivity extends Activity {          private ImageView iv;          private File file;                   @Override          protected void onCreate(Bundle savedInstanceState) {                    super.onCreate(savedInstanceState);                    setContentView(R.layout.activity_main);                                       iv = (ImageView) findViewById(R.id.iv);          }                   /**           * 当点击之后的效果           * @param view           */          public void click(View view) {                    Intent intent = new Intent();                    //指定拍照的意图ACTION_IMAGE_CAPTURE,如果是录像的可以用ACTION_VIDEO_CAPTURE,并且将文件后缀改成.3gp                    intent.setAction(MediaStore.ACTION_IMAGE_CAPTURE);                    Log.i("FILE-PATH", Environment.getExternalStorageDirectory().toString());                    //第一个参数是文件路径，第二个参数表示的是文件名称                    file =  new File(Environment.getExternalStorageDirectory(),System.currentTimeMillis()+".jpg");                    //指定保存文件的路径                    intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(file));                    //开启一个新的action，并且获得其返回值                    startActivityForResult(intent, 100);          }                   /**           * 当startActivityForResult返回结果的时候会执行下面的函数           */          @Override          protected void onActivityResult(int requestCode, int resultCode, Intent data) {                    if (resultCode == 100) {                             iv.setImageURI(Uri.fromFile(file));                    }                    super.onActivityResult(requestCode, resultCode, data);          } }

若是手机，例如我的手机，存储在/sdcard/emulated/0中。

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偷拍的案例，编写如下案例（将下面的图片显示区域变得很小可以实现偷拍功能）：

1 编写布局文件activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:tools="http://schemas.android.com/tools"     android:layout_width="match_parent"     android:orientation="vertical"     android:layout_height="match_parent"     tools:context=".MainActivity" >       <Button         android:onClick="click"         android:layout_width="fill_parent"         android:layout_height="wrap_content"         android:text="拍照"/>         <FrameLayout          android:id="@+id/camera_preview"          android:layout_width="100dip"          android:layout_height="100dip"/>         <ImageView         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:id="@+id/iv"/>     </LinearLayout>

2 CameraPreview的代码如下：

package com.itheima.camera2;   import java.io.IOException;   import android.content.Context; import android.hardware.Camera; import android.util.Log; import android.view.SurfaceHolder; import android.view.SurfaceView;   /** A basic Camera preview class */ public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {     private static final String TAG = "CameraPreview";     private SurfaceHolder mHolder;     private Camera mCamera;       @SuppressWarnings("deprecation")     public CameraPreview(Context context, Camera camera) {         super(context);         mCamera = camera;           // Install a SurfaceHolder.Callback so we get notified when the         // underlying surface is created and destroyed.         mHolder = getHolder();         mHolder.addCallback(this);         // deprecated setting, but required on Android versions prior to 3.0         mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);     }       public void surfaceCreated(SurfaceHolder holder) {         // The Surface has been created, now tell the camera where to draw the preview.         try {             mCamera.setPreviewDisplay(holder);             mCamera.startPreview();         } catch (IOException e) {             Log.d(TAG, "Error setting camera preview: " + e.getMessage());         }     }       public void surfaceDestroyed(SurfaceHolder holder) {         // empty. Take care of releasing the Camera preview in your activity.     }       public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {         // If your preview can change or rotate, take care of those events here.         // Make sure to stop the preview before resizing or reformatting it.           if (mHolder.getSurface() == null){           // preview surface does not exist           return;         }           // stop preview before making changes         try {             mCamera.stopPreview();         } catch (Exception e){           // ignore: tried to stop a non-existent preview         }           // set preview size and make any resize, rotate or         // reformatting changes here           // start preview with new settings         try {             mCamera.setPreviewDisplay(mHolder);             mCamera.startPreview();           } catch (Exception e){             Log.d(TAG, "Error starting camera preview: " + e.getMessage());         }     } }

1. MainActivity的代码如下：

package com.itheima.camera2;   import java.io.File; import java.io.FileOutputStream;   import android.app.Activity; import android.hardware.Camera; import android.hardware.Camera.AutoFocusCallback; import android.hardware.Camera.PictureCallback; import android.os.Bundle; import android.os.SystemClock; import android.view.View; import android.widget.FrameLayout; import android.widget.ImageView; import android.widget.Toast;   public class MainActivity extends Activity {     private ImageView iv;     private Camera mCamera;     private CameraPreview mPreview;       @Override     protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        iv = (ImageView) findViewById(R.id.iv);         // Create an instance of Camera         mCamera = getCameraInstance();         // Create our Preview view and set it as the content of our activity.         mPreview = new CameraPreview(this, mCamera);         FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);         preview.addView(mPreview);     }         public void click(View view){        mCamera.autoFocus(new AutoFocusCallback() {            @Override            public void onAutoFocus(boolean success, Camera camera) {               mCamera.takePicture(null, null, new PictureCallback() {                   @Override                   public void onPictureTaken(byte[] data, Camera camera) {                      try {                          //File file = new File(Environment.getExternalStorageDirectory(),SystemClock.uptimeMillis()+".jpg");                          File file = new File("/mnt/sdcard2",SystemClock.uptimeMillis()+".jpg");                          FileOutputStream fos = new FileOutputStream(file);                          fos.write(data);                          fos.close();                          Toast.makeText(getApplicationContext(), "成功", 0).show();                          mCamera.startPreview();                      } catch (Exception e) {                          e.printStackTrace();                      }                   }               });            }        });                    }         /** 获取一个照相机实例 */     public static Camera getCameraInstance(){         Camera c = null;         try {             c = Camera.open(); // attempt to get a Camera instance         }         catch (Exception e){             // Camera is not available (in use or does not exist)         }         return c; // returns null if camera is unavailable     }         @Override     protected void onDestroy() {        mCamera.stopPreview();        mCamera.release();        mCamera = null;        super.onDestroy();     } }

1. 编写AndroidManifest.xml的清单文件，代码如下：

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android"     package="com.itheima.camera2"     android:versionCode="1"     android:versionName="1.0" >       <uses-sdk         android:minSdkVersion="8"         android:targetSdkVersion="19" />        <uses-permission android:name="android.permission.CAMERA" />     <uses-feature android:name="android.hardware.camera" />     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />       <application         android:allowBackup="true"         android:icon="@drawable/ic_launcher"         android:label="@string/app_name"         android:theme="@style/AppTheme" >         <activity             android:name="com.itheima.camera2.MainActivity"             android:label="@string/app_name" >             <intent-filter>                 <action android:name="android.intent.action.MAIN" />                   <category android:name="android.intent.category.LAUNCHER" />             </intent-filter>         </activity>     </application>   </manifest>