Android学习笔记_26_多媒体之拍照
一、配置文件：
需要引入摄像头权限，sdcard读写权限。
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.takepicture" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="8" android:targetSdkVersion="17" /> <application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <!-- screenOrientation设置activity在屏幕上显示方式：横向 --> <activity android:name="com.example.takepicture.MainActivity" android:label="@string/app_name" android:screenOrientation="landscape" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> <!-- 摄像头权限 --> <uses-permission android:name="android.permission.CAMERA" /> <!-- 在SDCard中创建与删除文件权限 --> <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" /> <!-- 往SDCard写入数据权限 --> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> </manifest>
布局文件，当activity启动时在屏幕上横向显示，手指触摸屏幕时，出现拍照和对焦两个按钮，采用相对布局。
<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" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context=".MainActivity" > <SurfaceView android:id="@+id/surfaceView" android:layout_width="match_parent" android:layout_height="match_parent" /> <RelativeLayout android:id="@+id/buttonlayout" android:layout_width="match_parent" android:layout_height="match_parent" android:visibility="gone" > <Button android:id="@+id/autofouce" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:layout_alignParentRight="true" android:layout_alignTop="@+id/takePicture" android:layout_marginRight="5dp" android:layout_toLeftOf="@+id/takePicture" android:onClick="takePicture" android:text="@string/autofouce" /> <Button android:id="@+id/takePicture" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:layout_alignParentRight="true" android:layout_marginRight="59dp" android:onClick="takePicture" android:text="@string/takepicture" /> </RelativeLayout> </RelativeLayout>
二、代码实现：
package com.example.takepicture; import java.io.File; import java.io.FileOutputStream; import android.app.Activity; import android.graphics.Bitmap; import android.graphics.Bitmap.CompressFormat; import android.graphics.BitmapFactory; import android.graphics.PixelFormat; import android.hardware.Camera; import android.os.Bundle; import android.util.Log; import android.view.Menu; import android.view.MotionEvent; import android.view.SurfaceHolder; import android.view.SurfaceView; import android.view.View; import android.view.ViewGroup; import android.view.Window; import android.view.WindowManager; public class MainActivity extends Activity { private View layout; private static final String TAG = "TakePicture"; private SurfaceView surfaceView; private Camera camera; private boolean preview; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); //设置窗口没有标题 requestWindowFeature(Window.FEATURE_NO_TITLE); //全屏显示 getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN); //getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);//高亮 setContentView(R.layout.activity_main); layout= this.findViewById(R.id.buttonlayout); //确定surfaceView什么时候被时间 surfaceView = (SurfaceView) this.findViewById(R.id.surfaceView); surfaceView.getHolder().addCallback(new SufaceListener()); /*下面设置Surface不维护自己的缓冲区，而是等待屏幕的渲染引擎将内容推送到用户面前*/ surfaceView.getHolder().setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); surfaceView.getHolder().setFixedSize(176, 144); //设置分辨率 surfaceView.getHolder().setKeepScreenOn(true);//设置高亮 } //触摸事件 public boolean onTouchEvent(MotionEvent event) { //手指按下屏幕 if(event.getAction()==MotionEvent.ACTION_DOWN){ layout.setVisibility(ViewGroup.VISIBLE);//显示布局 return true; } return super.onTouchEvent(event); } private final class SufaceListener implements SurfaceHolder.Callback{ @Override public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) { } @Override public void surfaceCreated(SurfaceHolder holder) { try { Log.i(TAG, "surfaceCreated .... "); camera = Camera.open();//打开摄像头 Camera.Parameters parameters = camera.getParameters(); Log.i(TAG, parameters.flatten());//打印参数 //WindowManager wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE); //Display display = wm.getDefaultDisplay(); //图片大小的设置要符合手机上图片大小，否则会出现参数设置错误 //parameters.setPreviewSize(display.getWidth(), display.getHeight());//设置预览照片的大小 parameters.setPreviewFrameRate(3);//每秒3帧 parameters.setPictureFormat(PixelFormat.JPEG);//设置照片的输出格式 parameters.set("jpeg-quality", 85);//照片质量 //parameters.setPictureSize(display.getWidth(), display.getHeight());//设置照片的大小 camera.setParameters(parameters); camera.setPreviewDisplay(surfaceView.getHolder());//通过SurfaceView显示取景画面 camera.startPreview(); preview = true; Log.i(TAG, "surfaceCreated .. end .. "); } catch (Exception e) { Log.e(TAG, e.toString()); } } @Override public void surfaceDestroyed(SurfaceHolder holder) { //是否摄像头 if(camera!=null){ if(preview) camera.stopPreview(); camera.release(); camera = null; } } } public void takePicture(View v){ if (camera!=null) { switch (v.getId()) { case R.id.takePicture: Log.i(TAG, " start take picture ... "); //内部采用异步操作照片 camera.takePicture(null, null, new PictureCallbackListener()); Log.i(TAG, " end take picture ... "); break; case R.id.autofouce: camera.autoFocus(null);//自动对焦 break; } } } /* @Override public boolean onKeyDown(int keyCode, KeyEvent event) { if(camera!=null && event.getRepeatCount()==0){ switch (keyCode) { case KeyEvent.KEYCODE_SEARCH: camera.autoFocus(null);//自动对焦 break; case KeyEvent.KEYCODE_DPAD_CENTER: case KeyEvent.KEYCODE_CAMERA: //拍照 //camera.takePicture(null, null, new PictureCallbackListener()); break; } } return true; } */ private final class PictureCallbackListener implements Camera.PictureCallback{ /** * data:所拍摄图片数据 */ @Override public void onPictureTaken(byte[] data, Camera camera) { try { Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length); // File file = new File(Environment.getExternalStorageDirectory(), "my.jpg"); File file=new File("/storage/sdcard0/360/",System.currentTimeMillis()+".jpg"); FileOutputStream outStream = new FileOutputStream(file); bitmap.compress(CompressFormat.JPEG, 100, outStream); outStream.close(); //重新浏览，否则画面就不动 camera.stopPreview(); camera.startPreview(); preview = true; } catch (Exception e) { Log.e(TAG, e.toString()); } } } @Override public boolean onCreateOptionsMenu(Menu menu) { getMenuInflater().inflate(R.menu.main, menu); return true; } }
三、出现异常：
设置摄像头参数时，尤其是图片大小要符合手机匹配图片大小，否则会出现设置参数错误。
