Android[高级教程] Android程序调用摄像头

原址：http://www.2cto.com/kf/201202/119329.html

 

很多开发者都想在程序用来调用摄像头，并对拍出的照片进行处理。首先先对程序的进行一下预览

 



 

首先先对主页面进行设计，这里很简单，只是加了个按钮和一张图片

[html] <?xml version="1.0" encoding="utf-8"?> 
< LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:orientation="vertical" > 
 
 
    <Button 
        android:id="@+id/button1" 
        android:layout_width="match_parent" 
        android:layout_height="wrap_content" 
        android:text="@string/camera" /> 
 
 
 
 
    <ImageView 
        android:id="@+id/imageView1" 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        android:src="@drawable/ic_launcher" /> 
 
< /LinearLayout> 
< ?xml version="1.0" encoding="utf-8"?>
< LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <Button
        android:id="@+id/button1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/camera" />

 

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_launcher" />

</LinearLayout>

接下来就是对按钮事件进行处理，按下按钮的时候会调用本机摄像头

[java] //图片存入地址   www.2cto.com
        imageFilePath = Environment.getExternalStorageDirectory() 
                .getAbsolutePath() + "/mypicture.jpg"; 
        File imageFile = new File(imageFilePath); 
        Uri imageFileUri = Uri.fromFile(imageFile); 
 
        Intent i = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE); 
        i.putExtra(android.provider.MediaStore.EXTRA_OUTPUT, imageFileUri); 
        startActivityForResult(i, CAMERA_RESULT); 
//图片存入地址
  imageFilePath = Environment.getExternalStorageDirectory()
    .getAbsolutePath() + "/mypicture.jpg";
  File imageFile = new File(imageFilePath);
  Uri imageFileUri = Uri.fromFile(imageFile);

  Intent i = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
  i.putExtra(android.provider.MediaStore.EXTRA_OUTPUT, imageFileUri);
  startActivityForResult(i, CAMERA_RESULT);

 

Intent直接调用了本机的拍照程序，并把拍的图片存在内存卡里，接下来就是要在我们自己的程序里显示拍的照片了
这里我们直接用了Activity里的onActivityResult这个方法，这个方法是对Activity返回结果的处理
[java] @Override
    protected void onActivityResult(int requestCode, int resultCode, 
            Intent intent) { 
        // TODO Auto-generated method stub  
        super.onActivityResult(requestCode, resultCode, intent); 
 
        //如果拍照成功  
        if (resultCode == RESULT_OK) { 
 
            // Bundle extras = intent.getExtras();  
            // Bitmap bmp = (Bitmap)extras.get("data");  
 
            imv = (ImageView) findViewById(R.id.imageView1); 
 
            //取得屏幕的显示大小  
            Display currentDisplay = getWindowManager().getDefaultDisplay(); 
            int dw = currentDisplay.getWidth(); 
            int dh = currentDisplay.getHeight(); 
 
            //对拍出的照片进行缩放  
            BitmapFactory.Options bmpFactoryOptions = new BitmapFactory.Options(); 
            bmpFactoryOptions.inJustDecodeBounds = true; 
            Bitmap bmp = BitmapFactory.decodeFile(imageFilePath, 
                    bmpFactoryOptions); 
 
            int heightRatio = (int) Math.ceil(bmpFactoryOptions.outHeight 
                    / (float) dh); 
            int widthRatio = (int) Math.ceil(bmpFactoryOptions.outWidth 
                    / (float) dw); 
 
            if (heightRatio > 1 && widthRatio > 1) { 
 
                if (heightRatio > widthRatio) { 
 
                    bmpFactoryOptions.inSampleSize = heightRatio; 
                } else { 
                    bmpFactoryOptions.inSampleSize = widthRatio; 
                } 
 
            } 
 
            bmpFactoryOptions.inJustDecodeBounds = false; 
            bmp = BitmapFactory.decodeFile(imageFilePath, bmpFactoryOptions); 
 
            imv.setImageBitmap(bmp); 
 
        } 
    } 
@Override
 protected void onActivityResult(int requestCode, int resultCode,
   Intent intent) {
  // TODO Auto-generated method stub
  super.onActivityResult(requestCode, resultCode, intent);

  //如果拍照成功
  if (resultCode == RESULT_OK) {

   // Bundle extras = intent.getExtras();
   // Bitmap bmp = (Bitmap)extras.get("data");

   imv = (ImageView) findViewById(R.id.imageView1);

   //取得屏幕的显示大小
   Display currentDisplay = getWindowManager().getDefaultDisplay();
   int dw = currentDisplay.getWidth();
   int dh = currentDisplay.getHeight();

   //对拍出的照片进行缩放
   BitmapFactory.Options bmpFactoryOptions = new BitmapFactory.Options();
   bmpFactoryOptions.inJustDecodeBounds = true;
   Bitmap bmp = BitmapFactory.decodeFile(imageFilePath,
     bmpFactoryOptions);

   int heightRatio = (int) Math.ceil(bmpFactoryOptions.outHeight
     / (float) dh);
   int widthRatio = (int) Math.ceil(bmpFactoryOptions.outWidth
     / (float) dw);

   if (heightRatio > 1 && widthRatio > 1) {

    if (heightRatio > widthRatio) {

     bmpFactoryOptions.inSampleSize = heightRatio;
    } else {
     bmpFactoryOptions.inSampleSize = widthRatio;
    }

   }

   bmpFactoryOptions.inJustDecodeBounds = false;
   bmp = BitmapFactory.decodeFile(imageFilePath, bmpFactoryOptions);

   imv.setImageBitmap(bmp);

  }
 }
这里我们就完成了对本机摄像头的调用，其实在这里主要要学习的是startActivityForResult和onActivityResult这两个方法，一个是调用Activity并将结果返回给调用的Activity，一个就是处理返回的数据了，好了，如果哪位想要程序的话，可以直接留邮件地址。

 摘自 kangkangz4的专栏