Android之Bitmap使用心得(持续更新)

因为此代码里面有解释，因此直接上代码：

public class ChangeBitmapPixel extends Activity {
    private Button btn;
    private Bitmap photo;
    private ImageView image;
    FileOutputStream fos = null;
    BufferedOutputStream bos = null;
    private ByteArrayOutputStream baos;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        image = (ImageView) findViewById(R.id.image);
        btn = (Button) findViewById(R.id.button);
        btn.setOnClickListener(new OnClickListener(){

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                Intent i = new Intent("android.media.action.IMAGE_CAPTURE");
                //如果使用下面注释的代码，将不返回数据给Intent
//                i.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(new File(Environment
//                        .getExternalStorageDirectory(),"pic.jpg")));
                //启动摄像头并且在拍摄后返回
                startActivityForResult(i, 10);
            }});
        
    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        //两种读取文件的方法
         Uri uri = data.getData();
         if (uri != null) {
             System.out.println("uri不为空");
             photo = BitmapFactory.decodeFile(uri.getPath());
             System.out.println("uri:"+photo);
         }
         
          if (photo == null) {
              Bundle bundle = data.getExtras();
              if (bundle != null) {
                  photo = (Bitmap) bundle.get("data");
                  image.setImageBitmap(photo);
                  //保存照片
                  savePic(photo);
                  System.out.println("photo:"+photo);
              } else {
                  Toast.makeText(ChangeBitmapPixel.this,
                          "为空",
                          Toast.LENGTH_LONG).show();
                  return;
              }
          }
        super.onActivityResult(requestCode, resultCode, data);
        }
    public void savePic(Bitmap bitmap){
        //使用此流读取
        baos = new ByteArrayOutputStream();
        //第二个参数影响的是图片的质量，但是图片的宽度与高度是不会受影响滴
        bitmap.compress(Bitmap.CompressFormat.JPEG, 80, baos);
        //这个函数能够设定图片的宽度与高度
        //Bitmap map = Bitmap.createScaledBitmap(bitmap, 400, 400, true);
        //把数据转为为字节数组
        byte[] byteArray = baos.toByteArray();
        try {
            fos = new FileOutputStream(Environment.getExternalStorageDirectory()+"pic.jpg");
            bos = new BufferedOutputStream(fos);
            bos.write(byteArray);
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally{
            try {
                baos.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            
        }
        
    }

}