public class MainActivity extends Activity implements OnClickListener {
    private Button btn_photo;
    private Button btn_camare;
    private ImageView img;
    private static final int CAMARE = 999;
    private static final int PHOTO = 888;
    private static final int CAMARE_SD = 666;
    private File imgFile;
    private Uri imgUri;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initview();
    }
    private void initview() {
        // TODO Auto-generated method stub
        btn_photo = (Button)findViewById(R.id.btn_photo);
        btn_camare = (Button)findViewById(R.id.btn_camare);
        img = (ImageView)findViewById(R.id.img);
        
        btn_camare.setOnClickListener(this);
        btn_photo.setOnClickListener(this);
    
    }

重写onActivityResult方法 写好三个请求码

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        // TODO Auto-generated method stub
        super.onActivityResult(requestCode, resultCode, data);
        switch (requestCode) {

        case CAMARE:
            if (requestCode == RESULT_CANCELED) {
                Toast.makeText(this,"取消了拍照",Toast.LENGTH_SHORT).show();
                return;
            }
            Bitmap camarebit = data.getParcelableExtra("data");
            img.setImageBitmap(camarebit);
            
            break;

        case PHOTO:
            if (resultCode==RESULT_OK) {
                imgUri = data.getData();
                img.setImageURI(imgUri);
            }
            
            
            break;

        case CAMARE_SD:
//          if (hasSDcard()) {
//              img.setImageURI(imgUri);
//              
//          }
            if (resultCode==RESULT_OK) {
                String path = getPathFromUri(imgUri);
                BitmapFactory.Options options = new BitmapFactory.Options();
                options.inSampleSize=5;
                Bitmap bit = BitmapFactory.decodeFile(path, options);
                img.setImageBitmap(bit);
                
            }
            
            break;
        }
    }

点击事件

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        switch (v.getId()) {
        case R.id.btn_camare:
//          Intent in = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
//          if (hasSDcard()) {
//              File dir = getExternalCacheDir();
//              imgFile = new File(dir,System.currentTimeMillis()+"avatar.png");
//              imgUri = Uri.fromFile(imgFile);
//              
//              in.putExtra(MediaStore.EXTRA_OUTPUT, imgUri);
//              startActivityForResult(in, CAMARE_SD);
//          }

intent 跳转到系统相机，给一个之前写好的请求码

            Intent camarein = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
            imgUri = creatUri();
            getPathFromUri(imgUri);
            camarein.putExtra(MediaStore.EXTRA_OUTPUT, imgUri);
            startActivityForResult(camarein,CAMARE_SD);
            
            break;
            
        case R.id.btn_photo:
            Intent in = new Intent(Intent.ACTION_GET_CONTENT);
            in.setType("img/*");
            startActivityForResult(in,PHOTO);
            break;
        }
    }

判断sd卡是否存在

    private boolean hasSDcard(){
        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            return true;
            
        }else {
            return false;
        }
    
        
    }

    private Uri creatUri() {
    
        // TODO Auto-generated method stub
        String imgName = System.currentTimeMillis()+"avatar.jepg";
        ContentValues value = new ContentValues();
        value.put(MediaStore.Images.Media.TITLE,imgName);
        value.put(MediaStore.Images.Media.DISPLAY_NAME,imgName);
        value.put(MediaStore.Images.Media.MIME_TYPE,imgName );
        Uri uri = getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,value);
        
        
        
        return uri;
    }

获取 Uri 的方法

    private String getPathFromUri(Uri uri) {
        // TODO Auto-generated method stub
        if (uri!=null) {
            String path = null;

先初始化path
获得uri的头
判断是File还是content

            String scheme = uri.getScheme();

            if (ContentResolver.SCHEME_FILE.equals(scheme)) {
                path = uri.getPath();
            }else if(ContentResolver.SCHEME_CONTENT.equals(scheme)){
                Cursor cursor = getContentResolver().query(uri, new String[] {ImageColumns.DATA}, null,null,null);
                if (cursor.moveToFirst()) {
                    int index = cursor.getColumnIndex(ImageColumns.DATA);
                    path = cursor.getString(index);
                    
                }
                cursor.close();
    
            }
            return path;
            
        }
        return null;
    }


}