相信很多學習android的朋友，都和我一樣連一個簡單的獲取手機圖片的無從知曉，於是藉助於百度尋求幫助，於是乎有感寫，這篇部落格不僅僅是鞏固自身的基礎知識，希望能幫助到其他人。
     Uri mPhotoUri；
    private static final int REQUESTCODE_PICK = 0; // 相簿選圖示記
    private static final int REQUESTCODE_TAKE = 1;  // 相機拍照標記
 ／／如果不太明白Uri
 ／／請檢視連結：http://blog.csdn.net/sunny09290/article/details/7514963
 1.呼叫系統相機
     Intent intent＝new Intent（MediaStore.ACTION_IMAGE_CAPURE）
 

//獲取儲存路徑
intent.putExtra(android.provider.MediaStore.EXTRA_OUTPUT, mPhotoUri);//可以忽略
startActivityForResult(intent,REQUESTCODE_TAKE);//跳轉相機

 //從圖片庫獲取圖片
   Intent intent;
    if (Build.VERSION.SDK_INT < 19) {
        intent = new Intent(Intent.ACTION_GET_CONTENT);
        intent.setType("image/*");

    } else {
        intent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
    }
    startActivityForResult(intent, REQUESTCODE_PICK);
 

//重寫回調方法
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
if (resultCode == Activity.RESULT_OK) {//是否選中圖片
switch (requestCode) {
case REQUESTCODE_PICK:// 直接從相簿獲取

                Uri selectedImage = data.getData();
                String[] filePathColumn = {MediaStore.Images.Media.DATA};

                Cursor cursor = getContentResolver().query(selectedImage,
                        filePathColumn, null, null, null);
                cursor.moveToFirst();

                int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
                String picturePath = cursor.getString(columnIndex);
                cursor.close();
 

// Bitmap bitmap = BitmapFactory.decodeFile(picturePath);
Bitmap bitmap = FileUtil.getSmallBitmap(picturePath);//壓縮圖片
setPotoFeedImageItem(bitmap);
break;
case REQUESTCODE_TAKE:// 呼叫相機拍照

                if (resultCode == Activity.RESULT_OK) {
                    final Uri uri = mPhotoUri;
                    Log.e("resultCode", uri + "");
                    if (uri != null) {
                        processPicture(uri);
                    }
                }
                break;
        }
    }
    super.onActivityResult(requestCode, resultCode, data);
}

     /**
 * 圖片顯示
 *
 * @param uri
 */
private void processPicture(Uri uri) {
    final String[] projection = {MediaStore.Images.Media.DATA};
    final Cursor cursor = managedQuery(uri, projection, null, null, null);
    cursor.moveToFirst();
    final int columnIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
    String imagePath = cursor.getString(columnIndex);
    Debug.e("processPicture", imagePath);

    Bitmap bitmap = FileUtil.getSmallBitmap(imagePath);//壓縮圖片

    setPotoFeedImageItem(bitmap);

}

//將圖片顯示在控制元件上
privet void setPotoFeedImageItem(Bitmap bitmap){
ImageView acatarimg = (ImageView) findViewById(R.id.img);
acatarimg.setImageBitmap(bitmap);
}

下面的是一個壓縮圖片的工具類

public class FileUtil {

/**
 * 裁剪圖片方法實現
 *
 * @param uri
 */
public static void startPhotoZoom(Activity cot, Uri uri) {
    Intent intent = new Intent("com.android.camera.action.CROP");
    intent.setDataAndType(uri, "image/*");
    // crop=true是設定在開啟的Intent中設定顯示的VIEW可裁剪
    intent.putExtra("crop", "true");
    // aspectX aspectY 是寬高的比例
    intent.putExtra("aspectX", 1);
    intent.putExtra("aspectY", 1);
    // outputX outputY 是裁剪圖片寬高
    intent.putExtra("outputX", 300);
    intent.putExtra("outputY", 300);
    intent.putExtra("return-data", true);
    cot.startActivityForResult(intent, REQUESTCODE_CUTTING);
}
//計算圖片的縮放值
public static int calculateInSampleSize(BitmapFactory.Options options,int reqWidth, int reqHeight) {
    final int height = options.outHeight;
    final int width = options.outWidth;
    int inSampleSize = 1;

    if (height > reqHeight || width > reqWidth) {
        final int heightRatio = Math.round((float) height/ (float) reqHeight);
        final int widthRatio = Math.round((float) width / (float) reqWidth);
        inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
    }
    return inSampleSize;
}
// 根據路徑獲得圖片並壓縮，返回bitmap用於顯示
public static Bitmap getSmallBitmap(String filePath) {
    final BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeFile(filePath, options);
    // Calculate inSampleSize
    options.inSampleSize = calculateInSampleSize(options, 480, 800);

    // Decode bitmap with inSampleSize set
    options.inJustDecodeBounds = false;

    return BitmapFactory.decodeFile(filePath, options);
}

｝