android 从系统相册获取一张图片

package net.viralpatel.android.imagegalleray;

import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

public class ImageGalleryDemoActivity extends Activity {

private static int RESULT_LOAD_IMAGE = 1;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

Button buttonLoadImage = (Button) findViewById(R.id.buttonLoadPicture);
buttonLoadImage.setOnClickListener(new View.OnClickListener() {

@Override
public void onClick(View arg0) {

Intent i = new Intent(
Intent.ACTION_PICK,
android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);

startActivityForResult(i, RESULT_LOAD_IMAGE);
}
});
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);

if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK && null != data) {
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();

ImageView imageView = (ImageView) findViewById(R.id.imgView);
imageView.setImageBitmap(BitmapFactory.decodeFile(picturePath));

}

}
}