在Android项目中如何调用系统的分享功能

/**
 * 调用系统的分享功能
 * Created by admin on 15-4-13.
 */
public class ShareActivity extends Activity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.share_layout);
  }
  //分享文字
  public void shareText(View view) {
    Intent shareIntent = new Intent();
    shareIntent.setAction(Intent.ACTION_SEND);
    shareIntent.putExtra(Intent.EXTRA_TEXT, "This is my Share text.");
    shareIntent.setType("text/plain");
    //设置分享列表的标题，并且每次都显示分享列表
    startActivity(Intent.createChooser(shareIntent, "分享到"));
  }
  //分享单张图片
  public void shareSingleImage(View view) {
    String imagePath = Environment.getExternalStorageDirectory() + File.separator + "test.jpg";
    //由文件得到uri
    Uri imageUri = Uri.fromFile(new File(imagePath));
    Log.d("share", "uri:" + imageUri); //输出：file:///storage/emulated/0/test.jpg
    Intent shareIntent = new Intent();
    shareIntent.setAction(Intent.ACTION_SEND);
    shareIntent.putExtra(Intent.EXTRA_STREAM, imageUri);
    shareIntent.setType("image/*");
    startActivity(Intent.createChooser(shareIntent, "分享到"));
  }
  //分享多张图片
  public void shareMultipleImage(View view) {
    ArrayList<Uri> uriList = new ArrayList<>();
    String path = Environment.getExternalStorageDirectory() + File.separator;
    uriList.add(Uri.fromFile(new File(path+"australia_1.jpg")));
    uriList.add(Uri.fromFile(new File(path+"australia_2.jpg")));
    uriList.add(Uri.fromFile(new File(path+"australia_3.jpg")));
    Intent shareIntent = new Intent();
    shareIntent.setAction(Intent.ACTION_SEND_MULTIPLE);
    shareIntent.putParcelableArrayListExtra(Intent.EXTRA_STREAM, uriList);
    shareIntent.setType("image/*");
    startActivity(Intent.createChooser(shareIntent, "分享到"));
  }
}