该文章主要改动于CSDN某大神的一篇文章,本人认为这篇文章的面向对象非常透彻,以下分享例如以下可学习的几点:

Android应用经典主界面框架之中的一个:仿QQ (使用Fragment, 附源代码)

1.通过&符号实现计算优化:（后来通过问同事，说是计算机通过位运算 效率比平时的switch效率高,并解说了该算法的原理。）

public class Constant {

	public static final int SIGN_FRAGMENT_MESSAGE=0x01 <<1;

	public static final int SIGN_FRAGMENT_CONTACTS=0x01 <<2;

	public static final int SIGN_FRAGMENT_NEWS=0x01 <<3;

	public static final int SIGN_FRAGMENT_SETTENGS=0x01 <<4;

}

@Override

	public void onClickCallBack(int itemID) {

		String tag = "";

		if ((itemID & Constant.SIGN_FRAGMENT_MESSAGE) != 0) {

			tag = Constant.STR_FRAGMENT_MESSAGE;

		} else if ((itemID & Constant.SIGN_FRAGMENT_CONTACTS) != 0) {

			tag = Constant.STR_FRAGMENT_CONTACTS;

		} else if ((itemID & Constant.SIGN_FRAGMENT_NEWS) != 0) {

			tag = Constant.STR_FRAGMENT_NEWS;

		} else if ((itemID & Constant.SIGN_FRAGMENT_SETTENGS) != 0) {

			tag = Constant.STR_FRAGMENT_SETTINGS;

		}

		mHeaderPanelLayout.setText(tag);

		setTabSection(tag);

	}

2.通过onLayout对底部栏中间的button进行“动态”调整

@Override

	protected void onLayout(boolean changed, int l, int t, int r, int b) {

		super.onLayout(changed, l, t, r, b);

		layoutItem(l, t, r, b);

	}

	private void layoutItem(int left, int top, int right, int bottom) {

		int allChildWidth=0;

		int num=getChildCount();

		for (int i = 0; i < num; i++) {

			allChildWidth+=getChildAt(i).getWidth();

		}

		int absoluteWidth=right-left-getPaddingLeft()-getPaddingRight();

		int blankWidth=(absoluteWidth-allChildWidth)/(num-1);

		//设置第2 3个button的间距

		LayoutParams params1=(LayoutParams) mContactsBtn.getLayoutParams();

		params1.leftMargin=blankWidth;

		mContactsBtn.setLayoutParams(params1);

		LayoutParams params2=(LayoutParams) mNewsBtn.getLayoutParams();

		params2.leftMargin=blankWidth;

		mNewsBtn.setLayoutParams(params2);

	}

3.两种实例化布局的应用：

1）通过layoutInflater.

	public ImageText(Context context, AttributeSet attrs) {

		super(context, attrs);

		LayoutInflater.from(context).inflate(R.layout.image_text_layout, this,true);

		mImageView=(ImageView) findViewById(R.id.iv_imgae_text);

		mTextiew=(TextView) findViewById(R.id.tv_imgae_text);

	}

2）通过onFinishInflater()

<?xml version="1.0" encoding="utf-8"?>

<org.lean.ui.BottomPanelLayout

    xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="wrap_content"

    android:background="#FFF3F3F3"

    android:paddingLeft="20dp"

    android:paddingRight="20dp"

    android:layout_alignParentBottom="true" >

    <org.lean.ui.ImageText

        android:id="@+id/message_btn"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentLeft="true" />

    <org.lean.ui.ImageText

        android:id="@+id/contacts_btn"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_toRightOf="@id/message_btn" />

    <org.lean.ui.ImageText

        android:id="@+id/news_btn"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_toRightOf="@id/contacts_btn" />

    <org.lean.ui.ImageText

        android:id="@+id/settings_btn"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentRight="true" />

</org.lean.ui.BottomPanelLayout>

@Override

	protected void onFinishInflate() {

		super.onFinishInflate();

		mMessageBtn=(ImageText) findViewById(R.id.message_btn);

		mContactsBtn=(ImageText) findViewById(R.id.contacts_btn);

		mNewsBtn=(ImageText) findViewById(R.id.news_btn);

		mSettingsBtn=(ImageText) findViewById(R.id.settings_btn);

		initClickEvent();

	}

4.代理实现数据传递（IOS中最经常使用的一种设计模式）

public class BottomPanelLayout extends RelativeLayout implements OnClickListener{

	private BottomPanelCallBackProtocal mCallBackProtocal;

	//代理协议

	public void setCallBackProtocal(BottomPanelCallBackProtocal callBackProtocal) {

		this.mCallBackProtocal = callBackProtocal;

	}

	public interface BottomPanelCallBackProtocal{

		public void onClickCallBack(int itemID);

	}

	/**

	 * 1.改动本身样式

	 * 2.对外声明事件

	 */

	@Override

	public void onClick(View v) {

		initBottomPanel();

		int index=-1;

		switch (v.getId()) {

			case R.id.message_btn:

				index=Constant.SIGN_FRAGMENT_MESSAGE;

				mMessageBtn.setChecked(index);

				break;

			case R.id.contacts_btn:

				index=Constant.SIGN_FRAGMENT_CONTACTS;

				mContactsBtn.setChecked(index);

				break;

			case R.id.news_btn:

				index=Constant.SIGN_FRAGMENT_NEWS;

				mNewsBtn.setChecked(index);

				break;

			case R.id.settings_btn:

				index=Constant.SIGN_FRAGMENT_SETTENGS;

				mSettingsBtn.setChecked(index);

				break;

			default:

				break;

		}

		if (mCallBackProtocal!=null) {

			mCallBackProtocal.onClickCallBack(index);

		}

	}

}

public class MainActivity extends Activity implements

		BottomPanelCallBackProtocal {

	@Override

	public void onClickCallBack(int itemID) {

		String tag = "";

		if ((itemID & Constant.SIGN_FRAGMENT_MESSAGE) != 0) {

			tag = Constant.STR_FRAGMENT_MESSAGE;

		} else if ((itemID & Constant.SIGN_FRAGMENT_CONTACTS) != 0) {

			tag = Constant.STR_FRAGMENT_CONTACTS;

		} else if ((itemID & Constant.SIGN_FRAGMENT_NEWS) != 0) {

			tag = Constant.STR_FRAGMENT_NEWS;

		} else if ((itemID & Constant.SIGN_FRAGMENT_SETTENGS) != 0) {

			tag = Constant.STR_FRAGMENT_SETTINGS;

		}

		mHeaderPanelLayout.setText(tag);

		setTabSection(tag);

	}

}

5.改动原来Fragment跳转的代码（之前方法ensureTransaction()是在粘贴或者消除的时候都要推断，但作为一个事务，仅仅须要保证事物仅仅有一个開始就可以，而不须要每次都调用）

private void setTabSection(String tag) {

		if (TextUtils.equals(tag, currFagTag)) {

			return;

		}

		ensureTransaction();

		if (currFagTag != null && !currFagTag.equals("")) {

			detachFragment(getFragment(currFagTag));

		}

		attachFragment(R.id.fragment_panel, getFragment(tag), tag);

		commitTransaction();

	}

private void ensureTransaction() {

		if (mFragmentTransaction == null) {

			mFragmentTransaction = mFragmentManager.beginTransaction();

			mFragmentTransaction

					.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);

		}

	}

6.Fragment对Fragment进行跳转并传值的改进。(这里试验从MessageFragment 点击textview跳转到 ContactFragment );

1>在MessageFragment 中

	@Override

	public void onActivityCreated(Bundle savedInstanceState) {

		super.onActivityCreated(savedInstanceState);

		getActivity().findViewById(R.id.msg_tv).setOnClickListener(new OnClickListener() {

			@Override

			public void onClick(View v) {

				((MainActivity)getActivity()).setTabSection(Constant.STR_FRAGMENT_CONTACTS);

			}

		});

	}

2>在ContactFragment 中声明数据代理

	//声明一个变量,该变量存储该Fragment所须要的一切參数 当刷新View时手动调用其更新数据

	private ContactFragmentCallBack mContactFragmentCallBack;

	//声明该接口

	public interface ContactFragmentCallBack{

		//说明该Fragment更新时须要一个String对象

		public String getContentStr();

	}

3>MessageFragment 实现该代理

public class MessageFragment extends BaseFragment implements ContactFragmentCallBack{

	@Override

	public String getContentStr() {

		return "abc";

	}

}

4>在ContactFragment 中回调

	@Override

	public void onResume() {

		super.onResume();

		MainActivity.currFagTag=Constant.STR_FRAGMENT_CONTACTS;

		//通过取出 存储于上个Fragment中的数据

		Fragment f=((MainActivity)getActivity()).getFragment(Constant.STR_FRAGMENT_MESSAGE);

		if (f!=null&&f instanceof ContactFragmentCallBack) {

			mContactFragmentCallBack=(ContactFragmentCallBack)f;

			TextView textView=(TextView) ((MainActivity)getActivity()).findViewById(R.id.contact_tv);

			textView.setText(mContactFragmentCallBack.getContentStr());

		}

	}

改动后的项目源代码