編輯:關於Android編程
該文章主要修改於CSDN某大神的一篇文章,本人覺得這篇文章的面向對象很透徹,下面分享如下可學習的幾點:
Android應用經典主界面框架之一:仿QQ (使用Fragment, 附源碼)
1.通過&符號實現計算優化:(後來通過問同事,說是計算機通過位運算 效率比平時的switch效率高,並講解了該算法的原理。)
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.通過onLayout對底部欄中間的按鈕進行“動態”調整
@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); //設置第2 3個按鈕的間距 LayoutParams params1=(LayoutParams) mContactsBtn.getLayoutParams(); params1.leftMargin=blankWidth; mContactsBtn.setLayoutParams(params1); LayoutParams params2=(LayoutParams) mNewsBtn.getLayoutParams(); params2.leftMargin=blankWidth; mNewsBtn.setLayoutParams(params2); }
1)通過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)通過onFinishInflater()
@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.代理實現數據傳遞(IOS中最常用的一種設計模式)
public class BottomPanelLayout extends RelativeLayout implements OnClickListener{ private BottomPanelCallBackProtocal mCallBackProtocal; //代理協議 public void setCallBackProtocal(BottomPanelCallBackProtocal callBackProtocal) { this.mCallBackProtocal = callBackProtocal; } public interface BottomPanelCallBackProtocal{ public void onClickCallBack(int itemID); } /** * 1.修改本身樣式 * 2.對外聲明事件 */ @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); } }
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); } }
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); } }); }
//聲明一個變量,該變量存儲該Fragment所需要的一切參數 當刷新View時手動調用其更新數據 private ContactFragmentCallBack mContactFragmentCallBack; //聲明該接口 public interface ContactFragmentCallBack{ //說明該Fragment更新時需要一個String對象 public String getContentStr(); }3>MessageFragment 實現該代理
public class MessageFragment extends BaseFragment implements ContactFragmentCallBack{ @Override public String getContentStr() { return "abc"; } }
@Override public void onResume() { super.onResume(); MainActivity.currFagTag=Constant.STR_FRAGMENT_CONTACTS; //通過取出 存儲於上個Fragment中的數據 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()); } }
在Android開發中SQLite起著很重要的作用,網上SQLite的教程有很多很多,不過那些教程大多數都講得不是很全面。本人總結了一些SQLite命令,借著論壇的大賽,
一、服務器端實現 (1)創建動態服務器項目 個部分代碼如下: package com.lc.dao; import java.sql.Connection; imp
在前面的第二篇文章中,我們提過,View的事件分發是一種委托思想:上層委托下層,父容器委托子元素來處理這個流程。接下來,我們就將深入去學習View的事件分發機制。&nbs
1、概述傳統的Android開發架構一般是MVC模式, Model:業務邏輯和實體模型 View:對應於布局文件 Controllor:對應於Activity 單