美团(五)TabHost实现主界面

xml布局：

<?xml version="1.0" encoding="utf-8"?><TabHost xmlns:android="http://schemas.android.com/apk/res/android"    android:id="@android:id/tabhost"    android:layout_width="match_parent"    android:layout_height="match_parent" >    <RelativeLayout        android:layout_width="match_parent"        android:layout_height="match_parent" >        <TabWidget            android:id="@android:id/tabs"            android:layout_width="match_parent"            android:layout_height="50dp"            android:layout_alignParentBottom="true"            android:background="#ededed" />        <FrameLayout            android:id="@android:id/tabcontent"            android:layout_width="match_parent"            android:layout_height="match_parent"            android:layout_above="@android:id/tabs" />    </RelativeLayout></TabHost>

package com.myandroid.meituan;import android.app.TabActivity;import android.content.Context;import android.content.Intent;import android.os.Bundle;import android.util.Log;import android.view.KeyEvent;import android.view.LayoutInflater;import android.view.View;import android.view.Window;import android.view.WindowManager;import android.widget.ImageView;import android.widget.TabHost;import android.widget.TextView;import android.widget.Toast;import android.widget.TabHost.TabSpec;public class MyMeiTuanTabActivity extends TabActivity {private Context context;private View view;private static final int TG_TYPE = 0;private static final int SJ_TYPE = 1;private static final int WD_TYPE = 2;private static final int GD_TYPE = 3;    private  long exitTime=0;protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);requestWindowFeature(Window.FEATURE_NO_TITLE);setContentView(R.layout.activity_tab_meituan); //启动activity时不自动弹出软键盘        getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);context = this;TabHost tabhost = getTabHost();TabSpec tabSpec1 = tabhost.newTabSpec("tab1");tabSpec1.setIndicator(createIndcatorView(TG_TYPE));tabSpec1.setContent(new Intent(context, MeiTuanTuanGouActivity.class));TabSpec tabSpec2 = tabhost.newTabSpec("tab2");tabSpec2.setIndicator(createIndcatorView(SJ_TYPE));tabSpec2.setContent(new Intent(context, MeiTuanMerchantActivity.class));TabSpec tabSpec3 = tabhost.newTabSpec("tab3");tabSpec3.setIndicator(createIndcatorView(WD_TYPE));tabSpec3.setContent(new Intent(context, MeiTuanMineActicity.class));TabSpec tabSpec4 = tabhost.newTabSpec("tab4");tabSpec4.setIndicator(createIndcatorView(GD_TYPE));tabSpec4.setContent(new Intent(context,MeiTuanMroeActivity.class));tabhost.addTab(tabSpec1);tabhost.addTab(tabSpec2);tabhost.addTab(tabSpec3);tabhost.addTab(tabSpec4);}/** *返回键处理，按两次退出程序  */public boolean onKeyDown(int keyCode, KeyEvent event) {        if(keyCode==KeyEvent.KEYCODE_BACK){if ((System.currentTimeMillis() - exitTime)> 2000) {    Toast.makeText(getApplicationContext(), "再按一次退出程序",    Toast.LENGTH_SHORT).show();    exitTime = System.currentTimeMillis();    } else {    MyMeiTuanTabActivity.this.finish();    System.exit(0);    }return false;                }   return super.onKeyDown(keyCode, event);    }/** *  * @param tab * @return */public View createIndcatorView(int tab) {view = LayoutInflater.from(context).inflate(R.layout.tab_meituan, null);TextView textview = (TextView) view.findViewById(R.id.meituan_tab_textview);ImageView imageicon = (ImageView) view.findViewById(R.id.meituan_tab_imageview);switch (tab) {case TG_TYPE:textview.setText("团购");imageicon.setImageResource(R.drawable.selector_drawable_select_tuangou);break;case SJ_TYPE:textview.setText("商家");imageicon.setImageResource(R.drawable.selector_drawable_select_shangjia);break;case WD_TYPE:textview.setText("我的");imageicon.setImageResource(R.drawable.selector_drawable_select_wode);break;case GD_TYPE:textview.setText("更多");imageicon.setImageResource(R.drawable.selector_drawable_select_more);break;}return view;}}

这里我们主要要实现的是主界面底部的四个页卡功能，有的APP的页卡在顶部，不管在顶部还是底部，都要用TabHost,上面我们设置android:layout_alignParentBottom="true"
所以在底部，也可以设置为在顶部，在xml文件中的每个id都是用的系统的id。<TabWidget为页卡区,<FrameLayout为内容区。