学步园

何谓标签 印象最深刻的应该是这个

现在 我们将通过一系列的扩展来研究之

1. 标签页 在 屏幕下方

* 基本布局如下：

<?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="fill_parent"   
	android:layout_height="fill_parent" >
<LinearLayout   
	android:orientation="vertical"
	android:gravity="bottom"
	android:layout_width="fill_parent"   
	android:layout_height="fill_parent" >
<FrameLayout   
	android:id="@android:id/tabcontent"
	android:layout_width="fill_parent"   
	android:layout_height="200dip" >
	
	<RelativeLayout
    android:id="@+id/view1"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
		<TextView  
			android:id="@+id/text"
    		android:layout_width="wrap_content" 
    		android:layout_height="wrap_content" 
    		android:text="Hello to Johnny.Griffin!"
    		android:layout_centerInParent="true"
    		android:textStyle="bold|italic" />
		<ImageView  
    		android:layout_width="fill_parent" 
    		android:layout_height="fill_parent" 
    		android:src="@drawable/robot"
    		android:layout_toLeftOf="@id/text" />
	</RelativeLayout>
	
	<TextView
		android:id="@+id/view2"
		android:layout_width="fill_parent"
    	android:layout_height="fill_parent"
    	android:text="创新源于模仿！" />
    	
    <TextView
		android:id="@+id/view3"
		android:layout_width="fill_parent"
    	android:layout_height="fill_parent"
    	android:text="欢迎进入 droid 世界！" />
    	
    <ImageView
		android:id="@+id/view4"
		android:layout_width="fill_parent"
    	android:layout_height="fill_parent"
    	android:src="@drawable/robot" />
</FrameLayout>
<TabWidget   
	android:id="@android:id/tabs" 
	android:layout_width="fill_parent"   
	android:layout_height="wrap_content" />   
</LinearLayout>   
</TabHost> 

* 得到TabHost tHost 仅在TabActivity中有效

tHost = this.getTabHost();

* 创建4个标签 并指定所使用的布局

public static final String Tab1 = "Tab1";
public static final String Tab2 = "Tab2";
public static final String Tab3 = "Tab3";
public static final String Tab4 = "Tab4";
public static final String Tab5 = "Tab5";

tHost.addTab(tHost.newTabSpec(Tab1).setIndicator("Tab 1", getResources().getDrawable(R.drawable.icon)).setContent(R.id.view1));
        tHost.addTab(tHost.newTabSpec(Tab2).setIndicator("Tab 2", getResources().getDrawable(R.drawable.beijing_small)).setContent(R.id.view2));
        tHost.addTab(tHost.newTabSpec(Tab3).setIndicator("Tab 3").setContent(R.id.view3));
        tHost.addTab(tHost.newTabSpec(Tab4).setIndicator("Tab 4").setContent(R.id.view4));

* 设定监听器 用于监听 标签间切换事件

tHost.setOnTabChangedListener(new OnTabChangeListener(){
			@Override
			public void onTabChanged(String tabId) {
				// TODO Auto-generated method stub
			}
        	
        });

* emulator 运行情况：

2.  在 *.java 中定义标签所需布局

public class CustomLayout implements TabHost.TabContentFactory  {
    	Activity activity;
    	LayoutInflater inflaterHelper;
    	
    	LinearLayout layout;
    	
    	public CustomLayout (Activity a) {
    		activity = a;
    		
    		inflaterHelper = a.getLayoutInflater();
    	}
    	
    	/** {@inheritDoc} *///tag 标记各个标签
        public View createTabContent(String tag) {
        		return addCustomView(tag);
        }
        
        public View addCustomView(String id){
        	
        	layout = new LinearLayout(activity);
            layout.setOrientation(LinearLayout.VERTICAL);
            
            
            if(id.equals(Tab1)){
                ImageView iv = new ImageView(activity);
                iv.setImageResource(R.drawable.beijing_big);
                layout.addView(iv,
                		new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.FILL_PARENT));
            }
            else if(id.equals(Tab2)){
                EditText edit = new EditText(activity);
                layout.addView(edit,
                		new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.FILL_PARENT));
                
                Button btn = new Button(activity);
                btn.setText("OK");
                btn.setWidth(100);
                layout.addView(btn,
                		new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.FILL_PARENT));
                
                RadioGroup rGroup = new RadioGroup(activity);
                rGroup.setOrientation(LinearLayout.HORIZONTAL);
                RadioButton radio1 = new RadioButton(activity);
                radio1.setText("Radio A");
                rGroup.addView(radio1);
                RadioButton radio2 = new RadioButton(activity);
                radio2.setText("Radio B");
                rGroup.addView(radio2);
                
                layout.addView(rGroup,
                		new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));
            }
            else if(id.equals(Tab3)){
            	
            	LinearLayout.LayoutParams param3 =
                    new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.FILL_PARENT);
            	
                layout.addView(inflaterHelper.inflate(R.layout.hello, null),param3);
            }
            else if(id.equals(Tab4)){
            	TextView tv = new TextView(activity);
            	tv.setText("HelloTags!");
            	tv.setGravity(Gravity.CENTER);
            	layout.addView(tv);
            }

            return layout;
        }
        
    }

* 如何使用：

CustomLayout ct = new CustomLayout(this);

tHost.addTab(tHost.newTabSpec(Tab4).setIndicator("Tab 4").setContent(ct));

 * emulator 运行结果:

3. 改变标签布局

因此 我们甚至可以推算出其布局为：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<RelativeLayout
	android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content">
	<ImageView  />
    <TextView  />
</RelativeLayout>
<RelativeLayout
	android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content">
	<ImageView  />
    <TextView  />
</RelativeLayout>
<RelativeLayout
	android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content">
	<ImageView  />
    <TextView  />
</RelativeLayout>
<RelativeLayout
	android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content">
	<ImageView  />
    <TextView  />
</RelativeLayout>
</LinearLayout>

* 去掉系统默认的布局 即 在 setIndicator() 中置空 修改如下：

tHost.addTab(tHost.newTabSpec(Tab1).setIndicator("").setContent(ct)); 

* 自己定义布局 并 指定显示的内容

public View composeLayout(String s, int i){
    	LinearLayout layout = new LinearLayout(this);
        layout.setOrientation(LinearLayout.VERTICAL);
        
        TextView tv = new TextView(this);
        tv.setGravity(Gravity.CENTER);
        tv.setSingleLine(true);
        tv.setText(s);
        layout.addView(tv, 
        		new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT));
        
        ImageView iv = new ImageView(this);
        iv.setImageResource(i);
        layout.addView(iv, 
        		new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT));
        return layout;
    }

* 得到 TabWidget 实例 tw

LinearLayout ll=(LinearLayout)tHost.getChildAt(0); 
        tw =(TabWidget)ll.getChildAt(1);

* 得到 TabWidget 内的具体某个Layout 并使用上面的布局 composeLayout()

public void updateWidgetView(int i,String text,int image){
    	RelativeLayout rl =(RelativeLayout)tw.getChildAt(i);
    	
    	rl.addView(composeLayout(text,image));
    }

* emulator 运行截图 // 前面 3个是使用新布局 最后一个是使用TabActivity 默认的布局 哪个好看 大家自己选择之

that's all!