标签/TabActivity 深度研究

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

写道

1. 自定义TabActivity 使得标签处于屏幕下方
2. 各个标签所用布局 既可在 *.xml 中定义 也可在 *.java 中定义
3. 更改标签布局

1. 标签页 在 屏幕下方

写道

一个典型的标签Activity 是由2 部分构成的 且其id都有规定 即：
* TabWidget 用于展示标签页 id=tabs
* FrameLayout 用于展示隶属于各个标签的具体布局 id=tabcontent

* 基本布局如下：

<?xmlversion="1.0"encoding="utf-8"?>
<TabHostxmlns: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="HellotoJohnny.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>

<?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();

tHost = this.getTabHost();

* 创建4个标签 并指定所使用的布局

publicstaticfinalStringTab1="Tab1";
publicstaticfinalStringTab2="Tab2";
publicstaticfinalStringTab3="Tab3";
publicstaticfinalStringTab4="Tab4";
publicstaticfinalStringTab5="Tab5";

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

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(newOnTabChangeListener(){
@Override
publicvoidonTabChanged(StringtabId){
//TODOAuto-generatedmethodstub
}

});

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

publicclassCustomLayoutimplementsTabHost.TabContentFactory{
Activityactivity;
LayoutInflaterinflaterHelper;

LinearLayoutlayout;

publicCustomLayout(Activitya){
activity=a;

inflaterHelper=a.getLayoutInflater();
}

/**{@inheritDoc}*///tag标记各个标签
publicViewcreateTabContent(Stringtag){
returnaddCustomView(tag);
}

publicViewaddCustomView(Stringid){

layout=newLinearLayout(activity);
layout.setOrientation(LinearLayout.VERTICAL);


if(id.equals(Tab1)){
ImageViewiv=newImageView(activity);
iv.setImageResource(R.drawable.beijing_big);
layout.addView(iv,
newLinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT,LinearLayout.LayoutParams.FILL_PARENT));
}
elseif(id.equals(Tab2)){
EditTextedit=newEditText(activity);
layout.addView(edit,
newLinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT,LinearLayout.LayoutParams.FILL_PARENT));

Buttonbtn=newButton(activity);
btn.setText("OK");
btn.setWidth(100);
layout.addView(btn,
newLinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT,LinearLayout.LayoutParams.FILL_PARENT));

RadioGrouprGroup=newRadioGroup(activity);
rGroup.setOrientation(LinearLayout.HORIZONTAL);
RadioButtonradio1=newRadioButton(activity);
radio1.setText("RadioA");
rGroup.addView(radio1);
RadioButtonradio2=newRadioButton(activity);
radio2.setText("RadioB");
rGroup.addView(radio2);

layout.addView(rGroup,
newLinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,LinearLayout.LayoutParams.WRAP_CONTENT));
}
elseif(id.equals(Tab3)){

LinearLayout.LayoutParamsparam3=
newLinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT,LinearLayout.LayoutParams.FILL_PARENT);

layout.addView(inflaterHelper.inflate(R.layout.hello,null),param3);
}
elseif(id.equals(Tab4)){
TextViewtv=newTextView(activity);
tv.setText("HelloTags!");
tv.setGravity(Gravity.CENTER);
layout.addView(tv);
}

returnlayout;
}

}

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：

CustomLayoutct=newCustomLayout(this);

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

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

写道

可能很多人对TabActivity 不满意 原因之一：其很不美观 而不美观的根源就是：标签的问题 其图像和文字相互覆盖 导致的


那么 我们可以自己扩展么？ 当然

写道

TabWidget 理解：

1. TabWidget 为 horizontal 的 LinearLayout
2. 且 其包含的标签又是一个RelativeLayout
3. 每个标签RelativeLayout 里面包含2个View: TextView ImageView

因此 我们甚至可以推算出其布局为：

<?xmlversion="1.0"encoding="utf-8"?>
<LinearLayoutxmlns: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>

<?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));

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

写道

可能有人会说：那我不调用setIndicator() 不久可以了么 不行 否则 会报错

* 自己定义布局 并 指定显示的内容

publicViewcomposeLayout(Strings,inti){
LinearLayoutlayout=newLinearLayout(this);
layout.setOrientation(LinearLayout.VERTICAL);

TextViewtv=newTextView(this);
tv.setGravity(Gravity.CENTER);
tv.setSingleLine(true);
tv.setText(s);
layout.addView(tv,
newLinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT,LinearLayout.LayoutParams.WRAP_CONTENT));

ImageViewiv=newImageView(this);
iv.setImageResource(i);
layout.addView(iv,
newLinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT,LinearLayout.LayoutParams.WRAP_CONTENT));
returnlayout;
}

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

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

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()

publicvoidupdateWidgetView(inti,Stringtext,intimage){
RelativeLayoutrl=(RelativeLayout)tw.getChildAt(i);

rl.addView(composeLayout(text,image));
}

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!