Controlling Tab colour-state / size in a TabActivi

问题:

Ok, this is driving me nuts - I've searched all of the references and examples I can find and I still seem to be missing something really obvious. These are the tabs for a 7-day TV Guide (not normally with the red arrow, obviously :) )...

What I need to know is what is the object (View or Drawable I assume) that makes up the main body/background of a Tab itself? (as indicated by the red arrow) and how do I access it or have it automatically change its state colour to a list of my choice? Also, how can I get the state colour of the indicator TextView to follow suit?

Example: In the capture above, it's readable because I've set the textColor to a static grey (instead of the bright white which disappeared on a selected tab). But I want it to automatically become black text on white tab (selected) and bright white text on black (for unselected).

All help gratefully received.

回答1:

The view which represents each tab can be changed using

setIndicator(View)

I've been using this code to build each tab :

View view = buildTabView(this, "Friday");
TabHost.TabSpec spec = tabHost.newTabSpec("cat1").setIndicator(view).setContent(intent);
tabHost.addTab(spec);

public static LinearLayout buildTabView(Context context, String label){
    LayoutInflater li = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);          
    final LinearLayout ll = (LinearLayout)li.inflate(R.layout.tab, null);

    // the following lines will change the tabs size depending on the label (text) length.
    // the longer tab text - the wider tabs
    LinearLayout.LayoutParams layoutParams = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, label.length() + 1);
    ll.setLayoutParams(layoutParams);

    final TextView tv = (TextView)ll.findViewById(R.id.tab_tv);         
    tv.setOnTouchListener(new OnTouchListener() {               
        public boolean onTouch(View v, MotionEvent event) {
            ll.onTouchEvent(event);
            return false;
        }
    });

    tv.setText(label);          
    return ll;
}

And here comes layout/tab.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:background="@drawable/tab_bg_selector"
  android:clickable="true"
  >

  <TextView
  android:id="@+id/tab_tv"
  android:layout_width="wrap_content"
  android:layout_height="33dip"
  android:text="Text 1"
  android:textStyle="bold"
  android:textSize="16dip"
  android:gravity="center"
  android:textColor="@drawable/tab_color_selector"
  android:layout_weight="1.0"
  android:clickable="true"
  />

</LinearLayout>

Note that LinearLayout has a selector on it's background (to change backround, obviously :) ), and the TextView has a selector on the textColor (to change the text color when selected / pressed etc.). It this way you can make the text look black when tab is pressed, and white when it is not :)

回答2:

Kindly update your question with the code you use.. Do you use xml inside your drawable for animating the tabs? here is a sample tabs action handling using xml.

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- When selected, use grey -->
    <item android:drawable="@drawable/ic_tab_about_grey"
          android:state_selected="false" />
    <!-- When not selected, use white-->
    <item android:drawable="@drawable/ic_tab_about_color" android:state_selected="true"/>
</selector>

Customize tab behavior and icons using this xml file.

Here is the code to set this animation/customizing options in tabs:

intent = new Intent().setClass(this, sms.class);
spec = tabHost.newTabSpec("sms").setIndicator("SMS",
       res.getDrawable(R.drawable.ic_tab_sms))
       .setContent(intent);
tabHost.addTab(spec);

Now the XML in layout to define tab-host and tab-widgets.

<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">
        <TabWidget
            android:id="@android:id/tabs"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            />
</TabHost>

Customise this xml layout with your own colors, fonts and structure.