In my Android application, I am using FragmentTabHost. I have added 3 tabs in the tabhost now my problem is I could not change the tab icon dynamically when choose each tab.
My requirement is if I select a tab other tabs icon should be changed, I got null pointer exception when try to change the tab icon. This is the line I got null pointer exception. the following code under onTabChanged method
ImageView v1 = (ImageView) mTabHost.getTabWidget().getChildAt(0)
.findViewById(android.R.id.icon);
v1 is return null (checked by if condition)
public class MainActivity extends FragmentActivity implements
OnTabChangeListener {
private static final String TAB_1_TAG = "FindTab";
private static final String TAB_2_TAG = "AddPopUpTab";
private static final String TAB_3_TAG = "MyAccoutTab";
private FragmentTabHost mTabHost;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
InitView();
}
private void InitView() {
mTabHost = (FragmentTabHost) findViewById(android.R.id.tabhost);
mTabHost.setup(this, getSupportFragmentManager(), R.id.realtabcontent);
mTabHost.addTab(
setIndicator1(MainActivity.this,
mTabHost.newTabSpec(TAB_1_TAG), R.drawable.tab1),
Tab1Container.class, null);
mTabHost.addTab(
setIndicator1(MainActivity.this,
mTabHost.newTabSpec(TAB_2_TAG), R.drawable.tab2),
Tab2Container.class, null);
mTabHost.addTab(
setIndicator1(MainActivity.this,
mTabHost.newTabSpec(TAB_3_TAG), R.drawable.tab3),
Tab3Container.class, null);
mTabHost.getTabWidget().setDividerDrawable(null);
mTabHost.setOnTabChangedListener(MainActivity.this);
}
private TabSpec setIndicator1(Context ctx, TabSpec spec, int genresIcon) {
View v = LayoutInflater.from(ctx).inflate(R.layout.tab_item, null);
ImageView img = (ImageView) v.findViewById(R.id.img_tabtxt);
img.setBackgroundResource(genresIcon);
return spec.setIndicator(v);
}
@Override
public void onTabChanged(String arg0) {
Log.e("tab change string", arg0);
ImageView v1 = (ImageView) mTabHost.getTabWidget().getChildAt(0)
.findViewById(android.R.id.icon);
if (v1 == null) {
Log.e("v1", "null"); // Line
} else {
Log.e("v1", " Not null");
}
if (getResources().getDrawable(R.drawable.tab3) == null) {
Log.e("resource", "null");
} else {
Log.e("resource", "not null");
}
v1.setImageDrawable(getResources().getDrawable(R.drawable.tab3));
ImageView v2 = (ImageView) mTabHost.getTabWidget().getChildAt(1)
.findViewById(android.R.id.icon);
v2.setImageDrawable(getResources().getDrawable(R.drawable.tab1));
ImageView v3 = (ImageView) mTabHost.getTabWidget().getChildAt(2)
.findViewById(android.R.id.icon);
v3.setImageDrawable(getResources().getDrawable(R.drawable.tab2));
}
}
Layout for tab item:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical" >
<ImageView
android:id="@+id/img_tabtxt"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_marginTop="5dp"
android:layout_marginBottom="5dp"
android:layout_centerHorizontal="true" />
</RelativeLayout>
