Spoonface Spoonface - 5 months ago 46
Android Question

Loading a TextView from xml into a TextSwitcher

I've been trying to setup a TextSwitcher with the TextView loading in from an xml file. I have this basic TextSwitcher example that uses an empty TextView working ok:

.java

public class TextSwitcherTest extends Activity
{
private TextSwitcher textSwitcher;

private ViewFactory viewFactory = new ViewFactory()
{
public View makeView()
{
TextView textView = new TextView(TextSwitcherTest.this);

return textView;
}
};

@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);

setContentView(R.layout.main);

textSwitcher = (TextSwitcher) findViewById(R.id.textSwitcher);

textSwitcher.setFactory(viewFactory);

Animation in = AnimationUtils.loadAnimation(this,android.R.anim.fade_in);
Animation out = AnimationUtils.loadAnimation(this,android.R.anim.fade_out);

textSwitcher.setInAnimation(in);
textSwitcher.setOutAnimation(out);

textSwitcher.setText("test ok");
}
}


-

main.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >

<TextSwitcher
android:id="@+id/textSwitcher"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />

</LinearLayout>





But when I change the code to try and load a TextView from an xml file, it spits out a pile of errors. Here's the amended code:

.java

public class TextSwitcherTest extends Activity
{
private TextSwitcher textSwitcher;

private ViewFactory viewFactory = new ViewFactory()
{
public View makeView()
{
LayoutInflater inflater = LayoutInflater.from(TextSwitcherTest.this);

TextView textView = (TextView) inflater.inflate(R.id.textView,null);

return textView;
}
};

@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);

setContentView(R.layout.main);

textSwitcher = (TextSwitcher) findViewById(R.id.textSwitcher);

textSwitcher.setFactory(viewFactory);

Animation in = AnimationUtils.loadAnimation(this,android.R.anim.fade_in);
Animation out = AnimationUtils.loadAnimation(this,android.R.anim.fade_out);

textSwitcher.setInAnimation(in);
textSwitcher.setOutAnimation(out);

textSwitcher.setText("test ok");
}
}


-

textview.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<TextView
android:id="@+id/textView"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello" />

</LinearLayout>


Can anyone offer a suggestion where I'm going wrong? The code compiles ok but I'm sure it's with the LayoutInflater being misused in some way?




error messages (it didn't display the '11 more'):

07-22 03:51:24.096: W/dalvikvm(580): threadid=1: thread exiting with uncaught exception (group=0x409c01f8)
07-22 03:51:24.137: E/AndroidRuntime(580): FATAL EXCEPTION: main
07-22 03:51:24.137: E/AndroidRuntime(580): java.lang.RuntimeException: Unable to start activity ComponentInfo{test09.TextSwitcher01/test09.TextSwitcher01.TextSwitcherTest}: android.content.res.Resources$NotFoundException: Resource ID #0x7f050001 type #0x12 is not valid
07-22 03:51:24.137: E/AndroidRuntime(580): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956)
07-22 03:51:24.137: E/AndroidRuntime(580): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
07-22 03:51:24.137: E/AndroidRuntime(580): at android.app.ActivityThread.access$600(ActivityThread.java:123)
07-22 03:51:24.137: E/AndroidRuntime(580): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
07-22 03:51:24.137: E/AndroidRuntime(580): at android.os.Handler.dispatchMessage(Handler.java:99)
07-22 03:51:24.137: E/AndroidRuntime(580): at android.os.Looper.loop(Looper.java:137)
07-22 03:51:24.137: E/AndroidRuntime(580): at android.app.ActivityThread.main(ActivityThread.java:4424)
07-22 03:51:24.137: E/AndroidRuntime(580): at java.lang.reflect.Method.invokeNative(Native Method)
07-22 03:51:24.137: E/AndroidRuntime(580): at java.lang.reflect.Method.invoke(Method.java:511)
07-22 03:51:24.137: E/AndroidRuntime(580): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
07-22 03:51:24.137: E/AndroidRuntime(580): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
07-22 03:51:24.137: E/AndroidRuntime(580): at dalvik.system.NativeStart.main(Native Method)
07-22 03:51:24.137: E/AndroidRuntime(580): Caused by: android.content.res.Resources$NotFoundException: Resource ID #0x7f050001 type #0x12 is not valid
07-22 03:51:24.137: E/AndroidRuntime(580): at android.content.res.Resources.loadXmlResourceParser(Resources.java:2110)
07-22 03:51:24.137: E/AndroidRuntime(580): at android.content.res.Resources.getLayout(Resources.java:857)
07-22 03:51:24.137: E/AndroidRuntime(580): at android.view.LayoutInflater.inflate(LayoutInflater.java:394)
07-22 03:51:24.137: E/AndroidRuntime(580): at android.view.LayoutInflater.inflate(LayoutInflater.java:352)
07-22 03:51:24.137: E/AndroidRuntime(580): at test09.TextSwitcher01.TextSwitcherTest$1.makeView(TextSwitcherTest.java:23)
07-22 03:51:24.137: E/AndroidRuntime(580): at android.widget.ViewSwitcher.obtainView(ViewSwitcher.java:80)
07-22 03:51:24.137: E/AndroidRuntime(580): at android.widget.ViewSwitcher.setFactory(ViewSwitcher.java:99)
07-22 03:51:24.137: E/AndroidRuntime(580): at test09.TextSwitcher01.TextSwitcherTest.onCreate(TextSwitcherTest.java:38)
07-22 03:51:24.137: E/AndroidRuntime(580): at android.app.Activity.performCreate(Activity.java:4465)
07-22 03:51:24.137: E/AndroidRuntime(580): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
07-22 03:51:24.137: E/AndroidRuntime(580): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
07-22 03:51:24.137: E/AndroidRuntime(580): ... 11 more

Answer

There are several things wrong with your code:

First, the LayoutInflater.inflate() method expects the id of a layout file in the form of R.layout.layout_name and not in the form of R.id.some_id:

TextView textView = (TextView) inflater.inflate(R.layout.textView, null);

Second, the code you use will throw a ClassCastException because the root of the inflated layout is a LinearLayout and not a TextView as you try to cast it. Your code should be:

LinearLayout ll = (Linearlayout) inflater.inflate(R.layout.textView, null);

But even the line above will not work because, as its name suggest, a TextSwitcher will take only children of type TextView, nothing can come between the TextSwitcher and the two TextView children. The correct code to use will be in the end:

Layout for textview.xml:

<?xml version="1.0" encoding="utf-8"?>
<TextView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/textView"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/hello" />

And the viewFactory field will be:

private ViewFactory viewFactory = new ViewFactory() {
        public View makeView()  {
            LayoutInflater inflater = LayoutInflater.from(TextSwitcherTest.this);
            TextView textView = (TextView) inflater.inflate(R.layout.textView, null);
            return textView;
        }
};