I was playing around with the galleryview and image switcher, and I decided
to implement a textview that describes my images as I scroll through them. I
created a string array, and added a text view in my layout xml. I then added
the string and textview to my code. I thought I could reuse the position int
from the images to get the right string from my array. However, this
addition causes my app to force close when I try to run it.
I have a feeling that I have totally butchered my working java code and you
may very well cringe at what you are about to see. Apologies. I am learning
:)
If anyone could help me out, I would be most grateful. I have attached my
java code, some probably not relevant xml and my logcat.
Regards,
Mark (Java Abuser)
package com.markopolo.test;
import android.app.Activity;
import android.content.Context;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.AnimationUtils;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.TextView;
import android.widget.Gallery.LayoutParams;
import android.widget.ViewSwitcher.ViewFactory;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.AdapterView.OnItemClickListener;
public class MainMenuActivity extends Activity
implements ViewFactory
{
//---the images to display--
Integer[] imageIDs = {
R.drawable.swan1,
R.drawable.swan2,
R.drawable.swan3,
R.drawable.swan4,
R.drawable.swan5,
R.drawable.swan6 };
Resources res = getResources();
String[] swans = res.getStringArray(R.array.swan);
private ImageSwitcher imageSwitcher;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.displayview);
imageSwitcher = (ImageSwitcher) findViewById(R.id.switcher1);
imageSwitcher.setFactory(this);
imageSwitcher.setInAnimation(AnimationUtils.loadAnimation(this,
android.R.anim.fade_in));
imageSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this,
android.R.anim.fade_out));
Gallery gallery = (Gallery) findViewById(R.id.gallery1);
gallery.setAdapter(new ImageAdapter(this));
gallery.setOnItemClickListener(new OnItemClickListener()
{
public void onItemClick(AdapterView parent,
View v, int position, long id)
{
imageSwitcher.setImageResource(imageIDs[position]);
}
});
}
public View makeView()
{
ImageView imageView = new ImageView(this);
imageView.setBackgroundColor(0xFF000000);
imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);
imageView.setLayoutParams(new
ImageSwitcher.LayoutParams(
LayoutParams.FILL_PARENT,
LayoutParams.FILL_PARENT));
return imageView;
}
public class ImageAdapter extends BaseAdapter
{
private Context context;
private int itemBackground;
public ImageAdapter(Context c)
{
context = c;
//---setting the style---
TypedArray a = obtainStyledAttributes(R.styleable.Gallery1);
itemBackground = a.getResourceId(
R.styleable.Gallery1_android_galleryItemBackground, 0);
a.recycle();
}
//---returns the number of images---
public int getCount()
{
return imageIDs.length;
}
//---returns the ID of an item---
public Object getItem(int position)
{
return position;
}
public long getItemId(int position)
{
return position;
}
//---returns an ImageView and TextView view---
public View getView(int position, View convertView, ViewGroup
parent)
{
ImageView imageView = new ImageView(context);
imageView.setImageResource(imageIDs[position]);
imageView.setScaleType(ImageView.ScaleType.FIT_XY);
imageView.setLayoutParams(new Gallery.LayoutParams(150, 120));
imageView.setBackgroundResource(itemBackground);
TextView textview = (TextView) findViewById(R.id.textview1);
textview.setText(swans[position]);
return imageView;
}
}
}
And arrays.xml:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string-array
name="swan">
<item>swan_1</item>
<item>swan_2</item>
<item>swan_3</item>
<item>swan_4</item>
<item>swan_5</item>
<item>swan_6</item>
<item>swan_7</item>
</string-array>
</resources>
My layout xml:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android";>
<ImageSwitcher
android:id="@+id/switcher1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_alignParentBottom="true"
/>
<Gallery
android:id="@+id/gallery1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="20dip"
/>
<TextView
android:id="@+id/textview1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="10dip"
android:layout_gravity="center_horizontal|bottom"
/>
</FrameLayout>
And here is my logcat:
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): FATAL EXCEPTION: main
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): java.lang.RuntimeException:
Unable to instantiate activity
ComponentInfo{com.markopolo.test/com.markopolo.test.MainMenuActivity}:
java.lang.NullPointerException
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): at
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2585)
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): at
android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): at
android.app.ActivityThread.access$2300(ActivityThread.java:125)
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): at
android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): at
android.os.Handler.dispatchMessage(Handler.java:99)
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): at
android.os.Looper.loop(Looper.java:123)
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): at
android.app.ActivityThread.main(ActivityThread.java:4627)
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): at
java.lang.reflect.Method.invokeNative(Native Method)
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): at
java.lang.reflect.Method.invoke(Method.java:521)
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): at
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): at
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): at
dalvik.system.NativeStart.main(Native Method)
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): Caused by:
java.lang.NullPointerException
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): at
android.content.ContextWrapper.getResources(ContextWrapper.java:80)
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): at
com.markopolo.test.MainMenuActivity.<init>(MainMenuActivity.java:36)
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): at
java.lang.Class.newInstanceImpl(Native Method)
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): at
java.lang.Class.newInstance(Class.java:1429)
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): at
android.app.Instrumentation.newActivity(Instrumentation.java:1021)
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): at
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2577)
03-11 02:00:59.288: ERROR/AndroidRuntime(12636): ... 11 more
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