I've been trying to crack this all day reading many many posts and tutorials etc and I'm 0% closer to solving it. I think theres a high chance of a more experienced coder cracking it easily so posting it in the hope someone will correct it and other noobs will see it.
I have a simple button bagButton that when pressed should transition from MainActivity to BagActivity
On launch of the app it stops and I never get a chance to see it run let alone press the button.
When I take out this code the app runs fine (but obviously does not transition):
Button b = (Button)findViewById(R.id.buttonBag);
b.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent i = new Intent(MainActivity.this, BagActivity.class);
startActivity(i);
}
});
The greater MainActivity.java code is:
package nz.co.gamekeeper;
import android.support.v7.app.ActionBarActivity;
import android.support.v4.app.Fragment;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
public class MainActivity extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button b = (Button)findViewById(R.id.buttonBag);
b.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent i = new Intent(MainActivity.this, BagActivity.class);
startActivity(i);
}
});
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment())
.commit();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
return rootView;
}
}
}
The logcat output is as follows:
05-11 16:45:02.494: I/Process(1437): Sending signal. PID: 1437 SIG: 9
05-11 16:46:12.599: D/AndroidRuntime(2028): Shutting down VM
05-11 16:46:12.599: W/dalvikvm(2028): threadid=1: thread exiting with uncaught exception (group=0x4182b2a0)
05-11 16:46:12.599: E/AndroidRuntime(2028): FATAL EXCEPTION: main
05-11 16:46:12.599: E/AndroidRuntime(2028): java.lang.RuntimeException: Unable to start activity ComponentInfo{nz.co.gamekeeper/nz.co.gamekeeper.MainActivity}: java.lang.NullPointerException
05-11 16:46:12.599: E/AndroidRuntime(2028): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2110)
05-11 16:46:12.599: E/AndroidRuntime(2028): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2135)
05-11 16:46:12.599: E/AndroidRuntime(2028): at android.app.ActivityThread.access$700(ActivityThread.java:140)
05-11 16:46:12.599: E/AndroidRuntime(2028): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1237)
05-11 16:46:12.599: E/AndroidRuntime(2028): at android.os.Handler.dispatchMessage(Handler.java:99)
05-11 16:46:12.599: E/AndroidRuntime(2028): at android.os.Looper.loop(Looper.java:137)
05-11 16:46:12.599: E/AndroidRuntime(2028): at android.app.ActivityThread.main(ActivityThread.java:4921)
05-11 16:46:12.599: E/AndroidRuntime(2028): at java.lang.reflect.Method.invokeNative(Native Method)
05-11 16:46:12.599: E/AndroidRuntime(2028): at java.lang.reflect.Method.invoke(Method.java:511)
05-11 16:46:12.599: E/AndroidRuntime(2028): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
05-11 16:46:12.599: E/AndroidRuntime(2028): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794)
05-11 16:46:12.599: E/AndroidRuntime(2028): at dalvik.system.NativeStart.main(Native Method)
05-11 16:46:12.599: E/AndroidRuntime(2028): Caused by: java.lang.NullPointerException
05-11 16:46:12.599: E/AndroidRuntime(2028): at nz.co.gamekeeper.MainActivity.onCreate(MainActivity.java:35)
05-11 16:46:12.599: E/AndroidRuntime(2028): at android.app.Activity.performCreate(Activity.java:5206)
05-11 16:46:12.599: E/AndroidRuntime(2028): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
05-11 16:46:12.599: E/AndroidRuntime(2028): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2074)
05-11 16:46:12.599: E/AndroidRuntime(2028): ... 11 more
The XML has two parts activity_main.xml:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="nz.co.gamekeeper.MainActivity"
tools:ignore="MergeRootFrame" />
And its fragment_main.xml:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:baselineAligned="false"
android:orientation="vertical"
tools:context="nz.co.gamekeeper.MainActivity$PlaceholderFragment" >
<TableRow
android:id="@+id/tableRow1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" >
<Button
android:id="@+id/buttonBag"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/button_text_bag" />
<Button
android:id="@+id/buttonSeason"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/button_text_season" />
</TableRow>
<TableRow
android:id="@+id/tableRow2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" >
<Button
android:id="@+id/buttonMates"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/button_text_mates" />
<Button
android:id="@+id/buttonBirds"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/button_text_birds" />
</TableRow>
<TableRow
android:id="@+id/tableRow3"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" >
<Button
android:id="@+id/buttonSetup"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/button_text_setup" />
<Button
android:id="@+id/buttonSync"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/button_text_sync" />
</TableRow>
<TableRow
android:id="@+id/tableRow4"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1" >
<Button
android:id="@+id/buttonSpare1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/button_text_spare1" />
<Button
android:id="@+id/buttonSpare2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/button_text_spare2" />
</TableRow>
</LinearLayout>
I've tried cleaning it, restarting Eclipse, getting a better idea of the error by adding logs, trying different Intent args, making sure manifest is ok, plus loads more...
Can anyone shed light on what I might try?