android not found resource id

问题

i've created a new android project target 8, with default activity

I've assigned an id to textview with text "Hello world".

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

This is the unique activity

package it.prova;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;


public class EmptyActivity extends Activity
{

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    TextView tv = (TextView) findViewById(R.id.tvProva);
    tv.setText("Prova ");
}
}

And this is logcat

02-24 16:09:25.374: ERROR/AndroidRuntime(537): Caused by: java.lang.NullPointerException
02-24 16:09:25.374: ERROR/AndroidRuntime(537):     at      it.prova.EmptyActivity.onCreate(EmptyActivity.java:22)
02-24 16:09:25.374: ERROR/AndroidRuntime(537):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
02-24 16:09:25.374: ERROR/AndroidRuntime(537):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
02-24 16:09:25.374: ERROR/AndroidRuntime(537):     ... 11 more

I'm using sdk r11 and adt v10.

I think there is a problem with resources.

Any idea?

Thanks.

回答1:

have you declared your activity on your manifest.xml ?

Example of declaration of an activity :

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
  package="com.warriorpoint.taxman2"
  android:versionCode="1"
  android:versionName="1.0">
<application android:icon="@drawable/icon" android:label="@string/app_name">
    <activity android:name=".Activity1"
              android:label="@string/app_name">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity android:name=".Activity2"></activity>
</application>
<uses-sdk android:minSdkVersion="3" />
</manifest>

来源：https://stackoverflow.com/questions/5106708/android-not-found-resource-id

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