Problème nullpointer android
Bonjour à tous!
Alors voilà je suis actuellement en train de réaliser une application sur android mais j'éprouve quelques difficultés. Mon problème est que quand j'essaye de récupérer un composant à l'intérieur d'un layout en xml et que j'y applique une de ses méthode, j'obtiens tout simplement une exception.
Avec le code ci-dessous:
Code:
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public class WiFileManagerActivity extends Activity{
public static final int DIALOG_STARTED = 0;
public static final int DIALOG_EXITED = 1;
public static final int DIALOG_HOST_NOT_FOUND= 2;
private ServerInstance serverInstance;
private static LookingForHostView lfhv;
private CustomHostLoader cusDial = null;
private Void v;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
showDialog(DIALOG_STARTED);
lfhv = new LookingForHostView(this.getApplicationContext(), this);
setContentView(lfhv);
serverInstance = new ServerInstance(this);
serverInstance.execute(v);
}
@Override
protected Dialog onCreateDialog(int id) {
switch(id) {
case DIALOG_STARTED:
cusDial = new CustomHostLoader(this);
break;
case DIALOG_EXITED:
break;
case DIALOG_HOST_NOT_FOUND:
break;
}
return cusDial;
}
public void closeCustomHostLoaderDialog(){
if(cusDial != null){
cusDial.cancel();
}
}
} |
Code:
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public class CustomHostLoader extends Dialog implements OnClickListener{
private TextView hostTv;
private ImageButton helpButton;
public CustomHostLoader(Activity parentActivity) {
super(parentActivity);
setContentView(R.layout.host_loader);
hostTv = (TextView) parentActivity.findViewById(R.id.hostTv);
//Ici l'exception est déclenchée
hostTv.getText();
}
public TextView getHostTv(){
return hostTv;
}
@Override
public void onClick(View arg0) {
Log.i("ProgLog", "Yahoo");
}
} |
host_loader.xml
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<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/layout_root"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal"
android:padding="10dp" >
<ProgressBar
android:id="@+id/progressBar1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"/>
<TextView
android:id="@+id/hostTv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="@+id/progressBar1"
android:layout_toRightOf="@+id/progressBar1"
android:layout_marginTop="18dp"
android:layout_marginLeft="10dp"
android:text="Looking for host. Please wait..." />
<EditText
android:id="@+id/editText1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/progressBar1"
android:layout_alignRight="@+id/hostTv"
android:layout_below="@+id/progressBar1"
android:layout_marginTop="18dp"
android:inputType="textPersonName" >
</EditText>
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/editText1"
android:layout_alignRight="@+id/editText1"
android:layout_below="@+id/editText1"
android:text="Use this IP as host IP" />
<ImageButton
android:id="@+id/helpButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/button1"
android:layout_alignTop="@+id/hostTv"
android:layout_toRightOf="@+id/hostTv"
android:src="@drawable/help" />
</RelativeLayout> |
J'obtiens:
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| 12-11 01:19:06.720: E/AndroidRuntime(23834): FATAL EXCEPTION: main
12-11 01:19:06.720: E/AndroidRuntime(23834): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.wifilemanager.client/com.wifilemanager.client.activity.WiFileManagerActivity}: java.lang.NullPointerException
12-11 01:19:06.720: E/AndroidRuntime(23834): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1815)
12-11 01:19:06.720: E/AndroidRuntime(23834): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1831)
12-11 01:19:06.720: E/AndroidRuntime(23834): at android.app.ActivityThread.access$500(ActivityThread.java:122)
12-11 01:19:06.720: E/AndroidRuntime(23834): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1024)
12-11 01:19:06.720: E/AndroidRuntime(23834): at android.os.Handler.dispatchMessage(Handler.java:99)
12-11 01:19:06.720: E/AndroidRuntime(23834): at android.os.Looper.loop(Looper.java:132)
12-11 01:19:06.720: E/AndroidRuntime(23834): at android.app.ActivityThread.main(ActivityThread.java:4123)
12-11 01:19:06.720: E/AndroidRuntime(23834): at java.lang.reflect.Method.invokeNative(Native Method)
12-11 01:19:06.720: E/AndroidRuntime(23834): at java.lang.reflect.Method.invoke(Method.java:491)
12-11 01:19:06.720: E/AndroidRuntime(23834): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
12-11 01:19:06.720: E/AndroidRuntime(23834): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
12-11 01:19:06.720: E/AndroidRuntime(23834): at dalvik.system.NativeStart.main(Native Method)
12-11 01:19:06.720: E/AndroidRuntime(23834): Caused by: java.lang.NullPointerException
12-11 01:19:06.720: E/AndroidRuntime(23834): at com.wifilemanager.client.dialog.CustomHostLoader.<init>(CustomHostLoader.java:29)
12-11 01:19:06.720: E/AndroidRuntime(23834): at com.wifilemanager.client.activity.WiFileManagerActivity.onCreateDialog(WiFileManagerActivity.java:46)
12-11 01:19:06.720: E/AndroidRuntime(23834): at android.app.Activity.onCreateDialog(Activity.java:2758)
12-11 01:19:06.720: E/AndroidRuntime(23834): at android.app.Activity.createDialog(Activity.java:936)
12-11 01:19:06.720: E/AndroidRuntime(23834): at android.app.Activity.showDialog(Activity.java:2851)
12-11 01:19:06.720: E/AndroidRuntime(23834): at android.app.Activity.showDialog(Activity.java:2810)
12-11 01:19:06.720: E/AndroidRuntime(23834): at com.wifilemanager.client.activity.WiFileManagerActivity.onCreate(WiFileManagerActivity.java:33)
12-11 01:19:06.720: E/AndroidRuntime(23834): at android.app.Activity.performCreate(Activity.java:4397)
12-11 01:19:06.720: E/AndroidRuntime(23834): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1048)
12-11 01:19:06.720: E/AndroidRuntime(23834): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1779)
12-11 01:19:06.720: E/AndroidRuntime(23834): ... 11 more |
Quelqu'un saurait comment résoudre ce problème? Ce que je cherche à faire est simple en fait, c'est de pouvoir récupérer des composants de mon layout host_loader.xml dans le code java de ma classe CustomHostLoader et ainsi les modifier à ma guise, comme faire un hostTv.setText("Hello world!") par exemple. Merci d'avance
