Application Android impossible de démarrer l'activité componentinfo
Je suis un nouvel Android programmeur et récemment, un grand nombre de mes projets ont été faire cette erreur:
07-31 23:45:19.592: ERROR/AndroidRuntime(716): java.lang.RuntimeException: Unable to start
activity ComponentInfo{com.amrit.musifind/com.amrit.musifind.Main}:
java.lang.NullPointerExceptionQuelqu'un peut-il m'aider à résoudre ce problème?
Voici l'intégralité de logcat trace de la pile:
07-31 23:45:18.512: INFO/ActivityManager(63): Starting activity: Intent {
act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000
cmp=com.amrit.musifind/.Main }
07-31 23:45:18.682: INFO/ActivityManager(63): Start proc com.amrit.musifind for activity
com.amrit.musifind/.Main: pid=716 uid=10025 gids={3003}
07-31 23:45:18.962: INFO/jdwp(716): received file descriptor 20 from ADB
07-31 23:45:19.102: DEBUG/ddm-heap(716): Got feature list request
07-31 23:45:19.572: DEBUG/AndroidRuntime(716): Shutting down VM
07-31 23:45:19.572: WARN/dalvikvm(716): threadid=3: thread exiting with uncaught
exception (group=0x4001aa28)
07-31 23:45:19.572: ERROR/AndroidRuntime(716): Uncaught handler: thread main exiting due
to uncaught exception
07-31 23:45:19.592: ERROR/AndroidRuntime(716): java.lang.RuntimeException: Unable to
start activity ComponentInfo{com.amrit.musifind/com.amrit.musifind.Main}:
java.lang.NullPointerException
07-31 23:45:19.592: ERROR/AndroidRuntime(716): at
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2401)
07-31 23:45:19.592: ERROR/AndroidRuntime(716): at
android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2417)
07-31 23:45:19.592: ERROR/AndroidRuntime(716): at
android.app.ActivityThread.access$2100(ActivityThread.java:116)
07-31 23:45:19.592: ERROR/AndroidRuntime(716): at
android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794)
07-31 23:45:19.592: ERROR/AndroidRuntime(716): at
android.os.Handler.dispatchMessage(Handler.java:99)
07-31 23:45:19.592: ERROR/AndroidRuntime(716): at
android.os.Looper.loop(Looper.java:123)
07-31 23:45:19.592: ERROR/AndroidRuntime(716): at
android.app.ActivityThread.main(ActivityThread.java:4203)
07-31 23:45:19.592: ERROR/AndroidRuntime(716): at
java.lang.reflect.Method.invokeNative(Native Method)
07-31 23:45:19.592: ERROR/AndroidRuntime(716): at
java.lang.reflect.Method.invoke(Method.java:521)
07-31 23:45:19.592: ERROR/AndroidRuntime(716): at
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791)
07-31 23:45:19.592: ERROR/AndroidRuntime(716): at
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:549)
07-31 23:45:19.592: ERROR/AndroidRuntime(716): at
dalvik.system.NativeStart.main(Native Method)
07-31 23:45:19.592: ERROR/AndroidRuntime(716): Caused by: java.lang.NullPointerException
07-31 23:45:19.592: ERROR/AndroidRuntime(716): at
com.amrit.musifind.Main.onCreate(Main.java:44)
07-31 23:45:19.592: ERROR/AndroidRuntime(716): at
android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1123)
07-31 23:45:19.592: ERROR/AndroidRuntime(716): at
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2364)
07-31 23:45:19.592: ERROR/AndroidRuntime(716): ... 11 more
07-31 23:45:19.612: INFO/Process(63): Sending signal. PID: 716 SIG: 3
07-31 23:45:19.612: INFO/dalvikvm(716): threadid=7: reacting to signal 3
07-31 23:45:19.642: INFO/dalvikvm(716): Wrote stack trace to '/data/anr/traces.txt'
07-31 23:45:21.422: INFO/Process(716): Sending signal. PID: 716 SIG: 9
07-31 23:45:21.442: INFO/ActivityManager(63): Process com.amrit.musifind (pid 716) has
died.
07-31 23:45:21.583: WARN/UsageStats(63): Unexpected resume of com.android.launcher while
already resumed in com.amrit.musifind
07-31 23:45:21.712: WARN/InputManagerService(63): Window already focused, ignoring focus
gain of: com.android.internal.view.IInputMethodClient$Stub$Proxy@439559d0
07-31 23:45:23.482: DEBUG/AndroidRuntime(725): >>>>>>>>>>>>>> AndroidRuntime START
<<<<<<<<<<<<<<
07-31 23:45:23.482: DEBUG/AndroidRuntime(725): CheckJNI is ON
07-31 23:45:23.812: DEBUG/AndroidRuntime(725): --- registering native functions ---
07-31 23:45:23.832: INFO/jdwp(725): received file descriptor 20 from ADB
07-31 23:45:24.193: DEBUG/ddm-heap(725): Got feature list request
07-31 23:45:25.052: DEBUG/AndroidRuntime(725): Shutting down VM
07-31 23:45:25.052: DEBUG/dalvikvm(725): DestroyJavaVM waiting for non-daemon threads to
exit
07-31 23:45:25.062: DEBUG/dalvikvm(725): DestroyJavaVM shutting VM down
07-31 23:45:25.062: DEBUG/dalvikvm(725): HeapWorker thread shutting down
07-31 23:45:25.062: DEBUG/dalvikvm(725): HeapWorker thread has shut down
07-31 23:45:25.073: DEBUG/jdwp(725): JDWP shutting down net...
07-31 23:45:25.073: DEBUG/jdwp(725): +++ peer disconnected
07-31 23:45:25.073: INFO/dalvikvm(725): Debugger has detached; object registry had 1
entries
07-31 23:45:25.093: DEBUG/dalvikvm(725): VM cleaning up
07-31 23:45:25.113: DEBUG/dalvikvm(725): LinearAlloc 0x0 used 665652 of 4194304 (15%)
07-31 23:47:22.712: DEBUG/dalvikvm(104): GC freed 9173 objects / 524184 bytes in 149msHeres la 1ère activité: start.java
package com.amrit.musifind;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import com.amrit.musifind.R;
import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public abstract class start extends Activity implements OnClickListener {
Button buttonGo, buttonReset;
EditText EditTextinput;
String input = "";
String ur = "http://www.tastekid.com/ask/ws?q=";
String l = "&f=musifin2125&k=mjjlnzkyzwuz&format=JSON";
String url = "" ;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
buttonGo = (Button) findViewById(R.id.buttonGo);
buttonReset = (Button) findViewById(R.id.buttonReset);
EditTextinput = (EditText) findViewById(R.id.EditTextinput);
//Button listener
buttonReset.setOnClickListener(this);
buttonGo.setOnClickListener(this);
}
public void onClick (View src){
switch(src.getId()){
case R.id.buttonGo:
input = EditTextinput.getText().toString();
url = ur + input + l ;
Intent Main = new Intent(this,
ToClass.class);
Main.putExtra("userurl", url);
startActivity(Main);
break;
case R.id.buttonReset:
EditTextinput.setText("");
break;
}
}
}La deuxième activité: Main.java
package com.amrit.musifind;
import java.util.ArrayList;
import java.util.HashMap;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import com.amrit.musifind.JSONfunctions;
import com.amrit.musifind.R;
import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class Main extends ListActivity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.listplaceholder);
Intent intent = getIntent();
String url = intent.getExtras().getString("userurl");
ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>
();
JSONObject json = JSONfunctions.getJSONfromURL(url);
try{
JSONObject earthquakes = json.getJSONObject("Similar");
JSONArray info = earthquakes.getJSONArray("Results");
for (int i = 0; i < info.length(); i++) {
HashMap<String, String> map = new HashMap<String, String>();
JSONObject e = info.getJSONObject(i);
map.put("id", String.valueOf(i));
map.put("name", "Name:" + e.getString("Name"));
map.put("type", "Type: " + e.getString("Type"));
mylist.add(map);
}
JSONArray results = json.getJSONArray("Results");
for(int i=0;i<results.length();i++){
HashMap<String, String> map = new HashMap<String, String>();
JSONObject e = results.getJSONObject(i);
map.put("id", String.valueOf(i));
map.put("name", "Name:" + e.getString("name"));
map.put("type", "Type: " + e.getString("type"));
mylist.add(map);
}
}catch(JSONException e) {
Log.e("log_tag", "Error parsing data "+e.toString());
}
ListAdapter adapter = new SimpleAdapter(this, mylist , R.layout.main,
new String[] { "name", "type" },
new int[] { R.id.item_title, R.id.item_subtitle });
setListAdapter(adapter);
final ListView lv = getListView();
lv.setTextFilterEnabled(true);
lv.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view, int position, long
id) {
@SuppressWarnings("unchecked")
HashMap<String, String> o = (HashMap<String, String>)
lv.getItemAtPosition(position);
Toast.makeText(Main.this, "ID '" + o.get("id") + "' was clicked.",
Toast.LENGTH_SHORT).show();
}
});
}
}Enfin, mon fichier manifeste: AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.amrit.musifind"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="4" />
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".start"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.start" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name= ".Main"
>
<intent-filter>
<action android:name="android.intent.action.Main" />
</intent-filter>
</activity>
</application>
<uses-permission android:name="android.permission.INTERNET" />
</manifest>Toute aide est très appréciée, sans la résolution de ce problème je ne peux pas tester mon appli!
- pourriez-vous s'il vous plaît poster la trace de la pile complète?
- Comment dois-je faire? Désolé, je suis très nouveau pour android 🙂
- Vous pouvez trouver la pile d'appel dans le logcat de sortie. Vous avez déjà compris dès le début de votre post (celui avec l'exception de pointeur null).
- Ok, je pense que je l'ai ajouté.
- J'ai eu ce quand j'ai essayé d'attribuer un écouteur de clics avant de définir un contenu de la vue, de sorte que si une vue.setOnClickListener apparaît avant le setContentView appel pour configurer l'affichage, vous obtiendrez cette erreur, si votre code n'a que trop alors il suffit de changer l'ordre pour définir le point de vue d'abord, puis attribuer les auditeurs.
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Votre pointeur null exception semble être sur cette ligne:
parce que
intent.getExtras()renvoie la valeur null lorsque l'intention n'est pas d'extras.Vous vous rendez compte que ce morceau de code:
n'est pas le début de l'activité que vous avez écrit Main.java il tente de démarrer une activité appelée
ToClasset si cela n'existe pas, votre application se bloque.Aussi, il n'y a pas une telle chose comme
"android.intent.action.start"donc le manifeste doit ressembler à:J'espère que cela résout certains des problèmes que vous rencontrez mais je vous suggère fortement de consulter certains "prise en main" des tutoriels pour android de développement et de construire à partir de là.