android - 应用程序不适用于 Android 4.0.3，但适用于 Android 2.3.4

Question

我有一个应用程序可以在 Android 2.3.4(模拟器/手机)上完美运行。但我试图将它安装在 Android 4.0.3(模拟器/手机)上，当我运行它时它不工作。它向我展示了这条消息

"Unfortunately AppName has stopped"

当应用程序执行这些类时出现错误:

public class EmpleadosAct extends Activity {

private ArrayList<String> datos;
private ListView list;

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    ActualizarVehiculos();

}

public void ActualizarVehiculos() {

    try {
        NotesCenter messageCenter = new NotesCenterImpl();

        List<Vehiculo> vehiculo = messageCenter.getVehiculo();

        for (Vehiculo v : vehiculo) {
            AndroidOpenDbHelper androidOpenDbHelperObj = new AndroidOpenDbHelper(
                    this);

            SQLiteDatabase sqliteDatabase = androidOpenDbHelperObj
                    .getWritableDatabase();

            ContentValues contentValues = new ContentValues();
            contentValues.put(AndroidOpenDbHelper.matricula, v.matricula);

            long affectedColumnId = sqliteDatabase.insert("Vehiculos",
                    null, contentValues);
            sqliteDatabase.close();
        }
    } catch (Exception ex) {
        Log.v("blah", ex.getMessage());

    }

}
}

第二类:

public class SeleccionarEmpleado extends Activity implements OnClickListener,
OnItemClickListener {

private ListView listaEmpleados;
private EditText ECont;
String text;
Bundle dataBundle;
public EmpleadosAct actemple;
protected AppApplication app;

private ListAdapter uGraduateListAdapter;

private ArrayList<UndergraduateDetailsPojo> pojoArrayList;
private String contraseña;

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

    ***Intent actServicios = new Intent(this, EmpleadosAct.class);
    startActivity(actServicios);***

    listaEmpleados = (ListView) findViewById(R.id.ListaEmpleados);
    listaEmpleados.setOnItemClickListener(this);

    pojoArrayList = new ArrayList<UndergraduateDetailsPojo>();

    uGraduateListAdapter = new ArrayAdapter<String>(this,
            android.R.layout.simple_list_item_1, populateList());

    listaEmpleados.setAdapter(uGraduateListAdapter);

}

public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater menuInflater = getMenuInflater();
    menuInflater.inflate(R.menu.menu, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {

    switch (item.getItemId()) {
    case R.id.actualizar:
        //Intent actualizarEmpleados = new Intent(this,EmpleadosAct.class);
        //startActivity(actualizarEmpleados);


        //return true;

    case R.id.opciones:
        Toast.makeText(SeleccionarEmpleado.this, "Save is Selected",
                Toast.LENGTH_SHORT).show();
        return true;

    default:
        return super.onOptionsItemSelected(item);
    }
}

public void onClick(View v) {
    Intent addNewUndergraduateIntent = new Intent(this,
            InsertarPedido.class);
    startActivity(addNewUndergraduateIntent);
}

public List<String> populateList() {

    List<String> uGraduateNamesList = new ArrayList<String>();

    AndroidOpenDbHelper openHelperClass = new AndroidOpenDbHelper(this);

    SQLiteDatabase sqliteDatabase = openHelperClass.getReadableDatabase();

    Cursor cursor = sqliteDatabase.query("Empleados", null, null, null,
            null, null, null);

    startManagingCursor(cursor);

    while (cursor.moveToNext()) {

        String idempleado = cursor.getString(cursor
                .getColumnIndex(AndroidOpenDbHelper.idempleado));
        String nombre = cursor.getString(cursor
                .getColumnIndex(AndroidOpenDbHelper.nombre));
        String primerapellido = cursor.getString(cursor
                .getColumnIndex(AndroidOpenDbHelper.primerapellido));
        String segundoapellido = cursor.getString(cursor
                .getColumnIndex(AndroidOpenDbHelper.segundoapellido));
        String contra = cursor.getString(cursor
                .getColumnIndex(AndroidOpenDbHelper.contra));

        UndergraduateDetailsPojo ugPojoClass = new UndergraduateDetailsPojo();
        ugPojoClass.setIdEmpleado(idempleado);
        ugPojoClass.setNombreEmpleado(nombre);
        ugPojoClass.setPrimerApellido(primerapellido);
        ugPojoClass.setSegundoApellido(segundoapellido);
        ugPojoClass.setContra(contra);

        pojoArrayList.add(ugPojoClass);

        uGraduateNamesList.add(nombre + " " + primerapellido + " "
                + segundoapellido);
    }

    sqliteDatabase.close();

    return uGraduateNamesList;
}

@Override
protected void onResume() {
    super.onResume();
    uGraduateListAdapter = new ArrayAdapter(this,
            android.R.layout.simple_list_item_1, populateList());
    listaEmpleados.setAdapter(uGraduateListAdapter);
}

public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {

    UndergraduateDetailsPojo clickedObject = pojoArrayList.get(arg2);

    String Empleado = clickedObject.getNombreEmpleado() + " "
            + clickedObject.getPrimerApellido() + " "
            + clickedObject.getSegundoApellido();

    Empleado empleadoseleccionado = new Empleado();
    empleadoseleccionado.id = clickedObject.getIdEmpleado();
    empleadoseleccionado.nombre = Empleado;
    app = (AppApplication)getApplicationContext();
    app.setempleadoActual(empleadoseleccionado);
    app.setempleadoId(empleadoseleccionado);

}
}

一开始是在执行第二个类，在第二个类中有一个打开第一个类的Intent。第一类从某个远程服务器向 android SQLite 数据库添加数据。然后第二个类显示来自 android SQLite 数据库的结果。

这是日志:

06-04 21:08:13.034: W/dalvikvm(517): threadid=1: thread exiting with uncaught exception    (group=0x409c01f8)
06-04 21:08:13.054: E/AndroidRuntime(517): FATAL EXCEPTION: main
06-04 21:08:13.054: E/AndroidRuntime(517): java.lang.RuntimeException: Unable to start  activity ComponentInfo{dokesim.net/myapp.net.EmpleadosAct}: java.lang.NullPointerException:  println needs a message
06-04 21:08:13.054: E/AndroidRuntime(517):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956)
06-04 21:08:13.054: E/AndroidRuntime(517):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
06-04 21:08:13.054: E/AndroidRuntime(517):  at android.app.ActivityThread.access$600(ActivityThread.java:123)
06-04 21:08:13.054: E/AndroidRuntime(517):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
06-04 21:08:13.054: E/AndroidRuntime(517):  at android.os.Handler.dispatchMessage(Handler.java:99)
06-04 21:08:13.054: E/AndroidRuntime(517):  at android.os.Looper.loop(Looper.java:137)
06-04 21:08:13.054: E/AndroidRuntime(517):  at android.app.ActivityThread.main(ActivityThread.java:4424)
06-04 21:08:13.054: E/AndroidRuntime(517):  at java.lang.reflect.Method.invokeNative(Native Method)
06-04 21:08:13.054: E/AndroidRuntime(517):  at java.lang.reflect.Method.invoke(Method.java:511)
06-04 21:08:13.054: E/AndroidRuntime(517):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
06-04 21:08:13.054: E/AndroidRuntime(517):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
06-04 21:08:13.054: E/AndroidRuntime(517):  at dalvik.system.NativeStart.main(Native Method)
06-04 21:08:13.054: E/AndroidRuntime(517): Caused by: java.lang.NullPointerException: println needs a message
06-04 21:08:13.054: E/AndroidRuntime(517):  at android.util.Log.println_native(Native Method)
06-04 21:08:13.054: E/AndroidRuntime(517):  at android.util.Log.v(Log.java:117)
06-04 21:08:13.054: E/AndroidRuntime(517):  at myapp.net.EmpleadosAct.ActualizarVehiculos(EmpleadosAct.java:133)
06-04 21:08:13.054: E/AndroidRuntime(517):  at    myapp.net.EmpleadosAct.onCreate(EmpleadosAct.java:24)
06-04 21:08:13.054: E/AndroidRuntime(517):  at android.app.Activity.performCreate(Activity.java:4465)
06-04 21:08:13.054: E/AndroidRuntime(517):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
06-04 21:08:13.054: E/AndroidRuntime(517):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
06-04 21:08:13.054: E/AndroidRuntime(517):  ... 11 more

第二个日志:

06-04 21:40:03.225: V/blah(720): Error happened: 
06-04 21:40:03.225: V/blah(720): android.os.NetworkOnMainThreadException
06-04 21:40:03.225: V/blah(720):    at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1099)
06-04 21:40:03.225: V/blah(720):    at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84)
06-04 21:40:03.225: V/blah(720):    at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
06-04 21:40:03.225: V/blah(720):    at libcore.io.IoBridge.connect(IoBridge.java:112)
06-04 21:40:03.225: V/blah(720):    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
06-04 21:40:03.225: V/blah(720):    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)
06-04 21:40:03.225: V/blah(720):    at java.net.Socket.connect(Socket.java:842)
06-04 21:40:03.225: V/blah(720):    at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119)
06-04 21:40:03.225: V/blah(720):    at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:144)
06-04 21:40:03.225: V/blah(720):    at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
06-04 21:40:03.225: V/blah(720):    at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119 )
06-04 21:40:03.225: V/blah(720):    at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
06-04 21:40:03.225: V/blah(720):    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
06-04 21:40:03.225: V/blah(720):    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
06-04 21:40:03.225: V/blah(720):    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
06-04 21:40:03.225: V/blah(720):    at myapp.net.HttpNote.doGet(HttpNote.java:32)
06-04 21:40:03.225: V/blah(720):    at myapp.net.NotesCenterImpl.getVehiculo(NotesCenterImpl.java:23)
06-04 21:40:03.225: V/blah(720):    at myapp.net.EmpleadosAct.ActualizarVehiculo(EmpleadosAct.java:91)
06-04 21:40:03.225: V/blah(720):    at myapp.net.EmpleadosAct.onCreate(EmpleadosAct.java:24)
06-04 21:40:03.225: V/blah(720):    at android.app.Activity.performCreate(Activity.java:4465)
06-04 21:40:03.225: V/blah(720):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
06-04 21:40:03.225: V/blah(720):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
06-04 21:40:03.225: V/blah(720):    at  android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
06-04 21:40:03.225: V/blah(720):    at android.app.ActivityThread.access$600(ActivityThread.java:123)
06-04 21:40:03.225: V/blah(720):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
06-04 21:40:03.225: V/blah(720):    at android.os.Handler.dispatchMessage(Handler.java:99)
06-04 21:40:03.225: V/blah(720):    at android.os.Looper.loop(Looper.java:137)
06-04 21:40:03.225: V/blah(720):    at android.app.ActivityThread.main(ActivityThread.java:4424)
06-04 21:40:03.225: V/blah(720):    at java.lang.reflect.Method.invokeNative(Native Method)
06-04 21:40:03.225: V/blah(720):    at java.lang.reflect.Method.invoke(Method.java:511)
06-04 21:40:03.225: V/blah(720):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
06-04 21:40:03.225: V/blah(720):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
06-04 21:40:03.225: V/blah(720):    at dalvik.system.NativeStart.main(Native Method)

那么是什么原因导致 android 在 2.3.4 中一切正常，而在 4.0.3 中却不行？我的代码有问题不支持 4.0.3 版本？

感谢您的任何回答或建议。

Answer 1

Log.v("blah", ex.getMessage());

问题是 ex.getMessage() 正在返回 null。您可以检查 null，但更好的方法是将异常作为第三个参数显式传递给日志方法:

Log.v("blah", "Error happened: ", ex);