java - 调用对象时出错 - Android

Question

我在这里调用对象。

public class TestDetails extends ListActivity {

    protected TextView testNameText;
    protected SQLiteDatabase db;
    protected TextView testvalueText;
    protected List<TestAction> actions;
    protected TestItemAdapter adapter;
    protected int testId;
    protected int categoryId;

    @Override
    //adds options menu
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.menu, menu);
        return true;
    }

    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.list_search: onSearchRequested();
            break;
        }
        return true;
    }
    //end of add options menu
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.test_details);

     // Get the intent, verify the action and get the query
        db = (new DatabaseHelper(this)).getWritableDatabase();
        Intent intent1 = getIntent();
        SimpleSearch SSearch = new SimpleSearch();
        if (Intent.ACTION_SEARCH.equals(intent1.getAction())) {
          String query = intent1.getStringExtra(SearchManager.QUERY);
          SSearch.testSearch(query);
          }

        testId = getIntent().getIntExtra("EMPLOYEE_ID", 0);
        SQLiteDatabase db = (new DatabaseHelper(this)).getWritableDatabase();
        Cursor cursor = db.rawQuery("SELECT emp._id, emp.firstName, emp.lastName, emp.title, emp.officePhone, emp.cellPhone, emp.email, emp.managerId, mgr.firstName managerFirstName, mgr.lastName managerLastName FROM employee emp LEFT OUTER JOIN employee mgr ON emp.managerId = mgr._id WHERE emp._id = ?", 
                new String[]{""+testId});

        if (cursor.getCount() == 1)
        {
            cursor.moveToFirst();
            testNameText = (TextView) findViewById(R.id.employeeName);
            testNameText.setText(cursor.getString(cursor.getColumnIndex("firstName")) + " " + cursor.getString(cursor.getColumnIndex("lastName")));
            actions = new ArrayList<TestAction>();

            String officePhone = cursor.getString(cursor.getColumnIndex("officePhone"));
            if (officePhone != null) {
                actions.add(new TestAction("Call office", officePhone, TestAction.ACTION_CALL));
            }

            String cellPhone = cursor.getString(cursor.getColumnIndex("cellPhone"));
            if (cellPhone != null) {
                actions.add(new TestAction("Call mobile", cellPhone, TestAction.ACTION_CALL));
                actions.add(new TestAction("SMS", cellPhone, TestAction.ACTION_SMS));
            }

            String email = cursor.getString(cursor.getColumnIndex("email"));
            if (email != null) {
                actions.add(new TestAction("Email", email, TestAction.ACTION_EMAIL));
            }

            categoryId = cursor.getInt(cursor.getColumnIndex("managerId"));
            if (categoryId>0) {
                actions.add(new TestAction("View manager", cursor.getString(cursor.getColumnIndex("managerFirstName")) + " " + cursor.getString(cursor.getColumnIndex("managerLastName")), TestAction.ACTION_VIEW));
            }

            cursor = db.rawQuery("SELECT count(*) FROM employee WHERE managerId = ?", 
                    new String[]{""+testId});
            cursor.moveToFirst();
            int count = cursor.getInt(0);
            if (count>0) {
                actions.add(new TestAction("View direct reports", "(" + count + ")", TestAction.ACTION_REPORTS));
            }

            adapter = new TestItemAdapter();
            setListAdapter(adapter);
        }

    }

    class TestItemAdapter extends ArrayAdapter<TestAction> {
        TestItemAdapter() {
            super(TestDetails.this, R.layout.action_list_item, actions);
        }

        @Override
        public boolean areAllItemsEnabled() {
            return false;
        }
        public boolean isEnabled(int position) {
           return false;
        }
        public View getView(int position, View convertView, ViewGroup parent) {
            TestAction action = actions.get(position);
            LayoutInflater inflater = getLayoutInflater();
            View view = inflater.inflate(R.layout.action_list_item, parent, false);
            TextView label = (TextView) view.findViewById(R.id.label);
            label.setText(action.getLabel());
            TextView data = (TextView) view.findViewById(R.id.data);
            data.setText(action.getData());
            return view;
        }

    }

}

这是我从中调用对象的类。(类的一部分)

public class SimpleSearch extends ListActivity {
    protected SQLiteDatabase db;
    protected Cursor cursor;
    protected ListAdapter adapter;
    protected String query;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        db = (new DatabaseHelper(this)).getWritableDatabase();
        // Get the intent, verify the action and get the query
        Intent intent = getIntent();
        if (Intent.ACTION_SEARCH.equals(intent.getAction())) {
          String query = intent.getStringExtra(SearchManager.QUERY);
          testSearch(query);
          }
        else TestListAll();
        }

但是我正在强制关闭运行该应用程序。堆栈跟踪显示错误在 SSearch.testSearch(query); 语句中。我在这里缺少什么？

堆栈跟踪:

app_vercode:1
device_model:umts_jordan
build_version:1.11.18
condition:1
processName:com.simple.search
pid:3529
uid:10063
tag:null
shortMsg:java.lang.NullPointerException
longMsg:java.lang.NullPointerException: Unable to start activity ComponentInfo{com.simple.search/com.simple.search.TestDetails}: java.lang.NullPointerException
stackTrace:java.lang.RuntimeException: Unable to start activity ComponentInfo{com.simple.search/com.simple.search.TestDetails}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1664)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1680)
at android.app.ActivityThread.access$1500(ActivityThread.java:117)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:130)
at android.app.ActivityThread.main(ActivityThread.java:3703)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:507)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.simple.search.SimpleSearch.testSearch(SimpleSearch.java:68)
at com.simple.search.TestDetails.onCreate(TestDetails.java:59)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1628)
... 11 more

Answer 1

最有可能的线

String query = intent1.getStringExtra(SearchManager.QUERY);

正在为查询分配一个空值 - 您确定存在正确的额外值吗？我通常以这种方式获得额外的东西:

public static final String TAG = "MyActivity";
public static final String DATA_KEY = "DataKey";
public static final String MY_CUSTOM_ACTION = "MyCustomSearchAction";

public void onCreate(Bundle savedInstanceState) {
    Intent intent1 = getIntent();
    SimpleSearch SSearch = new SimpleSearch();
    if (intent1.getAction().equals(MY_CUSTOM_ACTION) 
          && intent1.hasExtra(SearchManager.QUERY)
          && intent.hasExtra(DATA_KEY)) {
        String query = intent1.getStringExtra(SearchManager.QUERY);
        DataObject data = intent1.getParcelableExtra(DATA_KEY);   
        if (query != null && data != null)
            SSearch.testSearch(query, data);
        else {
            //invalid query
           Log.d(TAG,"Activity started with invalid query data - closing");
           this.finish();
           return;
        }
    } else {
       //Invalid Intent
       Log.d(TAG,"Activity started with invalid intent - closing");
       this.finish();
       return;
    }
}

数据对象可以是这样的:

public class DataObject implements Parcelable {

    public String someData;
    public String someMoreData;

    @Override
    public int describeContents() {
        return 0;
}

@Override
public void writeToParcel(Parcel dest, int flags) {
    dest.writeString(someData);
    dest.writeString(someMoreDate);
}

//Constructor for parceler
public DataObject(Parcel src) {
    someData = src.readString();
    someMoreData = src.readString();
}

public static final Parcelable.Creator<DataObject> CREATOR = 
                new Parcelable.Creator<DataObject>() {

    public DataObject createFromParcel(Parcel in) {
        return new DataObject(in);
    }

    public DataObject[] newArray(int size) {
        return new DataObject[size];
    }
};

要开始您的 Activity ，请执行以下操作:

DataObject data = new DataObject();
data.someData = "test";
data.someMoreData = "test2";
Intent intent = new Intnent(this, MyActivity.class);
intent.setAction(MyActivity.MY_CUSTOM_ACTION);
intent.putExtra(MyActivity.DATA_KEY,data);
intent.putExtra(SearchManager.QUERY, "Query");
startActivity(intent);