Java 调用对象-Android时出错
我在这里调用对象Java 调用对象-Android时出错,java,android,class,object,Java,Android,Class,Object,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;
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;
}
}
}
但我正在努力运行这个应用程序。堆栈跟踪显示SSearch.testSearch(查询)中的错误代码>语句。我错过了什么
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
很有可能是这条线
String query = intent1.getStringExtra(SearchManager.QUERY);
正在为查询分配空值-是否确实存在正确的额外值?我通常会以这种方式获得额外服务:
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;
}
}
数据对象可以如下所示:
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];
}
};
@kabuko异常:11-22 19:09:41.094:E/AndroidRuntime(609):java.lang.RuntimeException:无法启动活动组件信息{com.simple.search/com.simple.search.TestDetails}:java.lang.NullPointerException
您当时显然没有包含相关代码。它可能在testSearch方法中,可能。。。只需发布完整的堆栈跟踪,并且在发布过程中,可能还会发布TestDetails活动的代码。请将其他详细信息添加到问题中,而不是添加到注释中:)您在哪里设置键入SearchManager.QUERY的字符串extra?那个字符串的值是多少?TestSearch的内容是什么?此外,您的第一个代码块表示您正在使用“new”关键字创建活动,这很奇怪。如果您是这样创建SimpleSearch对象的,那么就不会有数据作为捆绑包传递到onCreate方法中。您希望在您的意图中有很多键—最好将所有信息传递到可以验证数据正确性的自定义Parcelable对象中。另外-您不应该期望用户输入有效数据。我添加了代码,但Listdetails活动现在没有打开。标记需要是字符串-抱歉,我通常在所有活动中定义标记变量。我已修复了该问题,但我认为问题在于活动使用了alexander所说的“new”关键字。与无数据相关的内容将作为包传递到onCreate方法中。如果你的活动总是期望在包中有大量的值,你就应该考虑定义一个有数据的可分配对象,并且在你的意图中只发送一个对象。我将给你一个例子,一个使用包裹向一个活动发送多个值的例子。DataObject还可以进行数据验证和日志记录,以便更容易发现bug。另外,使用静态最终字符串作为键可以大大降低拼写键名的可能性,这是导致NullPointerException的常见原因。
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];
}
};
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);