Java 点击时，ActionBar图标图像没有执行任何操作？
我正在关注ActionBar的GoogleAPI库，但无法让它导航回家。LogCat没有捕获任何内容……因此没有错误，但语法不允许导航 我也承认，我对Actionbar也没有太多的经验 我不明白这为什么不起作用，非常感谢您的帮助 这里是我的活动代码：Java 点击时，ActionBar图标图像没有执行任何操作？,java,android,xml,android-actionbar,Java,Android,Xml,Android Actionbar,我正在关注ActionBar的GoogleAPI库，但无法让它导航回家。LogCat没有捕获任何内容……因此没有错误，但语法不允许导航 我也承认，我对Actionbar也没有太多的经验 我不明白这为什么不起作用，非常感谢您的帮助 这里是我的活动代码： @SuppressLint("NewApi") public class MoveContactsActivity extends ListActivity { @SuppressLint("NewApi") @Override
@SuppressLint("NewApi")
public class MoveContactsActivity extends ListActivity {
@SuppressLint("NewApi")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_move_contacts);
// getActionBar().setHomeButtonEnabled(true);
ActionBar actionBar = getActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setTitle("My Relocation");
actionBar.setIcon(R.drawable.menu_ic_launcher);
Bundle bundle = getIntent().getExtras();
final TextView welcomeText = (TextView) findViewById(R.id.WelcomeText);
final TextView relocationId = (TextView) findViewById(R.id.relocationID);
final TextView addressOne = (TextView) findViewById(R.id.addressOne);
final TextView addressTwo = (TextView) findViewById(R.id.addressTwo);
final String RelocationId = bundle.getString("UID1");
relocationId.setText("Your Relocation: #" + RelocationId);
new contentCall().execute("");
findViewById(R.id.WebAddressTwo).setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
Uri uri = Uri.parse("http://www.Relocationmw.com");
Intent intent = new Intent(Intent.ACTION_VIEW, uri);
startActivity(intent);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_move_contacts, menu);
return true;
}
private class contentCall extends AsyncTask<String, Void, String> {
ProgressDialog dialog = new ProgressDialog(MoveContactsActivity.this);
@Override
protected void onPreExecute() {
if (checkNullState() == false) {
showMyDialog();
}
}
@Override
protected String doInBackground(String... params) {
String xml = null;
String calling = "https://demo.relocationmw.com/ws_docmgmt/mobile.asmx/GetRelocationMoveContactsTrim?UserID=";
Bundle bundle = getIntent().getExtras();
// String UID = bundle.getString("UID");
String UID = "801";
String URL = calling + UID;
DefaultHttpClient client = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(URL);
HttpResponse httpResponse;
try {
httpResponse = client.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
xml = EntityUtils.toString(httpEntity);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return xml;
}
@Override
protected void onPostExecute(String result) {
String xml = result;
String KEY_ITEM = "Contact";
String KEY_CONTACTTITLE = "ContactTitle";
String KEY_NAME = "Name";
String KEY_MAINPHONE = "Phone";
String KEY_CELLPHONE = "Cell";
String KEY_FAX = "Fax";
String KEY_EMAIL = "Email";
ArrayList<HashMap<String, String>> menuItems = new ArrayList<HashMap<String, String>>();
Document doc = getDomElement(xml);
if (xml != null) {
{
NodeList nl = doc.getElementsByTagName(KEY_ITEM);
for (int i = 0; i < nl.getLength(); i++) {
HashMap<String, String> map = new HashMap<String, String>();
Element e = (Element) nl.item(i);
map.put(KEY_CONTACTTITLE, getValue(e, KEY_CONTACTTITLE));
map.put(KEY_NAME, getValue(e, KEY_NAME));
map.put(KEY_MAINPHONE, getValue(e, KEY_MAINPHONE));
map.put(KEY_CELLPHONE, getValue(e, KEY_CELLPHONE));
map.put(KEY_FAX, getValue(e, KEY_FAX));
map.put(KEY_EMAIL, getValue(e, KEY_EMAIL));
menuItems.add(map);
}
String[] hashMapObjects = { KEY_CONTACTTITLE, KEY_NAME,
KEY_MAINPHONE, KEY_CELLPHONE, KEY_FAX, KEY_EMAIL };
int[] listItemObjects = { R.id.ContactTitle, R.id.Name,
R.id.MainPhone, R.id.Cell, R.id.Fax, R.id.Email };
// ContactListAdapter adapter = new ContactListAdapter(MoveContactsActivity.this, 0, menuItems);
SimpleAdapter adapter = new SimpleAdapter (MoveContactsActivity.this,menuItems,R.layout.listed_contacts,hashMapObjects, listItemObjects);
SimpleAdapter.ViewBinder binder = new SimpleAdapter.ViewBinder() {
@Override
public boolean setViewValue(View view, Object object,
String value) {
if(!(view instanceof TextView)){
return false;
}
final TextView text = (TextView) view;
text.setVisibility(TextUtils.isEmpty(value) ? View.GONE : View.VISIBLE);
text.setText(value);
return true;
}
};
adapter.setViewBinder(binder);
setListAdapter(adapter);
}
if (checkNullState() == true) {
dismissMyDialog();
}
}
}
}
protected void onProgressUpdate(Map... values) {
}
// XML Parsing Start
public Document getDomElement(String xml) {
Document doc = null;
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
try {
DocumentBuilder db = dbf.newDocumentBuilder();
InputSource is = new InputSource();
is.setCharacterStream(new StringReader(xml));
doc = db.parse(is);
} catch (ParserConfigurationException e) {
Log.e("Error: ", e.getMessage());
return null;
} catch (SAXException e) {
Log.e("Error: ", e.getMessage());
return null;
} catch (IOException e) {
Log.e("Error: ", e.getMessage());
return null;
}
// return DOM
return doc;
}
public String getValue(Element item, String str) {
NodeList n = item.getElementsByTagName(str);
return getElementValue(n.item(0));
}
public final String getElementValue(Node elem) {
Node child;
if (elem != null) {
if (elem.hasChildNodes()) {
for (child = elem.getFirstChild(); child != null; child = child
.getNextSibling()) {
if (child.getNodeType() == Node.TEXT_NODE) {
return child.getNodeValue();
}
}
}
}
return null;
}
// XML Parsing Stop
// ProgressDialog Tracking
private ProgressDialog pd1;
private boolean isMyDialogShowing;
boolean checkNullState() {
boolean test;
if (pd1 != null) {
test = true;
} else {
test = false;
}
return test;
}
void showMyDialog() {
isMyDialogShowing = true;
pd1 = new ProgressDialog(MoveContactsActivity.this);
pd1.setTitle("Contacts");
pd1.setMessage("Loading Contacts....");
pd1.show();
}
void dismissMyDialog() {
pd1.dismiss();
isMyDialogShowing = false;
}
@Override
public boolean onOptionsItemSelected(MenuItem item){
switch(item.getItemId()){
case R.id.menu_settings:
Intent intent = new Intent(this, HomeActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
}
03-26 13:45:40.666: E/AndroidRuntime(19152): FATAL EXCEPTION: main
03-26 13:45:40.666: E/AndroidRuntime(19152): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.testingapp/com.testingapp.HomeActivity}: java.lang.NullPointerException
03-26 13:45:40.666: E/AndroidRuntime(19152): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2100)
03-26 13:45:40.666: E/AndroidRuntime(19152): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2125)
03-26 13:45:40.666: E/AndroidRuntime(19152): at android.app.ActivityThread.access$600(ActivityThread.java:140)
03-26 13:45:40.666: E/AndroidRuntime(19152): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1227)
03-26 13:45:40.666: E/AndroidRuntime(19152): at android.os.Handler.dispatchMessage(Handler.java:99)
03-26 13:45:40.666: E/AndroidRuntime(19152): at android.os.Looper.loop(Looper.java:137)
03-26 13:45:40.666: E/AndroidRuntime(19152): at android.app.ActivityThread.main(ActivityThread.java:4898)
03-26 13:45:40.666: E/AndroidRuntime(19152): at java.lang.reflect.Method.invokeNative(Native Method)
03-26 13:45:40.666: E/AndroidRuntime(19152): at java.lang.reflect.Method.invoke(Method.java:511)
03-26 13:45:40.666: E/AndroidRuntime(19152): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1008)
03-26 13:45:40.666: E/AndroidRuntime(19152): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:775)
03-26 13:45:40.666: E/AndroidRuntime(19152): at dalvik.system.NativeStart.main(Native Method)
03-26 13:45:40.666: E/AndroidRuntime(19152): Caused by: java.lang.NullPointerException
03-26 13:45:40.666: E/AndroidRuntime(19152): at com.testingapp.HomeActivity.onCreate(HomeActivity.java:50)
03-26 13:45:40.666: E/AndroidRuntime(19152): at android.app.Activity.performCreate(Activity.java:5206)
03-26 13:45:40.666: E/AndroidRuntime(19152): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
03-26 13:45:40.666: E/AndroidRuntime(19152): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2064)
03-26 13:45:40.666: E/AndroidRuntime(19152): ... 11 more
对于我来说，仅适用于以下代码：
@Override
protected void onCreate(Bundle savedInstanceState) {
// your code goes here...
ActionBar actionBar = getActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setHomeButtonEnabled(true);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
super.onOptionsItemSelected(item);
if (item.getItemId() == android.R.id.home) {
finish();
}
return true;
}
菜单或主页上没有任何内容。
您的问题是，您正在尝试访问
HomeActivityonCreate（）NULL检查HomeActivity.java中的第50行
Caused by: java.lang.NullPointerException
at com.testingapp.HomeActivity.onCreate(HomeActivity.java:50)
即：final String RelocationId=bundle.getString（“UID1”）；。。。。。。只有当意图在ActionBArbundle上被触发回家时，它才为Null。如果为Null，则在开始home活动之前，您没有设置任何额外值，您需要添加一个检查（Null！=bundle）{….}或在意图意图中放入一些数据。putExtra（“UID1”，“value”）；在开始活动之前。非常感谢，向我展示了原因，并且我能够更多地解释为什么我没有检查，但是我已经修复了它，现在它工作得非常好，谢谢！
@Override
protected void onCreate(Bundle savedInstanceState) {
// your code goes here...
ActionBar actionBar = getActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setHomeButtonEnabled(true);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
super.onOptionsItemSelected(item);
if (item.getItemId() == android.R.id.home) {
finish();
}
return true;
}
Caused by: java.lang.NullPointerException
at com.testingapp.HomeActivity.onCreate(HomeActivity.java:50)