我现在正在研究一些Android教程,准备在美国大学进行为期两周的训练营。我十七岁,请原谅我这是一个愚蠢的问题。我做了一些研究并尝试了几件事,但我无法让它发挥作用。
我正在使用此处的google标签/片段示例:http://developer.android.com/reference/android/app/TabActivity.html
我的问题是当重写createTabContent时,onTabChanged我一直得到错误必须覆盖超类方法。这是我的代码:
包matthews.zack.test;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentTransaction;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TabHost;
import android.widget.TextView;
public class _testActivity扩展了FragmentActivity {
ListView list;
Button save;
RadioGroup radioGroup;
RadioButton selectedType;
TabHost tabHost;
// People p = new People();
public List<People> people = new ArrayList<People>();
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
onInitialize();
if (savedInstanceState != null) {
tabHost.setCurrentTabByTag(savedInstanceState.getString("tab"));
}
}
private void onInitialize() {
tabHost = (TabHost) findViewById(R.id.tabHost);
tabHost.setup();
* TabManager tManager = new TabManager(this, tabHost,
* R.id.realtabcontent); tManager.addTab(
* tabHost.newTabSpec("details").setIndicator("Details",
* getResources().getDrawable(R.drawable.goldstar)), null, null);
* tManager.addTab( tabHost.newTabSpec("list").setIndicator("List",
* getResources().getDrawable(R.drawable.bluestar)), null, null);
*
* TabSpec spec = tabHost.newTabSpec("tab1");
* spec.setContent(R.id.listView1); spec.setIndicator("List",
* getResources().getDrawable(R.drawable.goldstar));
*
* TabSpec spec2 = tabHost.newTabSpec("tab2");
* spec2.setContent(R.id.details); spec2.setIndicator("Details",
* getResources().getDrawable(R.drawable.bluestar));
*
* tabHost.addTab(spec); tabHost.addTab(spec2);
*/
PeopleAdapter adapter = new PeopleAdapter();
list = (ListView) findViewById(R.id.listView1);
list.setAdapter(adapter);
radioGroup = (RadioGroup) findViewById(R.id.type);
// radioGroup.check(R.id.coWorker);
radioGroup
.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
public void onCheckedChanged(RadioGroup group, int checkedId) {
// TODO Auto-generated method stub
if (selectedType != (RadioButton) findViewById(radioGroup
.getCheckedRadioButtonId())) {
selectedType = (RadioButton) findViewById(radioGroup
.getCheckedRadioButtonId());
}
}
});
save = (Button) findViewById(R.id.button1);
save.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
People p = new People();
// TODO Auto-generated method stub
EditText firstName = (EditText) findViewById(R.id.editText1);
EditText lastName = (EditText) findViewById(R.id.editText2);
p.setFirstName(firstName.getText().toString());// firstName.getText().toString());
p.setLastName(lastName.getText().toString());// lastName.getText().toString());
p.setType(selectedType.getText().toString());
people.add(p);
}
});
}
static class PeopleHolder {
private TextView name;
private TextView title;
private ImageView icon;
PeopleHolder(View row) {
name = (TextView) row.findViewById(R.id.name);
title = (TextView) row.findViewById(R.id.title);
icon = (ImageView) row.findViewById(R.id.icon);
}
void populateForm(People p) {
name.setText(p.getFirstName() + " " + p.getLastName());
title.setText(p.getType().toString());
if (p.getType().equals("Family")) {
icon.setImageResource(R.drawable.android);
}
else if (p.getType().equals("Friend")) {
icon.setImageResource(R.drawable.xbox);
}
else {
icon.setImageResource(R.drawable.yinyang);
}
}
}
class PeopleAdapter extends ArrayAdapter<People> {
PeopleAdapter() {
super(_testActivity.this, android.R.layout.simple_list_item_1,
people);
}
public View getView(int position, View convertView, ViewGroup parent) {
View row = convertView;
PeopleHolder holder = null;
if (row == null) {
LayoutInflater inflater = getLayoutInflater();
row = inflater.inflate(R.layout.row, null);
holder = new PeopleHolder(row);
row.setTag(holder);
}
else {
holder = (PeopleHolder) row.getTag();
}
holder.populateForm(people.get(position));
return (row);
}
}
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putString("tab", tabHost.getCurrentTabTag());
}
public static class TabManager implements TabHost.OnTabChangeListener {
private final FragmentActivity activity;
private final TabHost host;
private final int containerID;
private final HashMap<String, TabInfo> tabs = new HashMap<String, TabInfo>();
TabInfo lastTab;
static final class TabInfo {
private final String tag;
private final Class<?> clss;
private final Bundle args;
private Fragment fragment;
TabInfo(String _tag, Class<?> clss, Bundle args) {
this.tag = _tag;
this.clss = clss;
this.args = args;
}
}
static class DummyTabFactory implements TabHost.TabContentFactory {
private final Context context;
public DummyTabFactory(Context context) {
this.context = context;
}
public View createTabContent(String tag) {
View v = new View(context);
v.setMinimumWidth(0);
v.setMinimumHeight(0);
return v;
}
}
public TabManager(FragmentActivity activity, TabHost host,
int containerID) {
this.activity = activity;
this.host = host;
this.containerID = containerID;
this.host.setOnTabChangedListener(this);
}
public void addTab(TabHost.TabSpec tabSpec, Class<?> clss, Bundle args) {
tabSpec.setContent(new DummyTabFactory(activity));
String tag = tabSpec.getTag();
TabInfo info = new TabInfo(tag, clss, args);
info.fragment = activity.getSupportFragmentManager()
.findFragmentByTag(tag);
if (info.fragment != null && !info.fragment.isDetached()) {
FragmentTransaction ft = activity.getSupportFragmentManager()
.beginTransaction();
ft.detach(info.fragment);
ft.commit();
}
tabs.put(tag, info);
host.addTab(tabSpec);
}
public void onTabChanged(String tabId) {
TabInfo newTab = tabs.get(tabId);
if (lastTab != newTab) {
FragmentTransaction ft = activity.getSupportFragmentManager()
.beginTransaction();
if (lastTab != null) {
if (lastTab.fragment != null) {
ft.detach(lastTab.fragment);
}
}
if (newTab != null) {
if (newTab.fragment == null) {
newTab.fragment = Fragment.instantiate(activity,
newTab.clss.getName(), newTab.args);
ft.add(containerID, newTab.fragment, newTab.tag);
}
else {
ft.attach(newTab.fragment);
}
}
lastTab = newTab;
ft.commit();
activity.getSupportFragmentManager()
.executePendingTransactions();
}
// TODO Auto-generated method stub
}
}
}
这是一个日食问题,还是我犯了一个粗心的错误?我检查并仔细检查我是否正在使用正确的类,并且它们包含我试图覆盖的方法。提前谢谢!
编辑:已发布完整代码。我能够编译并运行,但应用程序一旦启动就关闭。请帮忙!
答案 0 :(得分:7)
您可能使用的Java版本与示例代码的作者不同......您有两种选择:
您应该能够删除导致错误的@Override
行并毫无困难地运行您的应用。
您可以在Eclipse中将JDK编译器的合规性级别从1.5更改为1.6:
属性 - &gt; JDK编译器 - &gt;从编译器合规性级别下拉列表中选择“1.6” (Android仅支持1.5和1.6,它还不支持1.7)
答案 1 :(得分:0)
如果没有看到班级的所有代码,很难说出你的问题究竟是什么。
Sam说,根据您使用的示例,您可能不需要使用@Override。如果你的课不“扩展”任何类似的东西:
public class MyClass extends MySuperClass{...
然后你不需要过度骑行。如果您有一个继承方法的超类,并且您想要更改它们的运行方式,则会执行覆盖。可以将其视为存储在您正在扩展的类中的自定义方法。如果您没有超类,则无需覆盖可能导致问题的方法。
另一个问题可能是你没有覆盖超类中的正确方法。
但是没有看到所有的代码,很难给你更具体的东西。
希望这有帮助。
答案 2 :(得分:0)
旧版本的Java不喜欢使用@Override进行接口方法覆盖。当时只有超类方法才能与该注释一起使用。这在1.5之后改变,因此1.6和1.7不会为@Override抛出警告以覆盖接口方法。
你可以抑制这个警告,删除注释(这根本不会伤害你,但如果你输入方法名称或参数类型错误,Eclipse就不会告诉你),或者你可以改为1.6或者更高。
答案 3 :(得分:-1)
前段时间我遇到过类似问题,并通过将项目的编制级别更改为1.6来解决问题。
要做到这一点: