我看了四周但却无法弄清楚为什么我会收到错误
错误：方法不会覆盖或实现超类型
中的方法
这突出显示了方法中的两个@Override（子程序？）。这是我的MainActivity.java - 最后在queryBooks()方法中出现的代码部分 - @Override s都带有下划线红色。
package com.example.batman.myapplication;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.support.v4.view.MenuItemCompat;
//import android.support.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.ShareActionProvider;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.JsonHttpResponseHandler;
import org.json.JSONObject;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity implements View.OnClickListener, AdapterView.OnItemClickListener {
TextView mainTextView;
EditText mainEditText;
ListView mainListView;
ArrayAdapter mArrayAdapter;
// ArrayList<String> mNameList = new ArrayList<String>();
ArrayList mNameList = new ArrayList();
android.support.v7.widget.ShareActionProvider mShareActionProvider;
// This is for internet stuff
private static final String QUERY_URL = "http://openlibrary.org/search.json?q=";
// Setting up the storage of data
private static final String PREFS = "prefs";
private static final String PREF_NAME = "name";
SharedPreferences mSharedPreferences;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// 1. Access the TextView defined in layout XML
// and then set its text
mainTextView = (TextView) findViewById(R.id.main_textview);
// mainTextView.setText("Set in Java!");
Button mainButton;
mainButton = (Button) findViewById(R.id.main_button);
mainButton.setOnClickListener(this);
// 3. Access the EditText defined in layout XML
mainEditText = (EditText) findViewById(R.id.main_edittext);
// 4. Access the ListView
mainListView = (ListView) findViewById(R.id.main_listview);
// Create an ArrayAdapter for the ListView
mArrayAdapter = new ArrayAdapter(this,
android.R.layout.simple_list_item_1,
mNameList);
// Set the ListView to use the ArrayAdapter
mainListView.setAdapter(mArrayAdapter);
// 5. Set this activity to react to list items being pressed
mainListView.setOnItemClickListener(this);
// 7. Greet the user, or ask for their name if new
displayWelcome();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu.
// Adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
// Access the Share Item defined in menu XML
MenuItem shareItem = menu.findItem(R.id.menu_item_share);
// Access the object responsible for
// putting together the sharing submenu
if (shareItem != null) {
mShareActionProvider = (ShareActionProvider) MenuItemCompat.getActionProvider(shareItem);
}
// Create an Intent to share your content
setShareIntent();
return true;
}
private void setShareIntent() {
if (mShareActionProvider != null) {
// create an Intent with the contents of the TextView
Intent shareIntent = new Intent(Intent.ACTION_SEND);
shareIntent.setType("text/plain");
shareIntent.putExtra(Intent.EXTRA_SUBJECT, "Android Development");
shareIntent.putExtra(Intent.EXTRA_TEXT, mainTextView.getText());
// Make sure the provider knows
// it should work with that Intent
mShareActionProvider.setShareIntent(shareIntent);
}
}
@Override
public void onClick(View v) {
// // Take what was typed into the EditText
// // and use in TextView
// mainTextView.setText(mainEditText.getText().toString() + ".");
//
// // Also add that value to the list shown in the ListView
// mNameList.add(mainEditText.getText().toString());
// mArrayAdapter.notifyDataSetChanged();
// // 6. The text you'd like to share has changed,
// // and you need to update
// setShareIntent();
//
// if(v == mainEditText) {
// mainEditText.setText("");
// }
// 9. Take what was typed into the EditText and use in search
// (the above is commented out, per tutorial part 3 - this takes its place as input
queryBooks(mainEditText.getText().toString());
// mainEditText.setText("");
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
// Log the item's position and contents
// to the console in Debug
Log.d("My Application", position + ": " + mNameList.get(position));
}
public void displayWelcome() {
// Access the device's key-value storage
mSharedPreferences = getSharedPreferences(PREFS, MODE_PRIVATE);
// Read the user's name,
// or an empty string if nothing found
String name = mSharedPreferences.getString(PREF_NAME, "");
if (name.length() > 0) {
// If the name is valid, display a Toast welcoming them
Toast.makeText(this, "Welcome back, " + name + "!", Toast.LENGTH_LONG).show();
} else {
// otherwise, show a dialog to ask for their name
AlertDialog.Builder alert = new AlertDialog.Builder(this);
alert.setTitle("Hello!");
alert.setMessage("What is your name?");
// Create EditText for entry
final EditText input = new EditText(this);
alert.setView(input);
// Make an "OK" button to save the name
alert.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
// Grab the EditText's input
String inputName = input.getText().toString();
// Put it into memory (don't forget to commit!)
SharedPreferences.Editor e = mSharedPreferences.edit();
e.putString(PREF_NAME, inputName);
e.commit();
// Welcome the new user
Toast.makeText(getApplicationContext(), "Welcome, " + inputName + "!", Toast.LENGTH_LONG).show();
}
});
// Make a "Cancel" button
// that simply dismisses the alert
alert.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {}
});
alert.show();
}
}
// Internet stuff
private void queryBooks(String searchString) {
// Prepare your search string to be put in a URL
// It might have reserved characters or something
String urlString = "";
try {
urlString = URLEncoder.encode(searchString, "UTF-8");
} catch (UnsupportedEncodingException e) {
// if this fails for some reason, let the user know why
e.printStackTrace();
Toast.makeText(this, "Error: " + e.getMessage(), Toast.LENGTH_LONG).show();
}
// Create a client to perform networking
AsyncHttpClient client = new AsyncHttpClient();
// Have the client get a JSONArray of data
// and define how to respond
client.get(QUERY_URL + urlString,
new JsonHttpResponseHandler() {
@Override // THIS METHOD DOES NOT OVERRIDE METHOD FROM ITS SUPERCLASS ??
public void onSuccess(JSONObject jsonObject) {
// Display a "Toast" message
// to announce your success
Toast.makeText(getApplicationContext(), "Success!", Toast.LENGTH_LONG).show();
// 8. For now, just log results
Log.d("omg android", jsonObject.toString());
}
@Override // THIS METHOD DOES NOT OVERRIDE METHOD FROM ITS SUPERCLASS ??
public void onFailure(int statusCode, Throwable throwable, JSONObject error) {
// Display a "Toast" message
// to announce the failure
Toast.makeText(getApplicationContext(), "Error: " + statusCode + " " + throwable.getMessage(), Toast.LENGTH_LONG).show();
// Log error message
// to help solve any problems
Log.e("omg android", statusCode + " " + throwable.getMessage());
}
});
}
} // end class
（对于它的价值，我正在关注this教程）。
感谢您的任何想法！
答案 0 :(得分：6)
问题在于错误消息的含义：“该方法不会覆盖或实现超类型中的方法”。您使用Override annotation注释了这两种方法，但是，在超类型中找不到具有相同签名的 （即参数）的方法（{{1} }）。
如果您查看documentation of JsonHttpResponseHandler，则可以看到所有可用的JsonHttpResponseHandler和onSuccess(...)方法。
以下是代码的工作版本（请注意方法签名的更改）：
onFailure(...)请注意，从Android 6.0（API级别23）开始，Apache库（org.apache.http。*）不再可用。如果您想继续使用它，请参阅Behavior Changes以获取更多信息。
一些个人意见：我不建议使用异步HTTP库，因为它是在过时的（并且从API级别23，已删除）Apache client.get(QUERY_URL + urlString,
new JsonHttpResponseHandler() {
@Override
public void onSuccess(int statusCode, org.apache.http.Header[] headers, JSONObject jsonObject) {
// Display a "Toast" message
// to announce your success
Toast.makeText(getApplicationContext(), "Success!", Toast.LENGTH_LONG).show();
// 8. For now, just log results
Log.d("omg android", jsonObject.toString());
}
@Override
public void onFailure(int statusCode, org.apache.http.Header[] headers, Throwable throwable, JSONObject error) {
// Display a "Toast" message
// to announce the failure
Toast.makeText(getApplicationContext(), "Error: " + statusCode + " " + throwable.getMessage(), Toast.LENGTH_LONG).show();
// Log error message
// to help solve any problems
Log.e("omg android", statusCode + " " + throwable.getMessage());
}
});
之上构建的与HttpClient相比表现不佳。引用Android开发人员关于HttpURLConnection：
此API更有效，因为它通过透明压缩和响应缓存减少了网络使用，并最大限度地降低了功耗。
答案 1 :(得分：2)
简单的解决方案，用于解决上述问题
代码错误：
public class BatteryStatusPackage implements ReactPackage {
@Override
public List<NativeModule> createNativeModules(ReactApplicationContext reactContext) {
List<NativeModule> modules = new ArrayList<>();
modules.add(new BatteryStatusModule(reactContext));
return modules;
}
@Override
public List<Class<? extends JavaScriptModule>> createJSModules() {
return Collections.emptyList();
}
@Override
public List<ViewManager> createViewManagers(ReactApplicationContext reactContext) {
return Collections.emptyList();
}
}
解决方案：
在这里，我刚刚删除了 @override
public class BatteryStatusPackage implements ReactPackage {
public List<NativeModule> createNativeModules(ReactApplicationContext reactContext) {
List<NativeModule> modules = new ArrayList<>();
modules.add(new BatteryStatusModule(reactContext));
return modules;
}
public List<Class<? extends JavaScriptModule>> createJSModules() {
return Collections.emptyList();
}
public List<ViewManager> createViewManagers(ReactApplicationContext reactContext) {
return Collections.emptyList();
}
}
答案 2 :(得分：0)
为您的类添加Java文档，以覆盖或实现超类行为。
不幸的是，我没有消息来源，那就是我如何破解我的消息。
要点是，Java文档不仅是文档，它还是一种通知类的基于构造的工具。并将数据传递给吸气剂，设置器，类等
它以HTML DOCUMENT的形式处理API问题。
希望它对某些身体有帮助。 ?