我最近将项目从
Eclipse移到了
Android Studio.我试图让电子邮件功能正常工作,但我收到“findViewById”错误.我也收到“Toast.makeText”的错误.你能帮忙解决这两个错误.我班上的代码如下：
package com.example.ishonours.witsbusapp;
import android.app.Activity;
import android.net.Uri;
import android.os.Bundle;
import android.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.content.Intent;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class ComplaintsFragment extends Fragment {
//I added
private EditText recipient;
private EditText subject;
private EditText body;
private OnFragmentInteractionListener mListener;
private static final String ARG_SECTION_NUMBER = "5";
public static ComplaintsFragment newInstance(int menuNumber) {
ComplaintsFragment fragment = new ComplaintsFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER,menuNumber);
fragment.setArguments(args);
return fragment;
}
public ComplaintsFragment() {
// required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater,ViewGroup container,Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_complaints,container,false);
//i added
recipient = (EditText) findViewById(R.id.recipient);
subject = (EditText) findViewById(R.id.subject);
body = (EditText) findViewById(R.id.body);
Button sendBtn = (Button) findViewById(R.id.sendEmail);
sendBtn.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
sendEmail();
// after sending the email,clear the fields
recipient.setText("");
subject.setText("");
body.setText("");
}
});
}
//i added
protected void sendEmail() {
String[] recipients = {recipient.getText().toString()};
Intent email = new Intent(Intent.ACTION_SEND,Uri.parse("mailto:"));
// prompts email clients only
email.setType("message/rfc822");
email.putExtra(Intent.EXTRA_EMAIL,recipients);
email.putExtra(Intent.EXTRA_SUBJECT,subject.getText().toString());
email.putExtra(Intent.EXTRA_TEXT,body.getText().toString());
try {
// the user can choose the email client
startActivity(Intent.createChooser(email,"Choose an email client from..."));
} catch (android.content.ActivityNotFoundException ex) {
Toast.makeText(ComplaintsFragment.this,"No email client installed.",Toast.LENGTH_LONG).show();
}}
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
((MainActivity) activity).onSectionAttached(
getArguments().getInt(ARG_SECTION_NUMBER));
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
public void onFragmentInteraction(Uri uri);
}
}
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
tools:context="com.example.ishonours.witsbusapp.ComplaintsFragment">
<TextView
android:id="@+id/text1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="20dp"
android:gravity="center"
android:text="Complete the fields to log a complaint"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/recipient"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="textEmailAddress"
android:hint="Recipient" />
<EditText
android:id="@+id/subject"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:hint="Subject" />
<EditText
android:id="@+id/body"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:hint="Message body" />
<Button
android:id="@+id/sendEmail"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="30dp"
android:text="Compose an email" />
解决方法
问题出在你的onCreateView方法中.
@Override
public View onCreateView(LayoutInflater inflater,Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v = inflater.inflate(R.layout.fragment_complaints,false);
//i added
recipient = (EditText) v.findViewById(R.id.recipient);
[...]
return v;
}
看到不同？在碎片的情况下,您必须在实际的View对象上调用findViewById.
你有Toast的问题是因为你传递了worng对象作为第一个参数.你需要Context而你正在传递Fragment.片段不是一个上下文但幸运的是你的活动就是这样,你必须像这样构建你的Toast：
Toast.makeText(ComplaintsFragment.this.getActivity(),Toast.LENGTH_LONG).show();
注意getActivity()调用.
