这是我的注册活动＆amp;主要活动及其xml
public class SignupActivity extends AppCompatActivity {
protected EditText mUsername;
protected EditText mPassword;
protected EditText mEmail;
protected Button nbutton;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_signup);
mUsername = (EditText) findViewById(R.id.usernamefield);
mPassword = (EditText) findViewById(R.id.passwordtextfield);
mEmail = (EditText) findViewById(R.id.emailtextfield);
nbutton = (Button) findViewById(R.id.signbutton);
nbutton.setOnClickListener(new View.OnClickListener() {
public void onClick(View view){
// Retrieve the text entered from the EditText
String usernametxt = mUsername.getText().toString();
String password = mPassword.getText().toString();
String email= mEmail.getText().toString();
// Force user to fill up the form
if (usernametxt.equals("") && password.equals("")) {
Toast.makeText(getApplicationContext(),
"Please complete the sign up form",
Toast.LENGTH_LONG).show();
} else {
// Save new user data into Parse.com Data Storage
ParseUser newUser = new ParseUser();
newUser.setUsername(usernametxt);
newUser.setPassword(password);
newUser.setEmail(email);
newUser.signUpInBackground(new SignUpCallback() {
@Override
public void done(ParseException e) {
//SUCESS
if (e!= null){
AlertDialog.Builder builder=new AlertDialog.Builder(SignupActivity.this);
builder.setMessage(e.getMessage()).setTitle(R.string.signup_error_title).setPositiveButton(android.R.string.ok, null);
AlertDialog dialog = builder.create();
dialog.show();
}
else {
Intent intent= new Intent(SignupActivity.this,MainActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(intent);
}
}
});
}
}
});
}
假设从用户那里获取信息并从signupactivity转到主要活动。当应用程序从用户进入并按下登录时，应用程序崩溃...
这是xml
<RelativeLayout 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:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context="com.josephvarkey996gmail.test1.SignupActivity" >
<TextView android:text="@string/hello_world" android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/usernamefield"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginTop="89dp"
android:hint="@string/username_hint"/>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="textPassword"
android:ems="10"
android:id="@+id/passwordtextfield"
android:layout_centerHorizontal="true"
android:layout_below="@+id/usernamefield"
android:hint="@string/password_hint"/>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="textEmailAddress"
android:ems="10"
android:id="@+id/emailtextfield"
android:hint="@string/email_hint"
android:layout_below="@+id/passwordtextfield"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/signup_hint"
android:id="@+id/signbutton"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" />
</RelativeLayout>
here is the main activity code
package com.josephvarkey996gmail.test1;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import com.parse.Parse;
import com.parse.ParseAnalytics;
import com.parse.ParseUser;
public class MainActivity extends AppCompatActivity {
public static final String TAG = MainActivity.class.getSimpleName();
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Parse.enableLocalDatastore(this);
Parse.initialize(this, "XFigOgliUYKi9h5RanLfLkuKU14AG2f2NFQXADKI", "sMQBPkhZV5b74MEGpP3PdQ6eePWo5Y9O8lRcQvBP");
ParseAnalytics.trackAppOpenedInBackground(getIntent());
ParseUser currentUser = ParseUser.getCurrentUser();
if(currentUser==null) {
navigatetologin();
}
if(currentUser!=null)
{
Log.i(TAG ,currentUser.getUsername());
}
// Enable Local Datastore.
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
private void navigatetologin() {
Intent intent = new Intent(this, LoginActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(intent);
}
}
mainactivity xml
<RelativeLayout 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:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity" >
<TextView android:text="@string/hello_world" android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</RelativeLayout>
android manifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.josephvarkey996gmail.test1" >
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/Theme.AppCompat" >
<activity
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".SignupActivity"
android:label="@string/title_activity_signup" >
</activity>
<activity
android:name=".LoginActivity"
android:label="@string/title_activity_login" >
</activity>
</application>
</manifest>
答案 0 :(得分：0)
在你发布logcat之前我们无法帮助你。由于我没有足够的声誉来发表评论，我正在回答这个问题。
我看到有人收到此错误的最常见原因是： 他们从另一个类
复制-paste这一行R.id.usernamefield
所以它会尝试运行其他类的用户区域，这里不存在（注意：eclipse会自动导入，所以他们没有得到编译错误）。因此，要解决您的错误，您应该删除导入并写入正确的R.id.xyz
但这只是在黑暗中拍摄，直到我们看到你的logcat。