当我使用菜单按钮切换到新页面并调用新活动时，我的应用程序崩溃。我遵循了android开发人员网站上的教程，该教程显示了如何将按钮单击链接到新活动，但是当我单击按钮对象时，应用程序崩溃而未更改为新活动。
我有6个与主要活动相关的不同活动。
我的日志猫如下：
03-05 20:12:10.185: W/ActivityManager(288): Activity pause timeout for ActivityRecord{40d31ab0 u0 com.example.g00290342bvarley/.MainActivity}
03-05 20:12:10.394: E/SurfaceFlinger(36): ro.sf.lcd_density must be defined as a build property
03-05 20:12:10.954: E/SurfaceFlinger(36): ro.sf.lcd_density must be defined as a build property
03-05 20:12:11.065: W/EGL_emulation(863): eglSurfaceAttrib not implemented
03-05 20:12:11.474: I/QSB.SuggestionsProviderImpl(863): chars:0,corpora:[web, apps, com.android.contacts/.activities.PeopleActivity]
03-05 20:12:11.604: E/SurfaceFlinger(36): ro.sf.lcd_density must be defined as a build property
03-05 20:12:11.744: W/EGL_emulation(449): eglSurfaceAttrib not implemented
03-05 20:12:12.815: I/Choreographer(288): Skipped 32 frames! The application may be doing too much work on its main thread.
03-05 20:12:13.114: D/dalvikvm(863): GC_CONCURRENT freed 398K, 13% free 3825K/4348K, paused 11ms+154ms, total 867ms
03-05 20:12:15.115: I/Process(1467): Sending signal. PID: 1467 SIG: 9
03-05 20:12:15.285: I/WindowState(288): WIN DEATH: Window{40dbdb70 u0 com.example.g00290342bvarley/com.example.g00290342bvarley.MainActivity}
03-05 20:12:15.297: I/ActivityManager(288): Process com.example.g00290342bvarley (pid 1467) has died.
03-05 20:12:15.455: W/InputMethodManagerService(288): Got RemoteException sending setActive(false) notification to pid 1467 uid 10048
03-05 20:12:36.119: D/ExchangeService(688): Received deviceId from Email app: null
03-05 20:12:36.119: D/ExchangeService(688): !!! deviceId unknown; stopping self and retrying
03-05 20:12:41.254: D/ExchangeService(688): !!! EAS ExchangeService, onCreate
03-05 20:12:41.264: D/ExchangeService(688): !!! EAS ExchangeService, onStartCommand, startingUp = false, running = false
03-05 20:12:41.284: W/ActivityManager(288): Unable to start service Intent { act=com.android.email.ACCOUNT_INTENT } U=0: not found
03-05 20:12:41.294: D/ExchangeService(688): !!! Email application not found; stopping self
03-05 20:12:41.304: D/ExchangeService(688): !!! EAS ExchangeService, onStartCommand, startingUp = true, running = false
03-05 20:12:41.334: W/ActivityManager(288): Unable to start service Intent { act=com.android.email.ACCOUNT_INTENT } U=0: not found
03-05 20:12:41.354: E/ActivityThread(688): Service com.android.exchange.ExchangeService has leaked ServiceConnection com.android.emailcommon.service.ServiceProxy$ProxyConnection@40d06b20 that was originally bound here
MainActivity按钮方法所在的位置：import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
//methods for button clicks
public void aboutMeth(View view) {
// Do something in response to button
Intent intent = new Intent(this, AboutGmit.class);
EditText editText = (EditText) findViewById(R.id.about);
startActivity(intent);
}
public void mapMeth(View view) {
// Do something in response to button
Intent intent = new Intent(this, MapGmit.class);
EditText editText = (EditText) findViewById(R.id.map);
startActivity(intent);
}
public void courseMeth(View view) {
// Do something in response to button
Intent intent = new Intent(this, CourseInfo.class);
EditText editText = (EditText) findViewById(R.id.courseInfo);
startActivity(intent);
}
public void lifeMeth(View view) {
// Do something in response to button
Intent intent = new Intent(this, StudentLife.class);
EditText editText = (EditText) findViewById(R.id.studLife);
startActivity(intent);
}
public void portalMeth(View view) {
// Do something in response to button
Intent intent = new Intent(this, StudentPortal.class);
EditText editText = (EditText) findViewById(R.id.studPortal);
startActivity(intent);
}
public void contactMeth(View view) {
// Do something in response to button
Intent intent = new Intent(this, ContactInfo.class);
EditText editText = (EditText) findViewById(R.id.contact);
startActivity(intent);
}
}
新活动称为
ContactInfo.javaimport android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
public class ContactInfo extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_contact_info);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.contact_info, menu);
return true;
}
}
我在其中添加了活动元素的清单文件。
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.g00290342bvarley"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.g00290342bvarley.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="com.example.g00290342bvarley.AboutGmit"
android:label="@string/title_activity_about_gmit"
android:parentActivityName="com.example.g00290342bvarley.MainActivity"
>
</activity>
<activity
android:name="com.example.g00290342bvarley.MapGmit"
android:label="@string/title_activity_map_gmit"
android:parentActivityName="com.example.g00290342bvarley.MainActivity"
>
</activity>
<activity
android:name="com.example.g00290342bvarley.CourseInfo"
android:label="@string/title_activity_course_info"
android:parentActivityName="com.example.g00290342bvarley.MainActivity"
>
</activity>
<activity
android:name="com.example.g00290342bvarley.StudentLife"
android:label="@string/title_activity_student_life"
android:parentActivityName="com.example.g00290342bvarley.MainActivity"
>
</activity>
<activity
android:name="com.example.g00290342bvarley.StudentPortal"
android:label="@string/title_activity_student_portal"
android:parentActivityName="com.example.g00290342bvarley.MainActivity"
>
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="com.example.g00290342bvarley.MainActivity" />
</activity>
<activity
android:name="com.example.g00290342bvarley.ContactInfo"
android:label="@string/title_activity_contact_info"
android:parentActivityName="com.example.g00290342bvarley.MainActivity"
>
</activity>
</application>
</manifest>
activity_main.xml中的按钮布局
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/LinearLayout2"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<Button
android:id="@+id/about"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="0dp"
android:layout_weight="1"
android:onClick="aboutMeth"
android:hint="Details about GMIT"
android:text="@string/about" />
<Button
android:id="@+id/map"
style="?android:attr/buttonStyleSmall"
android:layout_width="95dp"
android:layout_height="0dp"
android:layout_weight="1"
android:onClick="mapMeth"
android:hint="Location of GMIT on google maps"
android:text="@string/map" />
<Button
android:id="@+id/courseInfo"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="0dp"
android:layout_weight="1"
android:onClick="courseMeth"
android:hint="Info about courses offered by GMIT"
android:text="@string/courseInfo" />
<Button
android:id="@+id/studLife"
style="?android:attr/buttonStyleSmall"
android:layout_width="98dp"
android:layout_height="0dp"
android:layout_weight="1"
android:hint="Gallery"
android:onClick="lifeMeth"
android:text="@string/studLife" />
<Button
android:id="@+id/studPortal"
style="?android:attr/buttonStyleSmall"
android:layout_width="93dp"
android:layout_height="0dp"
android:layout_weight="1"
android:onClick="portalMeth"
android:hint="The Student Portal!"
android:text="@string/studPortal" />
<Button
android:id="@+id/contact"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="0dp"
android:layout_weight="1"
android:onClick="contactMeth"
android:hint="GMIT contact info"
android:text="@string/contact" />
</LinearLayout>
最佳答案
我可能会缺少一些东西，但请尝试一下。
在每种onClick方法中，您都试图获得一个editText。
EditText editText = (EditText) findViewById(R.id.contact);
但是在布局中没有声明editText，因此它变成NullPointerException。
尝试删除此行。
希望对你有帮助
关于android - 从主要 Activity 切换到新 Activity 时，应用崩溃，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/15233429/