Android应用程序部队在关闭另一个活动时关闭
我正在制作一个使用android 2.2和eclipse的android应用程序。Android应用程序部队在关闭另一个活动时关闭
有应用的两个工作流:
WF1:CoverPageApp -> LoginActivity -> Dashboard.
WF2:CoverPageApp -> RegisterActivity -> Dashboard.
但是当我点击在CoverPageApp开始按钮去另一个活动,即LoginActivity,应用程序部队关闭。 我也包括这表明空异常的LoginActivity的Java和错误文件指向上线51 logcat的: btnLinkToRegistrScrn = (Button) findViewById(R.id.LinkToRegisterScreen);
AndroidManifest.xml中
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.app.android"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:targetSdkVersion="15" android:minSdkVersion="8" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.INTERNET" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:enabled="true"
android:name=".PageApp"
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:enabled="true"
android:name=".LoginActivity1"
android:label="Login Activity" >
</activity>
<activity
android:enabled="true"
android:name=".CAActivity"
android:label="Register Activity" >
</activity>
<activity
android:enabled="true"
android:name=".DashboardActivity"
android:label="Dashboard Activity" >
</activity>
</application>
</manifest>
PageApp.java
import android.app.Activity;
import android.os.Bundle;
//import android.content.Context;
import android.content.Intent;
import android.widget.Button;
import android.view.View;
public class PageApp extends Activity {
Button startbutton;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.coverpage);
addListenerOnButton();
}
public void addListenerOnButton() {
//final Context context1 = this;
startbutton = (Button) findViewById(R.id.button1);
startbutton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
Intent intent1 = new Intent(arg0.getContext(), LoginActivity1.class);
// intent1.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent1);
finish();
}
});
}
}
Log.java
import android.app.Activity;
//import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
//import android.view.View.OnClickListener;
import android.widget.Button;
//import android.widget.TextView;
public class Log extends Activity {
Button btnLinkToRegistrScrn;
Button loginbtn1;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.login);
addListenerOnButton();
// btnLinkToRegistrScrn = (Button) findViewById(R.id.LinkToRegisterScreen);
}
public void addListenerOnButton() {
//final Context context2 = this;
loginbtn1 = (Button) findViewById(R.id.btnLogin);
loginbtn1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
Intent intent = new Intent(arg0.getContext(), DashboardActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
}
});
}
{
// Link to Register Screen
btnLinkToRegistrScrn = (Button) findViewById(R.id.LinkToRegisterScreen);
btnLinkToRegistrScrn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent i = new Intent(v.getContext(), CAaactivity.class);
// i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);
}
});
}
}
logcat的
05-31 17:53:19.691: D/AndroidRuntime(1958): Shutting down VM
05-31 17:53:19.710: W/dalvikvm(1958): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
05-31 17:53:19.730: E/AndroidRuntime(1958): FATAL EXCEPTION: main
05-31 17:53:19.730: E/AndroidRuntime(1958): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2585)
05-31 17:53:19.730: E/AndroidRuntime(1958): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
05-31 17:53:19.730: E/AndroidRuntime(1958): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
05-31 17:53:19.730: E/AndroidRuntime(1958): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
05-31 17:53:19.730: E/AndroidRuntime(1958): at android.os.Handler.dispatchMessage(Handler.java:99)
05-31 17:53:19.730: E/AndroidRuntime(1958): at android.os.Looper.loop(Looper.java:123)
05-31 17:53:19.730: E/AndroidRuntime(1958): at android.app.ActivityThread.main(ActivityThread.java:4627)
05-31 17:53:19.730: E/AndroidRuntime(1958): at java.lang.reflect.Method.invokeNative(Native Method)
05-31 17:53:19.730: E/AndroidRuntime(1958): at java.lang.reflect.Method.invoke(Method.java:521)
05-31 17:53:19.730: E/AndroidRuntime(1958): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
05-31 17:53:19.730: E/AndroidRuntime(1958): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
05-31 17:53:19.730: E/AndroidRuntime(1958): at dalvik.system.NativeStart.main(Native Method)
05-31 17:53:19.730: E/AndroidRuntime(1958): Caused by: java.lang.NullPointerException
05-31 17:53:19.730: E/AndroidRuntime(1958): at android.app.Activity.findViewById\untime(1958): at java.lang.Class.newInstanceImpl(Native Method)
05-31 17:53:19.730: E/AndroidRuntime(1958): at java.lang.Class.newInstance(Class.java:1429)
05-31 17:53:19.730: E/AndroidRuntime(1958): at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
05-31 17:53:19.730: E/AndroidRuntime(1958): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2577)
05-31 17:53:19.730: E/AndroidRuntime(1958): ... 11 more
改变你LoginActivity1活动为:
public class LoginActivity1 extends Activity {
Button btnLinkToRegistrScrn;
Button loginbtn1;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.login);
addListenerOnButton();
// Link to Register Screen
btnLinkToRegistrScrn = (Button) findViewById(R.id.LinkToRegisterScreen);
btnLinkToRegistrScrn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent i = new Intent(v.getContext(), TrekEyesAndroidActivity.class);
// i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);
}
});
}
public void addListenerOnButton() {
//final Context context2 = this;
loginbtn1 = (Button) findViewById(R.id.btnLogin);
loginbtn1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
Intent intent = new Intent(arg0.getContext(), DashboardActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
}
});
}
}
,并在XML改变的TextView到按钮作为
<Button
android:id="@+id/LinkToRegisterScreen"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginTop="25dip"
android:textColor="#21dbd4"
android:textStyle="bold"
android:text="@string/noAccountRegisterME" />
你宣布
<TextView
android:id="@+id/LinkToRegisterScreen"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
,并同时映射LoginActivity1.java
btnLinkToRegistrScrn = (Button) findViewById(R.id.LinkToRegisterScreen);
所以才改变TextView
到Button
<Button
android:id="@+id/LinkToRegisterScreen"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
谢谢!它解决了一半的问题,但是imran khan的答案解决了整个问题。不管怎么说,还是要谢谢你。:) –
在您的登录。 xml
<TextView
android:id="@+id/LinkToRegisterScreen"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginTop="25dip"
android:textColor="#21dbd4"
android:textStyle="bold"
android:text="@string/noAccountRegisterME" />
android:id="@+id/LinkToRegisterScreen"
,这是EditText上和你正在做btnLinkToLoginScrn = (Button) findViewById(R.id.LinkToLoginScreen);
所以这将是空指针..
所以只是改变按钮,而不是TextView的在你的login.xml
它不是'EditText',它是'TextView'。 –
@CapDroid谢谢! –
我觉得你应该集中大括号。你给代码添加listeneraddListenerOnButton()
如果您在'addListenerOnButton()'中同时映射这两个按钮,会有什么区别? –
@imran khan谢谢你这么多:)我一直在处理这个错误的1周,今天你在我的应用程序中解决了这个最大的错误。 ThankYou非常感谢:)我非常感谢你的帮助。现在我的应用程序运行顺利。 :))))) –
@hotveryspicy:没问题,他可以同时在'addListenerOnButton()'中映射这两个按钮并使用相同的 –