从活动切换到MapActivity
问题描述:
Button showmapButton = (Button)findViewById(R.id.showmap);
showmapButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent intent = new Intent(HomePage.this,
ShowMap.class);
intent.putExtra("username", value);
startActivity(intent);
}
});
在我的主菜单我有一个按钮“ShowMap” 每次我showmap我的地图上点击会打一个空指针异常导致程序崩溃。 'ShowMap'works fi ne如果我直接进入该页面而不需要点击按钮来调用该活动。从活动切换到MapActivity
我想我的所有文件更改为“扩展MapActivity”,而不是常规的activitiy但程序每当我上显示地图点击
D/AndroidRuntime( 347): Shutting down VM
W/dalvikvm( 347): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
E/AndroidRuntime( 347): FATAL EXCEPTION: main
E/AndroidRuntime( 347): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mp/com.mp.ShowMap}: java.lang.NullPointerException
E/AndroidRuntime( 347): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
E/AndroidRuntime( 347): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
E/AndroidRuntime( 347): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
E/AndroidRuntime( 347): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
E/AndroidRuntime( 347): at android.os.Handler.dispatchMessage(Handler.java:99)
E/AndroidRuntime( 347): at android.os.Looper.loop(Looper.java:123)
E/AndroidRuntime( 347): at android.app.ActivityThread.main(ActivityThread.java:4627)
E/AndroidRuntime( 347): at java.lang.reflect.Method.invokeNative(Native Method)
E/AndroidRuntime( 347): at java.lang.reflect.Method.invoke(Method.java:521)
E/AndroidRuntime( 347): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
E/AndroidRuntime( 347): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
E/AndroidRuntime( 347): at dalvik.system.NativeStart.main(Native Method)
E/AndroidRuntime( 347): Caused by: java.lang.NullPointerException
E/AndroidRuntime( 347): at com.mp.ShowMap.onCreate(ShowMap.java:46)
E/AndroidRuntime( 347): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
E/AndroidRuntime( 347): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
E/AndroidRuntime( 347): ... 11 more
答
好的球员,我发现我的NPE仍然会崩溃!
(前)
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.main);
(后)
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.map);
,因为我们正试图整合出来的分配某些纰漏!
谢谢大家:d
答
Intent intent = new Intent();
intent.setClass(AndroidGPSTrackingActivity.this, mapslayout.class);
startActivity(intent);
<uses-library
android:name="com.google.android.maps"
android:required="true" />**
精神加入这行导致空指针异常? – 2010-08-30 10:17:18
“value”的定义在哪里?这是唯一可能导致NPE的事情 – Falmarri 2010-08-30 10:20:23