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);
}
});
在我的主菜单中,我有一个按钮'ShowMap' 每次我点击showmap我的地图都会遇到空指针异常,导致程序崩溃。 'ShowMap'适用于fi 如果我直接启动该页面而无需点击按钮来调用该活动。
我尝试将所有文件更改为“扩展MapActivity”而不是常规活动,但只要我点击“显示地图”,程序仍会崩溃
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
答案 0 :(得分:0)
好吧,伙计们,我找到了我的NPE!
(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作业,所以有些粗心的错误!
谢谢大家:D
答案 1 :(得分:0)
Intent intent = new Intent();
intent.setClass(AndroidGPSTrackingActivity.this, mapslayout.class);
startActivity(intent);
<uses-library
android:name="com.google.android.maps"
android:required="true" />**