我正在製作一個android應用程序,最初用戶可以看到「GO」按鈕。單擊按鈕時,將顯示一個新的相對佈局,其中有幾個選項按鈕,即「添加」和「減法」。 然後,我嘗試獲取用戶點擊哪個按鈕,並相應地呈現該組問題。 但是,一旦該GO按鈕被點擊應用程序崩潰.. 我的代碼檢查哪個按鈕是點擊---在android中找到一個按鈕「tag」
public void start(View view)
{
startbutton.setVisibility(View.INVISIBLE);
Log.i("YO:", "Start button ok!");
optionRelativeLayout.setVisibility(RelativeLayout.VISIBLE);
int tag = (Integer) view.getTag();
if(tag==4)
additionrelativelayout.setVisibility(RelativeLayout.VISIBLE);
if(tag==5)
subtractionrelativelayout.setVisibility(RelativeLayout.VISIBLE);
}
的XML代碼是
<Button
android:text="Go!"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"
android:id="@+id/start_button"
android:textSize="80sp"
android:paddingBottom="50dp"
android:paddingEnd="50dp"
android:paddingLeft="50dp"
android:paddingRight="50dp"
android:paddingStart="50dp"
android:paddingTop="50dp"
android:background="@android:color/holo_green_light"
android:onClick="start"
android:visibility="visible" />
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/optionrelativlayout"
android:visibility="visible">
<Button
android:text="Addition"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:tag="4 "
android:layout_centerHorizontal="true"
android:layout_marginTop="45dp"
android:id="@+id/addition" />
<Button
android:text="Button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:tag="5"
android:layout_centerHorizontal="true"
android:id="@+id/subtraction"
android:layout_marginTop="150dp" />
</RelativeLayout>
的錯誤是
04-24 22:21:39.525 10853-10853/com.example.rohit_136.brain_trainer I/YO:: Start button ok!
04-24 22:21:39.527 10853-10853/com.example.rohit_136.brain_trainer E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.rohit_136.brain_trainer, PID: 10853
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
at android.view.View.performClick(View.java:5226)
at android.view.View$PerformClick.run(View.java:21350)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5582)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:5226)
at android.view.View$PerformClick.run(View.java:21350)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5582)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.Integer.intValue()' on a null object reference
at com.example.rohit_136.brain_trainer.MainActivity.start(MainActivity.java:177)
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:5226)
at android.view.View$PerformClick.run(View.java:21350)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5582)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
04-24 22:21:39.535 10853-10865/com.example.rohit_136.brain_trainer I/ActivityThreadEui: schedulePauseActivity com.example.rohit_136.brain_trainer.MainActivity finished=true userLeaving=false configChanges=0 dontReport=false
04-24 22:21:41.098 10853-10853/com.example.rohit_136.brain_trainer I/Process: Sending signal. PID: 10853 SIG: 9
您的描述不符在'xml'東西是什麼'GO'?發佈你的堆棧跟蹤,否則我們無法猜測出錯的地方。 – Pztar
更新錯誤日誌! – Rohit