Programmatisch hinzufügen Schaltfläche auf Android

Question

Ich habe ein Problem, wenn ich versuche, ein ScrollView zu einer LinearLayout-App plötzlich beenden hinzuzufügen.

public class DynamicButtonAdd extends AppCompatActivity { 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

     Button b1=new Button(getBaseContext()); 
     b1.setText("Button 1"); 

     Button b2=new Button(getBaseContext()); 
     b2.setText("Button 2"); 

     Button b3=new Button(getBaseContext()); 
     b3.setText("Button 3"); 

     Button b4=new Button(getBaseContext()); 
     b4.setText("Button 4"); 

     Button b5=new Button(getBaseContext()); 
     b5.setText("Button 5"); 

     Button b6=new Button(getBaseContext()); 
     b6.setText("Button 6"); 

     Button b7=new Button(getBaseContext()); 
     b7.setText("Button 7"); 

     Button b8=new Button(getBaseContext()); 
     b8.setText("Button 8"); 

     Button b9=new Button(getBaseContext()); 
     b9.setText("Button 9"); 

     Button b10=new Button(getBaseContext()); 
     b10.setText("Button 10"); 

     Button b11=new Button(getBaseContext()); 
     b11.setText("Button 1"); 

     Button b12=new Button(getBaseContext()); 
     b12.setText("Button 12"); 

     TableLayout.LayoutParams l=new TableLayout.LayoutParams(); 
     l.width= l.height=Toolbar.LayoutParams.WRAP_CONTENT; 

     b1.setLayoutParams(l); 

     b2.setLayoutParams(l); 
     b3.setLayoutParams(l); 
     b4.setLayoutParams(l); 
     b5.setLayoutParams(l); 
     b6.setLayoutParams(l); 
     b7.setLayoutParams(l); 
     b8.setLayoutParams(l); 
     b9.setLayoutParams(l); 
     b10.setLayoutParams(l); 
     b11.setLayoutParams(l); 
     b12.setLayoutParams(l); 

     ScrollView sv=new ScrollView(getBaseContext()); 
     sv.setFillViewport(true); 


     LinearLayout linear=new LinearLayout(getBaseContext()); 

     sv.addView(linear);// the error appear here if I comment this line works fine without scroll 
     linear.setOrientation(LinearLayout.VERTICAL); 
     linear.setGravity(Gravity.CENTER); 

     linear.addView(b1); 
     linear.addView(b2); 
     linear.addView(b3); 
     linear.addView(b4); 
     linear.addView(b5); 
     linear.addView(b6); 
     linear.addView(b7); 
     linear.addView(b8); 
     linear.addView(b9); 
     linear.addView(b10); 
     linear.addView(b11); 
     linear.addView(b12); 

     setContentView(linear); 
     b1.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 
       Toast.makeText(getBaseContext(),"Clicked",Toast.LENGTH_SHORT).show(); 
      } 
     }); 
    } 
} 

Die Ausnahme, die angezeigt wird:

08-08 16:42:39.140 26674-26674/com.example.sid.test D/AndroidRuntime: Shutting down VM 
08-08 16:42:39.140 26674-26674/com.example.sid.test W/dalvikvm: threadid=1: thread exiting with uncaught exception (group=0xb60ab4f0) 
08-08 16:42:39.144 26674-26674/com.example.sid.test E/AndroidRuntime: FATAL EXCEPTION: main 
                     java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.sid.test/com.example.sid.test.DynamicButtonAdd}: java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first. 
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647) 
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 
                      at android.app.ActivityThread.access$1500(ActivityThread.java:117) 
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) 
                      at android.os.Handler.dispatchMessage(Handler.java:99) 
                      at android.os.Looper.loop(Looper.java:130) 
                      at android.app.ActivityThread.main(ActivityThread.java:3683) 
                      at java.lang.reflect.Method.invokeNative(Native Method) 
                      at java.lang.reflect.Method.invoke(Method.java:507) 
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 
                      at dalvik.system.NativeStart.main(Native Method) 
                     Caused by: java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first. 
                      at android.view.ViewGroup.addViewInner(ViewGroup.java:1976) 
                      at android.view.ViewGroup.addView(ViewGroup.java:1871) 
                      at android.view.ViewGroup.addView(ViewGroup.java:1828) 
                      at android.view.ViewGroup.addView(ViewGroup.java:1808) 
                      at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:271) 
                      at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:145) 
                      at com.example.sid.test.DynamicButtonAdd.onCreate(DynamicButtonAdd.java:106) 
                      at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)  
                      at android.app.ActivityThread.access$1500(ActivityThread.java:117)  
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)  
                      at android.os.Handler.dispatchMessage(Handler.java:99)  
                      at android.os.Looper.loop(Looper.java:130)  
                      at android.app.ActivityThread.main(ActivityThread.java:3683)  
                      at java.lang.reflect.Method.invokeNative(Native Method)  
                      at java.lang.reflect.Method.invoke(Method.java:507)  
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)  
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)  
                      at dalvik.system.NativeStart.main(Native Method)  

Ich kümmere mich nicht über das Verfahren, wenn überhaupt nützlich Schema Sie mir bitte sagen wissen. Eine weitere Sache ist ein Mindest-API-Level von 8 (Android 2.2).

Answer 1

Es gibt einige Probleme mit Ihrem Code. Dasjenige, das den Absturz verursacht, ist, dass Sie Ihre LinearLayout zu Ihrer ScrollView hinzufügen und dann setContentView(linear) aufrufen, d. H. Sie fügen Ihre LinearLayout zu Ihrer Tätigkeit und der ScrollView hinzu. Wahrscheinlich wollten Sie die ScrollView als Inhalt festlegen. Daher ist die einfache Lösung ist:

ScrollView sv=new ScrollView(getBaseContext()); 
sv.setFillViewport(true); 

LinearLayout linear=new LinearLayout(getBaseContext()); 
sv.addView(linear); 
... 
setContentView(sv); // you have linear here 

Zweitens ist das Problem:

TableLayout.LayoutParams l=new TableLayout.LayoutParams(); 
l.width= l.height=Toolbar.LayoutParams.WRAP_CONTENT; 

Du diese LayoutParam auf Ihre Button Instanzen einstellen, die zu einer LinearLayout hinzugefügt werden. Sie sollten die Layout params der Mutter gesetzt ViewGroup hier:

LinearLayout.LayoutParams l=new LinearLayout.LayoutParams(); 
l.width = l.height = LinearLayout.LayoutParams.WRAP_CONTENT; 

Drittens: Ich habe ein leichtes Gefühl (und ich könnte falsch sein, da ich nicht weiß, die wahre Verwendung Fall ist), können Sie zumindest einige bewegen dieser Layout-Beschreibung zu und XML-Datei