Here is my MainActivity :
public class MainActivity extends ActionBarActivity implements CompoundButton.OnCheckedChangeListener {
CheckBox cb;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getCheckBox();
/*
cb = (CheckBox) super.findViewById(R.id.checkbox);
cb.setOnCheckedChangeListener(this);
*/
}
public void getCheckBox(){
cb = (CheckBox) super.findViewById(R.id.checkbox);
cb.setOnCheckedChangeListener(this);
}
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if(buttonView.getId()==R.id.checkBox){
TextView tv = (TextView) findViewById(R.id.textView);
tv.setText(buttonView.getText().toString());
}
}
}
And here my layout :
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">
<CheckBox
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="My One"
android:id="@+id/checkBox"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginBottom="160dp" />
<CheckBox
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="My Two"
android:id="@+id/checkBox2"
android:layout_alignTop="@+id/checkBox"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginTop="40dp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceSmall"
android:text="Small Text"
android:id="@+id/textView"
android:layout_below="@+id/radioGroup"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:textSize="50dp" />
</RelativeLayout>
I get the following exceptions when i run
02-20 15:55:28.130 2110-2110/sqllistviewdemo.wptrafficanalyzer.in.radiobutton E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: sqllistviewdemo.wptrafficanalyzer.in.radiobutton, PID: 2110
java.lang.RuntimeException: Unable to start activity ComponentInfo{sqllistviewdemo.wptrafficanalyzer.in.radiobutton/sqllistviewdemo.wptrafficanalyzer.in.radiobutton.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.CheckBox.setOnCheckedChangeListener(android.widget.CompoundButton$OnCheckedChangeListener)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.CheckBox.setOnCheckedChangeListener(android.widget.CompoundButton$OnCheckedChangeListener)' on a null object reference
at sqllistviewdemo.wptrafficanalyzer.in.radiobutton.MainActivity.getCheckBox(MainActivity.java:34)
at sqllistviewdemo.wptrafficanalyzer.in.radiobutton.MainActivity.onCreate(MainActivity.java:27)
at android.app.Activity.performCreate(Activity.java:5933)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
????????????at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
????????????at android.app.ActivityThread.access$800(ActivityThread.java:144)
????????????at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
????????????at android.os.Handler.dispatchMessage(Handler.java:102)
????????????at android.os.Looper.loop(Looper.java:135)
????????????at android.app.ActivityThread.main(ActivityThread.java:5221)
????????????at java.lang.reflect.Method.invoke(Native Method)
????????????at java.lang.reflect.Method.invoke(Method.java:372)
????????????at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
????????????at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Can you please guide me ? how do you work with checkbox if you don't want to use a button click listener ?
Thanks a lot in advance :)
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