清除 EditText 字段按钮中的所有文本

Question

I am trying to run a programme in Android to clear all text in the EditText fields when the user presses the clear all button. Below is the code I have so far and at the moment it is not working as planned. I am new to java and adroid app development. Kindly let me know how I can resolve this problem, with examples,if possible. Many thanks in advance.

CEMMainActivity.java

public class CEMMainActivity extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) { // runs every time the app runs
    super.onCreate(savedInstanceState); // loads saved instant state
    setContentView(R.layout.activity_cemmain);//sets what the app will look like based on the graphical design created

    if (savedInstanceState == null) {// action if app does not start up correctly
        getSupportFragmentManager().beginTransaction()
                .add(R.id.container, new PlaceholderFragment()).commit();
    }

    // Clears all text in EditText fields

    Button clearalltext  = (Button) findViewById(R.id.cleartext); 
    clearalltext.setOnClickListener(new OnClickListener() {
        public void onClick(View c) {           
        ViewGroup group = (ViewGroup) findViewById(R.id.cleartext);
        clearText(group);       
        });
    }

        private void clearText((ViewGroup)group); {
            // TODO Auto-generated method stub
            for (int i = 0, count = group.getChildCount(); i < count; ++i) {
        View view = group.getChildAt(i);
        if (view instanceof EditText) {
            ((EditText)view).setText("");

        ViewGroup view;
        if(view instanceof ViewGroup && (((ViewGroup)view).getChildCount() > 0))
            clearText((ViewGroup)group);
        }
        }
            }

fragment_cemmain.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="clinical.equipment.monitor.CEMMainActivity$PlaceholderFragment" >
.....

<Button
    android:id="@+id/cleartext"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/findequip"
    android:layout_marginTop="56dp"
    android:onClick="cleartext"
    android:text="@string/cleartext" />

....

</RelativeLayout>

Answer 1

(ViewGroup) findViewById(R.id.cleartext); i think cleartext is button not a viewgroup you can use getParent() method of onclick argument parameter c like c.getParent() which return ViewGroup Relative Layout then you can fetch all children which wil define by you in clearText Method ...

or you can give id to relativelayout also

  // Clears all text in EditText fields

    Button clearalltext  = (Button) findViewById(R.id.cleartext); 
    clearalltext.setOnClickListener(new OnClickListener() {
        public void onClick(View c) {           
        ViewGroup group = (ViewGroup) c.getParent();
        clearText(group);       
        });
    }

Answer 2

I think problem with you are passing button id to view group so its child count will be zero.please pass you parent layout id to view group . make changes to below id

ViewGroup group = (ViewGroup) findViewById(R.id.cleartext);

replace cleartext with your parent layout id. ie RelativeLayout id

Answer 3

 ViewGroup group = (ViewGroup) findViewById(R.id.cleartext); 

It will access button and will only clear text of the button. Assign an id to RelativeLayout and use it to clear text of all the childs.