Android FragmentActivity 问题

Question

您好，您可以在这里查看我的代码。我的问题是:使用这段代码，我的 EditText 和我的 Button 字段为空，所以我无法对它们执行任何操作。

请你帮我访问这个按钮。对于由 eclipse 自动生成的 Activity 。

public class MainActivity extends ActionBarActivity {

private EditText commentaire;
private Button addReleve;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    if (savedInstanceState == null) {
        getSupportFragmentManager().beginTransaction()
                .add(R.id.container, new PlaceholderFragment()).commit();
    }

    this.commentaire = (EditText) findViewById(R.id.commentaire);
    this.addReleve = (Button) findViewById(R.id.addReleve);

    addReleve.setOnTouchListener(new OnTouchListener() {

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            Toast toast = Toast.makeText(getApplicationContext(), "LOL", Toast.LENGTH_LONG);
            toast.show();
            return false;
        }
    });
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {

    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

/**
 * A placeholder fragment containing a simple view.
 */
public static class PlaceholderFragment extends Fragment {

    public PlaceholderFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_main, container,
                false);
        return rootView;
    }
}

public void resetInterface(){

    this.commentaire.setText("");
    this.addReleve.setEnabled(true);
}

}

XML 布局(fragment_main.xml):

<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: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="com.example.relevegps.MainActivity$PlaceholderFragment" >

<TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="32dp"
    android:text="Relevé GPS"
    android:textAppearance="?android:attr/textAppearanceLarge" />

<Button
    android:id="@+id/addReleve"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:layout_marginBottom="92dp"
    android:text="Ajouter le relevé" />

<EditText
    android:id="@+id/commentaire"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true"
    android:ems="10" />

<TextView
    android:id="@+id/textView2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/commentaire"
    android:layout_centerHorizontal="true"
    android:layout_marginBottom="26dp"
    android:text="Commentaire" />
 </RelativeLayout>

Answer 1

try this also.
public static class PlaceholderFragment extends Fragment {

    public PlaceholderFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_main, container,
                false);
EditText commentaire = (EditText) rootView.findViewById(R.id.commentaire);
    Button addReleve = (Button)  rootView.findViewById(R.id.addReleve);

 commentaire.setText("");
addReleve.setEnabled(true);
        return rootView;
    }

    // Also this goes in this class
    public void resetInterface(){
        this.commentaire.setText("");
        this.addReleve.setEnabled(true);
    }
}