Question

我正在尝试创建一个Android应用程序。它有两个活动：MainActivity和Activity_Service。在MainActivity中，有一个用于传递给Activity_Service的按钮“service”。我想从MainActivity向Activity_Service发送一个字符串，然后在textview中显示它。我想告诉你代码。在MainActivity中创建Intent：

service.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                String message = "bla bla bla";
                Intent intent = new Intent(MainActivity.this, ActivityService.class);
                intent.putExtra("message", message);
                startActivity(intent);

            }
        });

Activity_Service中的onCreate（）方法：

public class ActivityService extends ActionBarActivity {

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

    if (savedInstanceState == null) {
        getSupportFragmentManager().beginTransaction()
                .add(R.id.container, new PlaceholderFragment()).commit();
    }
    Bundle bundle = getIntent().getExtras();
    String message = bundle.getString("message");
    System.out.println(message);
    //TextView txtView = new TextView(this); 
    TextView txtView = (TextView)findViewById(R.id.name);
    txtView.setText(message);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {

    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.activity, 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_activity,
                container, false);
        return rootView;
    }
}

}

Eclipse创建新活动（Activity_Service）时创建的XML文件： activity_service.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.alljoynandroid.ActivityService"
tools:ignore="MergeRootFrame" />

Fragment_activity.xml

<LinearLayout 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"
android:orientation="vertical"
tools:context="com.example.alljoynandroid.ActivityService$PlaceholderFragment" >

<TextView
    android:id = "@+id/name"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

在Activity_Service的onCreate（）方法中，如果我使用TextView txtView = new TextView(this);，它可以工作：它可以从MainActivity传递给Activity_Service，但是我们不能setText。另一方面，如果我使用TextView txtView = (TextView)findViewById(R.id.name);，则它不起作用。你能帮我解决一下吗？我试了2天，现在我不知道。

Answer 1

从Activity

中删除此代码部分

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

并更改

setContentView(R.layout.activity_service);

到

setContentView(R.layout.fragment_activity);

无法更改Android上第二个活动的TextView中的文本

1 个答案: