Question

Iam试图只用一个按钮来保留一个简单的片段。但是它会像这样出现2次

我有一个线性布局和另一个嵌套的线性布局。这些都存在于activity_welcome.xml中，其内容如下：

<?xml version="1.0" encoding="utf-8"?>
<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:background="#99cc00"
    android:orientation="vertical"
    tools:context="com.acs.AfterLogin.WelcomeActivity">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/replacable_container"
        android:orientation="vertical">
    </LinearLayout>

</LinearLayout>

Iam尝试用java类为的片段替换replacable_container（Linear Layout）：

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v7.widget.CardView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;

import com.acs.AfterLogin.WelcomeActivity;
import com.acs.R;
import com.squareup.picasso.Picasso;

import de.hdodenhof.circleimageview.CircleImageView;



public class WelcomeFragment1 extends Fragment{

    View v;
    CardView cardView1,cardView2,cardView3;
    CircleImageView userIcon;
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        v=inflater.inflate(R.layout.welcome_fragment_1,container);
        return inflater.inflate(R.layout.welcome_fragment_1,container,false);
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
    }
}

片段的xml内容是：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="#e0ebe5"
    android:orientation="vertical">
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="hello"/>
</LinearLayout>

片段转换等操作包含在mainactivity中，其java代码为：

import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import com.acs.AfterLogin.WelcomeFragments.WelcomeFragment1;
import com.acs.R;
import com.squareup.picasso.Picasso;

import de.hdodenhof.circleimageview.CircleImageView;


public class WelcomeActivity extends AppCompatActivity {
    FragmentTransaction transaction;
    WelcomeFragment1 frag1;
    FragmentManager manager;
    String imageUri;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_welcome);
        (new FragTask()).execute();
    }
    private class FragTask extends AsyncTask<Void, Void, Void> {
        @Override
        protected Void doInBackground(Void... voids) {
            transaction = manager.beginTransaction();
            frag1 = new WelcomeFragment1();
            transaction.replace(R.id.replacable_container, frag1, "welcome_1");
            transaction.commit();
            return null;
        }
    }
}

提前多多感谢：）

Answer 1

尝试更改此行

v=inflater.inflate(R.layout.welcome_fragment_1,container);

到

v=inflater.inflate(R.layout.welcome_fragment_1,container, false);

返回膨胀的视图。布尔值表示您不希望将视图附加到容器。检查this。片段将在稍后自行附加。

Answer 2

请返回虚高的视图，而不是在return语句中再次充气。

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
 v=inflater.inflate(R.layout.welcome_fragment_1,container);
 return v;
}

Android中的片段不必要地重复多次

2 个答案: