如何在Fragment中使用findViewById？

How to use findViewById in Fragment?

本示例演示有关如何在Fragment中使用findViewById

步骤1 ？在Android Studio中创建一个新项目，转到文件？新建项目，并填写所有必需的详细信息以创建一个新项目。

第2步？将以下代码添加到res / layout / activity_main.xml。

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<?xml version ="1.0" encoding ="utf-8"?>
<LinearLayout xmlns:android ="http://schemas.android.com/apk/res/android"
android:orientation ="vertical"
android:layout_width ="match_parent"
android:layout_height ="match_parent">
<LinearLayout
android:id ="@+id/linearlayout01"
android:layout_width ="fill_parent"
android:layout_height ="fill_parent"
android:background ="#ccc"
android:layout_weight ="1"
android:orientation ="vertical">
<fragment android:name ="com.example.myapplication.FirstFragment"
android:id ="@+id/frag_1"
android:layout_width ="fill_parent"
android:layout_height ="fill_parent" />
</LinearLayout>
<LinearLayout
android:id ="@+id/linearlayout02"
android:layout_width ="fill_parent"
android:layout_height ="fill_parent"
android:layout_weight ="1"
android:background ="#eee"
android:orientation ="vertical">
<fragment android:name ="com.example.myapplication.SecondFragment"
android:id ="@+id/frag_2"
android:layout_width ="fill_parent"
android:layout_height ="fill_parent" />
</LinearLayout>
</LinearLayout>

在上面的代码中，我们截取了两个片段。

第3步？将以下代码添加到src / MainActivity.java中

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<?xml version ="1.0" encoding ="utf-8"?>
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
public class MainActivity extends FragmentActivity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}

第四步？将以下代码添加到src / FirstFragment.java

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<?xml version ="1.0" encoding ="utf-8"?>
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class FirstFragment extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
ViewGroup root = (ViewGroup) inflater.inflate(R.layout.fragment, null);
TextView but = (TextView) root.findViewById(R.id.text);
return root;
}
}

第四步？将以下代码添加到src / SecondFragment.java中

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<?xml version ="1.0" encoding ="utf-8"?>
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class SecondFragment extends Fragment {
TextView textView;
View view;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
view = inflater.inflate(R.layout.fragment, container, false);
return view;
}
}

让我们尝试运行您的应用程序。我假设您已将实际的Android Mobile设备与计算机连接。要从android studio运行该应用，请打开您项目的活动文件之一，然后从工具栏中单击运行 icon。选择您的移动设备作为选项，然后检查将显示默认屏幕的移动设备–

点击这里下载项目代码