Question

我正在为Android创建一个简单的应用。

我有一个主要活动和两个片段。

Main布局包含一个片段容器：

    <?xml version="1.0" encoding="utf-8"?>
    <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:id="@+id/main_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:background="#6940">

<Button
    android:id="@+id/prevBtn"
    android:layout_width="160dp"
    android:layout_height="40dp"
    android:layout_marginBottom="16dp"
    android:layout_marginStart="20dp"
    android:clickable="false"
    android:onClick="prevWord"
    android:text="Previous"
    android:background="#ff4444"
    android:textColor="@android:color/white"
    android:textSize="25sp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintLeft_toLeftOf="@+id/nextBtn"
    app:layout_constraintStart_toStartOf="parent" />

<Button
    android:id="@+id/nextBtn"
    android:layout_width="160dp"
    android:layout_height="40dp"
    android:layout_marginBottom="16dp"
    android:layout_marginRight="36dp"
    android:background="#ff4444"
    android:clickable="false"
    android:onClick="nextWord"
    android:text="Next"
    android:textColor="@android:color/white"
    android:textSize="25sp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintRight_toRightOf="parent" />

<ImageView
    android:id="@+id/wordImage"
    android:layout_width="275dp"
    android:layout_height="219dp"
    android:layout_marginBottom="10dp"
    android:layout_marginTop="20dp"
    app:layout_constraintBottom_toTopOf="@+id/radioButton1"
    app:layout_constraintHorizontal_bias="0.504"
    app:layout_constraintHorizontal_weight="1"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    tools:ignore="NotSibling" />

<Button
    android:id="@+id/audioBtn"
    android:layout_width="136dp"
    android:layout_height="40dp"
    android:layout_marginStart="32dp"
    android:layout_marginTop="79dp"
    android:background="@android:color/holo_green_light"
    android:onClick="playAudio"
    android:text="Audio"
    android:textSize="24sp"
    app:layout_constraintLeft_toLeftOf="@+id/radioWords"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/wordImage" />

<RadioGroup
    android:id="@+id/radioWords"
    android:layout_width="wrap_content"
    android:layout_height="174dp"
    android:layout_marginTop="20dp"
    app:layout_constraintHorizontal_bias="0.778"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/wordImage">

    <RadioButton
        android:id="@+id/radioButton1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="10dp"
        android:layout_marginTop="8dp"
        android:checked="false"
        android:text="@string/word1"
        android:textSize="34sp"
        app:layout_constraintBottom_toTopOf="@+id/radioButton2"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/wordImage" />

    <RadioButton
        android:id="@+id/radioButton2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="10dp"
        android:text="@string/word2"
        android:textSize="34sp"
        app:layout_constraintBottom_toTopOf="@+id/radioButton3"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent" />

    <RadioButton
        android:id="@+id/radioButton3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="10dp"
        android:text="@string/word3"
        android:textSize="34sp"
        app:layout_constraintBottom_toTopOf="@+id/audioBtn"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent" />
</RadioGroup>

<RelativeLayout
    android:id="@+id/fragmentContainer"
    android:layout_width="match_parent"
    android:layout_height="238dp"
    android:layout_marginTop="10dp"
    app:layout_constraintTop_toTopOf="parent">

</RelativeLayout>

这两个片段的布局和类都已创建。其中之一是：

  public class resultsFrag extends android.app.Fragment {

      public static TextView attempts, correct;

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.resultsfragment, container, false);
        attempts = view.findViewById(R.id.attemptsTxt);
        correct = view.findViewById(R.id.correctTxt);

//（（MainActivity）getActivity（））。setViewPager（0）;

        return view;
    }
}

现在，从我的MainActivity，我想将片段容器设置为fragment1，然后设置为fragment2，并在字段'尝试'和'正确'中设置相应的值。

   FragmentManager fragmentMgr = getFragmentManager();
    android.app.FragmentTransaction fragTransaction = fragmentMgr.beginTransaction();
    niceWorkFrag nwork = new niceWorkFrag();
    fragTransaction.add(R.id.fragmentContainer, nwork);
    fragTransaction.commit();

    try {
        Thread.sleep(1000);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }

    fragmentMgr = getFragmentManager();
    fragTransaction = fragmentMgr.beginTransaction();
    resultsFrag res = new resultsFrag();
    fragTransaction.replace(R.id.fragmentContainer, res);
    fragTransaction.commit();

但我无法访问字段'尝试'和'正确'。变量总是为空。

    TextView att = findViewById(R.id.attemptsTxt);
    att.setText(attemptsTotal);
    TextView corr = findViewById(R.id.correctTxt);
    corr.setText(correct);

Answer 1

最后，我不得不在Bundle中传递变量。

如何访问片段中的字段

1 个答案: