android - 在android中访问动态生成的 View 的元素

Question

我通过预定义的 XML 在 android 中生成动态 View 。代码如下。我可以使用 card_identifier sting 为不同布局中的每个元素分配操作。问题是我无法访问动态布局中的元素，例如如果我想使用 sw1.setCheched(true) 在动态 View 1 中设置开关 1，那么如何处理该元素？

布局是这样的:

代码:

public void threeSwitchLayout(String card_name, String card_identifier) {

    // Generate dynamic layout
    LayoutInflater layoutInflater = (LayoutInflater) getBaseContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    // Use demo.xml to create layout
    final View addView = layoutInflater.inflate(R.layout.demo, null);

    final TextView cardTitle = (TextView)addView.findViewById(R.id.cardTitle);
    cardTitle.setText(card_name);

    final TextView cardIdentifier = (TextView)addView.findViewById(R.id.cardIdentifier);
    cardIdentifier.setText(card_identifier);

    LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
    layoutParams.setMargins(0, 0, 0, 15);
    addView.setLayoutParams(layoutParams);

    SwitchCompat sw1 = (SwitchCompat)addView.findViewById(R.id.switch1);
    SwitchCompat sw2 = (SwitchCompat)addView.findViewById(R.id.switch2);
    SwitchCompat sw3 = (SwitchCompat)addView.findViewById(R.id.switch3);

    sw1.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            Toast.makeText(getBaseContext(), cardIdentifier.getText().toString() + ":SW1 " + isChecked, Toast.LENGTH_SHORT).show();
        }
    });

    sw2.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            Toast.makeText(getBaseContext(), cardIdentifier.getText().toString() + ":SW2 " + isChecked, Toast.LENGTH_SHORT).show();
        }
    });

    sw3.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            Toast.makeText(getBaseContext(), cardIdentifier.getText().toString() + ":SW3 " + isChecked, Toast.LENGTH_SHORT).show();
        }
    });

    container.addView(addView);
}

demo.xml如下:

<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:background="@drawable/rounded_corners"
    android:layout_margin="5dp"
    android:layout_marginBottom="5dp"
    android:padding="5dp">

    <RelativeLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <TextView
            android:text="TextView"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/cardTitle"
            android:textStyle="normal|bold"
            android:textSize="25sp"
            android:padding="5dp"
            android:textAlignment="center"
            android:textColor="@android:color/background_dark"
            android:layout_weight="1" />

        <TextView
            android:text="TextView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/cardIdentifier"
            android:textSize="12sp" />

    </RelativeLayout>

    <RelativeLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:padding="10dp">

        <android.support.v7.widget.SwitchCompat
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:checked="false"
            android:id="@+id/switch1"
            android:text="SW 1 "
            android:theme="@style/SCBSwitch" />

        <android.support.v7.widget.SwitchCompat
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:checked="false"
            android:id="@+id/switch2"
            android:text="SW 2 "
            android:theme="@style/SCBSwitch"
            android:layout_alignParentTop="true"
            android:layout_centerHorizontal="true" />

        <android.support.v7.widget.SwitchCompat
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:checked="false"
            android:id="@+id/switch3"
            android:text="SW 3 "
            android:theme="@style/SCBSwitch"
            android:layout_alignParentTop="true"
            android:layout_alignParentEnd="true"
            android:layout_alignParentRight="true" />

    </RelativeLayout>

</LinearLayout>

Answer 1

请在下面找到代码 fragment

主 Activity

public class Main2Activity extends AppCompatActivity {

    LinearLayout container;
    View addView;
    RelativeLayout switchLay;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        container = (LinearLayout) findViewById(R.id.container);
    }

    public void addLayout(View v) {
        threeSwitchLayout("Try", "first");
    }

    public void ChangeState(View v) {
        try {
            SwitchCompat toChng = (SwitchCompat) switchLay.findViewById(R.id.switch1);
            toChng.setChecked(true);
        } catch (NullPointerException npe) {
            Toast.makeText(this, "please add view first", Toast.LENGTH_SHORT).show();
        }
    }

    public void threeSwitchLayout(String card_name, String card_identifier) {
        // Generate dynamic layout
        LayoutInflater layoutInflater = (LayoutInflater) getBaseContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        // Use demo.xml to create layout
        addView = layoutInflater.inflate(R.layout.demo, null);
        final TextView cardTitle = (TextView) addView.findViewById(R.id.cardTitle);
        cardTitle.setText(card_name);
        final TextView cardIdentifier = (TextView) addView.findViewById(R.id.cardIdentifier);
        cardIdentifier.setText(card_identifier);
        LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
        layoutParams.setMargins(0, 0, 0, 15);
        addView.setLayoutParams(layoutParams);

        switchLay = (RelativeLayout) addView.findViewById(R.id.switchLay);
        SwitchCompat sw1 = (SwitchCompat) addView.findViewById(R.id.switch1);
        SwitchCompat sw2 = (SwitchCompat) addView.findViewById(R.id.switch2);
        SwitchCompat sw3 = (SwitchCompat) addView.findViewById(R.id.switch3);

        sw1.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                Toast.makeText(getBaseContext(), cardIdentifier.getText().toString() + ":SW1 " + isChecked, Toast.LENGTH_SHORT).show();
            }
        });

        sw2.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                Toast.makeText(getBaseContext(), cardIdentifier.getText().toString() + ":SW2 " + isChecked, Toast.LENGTH_SHORT).show();
            }
        });

        sw3.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                Toast.makeText(getBaseContext(), cardIdentifier.getText().toString() + ":SW3 " + isChecked, Toast.LENGTH_SHORT).show();
            }
        });

        container.addView(addView);
    }
}

activity_main2.xml(MainActivity的布局文件)

<?xml version="1.0" encoding="utf-8"?>
<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"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/btnAdd"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:onClick="addLayout"
        android:text="add layout" />

    <Button
        android:id="@+id/btnChangeState"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_alignParentTop="true"
        android:onClick="ChangeState"
        android:text="Change switch state" />

    <LinearLayout
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@+id/btnAdd"
        android:orientation="vertical"></LinearLayout>


</RelativeLayout>

解释我所做的是，我只是给开关 View 的父布局一个 ID，然后在 java 类中全局引用它们(RelativeLayout switchLay)，同样声明你的“addview”，然后访问我们想要更新的开关这些全局 View 。

虽然这只是一个 fragment ，但您可能需要根据您的具体要求更新代码。