自定义视图中的 Android findViewById()

Question

我已经编写了我的自定义视图，我想在与我的自定义视图交互后更新一些其他视图。

主布局：

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:custom="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <EditText
        android:id="@+id/display_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="text"
        android:layout_centerHorizontal="true"
        android:tag="name"
        android:ems="10" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="number"
        android:ems="10"
        android:id="@+id/id_number"
        android:layout_centerHorizontal="true"
        android:layout_below="@id/display_name"/>

    <ge.altasoft.custom_views.IdNumber
        android:id="@+id/custom_id_number"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_below="@id/id_number"
        android:paddingLeft="35dip"
        custom:firstName="@id/display_name"/>
</RelativeLayout>

自定义视图布局：

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">

    <EditText
        android:id="@+id/id_number_custom"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="number"
        android:ems="10"
        android:paddingRight="35dip" />

    <ImageButton
        android:id="@+id/load_data_button"
        android:layout_width="30dip"
        android:layout_height="30dip"
        android:layout_centerVertical="true"
        android:src="@drawable/load_data"
        android:layout_toRightOf="@id/id_number_custom" />

</RelativeLayout>

自定义视图类、构造函数和监听器：

 private int firstNameViewID;

public IdNumber (Context context, AttributeSet attrs) {
        super(context, attrs);
        initViews();

        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.IdNumber);
        final int N = a.getIndexCount();
        for(int i = 0; i < N; i++){
            int attr = a.getIndex(i);
            switch(attr){
                case R.styleable.IdNumber_firstName:
                    firstNameViewID = a.getResourceId(attr, -1);
                    break;
            }
        }
        a.recycle();
    }



 private void initViews() {
        inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        inflater.inflate(R.layout.id_number_edit_text_custom, this, true);
        editText = (EditText) findViewById(R.id.id_number_custom);
        loadButton = (ImageButton) findViewById(R.id.load_data_button);
        loadButton.setVisibility(RelativeLayout.INVISIBLE);
        loadData();
    }

private void loadData(){
        loadButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                EditText firstName = (EditText) findViewById(R.id.display_name);
                firstName.setText("Some Text");
            }
        });
    }

问题是EditText firstName = (EditText) findViewById(R.id.display_name); 返回null。 我知道只要调用findViewById() 就会在我膨胀的布局中搜索视图。

如果可能的话，如何从主布局中获取带有 id: display_name 的 EditText 视图？

提前致谢。

Answer 1

如下更改您的方法并检查它是否有效

private void initViews() {
    inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    inflater.inflate(R.layout.id_number_edit_text_custom, this, true);
    View view = (View) inflater.inflate(R.layout.main, null);
    editText = (EditText) view.findViewById(R.id.id_number_custom);
    loadButton = (ImageButton) view.findViewById(R.id.load_data_button);
    loadButton.setVisibility(RelativeLayout.INVISIBLE);
    loadData();
} 

Answer 2

你可以试试这样的：

customview 构造函数内部：

mContext = context;

接下来可以在customview中调用：

((MainActivity) mContext).updateText( text );

在MainAcivity 内定义：

public void updateText(final String text) {

     TextView txtView = (TextView) findViewById(R.id.text);
     txtView.setText(text);
}

它对我有用。

Answer 3

在你的构造函数中试试这个

MainActivity maniActivity = (MainActivity)context;
EditText firstName = (EditText) maniActivity.findViewById(R.id.display_name);

Answer 4

View Custmv;

 private void initViews() {
        inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        Custmv = inflater.inflate(R.layout.id_number_edit_text_custom, this, true);
        editText = (EditText) findViewById(R.id.id_number_custom);
        loadButton = (ImageButton) findViewById(R.id.load_data_button);
        loadButton.setVisibility(RelativeLayout.INVISIBLE);
        loadData();
    }

private void loadData(){
        loadButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                EditText firstName = (EditText) Custmv.getParent().findViewById(R.id.display_name);
                firstName.setText("Some Text");
            }
        });
    }

像这样试试。

Answer 5

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View row = convertView;
    ImageHolder holder = null;
    if (row == null) {
        LayoutInflater inflater = ((Activity) context).getLayoutInflater();
        row = inflater.inflate(layoutResourceId, parent, false);
        holder = new ImageHolder();
        editText = (EditText) row.findViewById(R.id.id_number_custom);
        loadButton = (ImageButton) row.findViewById(R.id.load_data_button);
        row.setTag(holder);
    } else {
        holder = (ImageHolder) row.getTag();
    }


    holder.editText.setText("Your Value");
    holder.loadButton.setImageBitmap("Your Bitmap Value");
    return row;
}

Answer 6

如果是固定布局，你可以这样做：

public void onClick(View v) {
   ViewGroup parent = (ViewGroup) IdNumber.this.getParent();
   EditText firstName = (EditText) parent.findViewById(R.id.display_name);
   firstName.setText("Some Text");
}

如果你想在灵活的布局中找到 EditText，我稍后会帮助你。希望对您有所帮助。