java - OnKeyListener() 没有执行

Question

请问为什么 OnKey() 方法中的代码没有执行？请注意，我正试图通过点击 android 键盘上的“搜索”按钮来触发此操作。

主要代码如下:

package com.onkeyexample1;

import android.app.Activity;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnKeyListener;
import android.widget.EditText;

public class OnKeyExample1Activity extends Activity {
EditText editText;
OnKeyListener onKeyListener;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    editText = (EditText) findViewById(R.id.editText1);
    editText.setOnKeyListener(onKeyListener);
    editText.addTextChangedListener(inputTextWatcher);

onKeyListener = new OnKeyListener() {
    @Override
    public boolean onKey(View v, int keyCode, KeyEvent event) {
           System.out.println("Clicked");
        return true;
                 }
   };
}

我尝试添加下面的代码块作为建议的修复，但它没有帮助:

    private TextWatcher inputTextWatcher = new TextWatcher() {
        public void afterTextChanged(Editable s) { }
        public void beforeTextChanged(CharSequence s, int start, int count, int after)
            { }
        public void onTextChanged(CharSequence s, int start, int before, int count) {
           // Log.d(TAG, s.charAt(count-1) + " character to send");;          
        }
    };
}

这是我的布局 xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"
    />
<EditText android:imeOptions="actionSearch" android:layout_width="fill_parent" 
   android:id="@+id/editText1" android:layout_height="wrap_content">
    <requestFocus></requestFocus>
</EditText>
</LinearLayout>

非常感谢任何建议!

这是 Ted 建议的第一个实现:

public class OnKeyExample1Activity extends Activity {
EditText editText;
OnKeyListener onKeyListener;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    editText = (EditText) findViewById(R.id.editText1);
editText.setOnKeyListener(onKeyListener = new OnKeyListener() {
    @Override
    public boolean onKey(View v, int keyCode, KeyEvent event) {
           System.out.println("Clicked");
        return true;
                 }  
});
}
}

这是我评论中提到的双触发问题的修复:

editText.setOnKeyListener(onKeyListener = new OnKeyListener() {
    @Override
    public boolean onKey(View v, int keyCode, KeyEvent event) {
        if (event.getAction() != KeyEvent.ACTION_DOWN) {  
             System.out.println("Argh");
             return false;
         }
        return true;
    } 
});
}

Answer 1

在调用 editText.setOnKeyListener(onKeyListener); 之前，您需要为 onKeyListener 赋值。只需将赋值移到方法调用之前，它就会起作用。