Implementing onKeyPreIme(int keyCode, KeyEvent eve

问题:

I cannot figure how to implement onKeyPreIme(int keyCode, KeyEvent event) in a Fragment.

@Override
public boolean onKeyPreIme(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK && 
        event.getAction() == KeyEvent.ACTION_UP) {
            // do your stuff
            return false;
    }
    return super.dispatchKeyEvent(event);
}

I tried a lot but nothing works. Also, I could not find anything on Google or Stack Overflow. I would like to perform an action when the back key is pressed and the softkeyboard is up. Setting an onKeyListener on my EditTexts did not work, since KeyEvent.KEYCODE_BACK is not called when the soft keyboard is up. I appreciate any help and source code.

回答1:

I was able to implement onKeyPreIme by sub-classing my EditText views that were related to the keyboard input. The goal is to make a custom lock screen that the user must enter a pass code or leave the application. When the user taps the "keyboard down" button the keyboard does not disappear.

Make sure to create a separate .java file for the subclassed EditText. Additionally, be sure to use the constructor in the code below (must pass AttrubuteSet).

I realize that my implementation of onKeyPreIme may not match yours, however it does demonstrate how to intercept the keyboard events before the InputMethodManager does it's thing.

I hope this helps.

Screenshot UserLockActivity

EditText Subclass

public class LockEditText extends EditText {
    /* Must use this constructor in order for the layout files to instantiate the class properly */
    public LockEditText(Context context, AttributeSet attrs) 
    {
        super(context, attrs);
        // TODO Auto-generated constructor stub
    }

    @Override
    public boolean onKeyPreIme (int keyCode, KeyEvent event)
    {
        // Return true if I handle the event:
            // In my case i want the keyboard to not be dismissible so i simply return true
            // Other people might want to handle the event differently
        System.out.println("onKeyPreIme " +event);
        return true;
    }

}

UserLockActivity.java

public class UserLockActivity extends Activity 
{
    private LockEditText editText1;
    private LockEditText editText2;
    private LockEditText editText3;
    private LockEditText editText4;
    @Override
    protected void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_user_lock);
        editText1 = (LockEditText) findViewById(R.id.lock_text_1);
        editText2 = (LockEditText) findViewById(R.id.lock_text_2);
        editText3 = (LockEditText) findViewById(R.id.lock_text_3);
        editText4 = (LockEditText) findViewById(R.id.lock_text_4);
        setupTextChangedListener(editText1);
        setupTextChangedListener(editText2);
        setupTextChangedListener(editText3);
        setupTextChangedListener(editText4);
        // A method to bring out the keyboard when the view appears
        setFocusOnEditText(editText1);
    }

    public void setFocusOnEditText(LockEditText editText)
    {
        editText.clearFocus();
        editText.requestFocus();
        InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);

        imm.toggleSoftInput(InputMethodManager.SHOW_FORCED,0);
    }
    public void setupTextChangedListener(LockEditText editText)
    {
        editText.addTextChangedListener(new TextWatcher() 
        {
            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) 
            {

            }

            @Override
            public void afterTextChanged(Editable arg0) 
            {
                // TODO Auto-generated method stub
            }

            @Override
            public void beforeTextChanged(CharSequence arg0, int arg1,int arg2, int arg3) 
            {
                // TODO Auto-generated method stub
            }
        });
    }
}

activity_user_lock.xml Layout file

<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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".UserLockActivity" >

    <TextView
        android:id="@+id/main_lock_text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_alignParentTop="true"
        android:paddingTop="60dp"
        android:paddingBottom="20dp"
        android:text="@string/enter_passcode"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <LinearLayout
        android:id="@+id/lock_input_layout"
        android:layout_width="match_parent"
        android:layout_height="60dp"
        android:layout_below="@+id/main_lock_text"
        android:orientation="horizontal" >

        <com.yourpackage.yourappname.LockEditText
            android:id="@+id/lock_text_1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:layout_weight="1"
            android:ems="10"
            android:inputType="numberPassword"
            android:textSize="30sp"
            android:gravity="center_horizontal"
            android:textStyle="bold" >
        </com.yourpackage.yourappname.LockEditText>
        <com.yourpackage.yourappname.LockEditText
            android:id="@+id/lock_text_2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:layout_weight="1"
            android:ems="10"
            android:inputType="numberPassword"
            android:textSize="30sp"
            android:gravity="center_horizontal"
            android:textStyle="bold" >
        </com.yourpackage.yourappname.LockEditText>
        <com.yourpackage.yourappname.LockEditText
            android:id="@+id/lock_text_3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:layout_weight="1"
            android:ems="10"
            android:inputType="numberPassword"
            android:textSize="30sp" 
            android:gravity="center_horizontal"
            android:textStyle="bold">
        </com.yourpackage.yourappname.LockEditText>
        <com.yourpackage.yourappname.LockEditText
            android:id="@+id/lock_text_4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:layout_weight="1"
            android:ems="10"
            android:inputType="numberPassword"
            android:textSize="30sp"
            android:gravity="center_horizontal"
            android:textStyle="bold" >
        </com.yourpackage.yourappname.LockEditText>
    </LinearLayout>

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/lock_input_layout"
        android:layout_centerHorizontal="true"
        android:text="text" />

</RelativeLayout>

回答2:

This is my solution and it works really well for me, but everyones needs are different.

First i subclassed EditText and hooked up a listener (Google should make this the default)

public class ListenerEditText extends EditText {

    private KeyImeChange keyImeChangeListener;

    public ListenerEditText(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public void setKeyImeChangeListener(KeyImeChange listener){
        keyImeChangeListener = listener;
    }

    public interface KeyImeChange {
        public void onKeyIme(int keyCode, KeyEvent event);
    }

    @Override
    public boolean onKeyPreIme (int keyCode, KeyEvent event){
        if(keyImeChangeListener != null){
            keyImeChangeListener.onKeyIme(keyCode, event);
        }        
        return false;
    }
}

Then you can attach a listener from anywhere like so:

myListenerEditText.setKeyImeChangeListener(new KeyImeChange() {

    @Override
    public void onKeyIme(int keyCode, KeyEvent event) {
        // All keypresses with the keyboard open will come through here!
        // You could also bubble up the true/false if you wanted 
        // to disable propagation.
    }
});

回答3:

I was not able to figure out how to implement the onKeyPreIME, but I was able to perform an action after the keyboard disappeared with the following code:

You man need to change comparison heightDiff > 200. This comparison worked for me because I had a scrollview.

fragmentView.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {

        @Override
        public void onGlobalLayout() {
            if(getView() != null){
                int heightDiff = getView().getRootView().getHeight() - getView().getHeight();
                if (heightDiff < 200) { 
                    rlupdate.setVisibility(RelativeLayout.VISIBLE);
                }
                else {
                    rlupdate.setVisibility(RelativeLayout.GONE);
                }   
            }
        }
    });

回答4:

this is a more full code of answer by Deminetix.

i have used the answer by Deminetix to filter handheld barcode reader on android and have the result.

to make it usable on a screen only with buttons i have added a EditText with android:textColor="#FF000000" android:background="#00FFFFFF" android:enabled="false" disabled EditText still gets keyboard events.

optionally i could hide the software keyboard using the following but after disabling the EditText it was not required.

//InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
//imm.showSoftInput(textPatientId, InputMethodManager.HIDE_IMPLICIT_ONLY);

MainActivity.java:

package com.doodkin.keyboardtest;

import com.doodkin.keyboardtest.ListenerEditText.KeyImeChange;

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

public class MainActivity extends Activity {
    private static final String TAG = "keyboard test";
    //private EditText editText1;

    ListenerEditText editText1=null;
    public String barcodebuffer="";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        editText1 = (ListenerEditText) findViewById(R.id.editText1);

        editText1.setKeyImeChangeListener(new KeyImeChange() {

            @Override
            public boolean onKeyIme(int keyCode, KeyEvent event) {
                String deviceName=event.getDevice().getName();
                int keyboardType=event.getDevice().getKeyboardType();
                int indexof=deviceName.indexOf("USB");
                if(indexof!=-1 && keyboardType==InputDevice.KEYBOARD_TYPE_NON_ALPHABETIC)
                {
                    if(event.getKeyCode()==KeyEvent.KEYCODE_ENTER)
                     {
                         if(barcodebuffer!="")
                         {
                             Log.d(TAG, "filterBarcodeKeys Chars Flush: " + barcodebuffer );
                             barcodebuffer="";
                         }
                     }
                     else
                     {

                         barcodebuffer+=Character.toString((char)event.getUnicodeChar());
                         //Log.d(TAG, "filterBarcodeKeys Char: " + Character.toString((char)event.getUnicodeChar()) );
                     }
                     return true;
                }
                return false;
            }
        });


    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }


}

activity_main.xml:

<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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <com.doodkin.keyboardtest.ListenerEditText
        android:id="@+id/editText1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/textView1"
        android:layout_below="@+id/textView1"
        android:ems="10" >

        <requestFocus />
    </com.doodkin.keyboardtest.ListenerEditText>

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/editText1"
        android:layout_below="@+id/editText1"
        android:layout_marginTop="69dp"
        android:text="Button" />

</RelativeLayout>

ListenerEditText.java:

package com.doodkin.keyboardtest;

import android.content.Context;
import android.util.AttributeSet;
import android.view.KeyEvent;
import android.widget.EditText;

/*
 * example: 

 myListenerEditText.setKeyImeChangeListener(new KeyImeChange() {

    @Override
    public boolean onKeyIme(int keyCode, KeyEvent event) {
        // All keypresses with the keyboard open will come through here!
        // You could also bubble up the true/false if you wanted 
        // to disable propagation.
    }
});

 */

public class ListenerEditText extends EditText {

    private KeyImeChange keyImeChangeListener;

    public ListenerEditText(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public void setKeyImeChangeListener(KeyImeChange listener){
        keyImeChangeListener = listener;
    }

    public interface KeyImeChange {
        public boolean onKeyIme(int keyCode, KeyEvent event);
    }

    @Override
    public boolean onKeyPreIme (int keyCode, KeyEvent event){
        if(keyImeChangeListener != null){
            return keyImeChangeListener.onKeyIme(keyCode, event);
        }        
        return false;
    }
}