从软键盘截取后退按钮

是的,完全可以显示和隐藏键盘并截获对后退按钮的调用。这是一个小的额外的努力,因为它已经提到,没有直接的方式来做这个在API中。关键是要超越 boolean dispatchKeyEventPreIme(KeyEvent) 在布局中。我们所做的是创建我们的布局。我选择相对主义,因为它是我活动的基础。

<?xml version="1.0" encoding="utf-8"?>
<com.michaelhradek.superapp.utilities.SearchLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res/com.michaelhradek.superapp"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="@color/white">

setActivity(...) 功能。

private void initInputField() {
    mInputField = (EditText) findViewById(R.id.searchInput);        

    InputMethodManager imm = 
        (InputMethodManager)getSystemService(Context.INPUT_METHOD_SERVICE); 
    imm.toggleSoftInput(InputMethodManager.SHOW_FORCED, 
            InputMethodManager.HIDE_IMPLICIT_ONLY);

    mInputField.setOnEditorActionListener(new OnEditorActionListener() {

        @Override
        public boolean onEditorAction(TextView v, int actionId,
                KeyEvent event) {
            if (actionId == EditorInfo.IME_ACTION_SEARCH) {
                performSearch();
                return true;
            }

            return false;
        }
    });

    // Let the layout know we are going to be overriding the back button
    SearchLayout.setSearchActivity(this);
}

很明显 initInputField() 函数设置输入字段。它还允许回车键执行功能(在我的例子中是搜索)。

@Override
public void onBackPressed() {
    // It's expensive, if running turn it off.
    DataHelper.cancelSearch();
    hideKeyboard();
    super.onBackPressed();
}

所以当 onBackPressed()

private void hideKeyboard() {
    InputMethodManager imm = (InputMethodManager) 
        getSystemService(Context.INPUT_METHOD_SERVICE);
    imm.hideSoftInputFromWindow(mInputField.getWindowToken(), 0);
}

package com.michaelhradek.superapp.utilities;

import android.app.Activity;
import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.KeyEvent;
import android.widget.RelativeLayout;

/**
 * The root element in the search bar layout. This is a custom view just to 
 * override the handling of the back button.
 * 
 */
public class SearchLayout extends RelativeLayout {

    private static final String TAG = "SearchLayout";

    private static Activity mSearchActivity;;

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

    public SearchLayout(Context context) {
        super(context);
    }

    public static void setSearchActivity(Activity searchActivity) {
        mSearchActivity = searchActivity;
    }

    /**
     * Overrides the handling of the back key to move back to the 
     * previous sources or dismiss the search dialog, instead of 
     * dismissing the input method.
     */
    @Override
    public boolean dispatchKeyEventPreIme(KeyEvent event) {
        Log.d(TAG, "dispatchKeyEventPreIme(" + event + ")");
        if (mSearchActivity != null && 
                    event.getKeyCode() == KeyEvent.KEYCODE_BACK) {
            KeyEvent.DispatcherState state = getKeyDispatcherState();
            if (state != null) {
                if (event.getAction() == KeyEvent.ACTION_DOWN
                        && event.getRepeatCount() == 0) {
                    state.startTracking(event, this);
                    return true;
                } else if (event.getAction() == KeyEvent.ACTION_UP
                        && !event.isCanceled() && state.isTracking(event)) {
                    mSearchActivity.onBackPressed();
                    return true;
                }
            }
        }

        return super.dispatchKeyEventPreIme(event);
    }
}

不幸的是我不能接受所有的功劳。如果你检查安卓系统 source for the quick SearchDialog box

onBackPressed() onKeyPreIme .

最初,您必须创建扩展EditText的自定义编辑文本。然后你必须实现onkeypreme方法来控制 KeyEvent.KEYCODE返回

自定义编辑文本.java

public class CustomEditText extends EditText {

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

    @Override
    public boolean onKeyPreIme(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            // User has pressed Back key. So hide the keyboard
            InputMethodManager mgr = (InputMethodManager)         

           getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
            mgr.hideSoftInputFromWindow(this.getWindowToken(), 0);
            // TODO: Hide your view as you do it in your activity
        }
        return false;
}

在XML中

<com.YOURAPP.CustomEditText
     android:id="@+id/CEditText"
     android:layout_height="wrap_content"
     android:layout_width="match_parent"/> 

在你的活动中

public class MainActivity extends Activity {
   private CustomEditText editText;

   @Override
   public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      editText = (CustomEditText) findViewById(R.id.CEditText);
   }
}

我发现 Layout类的方法也很有效。只需将主活动设置为属性并启动预定义的方法。

public class LinearLayoutGradient extends LinearLayout {
    MainActivity a;

    public void setMainActivity(MainActivity a) {
        this.a = a;
    }

    @Override
    public boolean dispatchKeyEventPreIme(KeyEvent event) {
        if (a != null) {
            InputMethodManager imm = (InputMethodManager) a
                .getSystemService(Context.INPUT_METHOD_SERVICE);

            if (imm.isActive() && event.getKeyCode() == KeyEvent.KEYCODE_BACK) {
                a.launchMethod;
            }
        }

        return super.dispatchKeyEventPreIme(event);
    }
}

dispatchKeyEvent事件 :

@Override
public boolean dispatchKeyEvent(KeyEvent event) {
    if (event.getKeyCode() == KeyEvent.KEYCODE_BACK) {
        finish();
        return true;
    }
    return super.dispatchKeyEvent(event);
}

它隐藏键盘并完成活动。

如果你正在使用 InputMethodManager.showSoftInput() ,您可以尝试传入 ResultReceiver onReceiveResult() 处理 RESULT_HIDDEN

http://developer.android.com/reference/android/view/inputmethod/InputMethodManager.html

我也有同样的问题,但通过截取后面的按键来解决。在我的例子中(HTC Desire,Android 2.2,Application API Level 4),它关闭键盘并立即完成活动。不知道为什么这对你也不起作用:

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        return true;
    }
    return super.onKeyDown(keyCode, event);
}

@Override
public boolean onKeyUp(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        onBackPressed();
        return true;
    }
    return super.onKeyUp(keyCode, event);
}

/**
 * Called when the activity has detected the user's press of the back key
 */
private void onBackPressed() {
    Log.e(TAG, "back pressed");
    finish();
}

使用 onKeyPreIme(int keyCode, KeyEvent event) KeyEvent.KEYCODE_BACK 事件。它非常简单,没有做任何花哨的编码。

在背压实现中尝试此代码( Block Back Button in android ):

InputMethodManager imm = (InputMethodManager)getSystemService(Context.INPUT_METHOD_SERVICE);
imm.hideSoftInputFromWindow(myEditText.getWindowToken(), 0);

我建议你去看看@ Close/hide the Android Soft Keyboard

我的@mhradek解决方案版本:

class BazingaLayout @JvmOverloads constructor(context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0) :
    ConstraintLayout(context, attrs, defStyleAttr) {

var activity: Activity? = null

override fun dispatchKeyEventPreIme(event: KeyEvent): Boolean {
    activity?.let {
        if (event.keyCode == KeyEvent.KEYCODE_BACK) {
            val state = keyDispatcherState
            if (state != null) {
                if (event.action == KeyEvent.ACTION_DOWN
                    && event.repeatCount == 0) {
                    state.startTracking(event, this)
                    return true
                } else if (event.action == KeyEvent.ACTION_UP && !event.isCanceled && state.isTracking(event)) {
                    it.onBackPressed()
                    return true
                }
            }
        }
    }
    return super.dispatchKeyEventPreIme(event)
}

xml文件

<com... BazingaLayout 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="match_parent"
        android:background="@color/grey">
 </com... BazingaLayout>

碎片

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        (view as BazingaLayout).activity = activity
        super.onViewCreated(view, savedInstanceState)
}