[Android]聊聊ActionMode

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今天介绍一个很常见效果也最容易被忽略的弹出框：ActionMode。主要是ActionMode使用和自己使用过程中遇到的一些问题，相对还是比较简单的。

1、ActionMode的基本使用
2、使用ActionMode遇到的一些问题

ActionMode

1、ActionMode的基本使用

主要分两步：
1、实现ActionMode.Callback接口
2、调用startActionMode或者startSupportActionMode

1、实现ActionMode.Callback接口

ActionMode.Callback

对于ActionMode.Callback，我们需要实现其四个方法：

new ActionMode.Callback() {
            //Called when action mode is first created.
            // The menu supplied will be used to generate action buttons for the action mode
            //当ActionMode第一次被创建的时候调用
            //可在这里初始化menu
            @Override
            public boolean onCreateActionMode(ActionMode mode, Menu menu) {
            MenuInflater inflater = mode.getMenuInflater();
            inflater.inflate(R.menu.menu, menu);
            menu.findItem(R.id.action_edit).setIcon(R.drawable.ic_launcher);
                return true;//返回true表示action mode会被创建  false if entering this mode should be aborted.
            }
            //
            @Override
            public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
                return false;
            }
            //当ActionMode被点击时调用
            @Override
            public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
                 switch (item.getItemId()) {
                    case R.id.action_edit:
                            rename();
                        return true;
                    }
                return false;
            }
            //Called when an action mode is about to be exited and destroyed.
            //当ActionMode退出销毁时调用
            @Override
            public void onDestroyActionMode(ActionMode mode) {

            }
        };

2、调用startActionMode或者startSupportActionMode开启弹出框

ActionMode mActionMode = = startSupportActionMode(actionModeCallback)

可以为ActionMode设置属性：mActionMode.setTitle、mActionMode.setSubtitle

2、使用ActionMode遇到的坑

坑一：ActionMode把Toolbar压下去了

ActionMode Toolbar

在theme加入配置：
<item name="windowActionModeOverlay">true</item>
<item name="android:windowActionModeOverlay">true</item>

坑二：修改ActionMode背景

在theme加入配置：
<item name="android:actionModeBackground">@color/colorPrimary</item>
<item name="actionModeBackground">@color/colorPrimary</item>

坑三：屏蔽掉WebView的ActionMode用自己的选择复制
通过js与webView互调来实现文本复制
stackoverflow链接：http://stackoverflow.com/questions/6058843/android-how-to-select-texts-from-webview

public class MyCustomWebView extends WebView{
    private Context context;
    // override all other constructor to avoid crash
    public MyCustomWebView(Context context) {
        super(context);
        this.context = context;
        WebSettings webviewSettings = getSettings();
        webviewSettings.setJavaScriptEnabled(true);
        // add JavaScript interface for copy
        addJavascriptInterface(new WebAppInterface(context), "JSInterface");
    }

    // setting custom action bar
    private ActionMode mActionMode;
    private ActionMode.Callback mSelectActionModeCallback;
    private GestureDetector mDetector;

    // this will over ride the default action bar on long press
    @Override
    public ActionMode startActionMode(ActionMode.Callback callback) {
        ViewParent parent = getParent();
        if (parent == null) {
            return null;
        }
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.KITKAT) {
            String name = callback.getClass().toString();
            if (name.contains("SelectActionModeCallback")) {
                mSelectActionModeCallback = callback;
                mDetector = new GestureDetector(context,
                        new CustomGestureListener());
            }
        }
        CustomActionModeCallback mActionModeCallback = new CustomActionModeCallback();
        return parent.startActionModeForChild(this, mActionModeCallback);
    }

    private class CustomActionModeCallback implements ActionMode.Callback {

        @Override
        public boolean onCreateActionMode(ActionMode mode, Menu menu) {
            mActionMode = mode;
            MenuInflater inflater = mode.getMenuInflater();
            inflater.inflate(R.menu.menu, menu);
            return true;
        }

        @Override
        public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
            return false;
        }

        @Override
        public boolean onActionItemClicked(ActionMode mode, MenuItem item) {

            switch (item.getItemId()) {
                case R.id.copy:
                    getSelectedData();
                    mode.finish();
                    return true;
                case R.id.share:
                    mode.finish();
                    return true;
                default:
                    mode.finish();
                    return false;
            }
        }
        @Override
        public void onDestroyActionMode(ActionMode mode) {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
                clearFocus();
            }else{
                if (mSelectActionModeCallback != null) {
                    mSelectActionModeCallback.onDestroyActionMode(mode);
                }
                mActionMode = null;
            }
        }
    }
    private void getSelectedData(){

        String js= "(function getSelectedText() {"+
                "var txt;"+
                "if (window.getSelection) {"+
                "txt = window.getSelection().toString();"+
                "} else if (window.document.getSelection) {"+
                "txt = window.document.getSelection().toString();"+
                "} else if (window.document.selection) {"+
                "txt = window.document.selection.createRange().text;"+
                "}"+
                "JSInterface.getText(txt);"+
                "})()";
        // calling the js function
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            evaluateJavascript("javascript:"+js, null);
        }else{
            loadUrl("javascript:"+js);
        }
    }

    private class CustomGestureListener extends GestureDetector.SimpleOnGestureListener {
        @Override
        public boolean onSingleTapUp(MotionEvent e) {
            if (mActionMode != null) {
                mActionMode.finish();
                return true;
            }
            return false;
        }
    }
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        // Send the event to our gesture detector
        // If it is implemented, there will be a return value
        if(mDetector !=null)
            mDetector.onTouchEvent(event);
        // If the detected gesture is unimplemented, send it to the superclass
        return super.onTouchEvent(event);
    }
    public class WebAppInterface {
        Context mContext;
        WebAppInterface(Context c) {
            mContext = c;
        }
        @JavascriptInterface
        public void getText(String text) {
            // put selected text into clipdata
            ClipboardManager clipboard = (ClipboardManager)
                    mContext.getSystemService(Context.CLIPBOARD_SERVICE);
            ClipData clip = ClipData.newPlainText("simple text",text);
            clipboard.setPrimaryClip(clip);
            // gives the toast for selected text
            Toast.makeText(mContext, text, Toast.LENGTH_SHORT).show();
        }
    }
}

menu.xml:

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <item
        android:id="@+id/copy"
        android:icon="@android:drawable/ic_dialog_email"
        app:showAsAction="always"
        android:title="copy">
    </item>
    <item
        android:id="@+id/share"
        android:icon="@android:drawable/ic_dialog_alert"
        app:showAsAction="always"
        android:title="share">
    </item>
    </menu>

坑四：ActionMode显示时状态栏闪动，表现为变黑之后恢复正常
在onDestroyActionMode方法加入如下代码：

    @Override
    public final void onDestroyActionMode(ActionMode mode) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            new Handler().postDelayed(new Runnable() {
                @TargetApi(Build.VERSION_CODES.LOLLIPOP)
                @Override
                public void run() {
                    try {
                        mActivity.getWindow().setStatusBarColor(mActivity.getResources().getColor(android.R.color.transparent));
                    }
                    catch(Exception e)
                    {
                        e.printStackTrace();
                    }
                }
            }, 400);
        }
        //TODO ...
        
    }