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我正在自定義WebView內創建自定義上下文操作欄（CAB）。嵌套上下文操作欄
我的要求是，從第一個CAB中選擇一個特定的選項將打開第二個CAB。這是最終目標：
我做了這一點，但選擇工作不正常。我知道這看起來是正確的，但如果用戶點擊任何其他三個圖標，這就是結果：
如果用戶按下任意的四個初始圖標後觸及的選擇，該應用程序由於空指針異常而崩潰。
當用戶觸摸選擇的動作之後揮之不去的選擇，應用程序試圖訪問ActionMode（姑且稱之爲firstActionMode）創建與圖標的CAB，以無效/刷新。但是，創建具有顏色的CAB時（）導致空指針異常，firstActionMode將被銷燬。
爲了掃清選擇，我發現，調用clearFocus()內onDestroyActionMode(firstActionMode)方法做這項工作就好了。
private class CustomActionModeCallback extends ActionMode.Callback {
@Override
public void onDestroyActionMode(ActionMode mode) {
clearFocus();
}
}
然而，當這是實現，當secondActionMode創建了CAB的選擇並不堅持：
從這個角度選擇色彩實際上產生所需的功能。然而，雖然這個「有效」，但它（最不幸）並不符合我的要求。當顯示由secondActionMode創建的CAB時，我需要選擇保持可見和功能。
這裏是我的自定義類（
WebView）及其嵌套
ActionMode是代碼
public class CustomWebView extends WebView {
private ActionMode.Callback mActionModeCallback;
@Override
public ActionMode startActionMode(Callback callback) {
ViewParent parent = getParent();
if (parent == null) {
return null;
}
if (callback instanceof HighlightActionModeCallback) {
mActionModeCallback = callback;
} else {
mActionModeCallback = new CustomActionModeCallback();
}
return parent.startActionModeForChild(this, mActionModeCallback);
}
private class CustomActionModeCallback implements ActionMode.Callback {
// Called when the action mode is created; startActionMode() was called
@Override
public boolean onCreateActionMode(ActionMode mode, Menu menu) {
// Inflate a menu resource providing context menu items
MenuInflater inflater = mode.getMenuInflater();
inflater.inflate(R.menu.first_menu, menu);
return true;
}
// Called each time the action mode is shown.
// Always called after onCreateActionMode, but
// may be called multiple times if the mode is invalidated.
@Override
public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
// This method is called when the handlebars are moved.
return false; // Return false if nothing is done
}
// Called when the user selects a contextual menu item
@Override
public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
switch (item.getItemId()) {
case R.id.copy:
// Do stuff
break;
case R.id.bookmark:
// Do stuff
break;
case R.id.highlight:
startActionMode(new HighlightActionModeCallback());
break;
case R.id.note:
// Do stuff
break;
default:
return false;
}
mode.finish(); // Action picked, so close the CAB
return true;
}
// Called when the user exits the action mode
@Override
public void onDestroyActionMode(ActionMode mode) {
clearFocus(); // This is commented in the first four screens.
}
}
private class HighlightActionModeCallback implements ActionMode.Callback {
// Called when the action mode is created; startActionMode() was called
@Override
public boolean onCreateActionMode(ActionMode mode, Menu menu) {
// Inflate a menu resource providing context menu items
MenuInflater inflater = mode.getMenuInflater();
inflater.inflate(R.menu.highlight_colors, menu);
return true;
}
// Called each time the action mode is shown.
// Always called after onCreateActionMode, but
// may be called multiple times if the mode is invalidated.
@Override
public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
// This method is called when the handlebars are moved.
return false; // Return false if nothing is done
}
// Called when the user selects a contextual menu item
@Override
public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
mode.finish(); // Action picked, so close the CAB
return true;
}
// Called when the user exits the action mode
@Override
public void onDestroyActionMode(ActionMode mode) {
// Remove the selection highlight and handles.
clearFocus();
}
}
}
如何這個問題能解決？任何和所有的幫助表示讚賞。