AlertDialog 的奇怪行为

Question

我有一个编辑文本，如果我输入一些文本并单击后退按钮，它会显示一个对话框，询问我是否放弃更改，但我想在创建活动时显示键盘，所以我在我的片段的oncreateview

getActivity().getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_VISIBLE);

现在当我在编辑文本中进行更改时，AlertDialog 不会显示您是否要放弃更改？

如果我删除该行

getActivity().getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_VISIBLE);

从我的 onCreateView 中显示 AlertDialog。

    public class EditorFragment extends Fragment implements android.support.v4.app.LoaderManager.LoaderCallbacks<Cursor>, EditorActivity.OnBackPressedListener {


    private EditText TaskName, DueDate, DueTime;
private boolean taskChanged = false;
 private View.OnTouchListener onTouchListener = new View.OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            taskChanged = true;
            return false;
        }
    };

 @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_editor, container, false);
       TaskName = (EditText) view.findViewById(R.id.tasknameedittext);
        DueDate = (EditText) view.findViewById(R.id.duedateedittext);
        DueTime = (EditText) view.findViewById(R.id.duetimeedittext);

   TaskName.setOnTouchListener(onTouchListener);
        DueDate.setOnTouchListener(onTouchListener);
        DueTime.setOnTouchListener(onTouchListener);
 getActivity().getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_VISIBLE);
}
 @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        super.onCreateOptionsMenu(menu, inflater);
        getActivity().getMenuInflater().inflate(R.menu.menu_editor, menu);
    }


    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.editoractivitydelete:
                showDeleteConfirmationDialog();
                return true;
            case R.id.editoractivitysave:
                saveTask();

                return true;
            case android.R.id.home:
                //up button code
                if (!taskChanged) {
                    NavUtils.navigateUpFromSameTask(getActivity());
                    return true;
                }
                DialogInterface.OnClickListener onClickListener = new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        NavUtils.navigateUpFromSameTask(getActivity());
                    }
                };

                showUnsavedChangesDialog(onClickListener);
                return true;


        }
        return super.onOptionsItemSelected(item);
    }


 private void showUnsavedChangesDialog(DialogInterface.OnClickListener onClickListener) {
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder.setMessage(R.string.discardchanges);
        builder.setPositiveButton(R.string.yes, onClickListener);
        builder.setNegativeButton(R.string.no, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                if (dialog != null) {
                    dialog.dismiss();
                }
            }
        });

        AlertDialog alertDialog = builder.create();
        alertDialog.show();
    }

 @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        ((EditorActivity) getActivity()).setOnBackPressedListener(this);
    }

    //Back Button code
    @Override
    public void doBack() {
        if (!taskChanged) {
            NavUtils.navigateUpFromSameTask(getActivity());
            return;
        }

        DialogInterface.OnClickListener onClickListener = new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                NavUtils.navigateUpFromSameTask(getActivity());
            }
        };

        showUnsavedChangesDialog(onClickListener);
    }
}

Answer 1

我无法从您的问题中看出您是如何检测到状态变化的。

你试试这个策略怎么样。

1. 将onCreate中editText内容的状态保存到某个成员变量中。
2. 按下后退按钮时，检查editText 的当前内容是否与您在onCreate 中保存的成员变量相同。
3. 如果它们不同，则使用该条件调用您的方法以显示 alertDialog。否则让用户退出。

使用上述代码的示例

public class EditorFragment extends Fragment implements android.support.v4.app.LoaderManager.LoaderCallbacks<Cursor>, EditorActivity.OnBackPressedListener {


    private EditText TaskName, DueDate, DueTime;
    private String originalTask = "";

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_editor, container, false);
       TaskName = (EditText) view.findViewById(R.id.tasknameedittext);
        DueDate = (EditText) view.findViewById(R.id.duedateedittext);
        DueTime = (EditText) view.findViewById(R.id.duetimeedittext);
       originalTask = TaskName.getText().toString();

    TaskName.setOnTouchListener(onTouchListener);
        DueDate.setOnTouchListener(onTouchListener);
        DueTime.setOnTouchListener(onTouchListener);
 getActivity().getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_VISIBLE);
}
 @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        super.onCreateOptionsMenu(menu, inflater);
        getActivity().getMenuInflater().inflate(R.menu.menu_editor, menu);
    }


    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.editoractivitydelete:
                showDeleteConfirmationDialog();
                return true;
            case R.id.editoractivitysave:
                saveTask();

                return true;
            case android.R.id.home:
                //up button code
                if (!taskChanged) {
                    NavUtils.navigateUpFromSameTask(getActivity());
                    return true;
                }
                DialogInterface.OnClickListener onClickListener = new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        NavUtils.navigateUpFromSameTask(getActivity());
                    }
                };

                showUnsavedChangesDialog(onClickListener);
                return true;


        }
        return super.onOptionsItemSelected(item);
    }


 private void showUnsavedChangesDialog(DialogInterface.OnClickListener onClickListener) {
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder.setMessage(R.string.discardchanges);
        builder.setPositiveButton(R.string.yes, onClickListener);
        builder.setNegativeButton(R.string.no, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                if (dialog != null) {
                    dialog.dismiss();
                }
            }
        });

        AlertDialog alertDialog = builder.create();
        alertDialog.show();
    }

 @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        ((EditorActivity) getActivity()).setOnBackPressedListener(this);
    }

    //Back Button code
    @Override
    public void doBack() {
        if (!originalTask.equals(TaskName.getText().toString()))
        {
           NavUtils.navigateUpFromSameTask(getActivity());
           return;
        }

        DialogInterface.OnClickListener onClickListener = new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                NavUtils.navigateUpFromSameTask(getActivity());
            }
        };

        showUnsavedChangesDialog(onClickListener);
    }
}