Question

我正在尝试从片段中的按钮启动时间戳

我已经阅读了有关错误的相同问题的帖子，但代码与我开始的内容并不匹配，这就是为什么我发布了这个

TimePickerFragment.java

public class TimePickerFragment extends DialogFragment {
    @NonNull
    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        Calendar c = Calendar.getInstance();
        int cHour= c.get(Calendar.HOUR_OF_DAY);
        int cMinute = c.get(Calendar.MINUTE);

        return new TimePickerDialog(getActivity(),(TimePickerDialog.OnTimeSetListener) getActivity(), cHour, cMinute, android.text.format.DateFormat.is24HourFormat(getActivity()));
    }
}

我使用 BluetoothChat 应用程序进行编辑

BluetoothFrament.java中的

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    mMoistIn = (TextView) view.findViewById(R.id.moistIn);
    mTempIn = (TextView) view.findViewById(R.id.tempIn);
    mOutEditText = (EditText) view.findViewById(R.id.edit_text_out);
    mSendButton = (Button) view.findViewById(R.id.button_send);
    moistProgress = (CircleProgress)view.findViewById(R.id.moistcircle_progress);
    pbTemp = (CircleProgress)view.findViewById(R.id.tempcircle_progress);

    buttonGoSched = (Button)view.findViewById(R.id.gotoSched);


    //tempSwitch = (Switch)view.findViewById(R.id.switch1);
}

@RequiresApi(api = Build.VERSION_CODES.KITKAT)
private void setupChat() {
    Log.d(TAG, "setupChat()");

    Calendar calendar = Calendar.getInstance();
    SimpleDateFormat mdformat = new SimpleDateFormat("HH:mm");
    strDate  = "" + mdformat.format(calendar.getTime());

    // Initialize the compose field with a listener for the return key
    mOutEditText.setOnEditorActionListener(mWriteListener);
    //        tabHost.setup();

    try {
        buttonGoSched.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                android.support.v4.app.DialogFragment timePicker = new TimePickerFragment();                    timePicker.show(getActivity().getSupportFragmentManager(), "time picker");

            }
        });
    }catch(Exception e){
        Log.e(TAG,"error in sched: "+e);
    }

    // Initialize the send button with a listener that for click events
    mSendButton.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            // Send a message using content of the edit text widget
            View view = getView();
            if (null != view) {
                TextView textView = (TextView) view.findViewById(R.id.edit_text_out);
                String message = textView.getText().toString();
                sendMessage(message);
                Log.d(TAG, "Water pump duration set to: "+message);
            }
        }
    });

在 Logcat 。

04-10 18:55:22.647 17937-17937/com.example.android.bluetoothplantdroid E/AndroidRuntime: FATAL EXCEPTION: main
                 Process: com.example.android.bluetoothplantdroid, PID: 17937
                 java.lang.ClassCastException: com.example.android.bluetoothplantdroid.MainActivity cannot be cast to android.app.TimePickerDialog$OnTimeSetListener
                     at com.example.android.bluetoothplantdroid.TimePickerFragment.onCreateDialog(TimePickerFragment.java:23)
                     at android.support.v4.app.DialogFragment.onGetLayoutInflater(DialogFragment.java:310)
                     at android.support.v4.app.Fragment.performGetLayoutInflater(Fragment.java:1132)
                     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1419)
                     at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1750)
                     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1819)
                     at android.support.v4.app.BackStackRecord.executeOps(BackStackRecord.java:797)
                     at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2590)
                     at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2377)
                     at android.support.v4.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2332)
                     at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2239)
                     at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:700)
                     at android.os.Handler.handleCallback(Handler.java:815)
                     at android.os.Handler.dispatchMessage(Handler.java:104)
                     at android.os.Looper.loop(Looper.java:207)
                     at android.app.ActivityThread.main(ActivityThread.java:5728)
                     at java.lang.reflect.Method.invoke(Native Method)
                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:679)

我试图改变

timePicker.show(getActivity().getSupportFragmentManager(), "time picker");

到

timePicker.show(getSupportFragmentManager(), "time picker");

因为它是原始代码但它有错误＆＃34;无法解决方法＆＃39; getSupportFragmentManager（）＆＃39;＆＃34;

Answer 1

无法转换为MainActivity android.app.TimePickerDialog $ OnTimeSetListener

这意味着你不能调用在子类中声明的方法。

问题来自

 android.support.v4.app.DialogFragment timePicker = new TimePickerFragment();

尝试

TimePickerFragment  timePicker = new TimePickerFragment ();
timePicker.show(getActivity().getSupportFragmentManager(), "time picker");

＆＃34;无法解决方法＆＃39; getSupportFragmentManager（）＆＃39;＆＃34;

确保 ROOT活动 extends

的 AppCompatActivity / FragmentActivity

你用过吗？

import android.support.v4.app.DialogFragment; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentManager;

Answer 2

关于

MainActivity无法强制转换为android.app.TimePickerDialog $ OnTimeSetListener

它正在发生，因为您正在尝试将您的活动转换为OnTimeSetListener

return new TimePickerDialog(getActivity(),(TimePickerDialog.OnTimeSetListener) getActivity(), cHour, cMinute, android.text.format.DateFormat.is24HourFormat(getActivity()));

确保您的活动正在扩展OnTimeSetListener，如果是这样，您可以尝试将其转换为您的活动

return new TimePickerDialog(getActivity(),(MainActivity) getActivity(), cHour, cMinute, android.text.format.DateFormat.is24HourFormat(getActivity()));

因为您的活动将是OnTimeSetListener的实例。

另外，我不建议使用getActivity（）从你的片段中获取监听器，如果你的监听器没有附加到你的活动中，那就更好了。

Answer 3

使用getParentFragment（）代替getActivity（）。

显示TimePickerDialog片段错误

3 个答案: