显示时间选取器对话框片段错误

Question

我正在尝试从片段中的按钮启动时间选择器

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不匹配，这就是我发布此内容的原因

时间选取器片段.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()));
    }
}

我使用蓝牙聊天应用程序并对其进行编辑

在蓝牙框架中.java

@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);
            }
        }
    });

在日志猫中。

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)

我正在尝试更改

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

自

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

因为它是原始代码但它有错误"无法解析方法'getSupportFragmentManager(('">

Answer 1

主活动不能转换为 android.app.TimePickerDialog$OnTimeSetListener

这意味着您不能调用在子类中声明的方法。

问题来了

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

尝试使用

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

"无法解析方法'getSupportFragmentManager(('">

确保您的根活动 extends

• AppCompatActivity/FragmentActivity

你用了吗？

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

Answer 2

关于

MainActivity 不能投射到 android.app.TimePickerDialog$OnTimeSetListener

发生这种情况是因为您正在尝试将活动投射到 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，您可以尝试直接转换为您的活动

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

因为你的活动将是OnTimeSetListener的实例。

另外，我不建议使用 getActivity(( 从您的片段中获取侦听器，如果您没有将侦听器附加到您的活动，那就更好了。

Answer 3

使用 getParentFragment(( 而不是 getActivity((。