Java 带null的Android字符串

我对这个代码有问题

if ((equip != null) && equip.trim().equals("")){
    final Dialog dialog = new Dialog(getActivity());
    dialog.getWindow().requestFeature(Window.FEATURE_NO_TITLE);
    dialog.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN);
    dialog.setContentView(R.layout.dialog_layout_equip);

String equip = reserveComp.getString(TAG_EQUIP);
                        Log.d("Equip", equip);

我的另一半是

final Dialog dialog = new Dialog(getActivity());
dialog.getWindow().requestFeature(Window.FEATURE_NO_TITLE);
dialog.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN);
dialog.setContentView(R.layout.dialog_layout);

因此，如果我的字符串为null或空，我将使用此对话框 对话框.setContentView（R.layout.dialog\u布局）； 否则我就用这个 dialog.setContentView（R.layout.dialog\u layout\u设备）

我的logcat给我这个代码的输出

if ((equip != null) && equip.trim().equals("")){
    final Dialog dialog = new Dialog(getActivity());
    dialog.getWindow().requestFeature(Window.FEATURE_NO_TITLE);
    dialog.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN);
    dialog.setContentView(R.layout.dialog_layout_equip);

String equip = reserveComp.getString(TAG_EQUIP);
                        Log.d("Equip", equip);

D/装备﹕ Projetor，所以它打开了

dialog.setContentView(R.layout.dialog_layout);

但是当我有了这个输出 D/装备﹕ 空值，然后打开相同的

那怎么了

更新

这是我的全部代码

JSONObject reserveComp = reqFeitasDetail.getJSONObject(0);
                        String equip = reserveComp.getString(TAG_EQUIP);
                        Log.d("Equip", equip);
                        if ((equip == null) || equip.trim().equals("")){
                            final Dialog dialog = new Dialog(getActivity());
                            dialog.getWindow().requestFeature(Window.FEATURE_NO_TITLE);
                            dialog.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN);
                            dialog.setContentView(R.layout.dialog_layout);
                            dialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
                            dialog.show();
                            Button img = (Button) dialog.findViewById(R.id.close_button);
                            TextView data = (TextView) dialog.findViewById(R.id.data);
                            TextView sala = (TextView) dialog.findViewById(R.id.sala);
                            TextView hora = (TextView) dialog.findViewById(R.id.hora_inicial);
                            TextView fim = (TextView) dialog.findViewById(R.id.hora_final);
                            data.setText(reserveComp.getString(TAG_DATA));
                            sala.setText(reserveComp.getString(TAG_NOME));
                            hora.setText(reserveComp.getString(TAG_TEMPO));
                            fim.setText(reserveComp.getString(TAG_TEMPOFIM));
                            img.setOnClickListener(new View.OnClickListener() {
                                @Override
                                public void onClick(View v) {
                                    dialog.dismiss();
                                }
                            });
                        } else {
                            final Dialog dialog = new Dialog(getActivity());
                            dialog.getWindow().requestFeature(Window.FEATURE_NO_TITLE);
                            dialog.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN);
                            dialog.setContentView(R.layout.dialog_layout_equip);
                            dialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
                            dialog.show();
                            Button img = (Button) dialog.findViewById(R.id.close_button);
                            TextView data = (TextView) dialog.findViewById(R.id.data);
                            TextView sala = (TextView) dialog.findViewById(R.id.sala);
                            TextView equipamento = (TextView) dialog.findViewById(R.id.equip);
                            TextView hora = (TextView) dialog.findViewById(R.id.hora_inicial);
                            TextView fim = (TextView) dialog.findViewById(R.id.hora_final);
                            data.setText(reserveComp.getString(TAG_DATA));
                            sala.setText(reserveComp.getString(TAG_NOME));
                            equipamento.setText(reserveComp.getString(TAG_EQUIP));
                            hora.setText(reserveComp.getString(TAG_TEMPO));
                            fim.setText(reserveComp.getString(TAG_TEMPOFIM));
                            img.setOnClickListener(new View.OnClickListener() {
                                @Override
                                public void onClick(View v) {
                                    dialog.dismiss();
                                }
                            });
                        }

我有这个logcat输出

D/Reserva Sala completa﹕ {"tag":"reqEquipFull","success":1,"error":0,"reqEquipFull":[{"data":"2015-06-12","sala":"21","inicio":"14:05:00","fim":"15:45:00","nome":null}]}

D/装备﹕ 空的

我仍然有同样的对话框问题，所有（空和非空）打开这个对话框

dialog.setContentView(R.layout.dialog_layout_equip);

---

将if语句中的and条件更改为or条件

if ((equip != null) && equip.trim().equals(""))

到

---

将if语句中的and条件更改为or条件

if ((equip != null) && equip.trim().equals(""))

到

---

您的

和

条件将永远不会为

真

，您正在if语句中检查

非空

if ((equip != null) && equip.trim().equals("")){

应该是

或

，如果

=

为空

if (equip == null || equip.trim().equals("")){
    final Dialog dialog = new Dialog(getActivity());
    dialog.getWindow().requestFeature(Window.FEATURE_NO_TITLE);
    dialog.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN);
    dialog.setContentView(R.layout.dialog_layout_equip);
} else {
    final Dialog dialog = new Dialog(getActivity());
    dialog.getWindow().requestFeature(Window.FEATURE_NO_TITLE);
    dialog.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN);
    dialog.setContentView(R.layout.dialog_layout);
}

---

您的

和

条件将永远不会为

真

，您正在if语句中检查

非空

if ((equip != null) && equip.trim().equals("")){

应该是

或

，如果

=

为空

if (equip == null || equip.trim().equals("")){
    final Dialog dialog = new Dialog(getActivity());
    dialog.getWindow().requestFeature(Window.FEATURE_NO_TITLE);
    dialog.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN);
    dialog.setContentView(R.layout.dialog_layout_equip);
} else {
    final Dialog dialog = new Dialog(getActivity());
    dialog.getWindow().requestFeature(Window.FEATURE_NO_TITLE);
    dialog.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN);
    dialog.setContentView(R.layout.dialog_layout);
}

---

要检查字符串是否为null或空，if块内的条件应为

if ((equip == null) || equip.trim().equals("")){...}

如果要执行以下操作，还应切换if-else语句中的代码块

因此，如果我的字符串为null或空，我将使用dialog.setContentView（R.layout.dialog\u layout）；否则我使用这个对话框.setContentView（R.layout.dialog\u layout\u设备）

---

要检查字符串是否为null或空，if块内的条件应为

if ((equip == null) || equip.trim().equals("")){...}

如果要执行以下操作，还应切换if-else语句中的代码块

因此，如果我的字符串为null或空，我将使用dialog.setContentView（R.layout.dialog\u layout）；否则我使用这个对话框.setContentView（R.layout.dialog\u layout\u设备）

---

要测试

equipment

是否为空，您可以使用：

if（TextUtils.isEmpty（equipment））

不工作…我必须为空要测试

equipment

是否为空，您可以使用：

if（TextUtils.isEmpty（equipment））

不工作…我必须为空