Java 如何根据单击主活动中的按钮时所选微调器选项的文本在另一个活动中设置标题

我开始创建一个由3个活动组成的Android应用程序项目

第一个活动有一个包含3个元素、2个微调器和一个按钮的布局

我出发的目的是让他们以以下方式工作：

MainActivity.java： 1.假设我想让第一个微调器在应用程序启动时加载一组类别。e、 例如，收入、支出。 2.从第一个微调器中选择类别后，第二个微调器将在第二个微调器中加载其各自的子类别。e、 例如，如果我在第一个微调器中选择收入，则在第二个微调器中加载佣金、工资、奖金等。如果选择支出，则在第二个微调器中加载月度支出、交通工具、账单等。 3.现在，根据我选择的子类别，当我单击按钮时，它将打开一个新活动，并为该特定类别和子类别设置操作栏的标题。e、 例如，如果我选择了收入和薪资，那么在单击主活动中的按钮后，下一个活动将显示收入、薪资作为标题

我创建了一个名为Utils.java的类，将类别和子类别名称集存储为字符串数组

public class Utils{

    public static String[] mainCategoryList =
    {
        "Choose One",
        "Income",
        "Expenditure"
    };

    //
    public static String[] chooseOne_list=
    {
        "Choose One"
    };

    public static String[] income_subCategoryList =
    {
        "Bonus",
        "Commision",
        "Salary"                 
    };

    public static String[] expenditure_subCategoryList=
    {
         "Bills",
         "Conveyance",
         "Monthly Expenditure"
    };

    public static String[] income=
    {
        "Income, Bonus",
        "Income, Commission",
        "Income, Salary"
    };

    public static String[] expenditure=
    {
        "Expenditure, Bills",
        "Expenditure, Conveyance",
        "Expenditure, Monthly Expenditure"
    };
}

我为MainActivity.java所做的编码如下所示

public class MainActivity extends AppCompatActivity {

Spinner spinner1_mainCategory, spinner2_subCategory;
Button buttonChoose;
String spinner1Item, spinner2Item;
Intent intent;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    //Spinner element
    spinner1_mainCategory = (Spinner)findViewById(R.id.spinner1_mainCategory);
    spinner2_subCategory = (Spinner)findViewById(R.id.spinner2_subCategory);

    //Button element
    buttonChoose = (Button)findViewById(R.id.buttonChoose);

    //To keep onCreate() clean of multiple adapter setting
    adapterMethod(spinner1_mainCategory,mainCategoryList);

    // Spinner click listener
    spinner1_mainCategory.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> adapterView, View view, int position, long id) {
            //String.valueOf(array_name.getSelectedItem()) captures the value of the selected option of a specific string array onClick event
            spinner1Item = String.valueOf(spinner1_mainCategory.getSelectedItem());


            switch (position){
                case 0:
                    adapterMethod(spinner2_subCategory,chooseOne_list);
                    spinner2_subCategory.setVisibility(View.GONE);
                    //Button click listener
                    buttonChoose.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View view) {

                            if (spinner1Item.contentEquals(Utils.mainCategoryList[0])){
                                Toast toast = Toast.makeText(getApplicationContext(), "Choose a Category First", Toast.LENGTH_SHORT);
                                toast.setGravity(Gravity.CENTER|Gravity.CENTER_HORIZONTAL,0,0);
                                toast.show();
                            }
                        }
                    });
                    break;
                case 1:
                    adapterMethod(spinner2_subCategory,income_subCategoryList);
                    spinner2_subCategory.setVisibility(View.VISIBLE);
                    break;
                case 2:
                    adapterMethod(spinner2_subCategory,expenditure_subCategoryList);
                    spinner2_subCategory.setVisibility(View.VISIBLE);
                    break;
            }
        }

        @Override
        public void onNothingSelected(AdapterView<?> adapterView) {

        }
    });


    spinner2_subCategory.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> adapterView, View view, final int position, long id) {
            spinner2Item = String.valueOf(spinner2_subCategory.getSelectedItem());

            switch (position){
                case 0:
                    //Income Category, Bonus Sub-category
                    if (spinner2Item.contentEquals(Utils.mainCategoryList[1]) && spinner2Item.contentEquals(income_subCategoryList[0])){
                        buttonChoose.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View view) {
                                changeTitleInNextActivity(Utils.income[0]);
                            }
                        });
                    }
                    //Expenditure Category, Bills Sub-category
                    if (spinner2Item.contentEquals(Utils.mainCategoryList[2]) && spinner2Item.contentEquals(expenditure_subCategoryList[0])){
                        buttonChoose.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View view) {
                                changeTitleInNextActivity(Utils.expenditure[0]);
                            }
                        });
                    }

                    break;
                case 1:
                    //Income Category, Commission Sub-category
                    if (spinner2Item.contentEquals(Utils.mainCategoryList[1]) && spinner2Item.contentEquals(income_subCategoryList[1])){
                        buttonChoose.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View view) {
                                changeTitleInNextActivity(Utils.income[1]);
                            }
                        });
                    }
                    //Expenditure Category, Conveyance Sub-category
                    if (spinner2Item.contentEquals(Utils.mainCategoryList[2]) && spinner2Item.contentEquals(expenditure_subCategoryList[1])){
                    buttonChoose.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View view) {
                            changeTitleInNextActivity(Utils.expenditure[1]);
                        }
                    });
                }

                break;
                case 2:
                    //Income Category, Salary Sub-category
                    if (spinner2Item.contentEquals(Utils.mainCategoryList[1]) && spinner2Item.contentEquals(income_subCategoryList[2])){
                        buttonChoose.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View view) {
                                changeTitleInNextActivity(Utils.income[2]);
                            }
                        });
                    }
                    //Expenditure Category, Monthly Expenditure Sub-category
                    if (spinner2Item.contentEquals(Utils.mainCategoryList[2]) && spinner2Item.contentEquals(expenditure_subCategoryList[2])){
                        buttonChoose.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View view) {
                                changeTitleInNextActivity(Utils.expenditure[2]);
                            }
                        });
                    }
                    break;
            }
        }

        @Override
        public void onNothingSelected(AdapterView<?> adapterView) {

        }
    });
}

public void adapterMethod(View v, String[] list){
    // Creating adapter for spinner
    ArrayAdapter<String> dataAdapter = new ArrayAdapter<>(this,
            android.R.layout.simple_spinner_item, list);
    // Drop down layout style - list view with radio button
    dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    dataAdapter.notifyDataSetChanged();
    // attaching adapter to spinner for district
    if (v.getId()==R.id.spinner1_mainCategory){
        spinner1_mainCategory.setAdapter(dataAdapter);
        spinner1_mainCategory.setSelection(0, false);
    }
    if (v.getId()==R.id.spinner2_subCategory){
        spinner2_subCategory.setAdapter(dataAdapter);
        spinner2_subCategory.setSelection(0, false);
    }
}

public void changeTitleInNextActivity(String title){

    intent = new Intent(getApplicationContext(),SecondActivity.class);
    intent.putExtra("Title", title);
    startActivity(intent);

}

}

我不明白为什么，但我不能让代码按照我想要的方式为我工作。从第一个和第二个微调器中进行选择非常有效，但无论我尝试了多少种方法，我都无法使用该按钮在下一个活动中设置标题

告诉我，伙计们，我做错了什么？如何更好地编写代码以避免这种陷阱

无法使按钮“选择”：

参加第二次活动

在你的第二个活动中， 获取传递的字符串

String title=getIntent().getStringExtra("Title");

然后设置你的标题

getSupportActionBar().setTitle(title);

---

发布您的按钮活动类公共类SecondActivity扩展AppCompatActivity{public类SecondActivity扩展AppCompatActivity{@Override protected void onCreate（Bundle savedInstanceState）{super.onCreate（savedInstanceState）；setContentView（R.layout.activity_second）；}@菩萨瓦克拉波提在你的帖子中发布你的课程，而不是在评论中。很抱歉，stackoverflow新手刚刚熟悉整个网站^ u^现在，请你检查一下编码，让我知道我做错了什么吗？：-（感谢您指出，我忘了为第二个活动添加代码以在操作栏中设置标题，我已经纠正了这一点。但是，唉！但不，这不是我在实现代码时遇到问题的原因。请再次查看代码，并向我说明我哪里做错了。您可以测试代码中标题的值吗ChangeTitleInExtActivity方法，并且没有名称的actionbar是否显示？我认为唯一发生的事情是if-else语句args在spinner2的onItemSelectedListener中工作不正常

getSupportActionBar().setTitle(title);